/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *     Jacob Carlborg <jacob.carlborg@gmail.com>
 *******************************************************************************/
module dwt.graphics.ImageData;


import dwt.DWT;
import dwt.DWTException;
import dwt.internal.CloneableCompatibility;

public import dwt.dwthelper.InputStream;
import dwt.dwthelper.utils;
import dwt.graphics.Device;
import dwt.graphics.GC;
import dwt.graphics.Image;
import dwt.graphics.ImageDataLoader;
import dwt.graphics.PaletteData;
import dwt.graphics.RGB;


/**
 * Instances of this class are device-independent descriptions
 * of images. They are typically used as an intermediate format
 * between loading from or writing to streams and creating an
 * <code>Image</code>.
 * <p>
 * Note that the public fields <code>x</code>, <code>y</code>,
 * <code>disposalMethod</code> and <code>delayTime</code> are
 * typically only used when the image is in a set of images used
 * for animation.
 * </p>
 *
 * @see Image
 * @see ImageLoader
 * @see <a href="http://www.eclipse.org/swt/snippets/#image">ImageData snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">DWT Example: ImageAnalyzer</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */

public final class ImageData : CloneableCompatibility {

    /**
     * The width of the image, in pixels.
     */
    public int width;

    /**
     * The height of the image, in pixels.
     */
    public int height;

    /**
     * The color depth of the image, in bits per pixel.
     * <p>
     * Note that a depth of 8 or less does not necessarily
     * mean that the image is palette indexed, or
     * conversely that a depth greater than 8 means that
     * the image is direct color.  Check the associated
     * PaletteData's isDirect field for such determinations.
     */
    public int depth;

    /**
     * The scanline padding.
     * <p>
     * If one scanline of the image is not a multiple of
     * this number, it will be padded with zeros until it is.
     * </p>
     */
    public int scanlinePad;

    /**
     * The number of bytes per scanline.
     * <p>
     * This is a multiple of the scanline padding.
     * </p>
     */
    public int bytesPerLine;

    /**
     * The pixel data of the image.
     * <p>
     * Note that for 16 bit depth images the pixel data is stored
     * in least significant byte order; however, for 24bit and
     * 32bit depth images the pixel data is stored in most
     * significant byte order.
     * </p>
     */
    public byte[] data;

    /**
     * The color table for the image.
     */
    public PaletteData palette;

    /**
     * The transparent pixel.
     * <p>
     * Pixels with this value are transparent.
     * </p><p>
     * The default is -1 which means 'no transparent pixel'.
     * </p>
     */
    public int transparentPixel;

    /**
     * An icon-specific field containing the data from the icon mask.
     * <p>
     * This is a 1 bit bitmap stored with the most significant
     * bit first.  The number of bytes per scanline is
     * '((width + 7) / 8 + (maskPad - 1)) / maskPad * maskPad'.
     * </p><p>
     * The default is null which means 'no transparency mask'.
     * </p>
     */
    public byte[] maskData;

    /**
     * An icon-specific field containing the scanline pad of the mask.
     * <p>
     * If one scanline of the transparency mask is not a
     * multiple of this number, it will be padded with zeros until
     * it is.
     * </p>
     */
    public int maskPad;

    /**
     * The alpha data of the image.
     * <p>
     * Every pixel can have an <em>alpha blending</em> value that
     * varies from 0, meaning fully transparent, to 255 meaning
     * fully opaque.  The number of bytes per scanline is
     * 'width'.
     * </p>
     */
    public byte[] alphaData;

    /**
     * The global alpha value to be used for every pixel.
     * <p>
     * If this value is set, the <code>alphaData</code> field
     * is ignored and when the image is rendered each pixel
     * will be blended with the background an amount
     * proportional to this value.
     * </p><p>
     * The default is -1 which means 'no global alpha value'
     * </p>
     */
    public int alpha;

    /**
     * The type of file from which the image was read.
     *
     * It is expressed as one of the following values:
     * <dl>
     * <dt><code>IMAGE_BMP</code></dt>
     * <dd>Windows BMP file format, no compression</dd>
     * <dt><code>IMAGE_BMP_RLE</code></dt>
     * <dd>Windows BMP file format, RLE compression if appropriate</dd>
     * <dt><code>IMAGE_GIF</code></dt>
     * <dd>GIF file format</dd>
     * <dt><code>IMAGE_ICO</code></dt>
     * <dd>Windows ICO file format</dd>
     * <dt><code>IMAGE_JPEG</code></dt>
     * <dd>JPEG file format</dd>
     * <dt><code>IMAGE_PNG</code></dt>
     * <dd>PNG file format</dd>
     * </dl>
     */
    public int type;

    /**
     * The x coordinate of the top left corner of the image
     * within the logical screen (this field corresponds to
     * the GIF89a Image Left Position value).
     */
    public int x;

    /**
     * The y coordinate of the top left corner of the image
     * within the logical screen (this field corresponds to
     * the GIF89a Image Top Position value).
     */
    public int y;

    /**
     * A description of how to dispose of the current image
     * before displaying the next.
     *
     * It is expressed as one of the following values:
     * <dl>
     * <dt><code>DM_UNSPECIFIED</code></dt>
     * <dd>disposal method not specified</dd>
     * <dt><code>DM_FILL_NONE</code></dt>
     * <dd>do nothing - leave the image in place</dd>
     * <dt><code>DM_FILL_BACKGROUND</code></dt>
     * <dd>fill with the background color</dd>
     * <dt><code>DM_FILL_PREVIOUS</code></dt>
     * <dd>restore the previous picture</dd>
     * </dl>
     * (this field corresponds to the GIF89a Disposal Method value)
     */
    public int disposalMethod;

    /**
     * The time to delay before displaying the next image
     * in an animation (this field corresponds to the GIF89a
     * Delay Time value).
     */
    public int delayTime;

    /**
     * Arbitrary channel width data to 8-bit conversion table.
     */
    private static byte[][] ANY_TO_EIGHT;
    private static byte[] ONE_TO_ONE_MAPPING;

    private static bool static_this_completed = false;
    private static void static_this() {
        if( static_this_completed ) return;
        synchronized {
            if( static_this_completed ) return;
            ANY_TO_EIGHT = new byte[][](9);
            for (int b = 0; b < 9; ++b) {
                byte[] data = ANY_TO_EIGHT[b] = new byte[1 << b];
                if (b is 0) continue;
                int inc = 0;
                for (int bit = 0x10000; (bit >>= b) !is 0;) inc |= bit;
                for (int v = 0, p = 0; v < 0x10000; v+= inc) data[p++] = cast(byte)(v >> 8);
            }
            ONE_TO_ONE_MAPPING = ANY_TO_EIGHT[8];
            static_this_completed = true;
        }
    }

    /**
     * Scaled 8x8 Bayer dither matrix.
     */
    static const int[][] DITHER_MATRIX = [
        [ 0xfc0000, 0x7c0000, 0xdc0000, 0x5c0000, 0xf40000, 0x740000, 0xd40000, 0x540000 ],
        [ 0x3c0000, 0xbc0000, 0x1c0000, 0x9c0000, 0x340000, 0xb40000, 0x140000, 0x940000 ],
        [ 0xcc0000, 0x4c0000, 0xec0000, 0x6c0000, 0xc40000, 0x440000, 0xe40000, 0x640000 ],
        [ 0x0c0000, 0x8c0000, 0x2c0000, 0xac0000, 0x040000, 0x840000, 0x240000, 0xa40000 ],
        [ 0xf00000, 0x700000, 0xd00000, 0x500000, 0xf80000, 0x780000, 0xd80000, 0x580000 ],
        [ 0x300000, 0xb00000, 0x100000, 0x900000, 0x380000, 0xb80000, 0x180000, 0x980000 ],
        [ 0xc00000, 0x400000, 0xe00000, 0x600000, 0xc80000, 0x480000, 0xe80000, 0x680000 ],
        [ 0x000000, 0x800000, 0x200000, 0xa00000, 0x080000, 0x880000, 0x280000, 0xa80000 ]
    ];

/**
 * Constructs a new, empty ImageData with the given width, height,
 * depth and palette. The data will be initialized to an (all zero)
 * array of the appropriate size.
 *
 * @param width the width of the image
 * @param height the height of the image
 * @param depth the depth of the image
 * @param palette the palette of the image (must not be null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the width or height is negative, or if the depth is not
 *          one of 1, 2, 4, 8, 16, 24 or 32</li>
 *    <li>ERROR_NULL_ARGUMENT - if the palette is null</li>
 * </ul>
 */
public this(int width, int height, int depth, PaletteData palette) {
    this(width, height, depth, palette,
        4, null, 0, null,
        null, -1, -1, DWT.IMAGE_UNDEFINED,
        0, 0, 0, 0);
}

/**
 * Constructs a new, empty ImageData with the given width, height,
 * depth, palette, scanlinePad and data.
 *
 * @param width the width of the image
 * @param height the height of the image
 * @param depth the depth of the image
 * @param palette the palette of the image
 * @param scanlinePad the padding of each line, in bytes
 * @param data the data of the image
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the width or height is negative, or if the depth is not
 *          one of 1, 2, 4, 8, 16, 24 or 32, or the data array is too small to contain the image data</li>
 *    <li>ERROR_NULL_ARGUMENT - if the palette or data is null</li>
 *    <li>ERROR_CANNOT_BE_ZERO - if the scanlinePad is zero</li>
 * </ul>
 */
public this(int width, int height, int depth, PaletteData palette, int scanlinePad, byte[] data) {
    this(width, height, depth, palette,
        scanlinePad, checkData(data), 0, null,
        null, -1, -1, DWT.IMAGE_UNDEFINED,
        0, 0, 0, 0);
}

/**
 * Constructs an <code>ImageData</code> loaded from the specified
 * input stream. Throws an error if an error occurs while loading
 * the image, or if the image has an unsupported type.  Application
 * code is still responsible for closing the input stream.
 * <p>
 * This constructor is provided for convenience when loading a single
 * image only. If the stream contains multiple images, only the first
 * one will be loaded. To load multiple images, use
 * <code>ImageLoader.load()</code>.
 * </p><p>
 * This constructor may be used to load a resource as follows:
 * </p>
 * <pre>
 *     static ImageData loadImageData (Class clazz, String string) {
 *          InputStream stream = clazz.getResourceAsStream (string);
 *          if (stream is null) return null;
 *          ImageData imageData = null;
 *          try {
 *               imageData = new ImageData (stream);
 *          } catch (DWTException ex) {
 *          } finally {
 *               try {
 *                    stream.close ();
 *               } catch (IOException ex) {}
 *          }
 *          return imageData;
 *     }
 * </pre>
 *
 * @param stream the input stream to load the image from (must not be null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the stream is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_IO - if an IO error occurs while reading from the stream</li>
 *    <li>ERROR_INVALID_IMAGE - if the image stream contains invalid data</li>
 *    <li>ERROR_UNSUPPORTED_FORMAT - if the image stream contains an unrecognized format</li>
 * </ul>
 *
 * @see ImageLoader#load(InputStream)
 */
public this(InputStream stream) {
    ImageData[] data = ImageDataLoader.load(stream);
    if (data.length < 1) DWT.error(DWT.ERROR_INVALID_IMAGE);
    ImageData i = data[0];
    setAllFields(
        i.width,
        i.height,
        i.depth,
        i.scanlinePad,
        i.bytesPerLine,
        i.data,
        i.palette,
        i.transparentPixel,
        i.maskData,
        i.maskPad,
        i.alphaData,
        i.alpha,
        i.type,
        i.x,
        i.y,
        i.disposalMethod,
        i.delayTime);
}

/**
 * Constructs an <code>ImageData</code> loaded from a file with the
 * specified name. Throws an error if an error occurs loading the
 * image, or if the image has an unsupported type.
 * <p>
 * This constructor is provided for convenience when loading a single
 * image only. If the file contains multiple images, only the first
 * one will be loaded. To load multiple images, use
 * <code>ImageLoader.load()</code>.
 * </p>
 *
 * @param filename the name of the file to load the image from (must not be null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the file name is null</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_IO - if an IO error occurs while reading from the file</li>
 *    <li>ERROR_INVALID_IMAGE - if the image file contains invalid data</li>
 *    <li>ERROR_UNSUPPORTED_FORMAT - if the image file contains an unrecognized format</li>
 * </ul>
 */
public this(String filename) {
    ImageData[] data = ImageDataLoader.load(filename);
    if (data.length < 1) DWT.error(DWT.ERROR_INVALID_IMAGE);
    ImageData i = data[0];
    setAllFields(
        i.width,
        i.height,
        i.depth,
        i.scanlinePad,
        i.bytesPerLine,
        i.data,
        i.palette,
        i.transparentPixel,
        i.maskData,
        i.maskPad,
        i.alphaData,
        i.alpha,
        i.type,
        i.x,
        i.y,
        i.disposalMethod,
        i.delayTime);
}

/**
 * Prevents uninitialized instances from being created outside the package.
 */
private this() {
}

/**
 * Constructs an image data by giving values for all non-computable fields.
 * <p>
 * This method is for internal use, and is not described further.
 * </p>
 */
this(
    int width, int height, int depth, PaletteData palette,
    int scanlinePad, byte[] data, int maskPad, byte[] maskData,
    byte[] alphaData, int alpha, int transparentPixel, int type,
    int x, int y, int disposalMethod, int delayTime)
{
    if (palette is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (!(depth is 1 || depth is 2 || depth is 4 || depth is 8
        || depth is 16 || depth is 24 || depth is 32)) {
        DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    }
    if (width <= 0 || height <= 0) {
        DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    }
    if (scanlinePad is 0) DWT.error (DWT.ERROR_CANNOT_BE_ZERO);

    int bytesPerLine = (((width * depth + 7) / 8) + (scanlinePad - 1))
        / scanlinePad * scanlinePad;

    /*
     * When the image is being loaded from a PNG, we need to use the theoretical minimum
     * number of bytes per line to check whether there is enough data, because the actual
     * number of bytes per line is calculated based on the given depth, which may be larger
     * than the actual depth of the PNG.
     */
    int minBytesPerLine = type is DWT.IMAGE_PNG ? ((((width + 7) / 8) + 3) / 4) * 4 : bytesPerLine;
    if (data !is null && data.length < minBytesPerLine * height) {
        DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    }
    setAllFields(
        width,
        height,
        depth,
        scanlinePad,
        bytesPerLine,
        data !is null ? data : new byte[bytesPerLine * height],
        palette,
        transparentPixel,
        maskData,
        maskPad,
        alphaData,
        alpha,
        type,
        x,
        y,
        disposalMethod,
        delayTime);
}

/**
 * Initializes all fields in the receiver. This method must be called
 * by all public constructors to ensure that all fields are initialized
 * for a new ImageData object. If a new field is added to the class,
 * then it must be added to this method.
 * <p>
 * This method is for internal use, and is not described further.
 * </p>
 */
void setAllFields(int width, int height, int depth, int scanlinePad,
    int bytesPerLine, byte[] data, PaletteData palette, int transparentPixel,
    byte[] maskData, int maskPad, byte[] alphaData, int alpha,
    int type, int x, int y, int disposalMethod, int delayTime) {

    this.width = width;
    this.height = height;
    this.depth = depth;
    this.scanlinePad = scanlinePad;
    this.bytesPerLine = bytesPerLine;
    this.data = data;
    this.palette = palette;
    this.transparentPixel = transparentPixel;
    this.maskData = maskData;
    this.maskPad = maskPad;
    this.alphaData = alphaData;
    this.alpha = alpha;
    this.type = type;
    this.x = x;
    this.y = y;
    this.disposalMethod = disposalMethod;
    this.delayTime = delayTime;
}

