--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/internal/image/PngIhdrChunk.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,409 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2006 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
+ *******************************************************************************/
+module dwt.internal.image;
+
+
+import dwt.DWT;
+import dwt.graphics.PaletteData;
+import dwt.graphics.RGB;
+
+class PngIhdrChunk : PngChunk {
+    static final int IHDR_DATA_LENGTH = 13;
+    
+    static final int WIDTH_DATA_OFFSET = DATA_OFFSET + 0;
+    static final int HEIGHT_DATA_OFFSET = DATA_OFFSET + 4;
+    static final int BIT_DEPTH_OFFSET = DATA_OFFSET + 8;
+    static final int COLOR_TYPE_OFFSET = DATA_OFFSET + 9;
+    static final int COMPRESSION_METHOD_OFFSET = DATA_OFFSET + 10;
+    static final int FILTER_METHOD_OFFSET = DATA_OFFSET + 11;
+    static final int INTERLACE_METHOD_OFFSET = DATA_OFFSET + 12;
+    
+    static final byte COLOR_TYPE_GRAYSCALE = 0;
+    static final byte COLOR_TYPE_RGB = 2;
+    static final byte COLOR_TYPE_PALETTE = 3;
+    static final byte COLOR_TYPE_GRAYSCALE_WITH_ALPHA = 4;
+    static final byte COLOR_TYPE_RGB_WITH_ALPHA = 6;
+    
+    static final int INTERLACE_METHOD_NONE = 0;
+    static final int INTERLACE_METHOD_ADAM7 = 1;
+    
+    static final int FILTER_NONE = 0;
+    static final int FILTER_SUB = 1;
+    static final int FILTER_UP = 2;
+    static final int FILTER_AVERAGE = 3;
+    static final int FILTER_PAETH = 4;
+    
+    static final byte[] ValidBitDepths = {1, 2, 4, 8, 16};
+    static final byte[] ValidColorTypes = {0, 2, 3, 4, 6};
+    
+    int width, height;
+    byte bitDepth, colorType, compressionMethod, filterMethod, interlaceMethod;
+    
+PngIhdrChunk(int width, int height, byte bitDepth, byte colorType, byte compressionMethod, byte filterMethod, byte interlaceMethod) {
+    super(IHDR_DATA_LENGTH);
+    setType(TYPE_IHDR);
+    setWidth(width);
+    setHeight(height);
+    setBitDepth(bitDepth);
+    setColorType(colorType);
+    setCompressionMethod(compressionMethod);
+    setFilterMethod(filterMethod);
+    setInterlaceMethod(interlaceMethod);
+    setCRC(computeCRC());
+}
+
+/**
+ * Construct a PNGChunk using the reference bytes
+ * given.
+ */ 
+PngIhdrChunk(byte[] reference) {
+    super(reference);
+    if (reference.length <= IHDR_DATA_LENGTH) DWT.error(DWT.ERROR_INVALID_IMAGE);
+    width = getInt32(WIDTH_DATA_OFFSET);
+    height = getInt32(HEIGHT_DATA_OFFSET);
+    bitDepth = reference[BIT_DEPTH_OFFSET];
+    colorType = reference[COLOR_TYPE_OFFSET];
+    compressionMethod = reference[COMPRESSION_METHOD_OFFSET];
+    filterMethod = reference[FILTER_METHOD_OFFSET];
+    interlaceMethod = reference[INTERLACE_METHOD_OFFSET];
+}
+
+int getChunkType() {
+    return CHUNK_IHDR;
+}
+
+/**
+ * Get the image's width in pixels.
+ */
+int getWidth() {
+    return width;
+}
+
+/**
+ * Set the image's width in pixels.
+ */
+void setWidth(int value) {
+    setInt32(WIDTH_DATA_OFFSET, value);
+    width = value;
+}
+
+/**
+ * Get the image's height in pixels.
+ */
+int getHeight() {
+    return height;
+}
+
+/**
+ * Set the image's height in pixels.
+ */
+void setHeight(int value) {
+    setInt32(HEIGHT_DATA_OFFSET, value);
+    height = value;
+}
+
+/**
+ * Get the image's bit depth.
+ * This is limited to the values 1, 2, 4, 8, or 16.
+ */
+byte getBitDepth() {
+    return bitDepth;
+}
+
+/**
+ * Set the image's bit depth.
+ * This is limited to the values 1, 2, 4, 8, or 16.
+ */
+void setBitDepth(byte value) {
+    reference[BIT_DEPTH_OFFSET] = value;
+    bitDepth = value;
+}
+
+/**
+ * Get the image's color type.
+ * This is limited to the values:
+ * 0 - Grayscale image.
+ * 2 - RGB triple.