/**
 * Invokes internal DWT functionality to create a new instance of
 * this class.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>ImageData</code>. It is marked public only so that it
 * can be shared within the packages provided by DWT. It is subject
 * to change without notice, and should never be called from
 * application code.
 * </p>
 * <p>
 * This method is for internal use, and is not described further.
 * </p>
 */
public static ImageData internal_new(
    int width, int height, int depth, PaletteData palette,
    int scanlinePad, byte[] data, int maskPad, byte[] maskData,
    byte[] alphaData, int alpha, int transparentPixel, int type,
    int x, int y, int disposalMethod, int delayTime)
{
    return new ImageData(
        width, height, depth, palette, scanlinePad, data, maskPad, maskData,
        alphaData, alpha, transparentPixel, type, x, y, disposalMethod, delayTime);
}

ImageData colorMaskImage(int pixel) {
    ImageData mask = new ImageData(width, height, 1, bwPalette(),
        2, null, 0, null, null, -1, -1, DWT.IMAGE_UNDEFINED,
        0, 0, 0, 0);
    int[] row = new int[width];
    for (int y = 0; y < height; y++) {
        getPixels(0, y, width, row, 0);
        for (int i = 0; i < width; i++) {
            if (pixel !is -1 && row[i] is pixel) {
                row[i] = 0;
            } else {
                row[i] = 1;
            }
        }
        mask.setPixels(0, y, width, row, 0);
    }
    return mask;
}

static byte[] checkData(byte [] data) {
    if (data is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    return data;
}

/**
 * Returns a new instance of the same class as the receiver,
 * whose slots have been filled in with <em>copies</em> of
 * the values in the slots of the receiver. That is, the
 * returned object is a <em>deep copy</em> of the receiver.
 *
 * @return a copy of the receiver.
 */
public Object clone() {
    byte[] cloneData = new byte[data.length];
    System.arraycopy(data, 0, cloneData, 0, data.length);
    byte[] cloneMaskData = null;
    if (maskData !is null) {
        cloneMaskData = new byte[maskData.length];
        System.arraycopy(maskData, 0, cloneMaskData, 0, maskData.length);
    }
    byte[] cloneAlphaData = null;
    if (alphaData !is null) {
        cloneAlphaData = new byte[alphaData.length];
        System.arraycopy(alphaData, 0, cloneAlphaData, 0, alphaData.length);
    }
    return new ImageData(
        width,
        height,
        depth,
        palette,
        scanlinePad,
        cloneData,
        maskPad,
        cloneMaskData,
        cloneAlphaData,
        alpha,
        transparentPixel,
        type,
        x,
        y,
        disposalMethod,
        delayTime);
}

/**
 * Returns the alpha value at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's alpha data.
 * The alpha value is between 0 (transparent) and
 * 255 (opaque).
 *
 * @param x the x coordinate of the pixel to get the alpha value of
 * @param y the y coordinate of the pixel to get the alpha value of
 * @return the alpha value at the given coordinates
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if either argument is out of range</li>
 * </ul>
 */
public int getAlpha(int x, int y) {
    if (x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);

    if (alphaData is null) return 255;
    return alphaData[y * width + x] & 0xFF;
}

/**
 * Returns <code>getWidth</code> alpha values starting at offset
 * <code>x</code> in scanline <code>y</code> in the receiver's alpha
 * data starting at <code>startIndex</code>. The alpha values
 * are unsigned, between <code>(byte)0</code> (transparent) and
 * <code>(byte)255</code> (opaque).
 *
 * @param x the x position of the pixel to begin getting alpha values
 * @param y the y position of the pixel to begin getting alpha values
 * @param getWidth the width of the data to get
 * @param alphas the buffer in which to put the alpha values
 * @param startIndex the offset into the image to begin getting alpha values
 *
 * @exception IndexOutOfBoundsException if getWidth is too large
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if pixels is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *    <li>ERROR_INVALID_ARGUMENT - if getWidth is negative</li>
 * </ul>
 */
public void getAlphas(int x, int y, int getWidth, byte[] alphas, int startIndex) {
    if (alphas is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (getWidth < 0 || x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (getWidth is 0) return;

    if (alphaData is null) {
        int endIndex = startIndex + getWidth;
        for (int i = startIndex; i < endIndex; i++) {
            alphas[i] = cast(byte)255;
        }
        return;
    }
    // may throw an IndexOutOfBoundsException
    System.arraycopy(alphaData, y * width + x, alphas, startIndex, getWidth);
}

/**
 * Returns the pixel value at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's data.
 *
 * @param x the x position of the pixel to get
 * @param y the y position of the pixel to get
 * @return the pixel at the given coordinates
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if either argument is out of bounds</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8, 16, 24 or 32</li>
 * </ul>
 */
public int getPixel(int x, int y) {
    if (x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    int index;
    int theByte;
    int mask;
    switch (depth) {
        case 32:
            index = (y * bytesPerLine) + (x * 4);
            return ((data[index] & 0xFF) << 24) + ((data[index+1] & 0xFF) << 16) +
                    ((data[index+2] & 0xFF) << 8) + (data[index+3] & 0xFF);
        case 24:
            index = (y * bytesPerLine) + (x * 3);
            return ((data[index] & 0xFF) << 16) + ((data[index+1] & 0xFF) << 8) +
                (data[index+2] & 0xFF);
        case 16:
            index = (y * bytesPerLine) + (x * 2);
            return ((data[index+1] & 0xFF) << 8) + (data[index] & 0xFF);
        case 8:
            index = (y * bytesPerLine) + x ;
            return data[index] & 0xFF;
        case 4:
            index = (y * bytesPerLine) + (x >> 1);
            theByte = data[index] & 0xFF;
            if ((x & 0x1) is 0) {
                return theByte >> 4;
            } else {
                return theByte & 0x0F;
            }
        case 2:
            index = (y * bytesPerLine) + (x >> 2);
            theByte = data[index] & 0xFF;
            int offset = 3 - (x % 4);
            mask = 3 << (offset * 2);
            return (theByte & mask) >> (offset * 2);
        case 1:
            index = (y * bytesPerLine) + (x >> 3);
            theByte = data[index] & 0xFF;
            mask = 1 << (7 - (x & 0x7));
            if ((theByte & mask) is 0) {
                return 0;
            } else {
                return 1;
            }
        default:
    }
    DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
    return 0;
}

/**
 * Returns <code>getWidth</code> pixel values starting at offset
 * <code>x</code> in scanline <code>y</code> in the receiver's
 * data starting at <code>startIndex</code>.
 *
 * @param x the x position of the first pixel to get
 * @param y the y position of the first pixel to get
 * @param getWidth the width of the data to get
 * @param pixels the buffer in which to put the pixels
 * @param startIndex the offset into the byte array to begin storing pixels
 *
 * @exception IndexOutOfBoundsException if getWidth is too large
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if pixels is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *    <li>ERROR_INVALID_ARGUMENT - if getWidth is negative</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_UNSUPPORTED_DEPTH - if the depth is not one of 1, 2, 4 or 8
 *        (For higher depths, use the int[] version of this method.)</li>
 * </ul>
 */
public void getPixels(int x, int y, int getWidth, byte[] pixels, int startIndex) {
    if (pixels is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (getWidth < 0 || x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (getWidth is 0) return;
    int index;
    int theByte;
    int mask = 0;
    int n = getWidth;
    int i = startIndex;
    int srcX = x, srcY = y;
    switch (depth) {
        case 8:
            index = (y * bytesPerLine) + x;
            for (int j = 0; j < getWidth; j++) {
                pixels[i] = data[index];
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index++;
                }
            }
            return;
        case 4:
            index = (y * bytesPerLine) + (x >> 1);
            if ((x & 0x1) is 1) {
                theByte = data[index] & 0xFF;
                pixels[i] = cast(byte)(theByte & 0x0F);
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index++;
                }
            }
            while (n > 1) {
                theByte = data[index] & 0xFF;
                pixels[i] = cast(byte)(theByte >> 4);
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    pixels[i] = cast(byte)(theByte & 0x0F);
                    i++;
                    n--;
                    srcX++;
                    if (srcX >= width) {
                        srcY++;
                        index = srcY * bytesPerLine;
                        srcX = 0;
                    } else {
                        index++;
                    }
                }
            }
            if (n > 0) {
                theByte = data[index] & 0xFF;
                pixels[i] = cast(byte)(theByte >> 4);
            }
            return;
        case 2:
            index = (y * bytesPerLine) + (x >> 2);
            theByte = data[index] & 0xFF;
            int offset;
            while (n > 0) {
                offset = 3 - (srcX % 4);
                mask = 3 << (offset * 2);
                pixels[i] = cast(byte)((theByte & mask) >> (offset * 2));
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    if (n > 0) theByte = data[index] & 0xFF;
                    srcX = 0;
                } else {
                    if (offset is 0) {
                        index++;
                        theByte = data[index] & 0xFF;
                    }
                }
            }
            return;
        case 1:
            index = (y * bytesPerLine) + (x >> 3);
            theByte = data[index] & 0xFF;
            while (n > 0) {
                mask = 1 << (7 - (srcX & 0x7));
                if ((theByte & mask) is 0) {
                    pixels[i] = 0;
                } else {
                    pixels[i] = 1;
                }
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    if (n > 0) theByte = data[index] & 0xFF;
                    srcX = 0;
                } else {
                    if (mask is 1) {
                        index++;
                        if (n > 0) theByte = data[index] & 0xFF;
                    }
                }
            }
            return;
        default:
    }
    DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
}

/**
 * Returns <code>getWidth</code> pixel values starting at offset
 * <code>x</code> in scanline <code>y</code> in the receiver's
 * data starting at <code>startIndex</code>.
 *
 * @param x the x position of the first pixel to get
 * @param y the y position of the first pixel to get
 * @param getWidth the width of the data to get
 * @param pixels the buffer in which to put the pixels
 * @param startIndex the offset into the buffer to begin storing pixels
 *
 * @exception IndexOutOfBoundsException if getWidth is too large
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if pixels is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *    <li>ERROR_INVALID_ARGUMENT - if getWidth is negative</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_UNSUPPORTED_DEPTH - if the depth is not one of 1, 2, 4, 8, 16, 24 or 32</li>
 * </ul>
 */
public void getPixels(int x, int y, int getWidth, int[] pixels, int startIndex) {
    if (pixels is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (getWidth < 0 || x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (getWidth is 0) return;
    int index;
    int theByte;
    int mask;
    int n = getWidth;
    int i = startIndex;
    int srcX = x, srcY = y;
    switch (depth) {
        case 32:
            index = (y * bytesPerLine) + (x * 4);
            i = startIndex;
            for (int j = 0; j < getWidth; j++) {
                pixels[i] = ((data[index] & 0xFF) << 24) | ((data[index+1] & 0xFF) << 16)
                    | ((data[index+2] & 0xFF) << 8) | (data[index+3] & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index += 4;
                }
            }
            return;
        case 24:
            index = (y * bytesPerLine) + (x * 3);
            for (int j = 0; j < getWidth; j++) {
                pixels[i] = ((data[index] & 0xFF) << 16) | ((data[index+1] & 0xFF) << 8)
                    | (data[index+2] & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index += 3;
                }
            }
            return;
        case 16:
            index = (y * bytesPerLine) + (x * 2);
            for (int j = 0; j < getWidth; j++) {
                pixels[i] = ((data[index+1] & 0xFF) << 8) + (data[index] & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index += 2;
                }
            }
            return;
        case 8:
            index = (y * bytesPerLine) + x;
            for (int j = 0; j < getWidth; j++) {
                pixels[i] = data[index] & 0xFF;
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index++;
                }
            }
            return;
        case 4:
            index = (y * bytesPerLine) + (x >> 1);
            if ((x & 0x1) is 1) {
                theByte = data[index] & 0xFF;
                pixels[i] = theByte & 0x0F;
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index++;
                }
            }
            while (n > 1) {
                theByte = data[index] & 0xFF;
                pixels[i] = theByte >> 4;
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    pixels[i] = theByte & 0x0F;
                    i++;
                    n--;
                    srcX++;
                    if (srcX >= width) {
                        srcY++;
                        index = srcY * bytesPerLine;
                        srcX = 0;
                    } else {
                        index++;
                    }
                }
            }
            if (n > 0) {
                theByte = data[index] & 0xFF;
                pixels[i] = theByte >> 4;
            }
            return;
        case 2:
            index = (y * bytesPerLine) + (x >> 2);
            theByte = data[index] & 0xFF;
            int offset;
            while (n > 0) {
                offset = 3 - (srcX % 4);
                mask = 3 << (offset * 2);
                pixels[i] = cast(byte)((theByte & mask) >> (offset * 2));
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    if (n > 0) theByte = data[index] & 0xFF;
                    srcX = 0;
                } else {
                    if (offset is 0) {
                        index++;
                        theByte = data[index] & 0xFF;
                    }
                }
            }
            return;
        case 1:
            index = (y * bytesPerLine) + (x >> 3);
            theByte = data[index] & 0xFF;
            while (n > 0) {
                mask = 1 << (7 - (srcX & 0x7));
                if ((theByte & mask) is 0) {
                    pixels[i] = 0;
                } else {
                    pixels[i] = 1;
                }
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    if (n > 0) theByte = data[index] & 0xFF;
                    srcX = 0;
                } else {
                    if (mask is 1) {
                        index++;
                        if (n > 0) theByte = data[index] & 0xFF;
                    }
                }
            }
            return;
        default:
    }
    DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
}

/**
 * Returns an array of <code>RGB</code>s which comprise the
 * indexed color table of the receiver, or null if the receiver
 * has a direct color model.
 *
 * @return the RGB values for the image or null if direct color
 *
 * @see PaletteData#getRGBs()
 */
public RGB[] getRGBs() {
    return palette.getRGBs();
}

/**
 * Returns an <code>ImageData</code> which specifies the
 * transparency mask information for the receiver. If the
 * receiver has no transparency or is not an icon, returns
 * an opaque mask.
 *
 * @return the transparency mask
 */
public ImageData getTransparencyMask() {
    if (getTransparencyType() is DWT.TRANSPARENCY_MASK) {
        return new ImageData(width, height, 1, bwPalette(), maskPad, maskData);
    } else {
        return colorMaskImage(transparentPixel);
    }
}

/**
 * Returns the image transparency type, which will be one of
 * <code>DWT.TRANSPARENCY_NONE</code>, <code>DWT.TRANSPARENCY_MASK</code>,
 * <code>DWT.TRANSPARENCY_PIXEL</code> or <code>DWT.TRANSPARENCY_ALPHA</code>.
 *
 * @return the receiver's transparency type
 */
public int getTransparencyType() {
    if (maskData !is null) return DWT.TRANSPARENCY_MASK;
    if (transparentPixel !is -1) return DWT.TRANSPARENCY_PIXEL;
    if (alphaData !is null) return DWT.TRANSPARENCY_ALPHA;
    return DWT.TRANSPARENCY_NONE;
}

/**
 * Returns the byte order of the receiver.
 *
 * @return MSB_FIRST or LSB_FIRST
 */
int getByteOrder() {
    return depth !is 16 ? MSB_FIRST : LSB_FIRST;
}