+ * 3 - Palette.
+ * 4 - Grayscale with Alpha channel.
+ * 6 - RGB with Alpha channel.
+ */
+byte getColorType() {
+    return colorType;
+}
+
+/**
+ * Set the image's color type.
+ * This is limited to the values:
+ * 0 - Grayscale image.
+ * 2 - RGB triple.
+ * 3 - Palette.
+ * 4 - Grayscale with Alpha channel.
+ * 6 - RGB with Alpha channel.
+ */
+void setColorType(byte value) {
+    reference[COLOR_TYPE_OFFSET] = value;
+    colorType = value;
+}
+
+/**
+ * Get the image's compression method.
+ * This value must be 0.
+ */
+byte getCompressionMethod() {
+    return compressionMethod;
+}
+
+/**
+ * Set the image's compression method.
+ * This value must be 0.
+ */
+void setCompressionMethod(byte value) {
+    reference[COMPRESSION_METHOD_OFFSET] = value;
+    compressionMethod = value;
+}
+
+/**
+ * Get the image's filter method.
+ * This value must be 0.
+ */
+byte getFilterMethod() {
+    return filterMethod;
+}
+
+/**
+ * Set the image's filter method.
+ * This value must be 0.
+ */
+void setFilterMethod(byte value) {
+    reference[FILTER_METHOD_OFFSET] = value;
+    filterMethod = value;
+}
+
+/**
+ * Get the image's interlace method.
+ * This value is limited to:
+ * 0 - No interlacing used.
+ * 1 - Adam7 interlacing used.
+ */
+byte getInterlaceMethod() {
+    return interlaceMethod;
+}
+
+/**
+ * Set the image's interlace method.
+ * This value is limited to:
+ * 0 - No interlacing used.
+ * 1 - Adam7 interlacing used.
+ */
+void setInterlaceMethod(byte value) {
+    reference[INTERLACE_METHOD_OFFSET] = value;
+    interlaceMethod = value;
+}
+
+/**
+ * Answer whether the chunk is a valid IHDR chunk.
+ */
+void validate(PngFileReadState readState, PngIhdrChunk headerChunk) {
+    // An IHDR chunk is invalid if any other chunk has
+    // been read.
+    if (readState.readIHDR 
+        || readState.readPLTE
+        || readState.readIDAT
+        || readState.readIEND) 
+    {
+        DWT.error(DWT.ERROR_INVALID_IMAGE);
+    } else {
+        readState.readIHDR = true;
+    }
+    
+    super.validate(readState, headerChunk);
+    
+    if (length !is IHDR_DATA_LENGTH) DWT.error(DWT.ERROR_INVALID_IMAGE);
+    if (compressionMethod !is 0) DWT.error(DWT.ERROR_INVALID_IMAGE);
+    if (interlaceMethod !is INTERLACE_METHOD_NONE &&
+        interlaceMethod !is INTERLACE_METHOD_ADAM7) {
+            DWT.error(DWT.ERROR_INVALID_IMAGE);
+    }
+    
+    bool colorTypeIsValid = false;
+    for (int i = 0; i < ValidColorTypes.length; i++) {
+        if (ValidColorTypes[i] is colorType) {
+            colorTypeIsValid = true;
+            break;
+        }
+    }
+    if (!colorTypeIsValid) DWT.error(DWT.ERROR_INVALID_IMAGE);
+
+    bool bitDepthIsValid = false;
+    for (int i = 0; i < ValidBitDepths.length; i++) {
+        if (ValidBitDepths[i] is bitDepth) {
+            bitDepthIsValid = true;
+            break;
+        }
+    }
+    if (!bitDepthIsValid) DWT.error(DWT.ERROR_INVALID_IMAGE);
+    
+    if ((colorType is COLOR_TYPE_RGB 
+        || colorType is COLOR_TYPE_RGB_WITH_ALPHA
+        || colorType is COLOR_TYPE_GRAYSCALE_WITH_ALPHA)
+        && bitDepth < 8) 
+    {
+            DWT.error(DWT.ERROR_INVALID_IMAGE);
+    }
+    
+    if (colorType is COLOR_TYPE_PALETTE && bitDepth > 8) {
+        DWT.error(DWT.ERROR_INVALID_IMAGE);
+    }
+}
+
+String getColorTypeString() {
+    switch (colorType) {
+        case COLOR_TYPE_GRAYSCALE:              return "Grayscale";
+        case COLOR_TYPE_RGB:                    return "RGB";       
+        case COLOR_TYPE_PALETTE:                return "Palette";
+        case COLOR_TYPE_GRAYSCALE_WITH_ALPHA:   return "Grayscale with Alpha";
+        case COLOR_TYPE_RGB_WITH_ALPHA:         return "RGB with Alpha";