/**
 * Returns a copy of the receiver which has been stretched or
 * shrunk to the specified size. If either the width or height
 * is negative, the resulting image will be inverted in the
 * associated axis.
 *
 * @param width the width of the new ImageData
 * @param height the height of the new ImageData
 * @return a scaled copy of the image
 */
public ImageData scaledTo(int width, int height) {
    /* Create a destination image with no data */
    bool flipX = (width < 0);
    if (flipX) width = - width;
    bool flipY = (height < 0);
    if (flipY) height = - height;

    ImageData dest = new ImageData(
        width, height, depth, palette,
        scanlinePad, null, 0, null,
        null, -1, transparentPixel, type,
        x, y, disposalMethod, delayTime);

    /* Scale the image contents */
    if (palette.isDirect) blit(BLIT_SRC,
        this.data, this.depth, this.bytesPerLine, this.getByteOrder(), 0, 0, this.width, this.height, 0, 0, 0,
        ALPHA_OPAQUE, null, 0, 0, 0,
        dest.data, dest.depth, dest.bytesPerLine, dest.getByteOrder(), 0, 0, dest.width, dest.height, 0, 0, 0,
        flipX, flipY);
    else blit(BLIT_SRC,
        this.data, this.depth, this.bytesPerLine, this.getByteOrder(), 0, 0, this.width, this.height, null, null, null,
        ALPHA_OPAQUE, null, 0, 0, 0,
        dest.data, dest.depth, dest.bytesPerLine, dest.getByteOrder(), 0, 0, dest.width, dest.height, null, null, null,
        flipX, flipY);

    /* Scale the image mask or alpha */
    if (maskData !is null) {
        dest.maskPad = this.maskPad;
        int destBpl = (dest.width + 7) / 8;
        destBpl = (destBpl + (dest.maskPad - 1)) / dest.maskPad * dest.maskPad;
        dest.maskData = new byte[destBpl * dest.height];
        int srcBpl = (this.width + 7) / 8;
        srcBpl = (srcBpl + (this.maskPad - 1)) / this.maskPad * this.maskPad;
        blit(BLIT_SRC,
            this.maskData, 1, srcBpl, MSB_FIRST, 0, 0, this.width, this.height, null, null, null,
            ALPHA_OPAQUE, null, 0, 0, 0,
            dest.maskData, 1, destBpl, MSB_FIRST, 0, 0, dest.width, dest.height, null, null, null,
            flipX, flipY);
    } else if (alpha !is -1) {
        dest.alpha = this.alpha;
    } else if (alphaData !is null) {
        dest.alphaData = new byte[dest.width * dest.height];
        blit(BLIT_SRC,
            this.alphaData, 8, this.width, MSB_FIRST, 0, 0, this.width, this.height, null, null, null,
            ALPHA_OPAQUE, null, 0, 0, 0,
            dest.alphaData, 8, dest.width, MSB_FIRST, 0, 0, dest.width, dest.height, null, null, null,
            flipX, flipY);
    }
    return dest;
}

/**
 * Sets the alpha value at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's alpha data.
 * The alpha value must be between 0 (transparent)
 * and 255 (opaque).
 *
 * @param x the x coordinate of the alpha value to set
 * @param y the y coordinate of the alpha value to set
 * @param alpha the value to set the alpha to
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *  </ul>
 */
public void setAlpha(int x, int y, int alpha) {
    if (x >= width || y >= height || x < 0 || y < 0 || alpha < 0 || alpha > 255)
        DWT.error(DWT.ERROR_INVALID_ARGUMENT);

    if (alphaData is null) alphaData = new byte[width * height];
    alphaData[y * width + x] = cast(byte)alpha;
}

/**
 * Sets the alpha values starting at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's alpha data to the
 * values from the array <code>alphas</code> starting at
 * <code>startIndex</code>. The alpha values must be between
 * <code>(byte)0</code> (transparent) and <code>(byte)255</code> (opaque)
 *
 * @param x the x coordinate of the pixel to being setting the alpha values
 * @param y the y coordinate of the pixel to being setting the alpha values
 * @param putWidth the width of the alpha values to set
 * @param alphas the alpha values to set
 * @param startIndex the index at which to begin setting
 *
 * @exception IndexOutOfBoundsException if putWidth is too large
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if pixels is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *    <li>ERROR_INVALID_ARGUMENT - if putWidth is negative</li>
 * </ul>
 */
public void setAlphas(int x, int y, int putWidth, byte[] alphas, int startIndex) {
    if (alphas is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (putWidth < 0 || x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (putWidth is 0) return;

    if (alphaData is null) alphaData = new byte[width * height];
    // may throw an IndexOutOfBoundsException
    System.arraycopy(alphas, startIndex, alphaData, y * width + x, putWidth);
}

/**
 * Sets the pixel value at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's data.
 *
 * @param x the x coordinate of the pixel to set
 * @param y the y coordinate of the pixel to set
 * @param pixelValue the value to set the pixel to
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8, 16, 24 or 32</li>
 * </ul>
 */
public void setPixel(int x, int y, int pixelValue) {
    if (x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    int index;
    byte theByte;
    int mask;
    switch (depth) {
        case 32:
            index = (y * bytesPerLine) + (x * 4);
            data[index]  = cast(byte)((pixelValue >> 24) & 0xFF);
            data[index + 1] = cast(byte)((pixelValue >> 16) & 0xFF);
            data[index + 2] = cast(byte)((pixelValue >> 8) & 0xFF);
            data[index + 3] = cast(byte)(pixelValue & 0xFF);
            return;
        case 24:
            index = (y * bytesPerLine) + (x * 3);
            data[index] = cast(byte)((pixelValue >> 16) & 0xFF);
            data[index + 1] = cast(byte)((pixelValue >> 8) & 0xFF);
            data[index + 2] = cast(byte)(pixelValue & 0xFF);
            return;
        case 16:
            index = (y * bytesPerLine) + (x * 2);
            data[index + 1] = cast(byte)((pixelValue >> 8) & 0xFF);
            data[index] = cast(byte)(pixelValue & 0xFF);
            return;
        case 8:
            index = (y * bytesPerLine) + x ;
            data[index] = cast(byte)(pixelValue & 0xFF);
            return;
        case 4:
            index = (y * bytesPerLine) + (x >> 1);
            if ((x & 0x1) is 0) {
                data[index] = cast(byte)((data[index] & 0x0F) | ((pixelValue & 0x0F) << 4));
            } else {
                data[index] = cast(byte)((data[index] & 0xF0) | (pixelValue & 0x0F));
            }
            return;
        case 2:
            index = (y * bytesPerLine) + (x >> 2);
            theByte = data[index];
            int offset = 3 - (x % 4);
            mask = 0xFF ^ (3 << (offset * 2));
            data[index] = cast(byte)((data[index] & mask) | (pixelValue << (offset * 2)));
            return;
        case 1:
            index = (y * bytesPerLine) + (x >> 3);
            theByte = data[index];
            mask = 1 << (7 - (x & 0x7));
            if ((pixelValue & 0x1) is 1) {
                data[index] = cast(byte)(theByte | mask);
            } else {
                data[index] = cast(byte)(theByte & (mask ^ -1));
            }
            return;
        default:
    }
    DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
}

/**
 * Sets the pixel values starting at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's data to the
 * values from the array <code>pixels</code> starting at
 * <code>startIndex</code>.
 *
 * @param x the x position of the pixel to set
 * @param y the y position of the pixel to set
 * @param putWidth the width of the pixels to set
 * @param pixels the pixels to set
 * @param startIndex the index at which to begin setting
 *
 * @exception IndexOutOfBoundsException if putWidth is too large
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if pixels is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *    <li>ERROR_INVALID_ARGUMENT - if putWidth is negative</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8
 *        (For higher depths, use the int[] version of this method.)</li>
 * </ul>
 */
public void setPixels(int x, int y, int putWidth, byte[] pixels, int startIndex) {
    if (pixels is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (putWidth < 0 || x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (putWidth is 0) return;
    int index;
    int theByte;
    int mask;
    int n = putWidth;
    int i = startIndex;
    int srcX = x, srcY = y;
    switch (depth) {
        case 8:
            index = (y * bytesPerLine) + x;
            for (int j = 0; j < putWidth; j++) {
                data[index] = cast(byte)(pixels[i] & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index++;
                }
            }
            return;
        case 4:
            index = (y * bytesPerLine) + (x >> 1);
            bool high = (x & 0x1) is 0;
            while (n > 0) {
                theByte = pixels[i] & 0x0F;
                if (high) {
                    data[index] = cast(byte)((data[index] & 0x0F) | (theByte << 4));
                } else {
                    data[index] = cast(byte)((data[index] & 0xF0) | theByte);
                }
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    high = true;
                    srcX = 0;
                } else {
                    if (!high) index++;
                    high = !high;
                }
            }
            return;
        case 2:
            byte [] masks = [ cast(byte)0xFC, cast(byte)0xF3, cast(byte)0xCF, cast(byte)0x3F ];
            index = (y * bytesPerLine) + (x >> 2);
            int offset = 3 - (x % 4);
            while (n > 0) {
                theByte = pixels[i] & 0x3;
                data[index] = cast(byte)((data[index] & masks[offset]) | (theByte << (offset * 2)));
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    offset = 0;
                    srcX = 0;
                } else {
                    if (offset is 0) {
                        index++;
                        offset = 3;
                    } else {
                        offset--;
                    }
                }
            }
            return;
        case 1:
            index = (y * bytesPerLine) + (x >> 3);
            while (n > 0) {
                mask = 1 << (7 - (srcX & 0x7));
                if ((pixels[i] & 0x1) is 1) {
                    data[index] = cast(byte)((data[index] & 0xFF) | mask);
                } else {
                    data[index] = cast(byte)((data[index] & 0xFF) & (mask ^ -1));
                }
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    if (mask is 1) {
                        index++;
                    }
                }
            }
            return;
        default:
    }
    DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
}

/**
 * Sets the pixel values starting at offset <code>x</code> in
 * scanline <code>y</code> in the receiver's data to the
 * values from the array <code>pixels</code> starting at
 * <code>startIndex</code>.
 *
 * @param x the x position of the pixel to set
 * @param y the y position of the pixel to set
 * @param putWidth the width of the pixels to set
 * @param pixels the pixels to set
 * @param startIndex the index at which to begin setting
 *
 * @exception IndexOutOfBoundsException if putWidth is too large
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if pixels is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if x or y is out of bounds</li>
 *    <li>ERROR_INVALID_ARGUMENT - if putWidth is negative</li>
 * </ul>
 * @exception DWTException <ul>
 *    <li>ERROR_UNSUPPORTED_DEPTH if the depth is not one of 1, 2, 4, 8, 16, 24 or 32</li>
 * </ul>
 */
public void setPixels(int x, int y, int putWidth, int[] pixels, int startIndex) {
    if (pixels is null) DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (putWidth < 0 || x >= width || y >= height || x < 0 || y < 0) DWT.error(DWT.ERROR_INVALID_ARGUMENT);
    if (putWidth is 0) return;
    int index;
    int theByte;
    int mask;
    int n = putWidth;
    int i = startIndex;
    int pixel;
    int srcX = x, srcY = y;
    switch (depth) {
        case 32:
            index = (y * bytesPerLine) + (x * 4);
            for (int j = 0; j < putWidth; j++) {
                pixel = pixels[i];
                data[index] = cast(byte)((pixel >> 24) & 0xFF);
                data[index + 1] = cast(byte)((pixel >> 16) & 0xFF);
                data[index + 2] = cast(byte)((pixel >> 8) & 0xFF);
                data[index + 3] = cast(byte)(pixel & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index += 4;
                }
            }
            return;
        case 24:
            index = (y * bytesPerLine) + (x * 3);
            for (int j = 0; j < putWidth; j++) {
                pixel = pixels[i];
                data[index] = cast(byte)((pixel >> 16) & 0xFF);
                data[index + 1] = cast(byte)((pixel >> 8) & 0xFF);
                data[index + 2] = cast(byte)(pixel & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index += 3;
                }
            }
            return;
        case 16:
            index = (y * bytesPerLine) + (x * 2);
            for (int j = 0; j < putWidth; j++) {
                pixel = pixels[i];
                data[index] = cast(byte)(pixel & 0xFF);
                data[index + 1] = cast(byte)((pixel >> 8) & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index += 2;
                }
            }
            return;
        case 8:
            index = (y * bytesPerLine) + x;
            for (int j = 0; j < putWidth; j++) {
                data[index] = cast(byte)(pixels[i] & 0xFF);
                i++;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    index++;
                }
            }
            return;
        case 4:
            index = (y * bytesPerLine) + (x >> 1);
            bool high = (x & 0x1) is 0;
            while (n > 0) {
                theByte = pixels[i] & 0x0F;
                if (high) {
                    data[index] = cast(byte)((data[index] & 0x0F) | (theByte << 4));
                } else {
                    data[index] = cast(byte)((data[index] & 0xF0) | theByte);
                }
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    high = true;
                    srcX = 0;
                } else {
                    if (!high) index++;
                    high = !high;
                }
            }
            return;
        case 2:
            byte [] masks = [ cast(byte)0xFC, cast(byte)0xF3, cast(byte)0xCF, cast(byte)0x3F ];
            index = (y * bytesPerLine) + (x >> 2);
            int offset = 3 - (x % 4);
            while (n > 0) {
                theByte = pixels[i] & 0x3;
                data[index] = cast(byte)((data[index] & masks[offset]) | (theByte << (offset * 2)));
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    offset = 3;
                    srcX = 0;
                } else {
                    if (offset is 0) {
                        index++;
                        offset = 3;
                    } else {
                        offset--;
                    }
                }
            }
            return;
        case 1:
            index = (y * bytesPerLine) + (x >> 3);
            while (n > 0) {
                mask = 1 << (7 - (srcX & 0x7));
                if ((pixels[i] & 0x1) is 1) {
                    data[index] = cast(byte)((data[index] & 0xFF) | mask);
                } else {
                    data[index] = cast(byte)((data[index] & 0xFF) & (mask ^ -1));
                }
                i++;
                n--;
                srcX++;
                if (srcX >= width) {
                    srcY++;
                    index = srcY * bytesPerLine;
                    srcX = 0;
                } else {
                    if (mask is 1) {
                        index++;
                    }
                }
            }
            return;
        default:
    }
    DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
}

/**
 * Returns a palette with 2 colors: black & white.
 */
static PaletteData bwPalette() {
    return new PaletteData( [ new RGB(0, 0, 0), new RGB(255, 255, 255) ] );
}

/**
 * Gets the offset of the most significant bit for
 * the given mask.
 */
static int getMSBOffset(int mask) {
    for (int i = 31; i >= 0; i--) {
        if (((mask >> i) & 0x1) !is 0) return i + 1;
    }
    return 0;
}

/**
 * Finds the closest match.
 */
static int closestMatch(int depth, byte red, byte green, byte blue, int redMask, int greenMask, int blueMask, byte[] reds, byte[] greens, byte[] blues) {
    if (depth > 8) {
        int rshift = 32 - getMSBOffset(redMask);
        int gshift = 32 - getMSBOffset(greenMask);
        int bshift = 32 - getMSBOffset(blueMask);
        return (((red << 24) >>> rshift) & redMask) |
            (((green << 24) >>> gshift) & greenMask) |
            (((blue << 24) >>> bshift) & blueMask);
    }
    int r, g, b;
    int minDistance = 0x7fffffff;
    int nearestPixel = 0;
    int n = reds.length;
    for (int j = 0; j < n; j++) {
        r = (reds[j] & 0xFF) - (red & 0xFF);
        g = (greens[j] & 0xFF) - (green & 0xFF);
        b = (blues[j] & 0xFF) - (blue & 0xFF);
        int distance = r*r + g*g + b*b;
        if (distance < minDistance) {
            nearestPixel = j;
            if (distance is 0) break;
            minDistance = distance;
        }
    }
    return nearestPixel;
}

static final ImageData convertMask(ImageData mask) {
    if (mask.depth is 1) return mask;
    PaletteData palette = new PaletteData([new RGB(0, 0, 0), new RGB(255,255,255)]);
    ImageData newMask = new ImageData(mask.width, mask.height, 1, palette);
    /* Find index of black in mask palette */
    int blackIndex = 0;
    RGB[] rgbs = mask.getRGBs();
    if (rgbs !is null) {
        while (blackIndex < rgbs.length) {
            if (rgbs[blackIndex] is palette.colors[0] ) break;
            blackIndex++;
        }
    }
    int[] pixels = new int[mask.width];
    for (int y = 0; y < mask.height; y++) {
        mask.getPixels(0, y, mask.width, pixels, 0);
        for (int i = 0; i < pixels.length; i++) {
            if (pixels[i] is blackIndex) {
                pixels[i] = 0;
            } else {
                pixels[i] = 1;
            }
        }
        newMask.setPixels(0, y, mask.width, pixels, 0);
    }
    return newMask;
}

static final byte[] convertPad(byte[] data, int width, int height, int depth, int pad, int newPad) {
    if (pad is newPad) return data;
    int stride = (width * depth + 7) / 8;
    int bpl = (stride + (pad - 1)) / pad * pad;
    int newBpl = (stride + (newPad - 1)) / newPad * newPad;
    byte[] newData = new byte[height * newBpl];
    int srcIndex = 0, destIndex = 0;
    for (int y = 0; y < height; y++) {
        System.arraycopy(data, srcIndex, newData, destIndex, stride);
        srcIndex += bpl;
        destIndex += newBpl;
    }
    return newData;
}

/**
 * Blit operation bits to be OR'ed together to specify the desired operation.
 */
static const int
    BLIT_SRC = 1,     // copy source directly, else applies logic operations
    BLIT_ALPHA = 2,   // enable alpha blending
    BLIT_DITHER = 4;  // enable dithering in low color modes

/**
 * Alpha mode, values 0 - 255 specify global alpha level
 */
static const int
    ALPHA_OPAQUE = 255,           // Fully opaque (ignores any alpha data)
    ALPHA_TRANSPARENT = 0,        // Fully transparent (ignores any alpha data)
    ALPHA_CHANNEL_SEPARATE = -1,  // Use alpha channel from separate alphaData
    ALPHA_CHANNEL_SOURCE = -2,    // Use alpha channel embedded in sourceData
    ALPHA_MASK_UNPACKED = -3,     // Use transparency mask formed by bytes in alphaData (non-zero is opaque)
    ALPHA_MASK_PACKED = -4,       // Use transparency mask formed by packed bits in alphaData
    ALPHA_MASK_INDEX = -5,        // Consider source palette indices transparent if in alphaData array
    ALPHA_MASK_RGB = -6;          // Consider source RGBs transparent if in RGB888 format alphaData array

/**
 * Byte and bit order constants.
 */
static const int LSB_FIRST = 0;
static const int MSB_FIRST = 1;

/**
 * Data types (internal)
 */
private static const int
    // direct / true color formats with arbitrary masks & shifts
    TYPE_GENERIC_8 = 0,
    TYPE_GENERIC_16_MSB = 1,
    TYPE_GENERIC_16_LSB = 2,
    TYPE_GENERIC_24 = 3,
    TYPE_GENERIC_32_MSB = 4,
    TYPE_GENERIC_32_LSB = 5,
    // palette indexed color formats
    TYPE_INDEX_8 = 6,
    TYPE_INDEX_4 = 7,
    TYPE_INDEX_2 = 8,
    TYPE_INDEX_1_MSB = 9,
    TYPE_INDEX_1_LSB = 10;

/**
 * Blits a direct palette image into a direct palette image.
 * <p>
 * Note: When the source and destination depth, order and masks
 * are pairwise equal and the blitter operation is BLIT_SRC,
 * the masks are ignored.  Hence when not changing the image
 * data format, 0 may be specified for the masks.
 * </p>
 *
 * @param op the blitter operation: a combination of BLIT_xxx flags
 *        (see BLIT_xxx constants)
 * @param srcData the source byte array containing image data
 * @param srcDepth the source depth: one of 8, 16, 24, 32
 * @param srcStride the source number of bytes per line
 * @param srcOrder the source byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if srcDepth is not 16 or 32
 * @param srcX the top-left x-coord of the source blit region
 * @param srcY the top-left y-coord of the source blit region
 * @param srcWidth the width of the source blit region
 * @param srcHeight the height of the source blit region
 * @param srcRedMask the source red channel mask
 * @param srcGreenMask the source green channel mask
 * @param srcBlueMask the source blue channel mask
 * @param alphaMode the alpha blending or mask mode, may be
 *        an integer 0-255 for global alpha; ignored if BLIT_ALPHA
 *        not specified in the blitter operations
 *        (see ALPHA_MODE_xxx constants)
 * @param alphaData the alpha blending or mask data, varies depending
 *        on the value of alphaMode and sometimes ignored
 * @param alphaStride the alpha data number of bytes per line
 * @param alphaX the top-left x-coord of the alpha blit region
 * @param alphaY the top-left y-coord of the alpha blit region
 * @param destData the destination byte array containing image data
 * @param destDepth the destination depth: one of 8, 16, 24, 32
 * @param destStride the destination number of bytes per line
 * @param destOrder the destination byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if destDepth is not 16 or 32
 * @param destX the top-left x-coord of the destination blit region
 * @param destY the top-left y-coord of the destination blit region
 * @param destWidth the width of the destination blit region
 * @param destHeight the height of the destination blit region
 * @param destRedMask the destination red channel mask
 * @param destGreenMask the destination green channel mask
 * @param destBlueMask the destination blue channel mask
 * @param flipX if true the resulting image is flipped along the vertical axis
 * @param flipY if true the resulting image is flipped along the horizontal axis
 */
static void blit(int op,
    byte[] srcData, int srcDepth, int srcStride, int srcOrder,
    int srcX, int srcY, int srcWidth, int srcHeight,
    int srcRedMask, int srcGreenMask, int srcBlueMask,
    int alphaMode, byte[] alphaData, int alphaStride, int alphaX, int alphaY,
    byte[] destData, int destDepth, int destStride, int destOrder,
    int destX, int destY, int destWidth, int destHeight,
    int destRedMask, int destGreenMask, int destBlueMask,
    bool flipX, bool flipY) {

    static_this();

    if ((destWidth <= 0) || (destHeight <= 0) || (alphaMode is ALPHA_TRANSPARENT)) return;

    // these should be supplied as params later
    const int srcAlphaMask = 0, destAlphaMask = 0;

    /*** Prepare scaling data ***/
    int dwm1 = destWidth - 1;
    int sfxi = (dwm1 !is 0) ? cast(int)(((cast(long)srcWidth << 16) - 1) / dwm1) : 0;
    int dhm1 = destHeight - 1;
    int sfyi = (dhm1 !is 0) ? cast(int)(((cast(long)srcHeight << 16) - 1) / dhm1) : 0;

    /*** Prepare source-related data ***/
    int sbpp, stype;
    switch (srcDepth) {
        case 8:
            sbpp = 1;
            stype = TYPE_GENERIC_8;
            break;
        case 16:
            sbpp = 2;
            stype = (srcOrder is MSB_FIRST) ? TYPE_GENERIC_16_MSB : TYPE_GENERIC_16_LSB;
            break;
        case 24:
            sbpp = 3;
            stype = TYPE_GENERIC_24;
            break;
        case 32:
            sbpp = 4;
            stype = (srcOrder is MSB_FIRST) ? TYPE_GENERIC_32_MSB : TYPE_GENERIC_32_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid source type");
            return;
    }
    int spr = srcY * srcStride + srcX * sbpp;

    /*** Prepare destination-related data ***/
    int dbpp, dtype;
    switch (destDepth) {
        case 8:
            dbpp = 1;
            dtype = TYPE_GENERIC_8;
            break;
        case 16:
            dbpp = 2;
            dtype = (destOrder is MSB_FIRST) ? TYPE_GENERIC_16_MSB : TYPE_GENERIC_16_LSB;
            break;
        case 24:
            dbpp = 3;
            dtype = TYPE_GENERIC_24;
            break;
        case 32:
            dbpp = 4;
            dtype = (destOrder is MSB_FIRST) ? TYPE_GENERIC_32_MSB : TYPE_GENERIC_32_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid destination type");
            return;
    }
    int dpr = ((flipY) ? destY + dhm1 : destY) * destStride + ((flipX) ? destX + dwm1 : destX) * dbpp;
    int dprxi = (flipX) ? -dbpp : dbpp;
    int dpryi = (flipY) ? -destStride : destStride;

    /*** Prepare special processing data ***/
    int apr;
    if ((op & BLIT_ALPHA) !is 0) {
        switch (alphaMode) {
            case ALPHA_MASK_UNPACKED:
            case ALPHA_CHANNEL_SEPARATE:
                if (alphaData is null) alphaMode = 0x10000;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_PACKED:
                if (alphaData is null) alphaMode = 0x10000;
                alphaStride <<= 3;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_INDEX:
                //throw new IllegalArgumentException("Invalid alpha type");
                return;
            case ALPHA_MASK_RGB:
                if (alphaData is null) alphaMode = 0x10000;
                apr = 0;
                break;
            default:
                alphaMode = (alphaMode << 16) / 255; // prescale
            case ALPHA_CHANNEL_SOURCE:
                apr = 0;
                break;
        }
    } else {
        alphaMode = 0x10000;
        apr = 0;
    }

    /*** Blit ***/
    int dp = dpr;
    int sp = spr;
    if ((alphaMode is 0x10000) && (stype is dtype) &&
        (srcRedMask is destRedMask) && (srcGreenMask is destGreenMask) &&
        (srcBlueMask is destBlueMask) && (srcAlphaMask is destAlphaMask)) {
        /*** Fast blit (straight copy) ***/
        switch (sbpp) {
            case 1:
                for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                    for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                        destData[dp] = srcData[sp];
                        sp += (sfx >>> 16);
                    }
                }
                break;
            case 2:
                for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                    for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                        destData[dp] = srcData[sp];
                        destData[dp + 1] = srcData[sp + 1];
                        sp += (sfx >>> 16) * 2;
                    }
                }
                break;
            case 3:
                for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                    for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                        destData[dp] = srcData[sp];
                        destData[dp + 1] = srcData[sp + 1];
                        destData[dp + 2] = srcData[sp + 2];
                        sp += (sfx >>> 16) * 3;
                    }
                }
                break;
            case 4:
                for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                    for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                        destData[dp] = srcData[sp];
                        destData[dp + 1] = srcData[sp + 1];
                        destData[dp + 2] = srcData[sp + 2];
                        destData[dp + 3] = srcData[sp + 3];
                        sp += (sfx >>> 16) * 4;
                    }
                }
                break;
        default:
        }
        return;
    }
    /*** Comprehensive blit (apply transformations) ***/
    int srcRedShift = getChannelShift(srcRedMask);
    byte[] srcReds = ANY_TO_EIGHT[getChannelWidth(srcRedMask, srcRedShift)];
    int srcGreenShift = getChannelShift(srcGreenMask);
    byte[] srcGreens = ANY_TO_EIGHT[getChannelWidth(srcGreenMask, srcGreenShift)];
    int srcBlueShift = getChannelShift(srcBlueMask);
    byte[] srcBlues = ANY_TO_EIGHT[getChannelWidth(srcBlueMask, srcBlueShift)];
    int srcAlphaShift = getChannelShift(srcAlphaMask);
    byte[] srcAlphas = ANY_TO_EIGHT[getChannelWidth(srcAlphaMask, srcAlphaShift)];

    int destRedShift = getChannelShift(destRedMask);
    int destRedWidth = getChannelWidth(destRedMask, destRedShift);
    byte[] destReds = ANY_TO_EIGHT[destRedWidth];
    int destRedPreShift = 8 - destRedWidth;
    int destGreenShift = getChannelShift(destGreenMask);
    int destGreenWidth = getChannelWidth(destGreenMask, destGreenShift);
    byte[] destGreens = ANY_TO_EIGHT[destGreenWidth];
    int destGreenPreShift = 8 - destGreenWidth;
    int destBlueShift = getChannelShift(destBlueMask);
    int destBlueWidth = getChannelWidth(destBlueMask, destBlueShift);
    byte[] destBlues = ANY_TO_EIGHT[destBlueWidth];
    int destBluePreShift = 8 - destBlueWidth;
    int destAlphaShift = getChannelShift(destAlphaMask);
    int destAlphaWidth = getChannelWidth(destAlphaMask, destAlphaShift);
    byte[] destAlphas = ANY_TO_EIGHT[destAlphaWidth];
    int destAlphaPreShift = 8 - destAlphaWidth;

    int ap = apr, alpha = alphaMode;
    int r = 0, g = 0, b = 0, a = 0;
    int rq = 0, gq = 0, bq = 0, aq = 0;
    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy,
            sp = spr += (sfy >>> 16) * srcStride,
            ap = apr += (sfy >>> 16) * alphaStride,
            sfy = (sfy & 0xffff) + sfyi,
            dp = dpr += dpryi) {
        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx,
                dp += dprxi,
                sfx = (sfx & 0xffff) + sfxi) {
            /*** READ NEXT PIXEL ***/
            switch (stype) {
                case TYPE_GENERIC_8: {
                    int data = srcData[sp] & 0xff;
                    sp += (sfx >>> 16);
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_16_MSB: {
                    int data = ((srcData[sp] & 0xff) << 8) | (srcData[sp + 1] & 0xff);
                    sp += (sfx >>> 16) * 2;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_16_LSB: {
                    int data = ((srcData[sp + 1] & 0xff) << 8) | (srcData[sp] & 0xff);
                    sp += (sfx >>> 16) * 2;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_24: {
                    int data = (( ((srcData[sp] & 0xff) << 8) |
                        (srcData[sp + 1] & 0xff)) << 8) |
                        (srcData[sp + 2] & 0xff);
                    sp += (sfx >>> 16) * 3;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_32_MSB: {
                    int data = (( (( ((srcData[sp] & 0xff) << 8) |
                        (srcData[sp + 1] & 0xff)) << 8) |
                        (srcData[sp + 2] & 0xff)) << 8) |
                        (srcData[sp + 3] & 0xff);
                    sp += (sfx >>> 16) * 4;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_32_LSB: {
                    int data = (( (( ((srcData[sp + 3] & 0xff) << 8) |
                        (srcData[sp + 2] & 0xff)) << 8) |
                        (srcData[sp + 1] & 0xff)) << 8) |
                        (srcData[sp] & 0xff);
                    sp += (sfx >>> 16) * 4;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                default:
            }