+        default:                                return "Unknown - " + colorType;
+    }
+}
+
+String getFilterMethodString() {
+    switch (filterMethod) {
+        case FILTER_NONE:       return "None";
+        case FILTER_SUB:        return "Sub";
+        case FILTER_UP:         return "Up";
+        case FILTER_AVERAGE:    return "Average";
+        case FILTER_PAETH:      return "Paeth";
+        default:                return "Unknown";
+    }
+}
+
+String getInterlaceMethodString() {
+    switch (interlaceMethod) {
+        case INTERLACE_METHOD_NONE:     return "Not Interlaced";
+        case INTERLACE_METHOD_ADAM7:    return "Interlaced - ADAM7";
+        default:                return "Unknown";
+    }
+}
+
+void contributeToString(StringBuffer buffer) {
+    buffer.append("\n\tWidth: ");
+    buffer.append(width);
+    buffer.append("\n\tHeight: ");
+    buffer.append(height);
+    buffer.append("\n\tBit Depth: ");
+    buffer.append(bitDepth);
+    buffer.append("\n\tColor Type: ");
+    buffer.append(getColorTypeString());
+    buffer.append("\n\tCompression Method: ");
+    buffer.append(compressionMethod);
+    buffer.append("\n\tFilter Method: ");
+    buffer.append(getFilterMethodString());
+    buffer.append("\n\tInterlace Method: ");
+    buffer.append(getInterlaceMethodString());
+}
+
+bool getMustHavePalette() {
+    return colorType is COLOR_TYPE_PALETTE;
+}
+
+bool getCanHavePalette() {
+    return colorType !is COLOR_TYPE_GRAYSCALE && 
+        colorType !is COLOR_TYPE_GRAYSCALE_WITH_ALPHA;
+}
+
+/**
+ * Answer the pixel size in bits based on the color type
+ * and bit depth.
+ */
+int getBitsPerPixel() {
+    switch (colorType) {
+        case COLOR_TYPE_RGB_WITH_ALPHA:
+            return 4 * bitDepth;
+        case COLOR_TYPE_RGB:
+            return 3 * bitDepth;
+        case COLOR_TYPE_GRAYSCALE_WITH_ALPHA:
+            return 2 * bitDepth;
+        case COLOR_TYPE_GRAYSCALE:
+        case COLOR_TYPE_PALETTE:
+            return bitDepth;
+        default:
+            DWT.error(DWT.ERROR_INVALID_IMAGE);
+            return 0;
+    }
+}
+
+/**
+ * Answer the pixel size in bits based on the color type
+ * and bit depth.
+ */
+int getSwtBitsPerPixel() {
+    switch (colorType) {
+        case COLOR_TYPE_RGB_WITH_ALPHA:
+        case COLOR_TYPE_RGB:
+        case COLOR_TYPE_GRAYSCALE_WITH_ALPHA:
+            return 24;
+        case COLOR_TYPE_GRAYSCALE:
+        case COLOR_TYPE_PALETTE:
+            return Math.min(bitDepth, 8);
+        default:
+            DWT.error(DWT.ERROR_INVALID_IMAGE);
+            return 0;
+    }
+}
+
+int getFilterByteOffset() {
+    if (bitDepth < 8) return 1;
+    return getBitsPerPixel() / 8;
+}
+
+bool usesDirectColor() {
+    switch (colorType) {
+        case COLOR_TYPE_GRAYSCALE:
+        case COLOR_TYPE_GRAYSCALE_WITH_ALPHA:
+        case COLOR_TYPE_RGB:
+        case COLOR_TYPE_RGB_WITH_ALPHA:
+            return true;
+        default:
+            return false;
+    }
+}
+
+PaletteData createGrayscalePalette() {
+    int depth = Math.min(bitDepth, 8);
+    int max = (1 << depth) - 1;
+    int delta = 255 / max;
+    int gray = 0;
+    RGB[] rgbs = new RGB[max + 1]; 
+    for (int i = 0; i <= max; i++) {
+        rgbs[i] = new RGB(gray, gray, gray);
+        gray += delta;
+    }
+    return new PaletteData(rgbs);
+}
+
+PaletteData getPaletteData() {
+    switch (colorType) {
+        case COLOR_TYPE_GRAYSCALE:
+            return createGrayscalePalette();
+        case COLOR_TYPE_GRAYSCALE_WITH_ALPHA:
+        case COLOR_TYPE_RGB:
+        case COLOR_TYPE_RGB_WITH_ALPHA:
+            return new PaletteData(0xFF0000, 0xFF00, 0xFF);
+        default:
+            return null;
+    }   
+}
+
+
+
+}