            /*** DO SPECIAL PROCESSING IF REQUIRED ***/
            switch (alphaMode) {
                case ALPHA_CHANNEL_SEPARATE:
                    alpha = ((alphaData[ap] & 0xff) << 16) / 255;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_CHANNEL_SOURCE:
                    alpha = (a << 16) / 255;
                    break;
                case ALPHA_MASK_UNPACKED:
                    alpha = (alphaData[ap] !is 0) ? 0x10000 : 0;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_PACKED:
                    alpha = (alphaData[ap >> 3] << ((ap & 7) + 9)) & 0x10000;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_RGB:
                    alpha = 0x10000;
                    for (int i = 0; i < alphaData.length; i += 3) {
                        if ((r is alphaData[i]) && (g is alphaData[i + 1]) && (b is alphaData[i + 2])) {
                            alpha = 0x0000;
                            break;
                        }
                    }
                    break;
                default:
            }
            if (alpha !is 0x10000) {
                if (alpha is 0x0000) continue;
                switch (dtype) {
                    case TYPE_GENERIC_8: {
                        int data = destData[dp] & 0xff;
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_16_MSB: {
                        int data = ((destData[dp] & 0xff) << 8) | (destData[dp + 1] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_16_LSB: {
                        int data = ((destData[dp + 1] & 0xff) << 8) | (destData[dp] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_24: {
                        int data = (( ((destData[dp] & 0xff) << 8) |
                            (destData[dp + 1] & 0xff)) << 8) |
                            (destData[dp + 2] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_32_MSB: {
                        int data = (( (( ((destData[dp] & 0xff) << 8) |
                            (destData[dp + 1] & 0xff)) << 8) |
                            (destData[dp + 2] & 0xff)) << 8) |
                            (destData[dp + 3] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_32_LSB: {
                        int data = (( (( ((destData[dp + 3] & 0xff) << 8) |
                            (destData[dp + 2] & 0xff)) << 8) |
                            (destData[dp + 1] & 0xff)) << 8) |
                            (destData[dp] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    default:
                }
                // Perform alpha blending
                a = aq + ((a - aq) * alpha >> 16);
                r = rq + ((r - rq) * alpha >> 16);
                g = gq + ((g - gq) * alpha >> 16);
                b = bq + ((b - bq) * alpha >> 16);
            }

            /*** WRITE NEXT PIXEL ***/
            int data =
                (r >>> destRedPreShift << destRedShift) |
                (g >>> destGreenPreShift << destGreenShift) |
                (b >>> destBluePreShift << destBlueShift) |
                (a >>> destAlphaPreShift << destAlphaShift);
            switch (dtype) {
                case TYPE_GENERIC_8: {
                    destData[dp] = cast(byte) data;
                } break;
                case TYPE_GENERIC_16_MSB: {
                    destData[dp] = cast(byte) (data >>> 8);
                    destData[dp + 1] = cast(byte) (data & 0xff);
                } break;
                case TYPE_GENERIC_16_LSB: {
                    destData[dp] = cast(byte) (data & 0xff);
                    destData[dp + 1] = cast(byte) (data >>> 8);
                } break;
                case TYPE_GENERIC_24: {
                    destData[dp] = cast(byte) (data >>> 16);
                    destData[dp + 1] = cast(byte) (data >>> 8);
                    destData[dp + 2] = cast(byte) (data & 0xff);
                } break;
                case TYPE_GENERIC_32_MSB: {
                    destData[dp] = cast(byte) (data >>> 24);
                    destData[dp + 1] = cast(byte) (data >>> 16);
                    destData[dp + 2] = cast(byte) (data >>> 8);
                    destData[dp + 3] = cast(byte) (data & 0xff);
                } break;
                case TYPE_GENERIC_32_LSB: {
                    destData[dp] = cast(byte) (data & 0xff);
                    destData[dp + 1] = cast(byte) (data >>> 8);
                    destData[dp + 2] = cast(byte) (data >>> 16);
                    destData[dp + 3] = cast(byte) (data >>> 24);
                } break;
                default:
            }
        }
    }
}

/**
 * Blits an index palette image into an index palette image.
 * <p>
 * Note: The source and destination red, green, and blue
 * arrays may be null if no alpha blending or dither is to be
 * performed.
 * </p>
 *
 * @param op the blitter operation: a combination of BLIT_xxx flags
 *        (see BLIT_xxx constants)
 * @param srcData the source byte array containing image data
 * @param srcDepth the source depth: one of 1, 2, 4, 8
 * @param srcStride the source number of bytes per line
 * @param srcOrder the source byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if srcDepth is not 1
 * @param srcX the top-left x-coord of the source blit region
 * @param srcY the top-left y-coord of the source blit region
 * @param srcWidth the width of the source blit region
 * @param srcHeight the height of the source blit region
 * @param srcReds the source palette red component intensities
 * @param srcGreens the source palette green component intensities
 * @param srcBlues the source palette blue component intensities
 * @param alphaMode the alpha blending or mask mode, may be
 *        an integer 0-255 for global alpha; ignored if BLIT_ALPHA
 *        not specified in the blitter operations
 *        (see ALPHA_MODE_xxx constants)
 * @param alphaData the alpha blending or mask data, varies depending
 *        on the value of alphaMode and sometimes ignored
 * @param alphaStride the alpha data number of bytes per line
 * @param alphaX the top-left x-coord of the alpha blit region
 * @param alphaY the top-left y-coord of the alpha blit region
 * @param destData the destination byte array containing image data
 * @param destDepth the destination depth: one of 1, 2, 4, 8
 * @param destStride the destination number of bytes per line
 * @param destOrder the destination byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if destDepth is not 1
 * @param destX the top-left x-coord of the destination blit region
 * @param destY the top-left y-coord of the destination blit region
 * @param destWidth the width of the destination blit region
 * @param destHeight the height of the destination blit region
 * @param destReds the destination palette red component intensities
 * @param destGreens the destination palette green component intensities
 * @param destBlues the destination palette blue component intensities
 * @param flipX if true the resulting image is flipped along the vertical axis
 * @param flipY if true the resulting image is flipped along the horizontal axis
 */
static void blit(int op,
    byte[] srcData, int srcDepth, int srcStride, int srcOrder,
    int srcX, int srcY, int srcWidth, int srcHeight,
    byte[] srcReds, byte[] srcGreens, byte[] srcBlues,
    int alphaMode, byte[] alphaData, int alphaStride, int alphaX, int alphaY,
    byte[] destData, int destDepth, int destStride, int destOrder,
    int destX, int destY, int destWidth, int destHeight,
    byte[] destReds, byte[] destGreens, byte[] destBlues,
    bool flipX, bool flipY) {

    static_this();

    if ((destWidth <= 0) || (destHeight <= 0) || (alphaMode is ALPHA_TRANSPARENT)) return;

    /*** Prepare scaling data ***/
    int dwm1 = destWidth - 1;
    int sfxi = (dwm1 !is 0) ? cast(int)(((cast(long)srcWidth << 16) - 1) / dwm1) : 0;
    int dhm1 = destHeight - 1;
    int sfyi = (dhm1 !is 0) ? cast(int)(((cast(long)srcHeight << 16) - 1) / dhm1) : 0;

    /*** Prepare source-related data ***/
    int stype;
    switch (srcDepth) {
        case 8:
            stype = TYPE_INDEX_8;
            break;
        case 4:
            srcStride <<= 1;
            stype = TYPE_INDEX_4;
            break;
        case 2:
            srcStride <<= 2;
            stype = TYPE_INDEX_2;
            break;
        case 1:
            srcStride <<= 3;
            stype = (srcOrder is MSB_FIRST) ? TYPE_INDEX_1_MSB : TYPE_INDEX_1_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid source type");
            return;
    }
    int spr = srcY * srcStride + srcX;

    /*** Prepare destination-related data ***/
    int dtype;
    switch (destDepth) {
        case 8:
            dtype = TYPE_INDEX_8;
            break;
        case 4:
            destStride <<= 1;
            dtype = TYPE_INDEX_4;
            break;
        case 2:
            destStride <<= 2;
            dtype = TYPE_INDEX_2;
            break;
        case 1:
            destStride <<= 3;
            dtype = (destOrder is MSB_FIRST) ? TYPE_INDEX_1_MSB : TYPE_INDEX_1_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid source type");
            return;
    }
    int dpr = ((flipY) ? destY + dhm1 : destY) * destStride + ((flipX) ? destX + dwm1 : destX);
    int dprxi = (flipX) ? -1 : 1;
    int dpryi = (flipY) ? -destStride : destStride;

    /*** Prepare special processing data ***/
    int apr;
    if ((op & BLIT_ALPHA) !is 0) {
        switch (alphaMode) {
            case ALPHA_MASK_UNPACKED:
            case ALPHA_CHANNEL_SEPARATE:
                if (alphaData is null) alphaMode = 0x10000;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_PACKED:
                if (alphaData is null) alphaMode = 0x10000;
                alphaStride <<= 3;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_INDEX:
            case ALPHA_MASK_RGB:
                if (alphaData is null) alphaMode = 0x10000;
                apr = 0;
                break;
            default:
                alphaMode = (alphaMode << 16) / 255; // prescale
            case ALPHA_CHANNEL_SOURCE:
                apr = 0;
                break;
        }
    } else {
        alphaMode = 0x10000;
        apr = 0;
    }
    bool ditherEnabled = (op & BLIT_DITHER) !is 0;

    /*** Blit ***/
    int dp = dpr;
    int sp = spr;
    int ap = apr;
    int destPaletteSize = 1 << destDepth;
    if ((destReds !is null) && (destReds.length < destPaletteSize)) destPaletteSize = destReds.length;
    byte[] paletteMapping = null;
    bool isExactPaletteMapping = true;
    switch (alphaMode) {
        case 0x10000:
            /*** If the palettes and formats are equivalent use a one-to-one mapping ***/
            if ((stype is dtype) &&
                (srcReds is destReds) && (srcGreens is destGreens) && (srcBlues is destBlues)) {
                paletteMapping = ONE_TO_ONE_MAPPING;
                break;
            /*** If palettes have not been supplied, supply a suitable mapping ***/
            } else if ((srcReds is null) || (destReds is null)) {
                if (srcDepth <= destDepth) {
                    paletteMapping = ONE_TO_ONE_MAPPING;
                } else {
                    paletteMapping = new byte[1 << srcDepth];
                    int mask = (0xff << destDepth) >>> 8;
                    for (int i = 0; i < paletteMapping.length; ++i) paletteMapping[i] = cast(byte)(i & mask);
                }
                break;
            }
        case ALPHA_MASK_UNPACKED:
        case ALPHA_MASK_PACKED:
        case ALPHA_MASK_INDEX:
        case ALPHA_MASK_RGB:
            /*** Generate a palette mapping ***/
            int srcPaletteSize = 1 << srcDepth;
            paletteMapping = new byte[srcPaletteSize];
            if ((srcReds !is null) && (srcReds.length < srcPaletteSize)) srcPaletteSize = srcReds.length;
            for (int i = 0, r, g, b, index; i < srcPaletteSize; ++i) {
                r = srcReds[i] & 0xff;
                g = srcGreens[i] & 0xff;
                b = srcBlues[i] & 0xff;
                index = 0;
                int minDistance = 0x7fffffff;
                for (int j = 0, dr, dg, db, distance; j < destPaletteSize; ++j) {
                    dr = (destReds[j] & 0xff) - r;
                    dg = (destGreens[j] & 0xff) - g;
                    db = (destBlues[j] & 0xff) - b;
                    distance = dr * dr + dg * dg + db * db;
                    if (distance < minDistance) {
                        index = j;
                        if (distance is 0) break;
                        minDistance = distance;
                    }
                }
                paletteMapping[i] = cast(byte)index;
                if (minDistance !is 0) isExactPaletteMapping = false;
            }
            break;
        default:
    }
    if ((paletteMapping !is null) && (isExactPaletteMapping || ! ditherEnabled)) {
        if ((stype is dtype) && (alphaMode is 0x10000)) {
            /*** Fast blit (copy w/ mapping) ***/
            switch (stype) {
                case TYPE_INDEX_8:
                    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                            destData[dp] = paletteMapping[srcData[sp] & 0xff];
                            sp += (sfx >>> 16);
                        }
                    }
                    break;
                case TYPE_INDEX_4:
                    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                            int v;
                            if ((sp & 1) !is 0) v = paletteMapping[srcData[sp >> 1] & 0x0f];
                            else v = (srcData[sp >> 1] >>> 4) & 0x0f;
                            sp += (sfx >>> 16);
                            if ((dp & 1) !is 0) destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0xf0) | v);
                            else destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0x0f) | (v << 4));
                        }
                    }
                    break;
                case TYPE_INDEX_2:
                    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                            int index = paletteMapping[(srcData[sp >> 2] >>> (6 - (sp & 3) * 2)) & 0x03];
                            sp += (sfx >>> 16);
                            int shift = 6 - (dp & 3) * 2;
                            destData[dp >> 2] = cast(byte)(destData[dp >> 2] & ~(0x03 << shift) | (index << shift));
                        }
                    }
                    break;
                case TYPE_INDEX_1_MSB:
                    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                            int index = paletteMapping[(srcData[sp >> 3] >>> (7 - (sp & 7))) & 0x01];
                            sp += (sfx >>> 16);
                            int shift = 7 - (dp & 7);
                            destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (index << shift));
                        }
                    }
                    break;
                case TYPE_INDEX_1_LSB:
                    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy, sp = spr += (sfy >>> 16) * srcStride, sfy = (sfy & 0xffff) + sfyi, dp = dpr += dpryi) {
                        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx, dp += dprxi, sfx = (sfx & 0xffff) + sfxi) {
                            int index = paletteMapping[(srcData[sp >> 3] >>> (sp & 7)) & 0x01];
                            sp += (sfx >>> 16);
                            int shift = dp & 7;
                            destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (index << shift));
                        }
                    }
                    break;
                default:
            }
        } else {
            /*** Convert between indexed modes using mapping and mask ***/
            for (int dy = destHeight, sfy = sfyi; dy > 0; --dy,
                    sp = spr += (sfy >>> 16) * srcStride,
                    sfy = (sfy & 0xffff) + sfyi,
                    dp = dpr += dpryi) {
                for (int dx = destWidth, sfx = sfxi; dx > 0; --dx,
                        dp += dprxi,
                        sfx = (sfx & 0xffff) + sfxi) {
                    int index;
                    /*** READ NEXT PIXEL ***/
                    switch (stype) {
                        case TYPE_INDEX_8:
                            index = srcData[sp] & 0xff;
                            sp += (sfx >>> 16);
                            break;
                        case TYPE_INDEX_4:
                            if ((sp & 1) !is 0) index = srcData[sp >> 1] & 0x0f;
                            else index = (srcData[sp >> 1] >>> 4) & 0x0f;
                            sp += (sfx >>> 16);
                            break;
                        case TYPE_INDEX_2:
                            index = (srcData[sp >> 2] >>> (6 - (sp & 3) * 2)) & 0x03;
                            sp += (sfx >>> 16);
                            break;
                        case TYPE_INDEX_1_MSB:
                            index = (srcData[sp >> 3] >>> (7 - (sp & 7))) & 0x01;
                            sp += (sfx >>> 16);
                            break;
                        case TYPE_INDEX_1_LSB:
                            index = (srcData[sp >> 3] >>> (sp & 7)) & 0x01;
                            sp += (sfx >>> 16);
                            break;
                        default:
                            return;
                    }
                    /*** APPLY MASK ***/
                    switch (alphaMode) {
                        case ALPHA_MASK_UNPACKED: {
                            byte mask = alphaData[ap];
                            ap += (sfx >> 16);
                            if (mask is 0) continue;
                        } break;
                        case ALPHA_MASK_PACKED: {
                            int mask = alphaData[ap >> 3] & (1 << (ap & 7));
                            ap += (sfx >> 16);
                            if (mask is 0) continue;
                        } break;
                        case ALPHA_MASK_INDEX: {
                            int i = 0;
                            while (i < alphaData.length) {
                                if (index is (alphaData[i] & 0xff)) break;
                            }
                            if (i < alphaData.length) continue;
                        } break;
                        case ALPHA_MASK_RGB: {
                            byte r = srcReds[index], g = srcGreens[index], b = srcBlues[index];
                            int i = 0;
                            while (i < alphaData.length) {
                                if ((r is alphaData[i]) && (g is alphaData[i + 1]) && (b is alphaData[i + 2])) break;
                                i += 3;
                            }
                            if (i < alphaData.length) continue;
                        } break;
                        default:
                    }
                    index = paletteMapping[index] & 0xff;

                    /*** WRITE NEXT PIXEL ***/
                    switch (dtype) {
                        case TYPE_INDEX_8:
                            destData[dp] = cast(byte) index;
                            break;
                        case TYPE_INDEX_4:
                            if ((dp & 1) !is 0) destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0xf0) | index);
                            else destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0x0f) | (index << 4));
                            break;
                        case TYPE_INDEX_2: {
                            int shift = 6 - (dp & 3) * 2;
                            destData[dp >> 2] = cast(byte)(destData[dp >> 2] & ~(0x03 << shift) | (index << shift));
                        } break;
                        case TYPE_INDEX_1_MSB: {
                            int shift = 7 - (dp & 7);
                            destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (index << shift));
                        } break;
                        case TYPE_INDEX_1_LSB: {
                            int shift = dp & 7;
                            destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (index << shift));
                        } break;
                        default:
                    }
                }
            }
        }
        return;
    }

    /*** Comprehensive blit (apply transformations) ***/
    int alpha = alphaMode;
    int index = 0;
    int indexq = 0;
    int lastindex = 0, lastr = -1, lastg = -1, lastb = -1;
    int[] rerr, gerr, berr;
    if (ditherEnabled) {
        rerr = new int[destWidth + 2];
        gerr = new int[destWidth + 2];
        berr = new int[destWidth + 2];
    } else {
        rerr = null; gerr = null; berr = null;
    }
    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy,
            sp = spr += (sfy >>> 16) * srcStride,
            ap = apr += (sfy >>> 16) * alphaStride,
            sfy = (sfy & 0xffff) + sfyi,
            dp = dpr += dpryi) {
        int lrerr = 0, lgerr = 0, lberr = 0;
        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx,
                dp += dprxi,
                sfx = (sfx & 0xffff) + sfxi) {
            /*** READ NEXT PIXEL ***/
            switch (stype) {
                case TYPE_INDEX_8:
                    index = srcData[sp] & 0xff;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_4:
                    if ((sp & 1) !is 0) index = srcData[sp >> 1] & 0x0f;
                    else index = (srcData[sp >> 1] >>> 4) & 0x0f;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_2:
                    index = (srcData[sp >> 2] >>> (6 - (sp & 3) * 2)) & 0x03;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_1_MSB:
                    index = (srcData[sp >> 3] >>> (7 - (sp & 7))) & 0x01;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_1_LSB:
                    index = (srcData[sp >> 3] >>> (sp & 7)) & 0x01;
                    sp += (sfx >>> 16);
                    break;
                default:
            }

            /*** DO SPECIAL PROCESSING IF REQUIRED ***/
            int r = srcReds[index] & 0xff, g = srcGreens[index] & 0xff, b = srcBlues[index] & 0xff;
            switch (alphaMode) {
                case ALPHA_CHANNEL_SEPARATE:
                    alpha = ((alphaData[ap] & 0xff) << 16) / 255;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_UNPACKED:
                    alpha = (alphaData[ap] !is 0) ? 0x10000 : 0;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_PACKED:
                    alpha = (alphaData[ap >> 3] << ((ap & 7) + 9)) & 0x10000;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_INDEX: { // could speed up using binary search if we sorted the indices
                    int i = 0;
                    while (i < alphaData.length) {
                        if (index is (alphaData[i] & 0xff)) break;
                    }
                    if (i < alphaData.length) continue;
                } break;
                case ALPHA_MASK_RGB: {
                    int i = 0;
                    while (i < alphaData.length) {
                        if ((r is (alphaData[i] & 0xff)) &&
                            (g is (alphaData[i + 1] & 0xff)) &&
                            (b is (alphaData[i + 2] & 0xff))) break;
                        i += 3;
                    }
                    if (i < alphaData.length) continue;
                } break;
                default:
            }
            if (alpha !is 0x10000) {
                if (alpha is 0x0000) continue;
                switch (dtype) {
                    case TYPE_INDEX_8:
                        indexq = destData[dp] & 0xff;
                        break;
                    case TYPE_INDEX_4:
                        if ((dp & 1) !is 0) indexq = destData[dp >> 1] & 0x0f;
                        else indexq = (destData[dp >> 1] >>> 4) & 0x0f;
                        break;
                    case TYPE_INDEX_2:
                        indexq = (destData[dp >> 2] >>> (6 - (dp & 3) * 2)) & 0x03;
                        break;
                    case TYPE_INDEX_1_MSB:
                        indexq = (destData[dp >> 3] >>> (7 - (dp & 7))) & 0x01;
                        break;
                    case TYPE_INDEX_1_LSB:
                        indexq = (destData[dp >> 3] >>> (dp & 7)) & 0x01;
                        break;
                    default:
                }
                // Perform alpha blending
                int rq = destReds[indexq] & 0xff;
                int gq = destGreens[indexq] & 0xff;
                int bq = destBlues[indexq] & 0xff;
                r = rq + ((r - rq) * alpha >> 16);
                g = gq + ((g - gq) * alpha >> 16);
                b = bq + ((b - bq) * alpha >> 16);
            }

            /*** MAP COLOR TO THE PALETTE ***/
            if (ditherEnabled) {
                // Floyd-Steinberg error diffusion
                r += rerr[dx] >> 4;
                if (r < 0) r = 0; else if (r > 255) r = 255;
                g += gerr[dx] >> 4;
                if (g < 0) g = 0; else if (g > 255) g = 255;
                b += berr[dx] >> 4;
                if (b < 0) b = 0; else if (b > 255) b = 255;
                rerr[dx] = lrerr;
                gerr[dx] = lgerr;
                berr[dx] = lberr;
            }
            if (r !is lastr || g !is lastg || b !is lastb) {
                // moving the variable declarations out seems to make the JDK JIT happier...
                for (int j = 0, dr, dg, db, distance, minDistance = 0x7fffffff; j < destPaletteSize; ++j) {
                    dr = (destReds[j] & 0xff) - r;
                    dg = (destGreens[j] & 0xff) - g;
                    db = (destBlues[j] & 0xff) - b;
                    distance = dr * dr + dg * dg + db * db;
                    if (distance < minDistance) {
                        lastindex = j;
                        if (distance is 0) break;
                        minDistance = distance;
                    }
                }
                lastr = r; lastg = g; lastb = b;
            }
            if (ditherEnabled) {
                // Floyd-Steinberg error diffusion, cont'd...
                int dxm1 = dx - 1, dxp1 = dx + 1;
                int acc;
                rerr[dxp1] += acc = (lrerr = r - (destReds[lastindex] & 0xff)) + lrerr + lrerr;
                rerr[dx] += acc += lrerr + lrerr;
                rerr[dxm1] += acc + lrerr + lrerr;
                gerr[dxp1] += acc = (lgerr = g - (destGreens[lastindex] & 0xff)) + lgerr + lgerr;
                gerr[dx] += acc += lgerr + lgerr;
                gerr[dxm1] += acc + lgerr + lgerr;
                berr[dxp1] += acc = (lberr = b - (destBlues[lastindex] & 0xff)) + lberr + lberr;
                berr[dx] += acc += lberr + lberr;
                berr[dxm1] += acc + lberr + lberr;
            }

            /*** WRITE NEXT PIXEL ***/
            switch (dtype) {
                case TYPE_INDEX_8:
                    destData[dp] = cast(byte) lastindex;
                    break;
                case TYPE_INDEX_4:
                    if ((dp & 1) !is 0) destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0xf0) | lastindex);
                    else destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0x0f) | (lastindex << 4));
                    break;
                case TYPE_INDEX_2: {
                    int shift = 6 - (dp & 3) * 2;
                    destData[dp >> 2] = cast(byte)(destData[dp >> 2] & ~(0x03 << shift) | (lastindex << shift));
                } break;
                case TYPE_INDEX_1_MSB: {
                    int shift = 7 - (dp & 7);
                    destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (lastindex << shift));
                } break;
                case TYPE_INDEX_1_LSB: {
                    int shift = dp & 7;
                    destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (lastindex << shift));
                } break;
                default:
            }
        }
    }
}

/**
 * Blits an index palette image into a direct palette image.
 * <p>
 * Note: The source and destination masks and palettes must
 * always be fully specified.
 * </p>
 *
 * @param op the blitter operation: a combination of BLIT_xxx flags
 *        (see BLIT_xxx constants)
 * @param srcData the source byte array containing image data
 * @param srcDepth the source depth: one of 1, 2, 4, 8
 * @param srcStride the source number of bytes per line
 * @param srcOrder the source byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if srcDepth is not 1
 * @param srcX the top-left x-coord of the source blit region
 * @param srcY the top-left y-coord of the source blit region
 * @param srcWidth the width of the source blit region
 * @param srcHeight the height of the source blit region
 * @param srcReds the source palette red component intensities
 * @param srcGreens the source palette green component intensities
 * @param srcBlues the source palette blue component intensities
 * @param alphaMode the alpha blending or mask mode, may be
 *        an integer 0-255 for global alpha; ignored if BLIT_ALPHA
 *        not specified in the blitter operations
 *        (see ALPHA_MODE_xxx constants)
 * @param alphaData the alpha blending or mask data, varies depending
 *        on the value of alphaMode and sometimes ignored
 * @param alphaStride the alpha data number of bytes per line
 * @param alphaX the top-left x-coord of the alpha blit region
 * @param alphaY the top-left y-coord of the alpha blit region
 * @param destData the destination byte array containing image data
 * @param destDepth the destination depth: one of 8, 16, 24, 32
 * @param destStride the destination number of bytes per line
 * @param destOrder the destination byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if destDepth is not 16 or 32
 * @param destX the top-left x-coord of the destination blit region
 * @param destY the top-left y-coord of the destination blit region
 * @param destWidth the width of the destination blit region
 * @param destHeight the height of the destination blit region
 * @param destRedMask the destination red channel mask
 * @param destGreenMask the destination green channel mask
 * @param destBlueMask the destination blue channel mask
 * @param flipX if true the resulting image is flipped along the vertical axis
 * @param flipY if true the resulting image is flipped along the horizontal axis
 */
static void blit(int op,
    byte[] srcData, int srcDepth, int srcStride, int srcOrder,
    int srcX, int srcY, int srcWidth, int srcHeight,
    byte[] srcReds, byte[] srcGreens, byte[] srcBlues,
    int alphaMode, byte[] alphaData, int alphaStride, int alphaX, int alphaY,
    byte[] destData, int destDepth, int destStride, int destOrder,
    int destX, int destY, int destWidth, int destHeight,
    int destRedMask, int destGreenMask, int destBlueMask,
    bool flipX, bool flipY) {

    static_this();

    if ((destWidth <= 0) || (destHeight <= 0) || (alphaMode is ALPHA_TRANSPARENT)) return;

    // these should be supplied as params later
    int destAlphaMask = 0;

    /*** Prepare scaling data ***/
    int dwm1 = destWidth - 1;
    int sfxi = (dwm1 !is 0) ? cast(int)(((cast(long)srcWidth << 16) - 1) / dwm1) : 0;
    int dhm1 = destHeight - 1;
    int sfyi = (dhm1 !is 0) ? cast(int)(((cast(long)srcHeight << 16) - 1) / dhm1) : 0;

    /*** Prepare source-related data ***/
    int stype;
    switch (srcDepth) {
        case 8:
            stype = TYPE_INDEX_8;
            break;
        case 4:
            srcStride <<= 1;
            stype = TYPE_INDEX_4;
            break;
        case 2:
            srcStride <<= 2;
            stype = TYPE_INDEX_2;
            break;
        case 1:
            srcStride <<= 3;
            stype = (srcOrder is MSB_FIRST) ? TYPE_INDEX_1_MSB : TYPE_INDEX_1_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid source type");
            return;
    }
    int spr = srcY * srcStride + srcX;

    /*** Prepare destination-related data ***/
    int dbpp, dtype;
    switch (destDepth) {
        case 8:
            dbpp = 1;
            dtype = TYPE_GENERIC_8;
            break;
        case 16:
            dbpp = 2;
            dtype = (destOrder is MSB_FIRST) ? TYPE_GENERIC_16_MSB : TYPE_GENERIC_16_LSB;
            break;
        case 24:
            dbpp = 3;
            dtype = TYPE_GENERIC_24;
            break;
        case 32:
            dbpp = 4;
            dtype = (destOrder is MSB_FIRST) ? TYPE_GENERIC_32_MSB : TYPE_GENERIC_32_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid destination type");
            return;
    }
    int dpr = ((flipY) ? destY + dhm1 : destY) * destStride + ((flipX) ? destX + dwm1 : destX) * dbpp;
    int dprxi = (flipX) ? -dbpp : dbpp;
    int dpryi = (flipY) ? -destStride : destStride;

    /*** Prepare special processing data ***/
    int apr;
    if ((op & BLIT_ALPHA) !is 0) {
        switch (alphaMode) {
            case ALPHA_MASK_UNPACKED:
            case ALPHA_CHANNEL_SEPARATE:
                if (alphaData is null) alphaMode = 0x10000;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_PACKED:
                if (alphaData is null) alphaMode = 0x10000;
                alphaStride <<= 3;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_INDEX:
            case ALPHA_MASK_RGB:
                if (alphaData is null) alphaMode = 0x10000;
                apr = 0;
                break;
            default:
                alphaMode = (alphaMode << 16) / 255; // prescale
            case ALPHA_CHANNEL_SOURCE:
                apr = 0;
                break;
        }
    } else {
        alphaMode = 0x10000;
        apr = 0;
    }

    /*** Comprehensive blit (apply transformations) ***/
    int destRedShift = getChannelShift(destRedMask);
    int destRedWidth = getChannelWidth(destRedMask, destRedShift);
    byte[] destReds = ANY_TO_EIGHT[destRedWidth];
    int destRedPreShift = 8 - destRedWidth;
    int destGreenShift = getChannelShift(destGreenMask);
    int destGreenWidth = getChannelWidth(destGreenMask, destGreenShift);
    byte[] destGreens = ANY_TO_EIGHT[destGreenWidth];
    int destGreenPreShift = 8 - destGreenWidth;
    int destBlueShift = getChannelShift(destBlueMask);
    int destBlueWidth = getChannelWidth(destBlueMask, destBlueShift);
    byte[] destBlues = ANY_TO_EIGHT[destBlueWidth];
    int destBluePreShift = 8 - destBlueWidth;
    int destAlphaShift = getChannelShift(destAlphaMask);
    int destAlphaWidth = getChannelWidth(destAlphaMask, destAlphaShift);
    byte[] destAlphas = ANY_TO_EIGHT[destAlphaWidth];
    int destAlphaPreShift = 8 - destAlphaWidth;

    int dp = dpr;
    int sp = spr;
    int ap = apr, alpha = alphaMode;
    int r = 0, g = 0, b = 0, a = 0, index = 0;
    int rq = 0, gq = 0, bq = 0, aq = 0;
    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy,
            sp = spr += (sfy >>> 16) * srcStride,
            ap = apr += (sfy >>> 16) * alphaStride,
            sfy = (sfy & 0xffff) + sfyi,
            dp = dpr += dpryi) {
        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx,
                dp += dprxi,
                sfx = (sfx & 0xffff) + sfxi) {
            /*** READ NEXT PIXEL ***/
            switch (stype) {
                case TYPE_INDEX_8:
                    index = srcData[sp] & 0xff;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_4:
                    if ((sp & 1) !is 0) index = srcData[sp >> 1] & 0x0f;
                    else index = (srcData[sp >> 1] >>> 4) & 0x0f;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_2:
                    index = (srcData[sp >> 2] >>> (6 - (sp & 3) * 2)) & 0x03;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_1_MSB:
                    index = (srcData[sp >> 3] >>> (7 - (sp & 7))) & 0x01;
                    sp += (sfx >>> 16);
                    break;
                case TYPE_INDEX_1_LSB:
                    index = (srcData[sp >> 3] >>> (sp & 7)) & 0x01;
                    sp += (sfx >>> 16);
                    break;
                default:
            }

            /*** DO SPECIAL PROCESSING IF REQUIRED ***/
            r = srcReds[index] & 0xff;
            g = srcGreens[index] & 0xff;
            b = srcBlues[index] & 0xff;
            switch (alphaMode) {
                case ALPHA_CHANNEL_SEPARATE:
                    alpha = ((alphaData[ap] & 0xff) << 16) / 255;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_UNPACKED:
                    alpha = (alphaData[ap] !is 0) ? 0x10000 : 0;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_PACKED:
                    alpha = (alphaData[ap >> 3] << ((ap & 7) + 9)) & 0x10000;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_INDEX: { // could speed up using binary search if we sorted the indices
                    int i = 0;
                    while (i < alphaData.length) {
                        if (index is (alphaData[i] & 0xff)) break;
                    }
                    if (i < alphaData.length) continue;
                } break;
                case ALPHA_MASK_RGB: {
                    int i = 0;
                    while (i < alphaData.length) {
                        if ((r is (alphaData[i] & 0xff)) &&
                            (g is (alphaData[i + 1] & 0xff)) &&
                            (b is (alphaData[i + 2] & 0xff))) break;
                        i += 3;
                    }
                    if (i < alphaData.length) continue;
                } break;
                default:
            }
            if (alpha !is 0x10000) {
                if (alpha is 0x0000) continue;
                switch (dtype) {
                    case TYPE_GENERIC_8: {
                        int data = destData[dp] & 0xff;
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_16_MSB: {
                        int data = ((destData[dp] & 0xff) << 8) | (destData[dp + 1] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_16_LSB: {
                        int data = ((destData[dp + 1] & 0xff) << 8) | (destData[dp] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_24: {
                        int data = (( ((destData[dp] & 0xff) << 8) |
                            (destData[dp + 1] & 0xff)) << 8) |
                            (destData[dp + 2] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_32_MSB: {
                        int data = (( (( ((destData[dp] & 0xff) << 8) |
                            (destData[dp + 1] & 0xff)) << 8) |
                            (destData[dp + 2] & 0xff)) << 8) |
                            (destData[dp + 3] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    case TYPE_GENERIC_32_LSB: {
                        int data = (( (( ((destData[dp + 3] & 0xff) << 8) |
                            (destData[dp + 2] & 0xff)) << 8) |
                            (destData[dp + 1] & 0xff)) << 8) |
                            (destData[dp] & 0xff);
                        rq = destReds[(data & destRedMask) >>> destRedShift] & 0xff;
                        gq = destGreens[(data & destGreenMask) >>> destGreenShift] & 0xff;
                        bq = destBlues[(data & destBlueMask) >>> destBlueShift] & 0xff;
                        aq = destAlphas[(data & destAlphaMask) >>> destAlphaShift] & 0xff;
                    } break;
                    default:
                }
                // Perform alpha blending
                a = aq + ((a - aq) * alpha >> 16);
                r = rq + ((r - rq) * alpha >> 16);
                g = gq + ((g - gq) * alpha >> 16);
                b = bq + ((b - bq) * alpha >> 16);
            }

            /*** WRITE NEXT PIXEL ***/
            int data =
                (r >>> destRedPreShift << destRedShift) |
                (g >>> destGreenPreShift << destGreenShift) |
                (b >>> destBluePreShift << destBlueShift) |
                (a >>> destAlphaPreShift << destAlphaShift);
            switch (dtype) {
                case TYPE_GENERIC_8: {
                    destData[dp] = cast(byte) data;
                } break;
                case TYPE_GENERIC_16_MSB: {
                    destData[dp] = cast(byte) (data >>> 8);
                    destData[dp + 1] = cast(byte) (data & 0xff);
                } break;
                case TYPE_GENERIC_16_LSB: {
                    destData[dp] = cast(byte) (data & 0xff);
                    destData[dp + 1] = cast(byte) (data >>> 8);
                } break;
                case TYPE_GENERIC_24: {
                    destData[dp] = cast(byte) (data >>> 16);
                    destData[dp + 1] = cast(byte) (data >>> 8);
                    destData[dp + 2] = cast(byte) (data & 0xff);
                } break;
                case TYPE_GENERIC_32_MSB: {
                    destData[dp] = cast(byte) (data >>> 24);
                    destData[dp + 1] = cast(byte) (data >>> 16);
                    destData[dp + 2] = cast(byte) (data >>> 8);
                    destData[dp + 3] = cast(byte) (data & 0xff);
                } break;
                case TYPE_GENERIC_32_LSB: {
                    destData[dp] = cast(byte) (data & 0xff);
                    destData[dp + 1] = cast(byte) (data >>> 8);
                    destData[dp + 2] = cast(byte) (data >>> 16);
                    destData[dp + 3] = cast(byte) (data >>> 24);
                } break;
                default:
            }
        }
    }
}

/**
 * Blits a direct palette image into an index palette image.
 * <p>
 * Note: The source and destination masks and palettes must
 * always be fully specified.
 * </p>
 *
 * @param op the blitter operation: a combination of BLIT_xxx flags
 *        (see BLIT_xxx constants)
 * @param srcData the source byte array containing image data
 * @param srcDepth the source depth: one of 8, 16, 24, 32
 * @param srcStride the source number of bytes per line
 * @param srcOrder the source byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if srcDepth is not 16 or 32
 * @param srcX the top-left x-coord of the source blit region
 * @param srcY the top-left y-coord of the source blit region
 * @param srcWidth the width of the source blit region
 * @param srcHeight the height of the source blit region
 * @param srcRedMask the source red channel mask
 * @param srcGreenMask the source green channel mask
 * @param srcBlueMask the source blue channel mask
 * @param alphaMode the alpha blending or mask mode, may be
 *        an integer 0-255 for global alpha; ignored if BLIT_ALPHA
 *        not specified in the blitter operations
 *        (see ALPHA_MODE_xxx constants)
 * @param alphaData the alpha blending or mask data, varies depending
 *        on the value of alphaMode and sometimes ignored
 * @param alphaStride the alpha data number of bytes per line
 * @param alphaX the top-left x-coord of the alpha blit region
 * @param alphaY the top-left y-coord of the alpha blit region
 * @param destData the destination byte array containing image data
 * @param destDepth the destination depth: one of 1, 2, 4, 8
 * @param destStride the destination number of bytes per line
 * @param destOrder the destination byte ordering: one of MSB_FIRST or LSB_FIRST;
 *        ignored if destDepth is not 1
 * @param destX the top-left x-coord of the destination blit region
 * @param destY the top-left y-coord of the destination blit region
 * @param destWidth the width of the destination blit region
 * @param destHeight the height of the destination blit region
 * @param destReds the destination palette red component intensities
 * @param destGreens the destination palette green component intensities
 * @param destBlues the destination palette blue component intensities
 * @param flipX if true the resulting image is flipped along the vertical axis
 * @param flipY if true the resulting image is flipped along the horizontal axis
 */
static void blit(int op,
    byte[] srcData, int srcDepth, int srcStride, int srcOrder,
    int srcX, int srcY, int srcWidth, int srcHeight,
    int srcRedMask, int srcGreenMask, int srcBlueMask,
    int alphaMode, byte[] alphaData, int alphaStride, int alphaX, int alphaY,
    byte[] destData, int destDepth, int destStride, int destOrder,
    int destX, int destY, int destWidth, int destHeight,
    byte[] destReds, byte[] destGreens, byte[] destBlues,
    bool flipX, bool flipY) {

    static_this();

    if ((destWidth <= 0) || (destHeight <= 0) || (alphaMode is ALPHA_TRANSPARENT)) return;

    // these should be supplied as params later
    int srcAlphaMask = 0;

    /*** Prepare scaling data ***/
    int dwm1 = destWidth - 1;
    int sfxi = (dwm1 !is 0) ? cast(int)(((cast(long)srcWidth << 16) - 1) / dwm1) : 0;
    int dhm1 = destHeight - 1;
    int sfyi = (dhm1 !is 0) ? cast(int)(((cast(long)srcHeight << 16) - 1) / dhm1) : 0;

    /*** Prepare source-related data ***/
    int sbpp, stype;
    switch (srcDepth) {
        case 8:
            sbpp = 1;
            stype = TYPE_GENERIC_8;
            break;
        case 16:
            sbpp = 2;
            stype = (srcOrder is MSB_FIRST) ? TYPE_GENERIC_16_MSB : TYPE_GENERIC_16_LSB;
            break;
        case 24:
            sbpp = 3;
            stype = TYPE_GENERIC_24;
            break;
        case 32:
            sbpp = 4;
            stype = (srcOrder is MSB_FIRST) ? TYPE_GENERIC_32_MSB : TYPE_GENERIC_32_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid source type");
            return;
    }
    int spr = srcY * srcStride + srcX * sbpp;

    /*** Prepare destination-related data ***/
    int dtype;
    switch (destDepth) {
        case 8:
            dtype = TYPE_INDEX_8;
            break;
        case 4:
            destStride <<= 1;
            dtype = TYPE_INDEX_4;
            break;
        case 2:
            destStride <<= 2;
            dtype = TYPE_INDEX_2;
            break;
        case 1:
            destStride <<= 3;
            dtype = (destOrder is MSB_FIRST) ? TYPE_INDEX_1_MSB : TYPE_INDEX_1_LSB;
            break;
        default:
            //throw new IllegalArgumentException("Invalid source type");
            return;
    }
    int dpr = ((flipY) ? destY + dhm1 : destY) * destStride + ((flipX) ? destX + dwm1 : destX);
    int dprxi = (flipX) ? -1 : 1;
    int dpryi = (flipY) ? -destStride : destStride;

    /*** Prepare special processing data ***/
    int apr;
    if ((op & BLIT_ALPHA) !is 0) {
        switch (alphaMode) {
            case ALPHA_MASK_UNPACKED:
            case ALPHA_CHANNEL_SEPARATE:
                if (alphaData is null) alphaMode = 0x10000;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_PACKED:
                if (alphaData is null) alphaMode = 0x10000;
                alphaStride <<= 3;
                apr = alphaY * alphaStride + alphaX;
                break;
            case ALPHA_MASK_INDEX:
                //throw new IllegalArgumentException("Invalid alpha type");
                return;
            case ALPHA_MASK_RGB:
                if (alphaData is null) alphaMode = 0x10000;
                apr = 0;
                break;
            default:
                alphaMode = (alphaMode << 16) / 255; // prescale
            case ALPHA_CHANNEL_SOURCE:
                apr = 0;
                break;
        }
    } else {
        alphaMode = 0x10000;
        apr = 0;
    }
    bool ditherEnabled = (op & BLIT_DITHER) !is 0;

    /*** Comprehensive blit (apply transformations) ***/
    int srcRedShift = getChannelShift(srcRedMask);
    byte[] srcReds = ANY_TO_EIGHT[getChannelWidth(srcRedMask, srcRedShift)];
    int srcGreenShift = getChannelShift(srcGreenMask);
    byte[] srcGreens = ANY_TO_EIGHT[getChannelWidth(srcGreenMask, srcGreenShift)];
    int srcBlueShift = getChannelShift(srcBlueMask);
    byte[] srcBlues = ANY_TO_EIGHT[getChannelWidth(srcBlueMask, srcBlueShift)];
    int srcAlphaShift = getChannelShift(srcAlphaMask);
    byte[] srcAlphas = ANY_TO_EIGHT[getChannelWidth(srcAlphaMask, srcAlphaShift)];

    int dp = dpr;
    int sp = spr;
    int ap = apr, alpha = alphaMode;
    int r = 0, g = 0, b = 0, a = 0;
    int indexq = 0;
    int lastindex = 0, lastr = -1, lastg = -1, lastb = -1;
    int[] rerr, gerr, berr;
    int destPaletteSize = 1 << destDepth;
    if ((destReds !is null) && (destReds.length < destPaletteSize)) destPaletteSize = destReds.length;
    if (ditherEnabled) {
        rerr = new int[destWidth + 2];
        gerr = new int[destWidth + 2];
        berr = new int[destWidth + 2];
    } else {
        rerr = null; gerr = null; berr = null;
    }
    for (int dy = destHeight, sfy = sfyi; dy > 0; --dy,
            sp = spr += (sfy >>> 16) * srcStride,
            ap = apr += (sfy >>> 16) * alphaStride,
            sfy = (sfy & 0xffff) + sfyi,
            dp = dpr += dpryi) {
        int lrerr = 0, lgerr = 0, lberr = 0;
        for (int dx = destWidth, sfx = sfxi; dx > 0; --dx,
                dp += dprxi,
                sfx = (sfx & 0xffff) + sfxi) {
            /*** READ NEXT PIXEL ***/
            switch (stype) {
                case TYPE_GENERIC_8: {
                    int data = srcData[sp] & 0xff;
                    sp += (sfx >>> 16);
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_16_MSB: {
                    int data = ((srcData[sp] & 0xff) << 8) | (srcData[sp + 1] & 0xff);
                    sp += (sfx >>> 16) * 2;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_16_LSB: {
                    int data = ((srcData[sp + 1] & 0xff) << 8) | (srcData[sp] & 0xff);
                    sp += (sfx >>> 16) * 2;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_24: {
                    int data = (( ((srcData[sp] & 0xff) << 8) |
                        (srcData[sp + 1] & 0xff)) << 8) |
                        (srcData[sp + 2] & 0xff);
                    sp += (sfx >>> 16) * 3;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_32_MSB: {
                    int data = (( (( ((srcData[sp] & 0xff) << 8) |
                        (srcData[sp + 1] & 0xff)) << 8) |
                        (srcData[sp + 2] & 0xff)) << 8) |
                        (srcData[sp + 3] & 0xff);
                    sp += (sfx >>> 16) * 4;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                case TYPE_GENERIC_32_LSB: {
                    int data = (( (( ((srcData[sp + 3] & 0xff) << 8) |
                        (srcData[sp + 2] & 0xff)) << 8) |
                        (srcData[sp + 1] & 0xff)) << 8) |
                        (srcData[sp] & 0xff);
                    sp += (sfx >>> 16) * 4;
                    r = srcReds[(data & srcRedMask) >>> srcRedShift] & 0xff;
                    g = srcGreens[(data & srcGreenMask) >>> srcGreenShift] & 0xff;
                    b = srcBlues[(data & srcBlueMask) >>> srcBlueShift] & 0xff;
                    a = srcAlphas[(data & srcAlphaMask) >>> srcAlphaShift] & 0xff;
                } break;
                default:
            }

            /*** DO SPECIAL PROCESSING IF REQUIRED ***/
            switch (alphaMode) {
                case ALPHA_CHANNEL_SEPARATE:
                    alpha = ((alphaData[ap] & 0xff) << 16) / 255;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_CHANNEL_SOURCE:
                    alpha = (a << 16) / 255;
                    break;
                case ALPHA_MASK_UNPACKED:
                    alpha = (alphaData[ap] !is 0) ? 0x10000 : 0;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_PACKED:
                    alpha = (alphaData[ap >> 3] << ((ap & 7) + 9)) & 0x10000;
                    ap += (sfx >> 16);
                    break;
                case ALPHA_MASK_RGB:
                    alpha = 0x10000;
                    for (int i = 0; i < alphaData.length; i += 3) {
                        if ((r is alphaData[i]) && (g is alphaData[i + 1]) && (b is alphaData[i + 2])) {
                            alpha = 0x0000;
                            break;
                        }
                    }
                    break;
                default:
            }
            if (alpha !is 0x10000) {
                if (alpha is 0x0000) continue;
                switch (dtype) {
                    case TYPE_INDEX_8:
                        indexq = destData[dp] & 0xff;
                        break;
                    case TYPE_INDEX_4:
                        if ((dp & 1) !is 0) indexq = destData[dp >> 1] & 0x0f;
                        else indexq = (destData[dp >> 1] >>> 4) & 0x0f;
                        break;
                    case TYPE_INDEX_2:
                        indexq = (destData[dp >> 2] >>> (6 - (dp & 3) * 2)) & 0x03;
                        break;
                    case TYPE_INDEX_1_MSB:
                        indexq = (destData[dp >> 3] >>> (7 - (dp & 7))) & 0x01;
                        break;
                    case TYPE_INDEX_1_LSB:
                        indexq = (destData[dp >> 3] >>> (dp & 7)) & 0x01;
                        break;
                    default:
                }
                // Perform alpha blending
                int rq = destReds[indexq] & 0xff;
                int gq = destGreens[indexq] & 0xff;
                int bq = destBlues[indexq] & 0xff;
                r = rq + ((r - rq) * alpha >> 16);
                g = gq + ((g - gq) * alpha >> 16);
                b = bq + ((b - bq) * alpha >> 16);
            }

            /*** MAP COLOR TO THE PALETTE ***/
            if (ditherEnabled) {
                // Floyd-Steinberg error diffusion
                r += rerr[dx] >> 4;
                if (r < 0) r = 0; else if (r > 255) r = 255;
                g += gerr[dx] >> 4;
                if (g < 0) g = 0; else if (g > 255) g = 255;
                b += berr[dx] >> 4;
                if (b < 0) b = 0; else if (b > 255) b = 255;
                rerr[dx] = lrerr;
                gerr[dx] = lgerr;
                berr[dx] = lberr;
            }
            if (r !is lastr || g !is lastg || b !is lastb) {
                // moving the variable declarations out seems to make the JDK JIT happier...
                for (int j = 0, dr, dg, db, distance, minDistance = 0x7fffffff; j < destPaletteSize; ++j) {
                    dr = (destReds[j] & 0xff) - r;
                    dg = (destGreens[j] & 0xff) - g;
                    db = (destBlues[j] & 0xff) - b;
                    distance = dr * dr + dg * dg + db * db;
                    if (distance < minDistance) {
                        lastindex = j;
                        if (distance is 0) break;
                        minDistance = distance;
                    }
                }
                lastr = r; lastg = g; lastb = b;
            }
            if (ditherEnabled) {
                // Floyd-Steinberg error diffusion, cont'd...
                int dxm1 = dx - 1, dxp1 = dx + 1;
                int acc;
                rerr[dxp1] += acc = (lrerr = r - (destReds[lastindex] & 0xff)) + lrerr + lrerr;
                rerr[dx] += acc += lrerr + lrerr;
                rerr[dxm1] += acc + lrerr + lrerr;
                gerr[dxp1] += acc = (lgerr = g - (destGreens[lastindex] & 0xff)) + lgerr + lgerr;
                gerr[dx] += acc += lgerr + lgerr;
                gerr[dxm1] += acc + lgerr + lgerr;
                berr[dxp1] += acc = (lberr = b - (destBlues[lastindex] & 0xff)) + lberr + lberr;
                berr[dx] += acc += lberr + lberr;
                berr[dxm1] += acc + lberr + lberr;
            }

            /*** WRITE NEXT PIXEL ***/
            switch (dtype) {
                case TYPE_INDEX_8:
                    destData[dp] = cast(byte) lastindex;
                    break;
                case TYPE_INDEX_4:
                    if ((dp & 1) !is 0) destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0xf0) | lastindex);
                    else destData[dp >> 1] = cast(byte)((destData[dp >> 1] & 0x0f) | (lastindex << 4));
                    break;
                case TYPE_INDEX_2: {
                    int shift = 6 - (dp & 3) * 2;
                    destData[dp >> 2] = cast(byte)(destData[dp >> 2] & ~(0x03 << shift) | (lastindex << shift));
                } break;
                case TYPE_INDEX_1_MSB: {
                    int shift = 7 - (dp & 7);
                    destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (lastindex << shift));
                } break;
                case TYPE_INDEX_1_LSB: {
                    int shift = dp & 7;
                    destData[dp >> 3] = cast(byte)(destData[dp >> 3] & ~(0x01 << shift) | (lastindex << shift));
                } break;
                default:
            }
        }
    }
}

/**
 * Computes the required channel shift from a mask.
 */
static int getChannelShift(int mask) {
    if (mask is 0) return 0;
    int i;
    for (i = 0; ((mask & 1) is 0) && (i < 32); ++i) {
        mask >>>= 1;
    }
    return i;
}

/**
 * Computes the required channel width (depth) from a mask.
 */
static int getChannelWidth(int mask, int shift) {
    if (mask is 0) return 0;
    int i;
    mask >>>= shift;
    for (i = shift; ((mask & 1) !is 0) && (i < 32); ++i) {
        mask >>>= 1;
    }
    return i - shift;
}

/**
 * Extracts a field from packed RGB data given a mask for that field.
 */
static byte getChannelField(int data, int mask) {
    static_this();
    int shift = getChannelShift(mask);
    return ANY_TO_EIGHT[getChannelWidth(mask, shift)][(data & mask) >>> shift];
}

/**
 * Creates an ImageData containing one band's worth of a gradient filled
 * block.  If <code>vertical</code> is true, the band must be tiled
 * horizontally to fill a region, otherwise it must be tiled vertically.
 *
 * @param width the width of the region to be filled
 * @param height the height of the region to be filled
 * @param vertical if true sweeps from top to bottom, else
 *        sweeps from left to right
 * @param fromRGB the color to start with
 * @param toRGB the color to end with
 * @param redBits the number of significant red bits, 0 for palette modes
 * @param greenBits the number of significant green bits, 0 for palette modes
 * @param blueBits the number of significant blue bits, 0 for palette modes
 * @return the new ImageData
 */
static ImageData createGradientBand(
    int width, int height, bool vertical,
    RGB fromRGB, RGB toRGB,
    int redBits, int greenBits, int blueBits) {
    /* Gradients are drawn as tiled bands */
    int bandWidth, bandHeight, bitmapDepth;
    byte[] bitmapData;
    PaletteData paletteData;
    /* Select an algorithm depending on the depth of the screen */
    if (redBits !is 0 && greenBits !is 0 && blueBits !is 0) {
        paletteData = new PaletteData(0x0000ff00, 0x00ff0000, 0xff000000);
        bitmapDepth = 32;
        if (redBits >= 8 && greenBits >= 8 && blueBits >= 8) {
            /* Precise color */
            int steps;
            if (vertical) {
                bandWidth = 1;
                bandHeight = height;
                steps = bandHeight > 1 ? bandHeight - 1 : 1;
            } else {
                bandWidth = width;
                bandHeight = 1;
                steps = bandWidth > 1 ? bandWidth - 1 : 1;
            }
            int bytesPerLine = bandWidth * 4;
            bitmapData = new byte[bandHeight * bytesPerLine];
            buildPreciseGradientChannel(fromRGB.blue, toRGB.blue, steps, bandWidth, bandHeight, vertical, bitmapData, 0, bytesPerLine);
            buildPreciseGradientChannel(fromRGB.green, toRGB.green, steps, bandWidth, bandHeight, vertical, bitmapData, 1, bytesPerLine);
            buildPreciseGradientChannel(fromRGB.red, toRGB.red, steps, bandWidth, bandHeight, vertical, bitmapData, 2, bytesPerLine);
        } else {
            /* Dithered color */
            int steps;
            if (vertical) {
                bandWidth = (width < 8) ? width : 8;
                bandHeight = height;
                steps = bandHeight > 1 ? bandHeight - 1 : 1;
            } else {
                bandWidth = width;
                bandHeight = (height < 8) ? height : 8;
                steps = bandWidth > 1 ? bandWidth - 1 : 1;
            }
            int bytesPerLine = bandWidth * 4;
            bitmapData = new byte[bandHeight * bytesPerLine];
            buildDitheredGradientChannel(fromRGB.blue, toRGB.blue, steps, bandWidth, bandHeight, vertical, bitmapData, 0, bytesPerLine, blueBits);
            buildDitheredGradientChannel(fromRGB.green, toRGB.green, steps, bandWidth, bandHeight, vertical, bitmapData, 1, bytesPerLine, greenBits);
            buildDitheredGradientChannel(fromRGB.red, toRGB.red, steps, bandWidth, bandHeight, vertical, bitmapData, 2, bytesPerLine, redBits);
        }
    } else {
        /* Dithered two tone */
        paletteData = new PaletteData([ fromRGB, toRGB ]);
        bitmapDepth = 8;
        int blendi;
        if (vertical) {
            bandWidth = (width < 8) ? width : 8;
            bandHeight = height;
            blendi = (bandHeight > 1) ? 0x1040000 / (bandHeight - 1) + 1 : 1;
        } else {
            bandWidth = width;
            bandHeight = (height < 8) ? height : 8;
            blendi = (bandWidth > 1) ? 0x1040000 / (bandWidth - 1) + 1 : 1;
        }
        int bytesPerLine = (bandWidth + 3) & -4;
        bitmapData = new byte[bandHeight * bytesPerLine];
        if (vertical) {
            for (int dy = 0, blend = 0, dp = 0; dy < bandHeight;
                ++dy, blend += blendi, dp += bytesPerLine) {
                for (int dx = 0; dx < bandWidth; ++dx) {
                    bitmapData[dp + dx] = (blend + DITHER_MATRIX[dy & 7][dx]) <
                        0x1000000 ? cast(byte)0 : cast(byte)1;
                }
            }
        } else {
            for (int dx = 0, blend = 0; dx < bandWidth; ++dx, blend += blendi) {
                for (int dy = 0, dptr = dx; dy < bandHeight; ++dy, dptr += bytesPerLine) {
                    bitmapData[dptr] = (blend + DITHER_MATRIX[dy][dx & 7]) <
                        0x1000000 ? cast(byte)0 : cast(byte)1;
                }
            }
        }
    }
    return new ImageData(bandWidth, bandHeight, bitmapDepth, paletteData, 4, bitmapData);
}

/*
 * Fill in gradated values for a color channel
 */
static final void buildPreciseGradientChannel(int from, int to, int steps,
    int bandWidth, int bandHeight, bool vertical,
    byte[] bitmapData, int dp, int bytesPerLine) {
    int val = from << 16;
    int inc = ((to << 16) - val) / steps + 1;
    if (vertical) {
        for (int dy = 0; dy < bandHeight; ++dy, dp += bytesPerLine) {
            bitmapData[dp] = cast(byte)(val >>> 16);
            val += inc;
        }
    } else {
        for (int dx = 0; dx < bandWidth; ++dx, dp += 4) {
            bitmapData[dp] = cast(byte)(val >>> 16);
            val += inc;
        }
    }
}

/*
 * Fill in dithered gradated values for a color channel
 */
static final void buildDitheredGradientChannel(int from, int to, int steps,
    int bandWidth, int bandHeight, bool vertical,
    byte[] bitmapData, int dp, int bytesPerLine, int bits) {
    int mask = 0xff00 >>> bits;
    int val = from << 16;
    int inc = ((to << 16) - val) / steps + 1;
    if (vertical) {
        for (int dy = 0; dy < bandHeight; ++dy, dp += bytesPerLine) {
            for (int dx = 0, dptr = dp; dx < bandWidth; ++dx, dptr += 4) {
                int thresh = DITHER_MATRIX[dy & 7][dx] >>> bits;
                int temp = val + thresh;
                if (temp > 0xffffff) bitmapData[dptr] = -1;
                else bitmapData[dptr] = cast(byte)((temp >>> 16) & mask);
            }
            val += inc;
        }
    } else {
        for (int dx = 0; dx < bandWidth; ++dx, dp += 4) {
            for (int dy = 0, dptr = dp; dy < bandHeight; ++dy, dptr += bytesPerLine) {
                int thresh = DITHER_MATRIX[dy][dx & 7] >>> bits;
                int temp = val + thresh;
                if (temp > 0xffffff) bitmapData[dptr] = -1;
                else bitmapData[dptr] = cast(byte)((temp >>> 16) & mask);
            }
            val += inc;
        }
    }
}

/**
 * Renders a gradient onto a GC.
 * <p>
 * This is a GC helper.
 * </p>
 *
 * @param gc the GC to render the gradient onto
 * @param device the device the GC belongs to
 * @param x the top-left x coordinate of the region to be filled
 * @param y the top-left y coordinate of the region to be filled
 * @param width the width of the region to be filled
 * @param height the height of the region to be filled
 * @param vertical if true sweeps from top to bottom, else
 *        sweeps from left to right
 * @param fromRGB the color to start with
 * @param toRGB the color to end with
 * @param redBits the number of significant red bits, 0 for palette modes
 * @param greenBits the number of significant green bits, 0 for palette modes
 * @param blueBits the number of significant blue bits, 0 for palette modes
 */
static void fillGradientRectangle(GC gc, Device device,
    int x, int y, int width, int height, bool vertical,
    RGB fromRGB, RGB toRGB,
    int redBits, int greenBits, int blueBits) {
    /* Create the bitmap and tile it */
    ImageData band = createGradientBand(width, height, vertical,
        fromRGB, toRGB, redBits, greenBits, blueBits);
    Image image = new Image(device, band);
    if ((band.width is 1) || (band.height is 1)) {
        gc.drawImage(image, 0, 0, band.width, band.height, x, y, width, height);
    } else {
        if (vertical) {
            for (int dx = 0; dx < width; dx += band.width) {
                int blitWidth = width - dx;
                if (blitWidth > band.width) blitWidth = band.width;
                gc.drawImage(image, 0, 0, blitWidth, band.height, dx + x, y, blitWidth, band.height);
            }
        } else {
            for (int dy = 0; dy < height; dy += band.height) {
                int blitHeight = height - dy;
                if (blitHeight > band.height) blitHeight = band.height;
                gc.drawImage(image, 0, 0, band.width, blitHeight, x, dy + y, band.width, blitHeight);
            }
        }
    }
    image.dispose();
}

}