--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/internal/image/PngPlteChunk.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,124 @@
+/*******************************************************************************
+ * 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 PngPlteChunk : PngChunk {
+    
+    int paletteSize;
+
+PngPlteChunk(PaletteData palette) {
+    super(palette.getRGBs().length * 3);
+    paletteSize = length / 3;
+    setType(TYPE_PLTE);
+    setPaletteData(palette);
+    setCRC(computeCRC());
+}       
+
+PngPlteChunk(byte[] reference){
+    super(reference);
+    paletteSize = length / 3;
+}
+
+int getChunkType() {
+    return CHUNK_PLTE;
+}
+
+/**
+ * Get the number of colors in this palette.
+ */
+int getPaletteSize() {
+    return paletteSize;
+}
+
+/**
+ * Get a PaletteData object representing the colors
+ * stored in this PLTE chunk.
+ * The result should be cached as the PLTE chunk
+ * does not store the palette data created.
+ */
+PaletteData getPaletteData() {
+    RGB[] rgbs = new RGB[paletteSize];
+//  int start = DATA_OFFSET;
+//  int end = DATA_OFFSET + length;
+    for (int i = 0; i < rgbs.length; i++) {
+        int offset = DATA_OFFSET + (i * 3);
+        int red = reference[offset] & 0xFF;
+        int green = reference[offset + 1] & 0xFF;
+        int blue = reference[offset + 2] & 0xFF;
+        rgbs[i] = new RGB(red, green, blue);        
+    }
+    return new PaletteData(rgbs);
+}
+
+/**
+ * Set the data of a PLTE chunk to the colors
+ * stored in the specified PaletteData object.
+ */
+void setPaletteData(PaletteData palette) {
+    RGB[] rgbs = palette.getRGBs();
+    for (int i = 0; i < rgbs.length; i++) {
+        int offset = DATA_OFFSET + (i * 3);
+        reference[offset] = (byte) rgbs[i].red;
+        reference[offset + 1] = (byte) rgbs[i].green;
+        reference[offset + 2] = (byte) rgbs[i].blue;
+    }
+}
+
+/**
+ * Answer whether the chunk is a valid PLTE chunk.
+ */
+void validate(PngFileReadState readState, PngIhdrChunk headerChunk) {
+    // A PLTE chunk is invalid if no IHDR has been read or if any PLTE,
+    // IDAT, or IEND chunk has been read.
+    if (!readState.readIHDR
+        || readState.readPLTE
+        || readState.readTRNS
+        || readState.readIDAT
+        || readState.readIEND) 
+    {
+        DWT.error(DWT.ERROR_INVALID_IMAGE);
+    } else {
+        readState.readPLTE = true;
+    }
+    
+    super.validate(readState, headerChunk);
+    
+    // Palettes cannot be included in grayscale images.
+    // 
+    // Note: just ignore the palette.
+//  if (!headerChunk.getCanHavePalette()) DWT.error(DWT.ERROR_INVALID_IMAGE);
+    
+    // Palette chunks' data fields must be event multiples
+    // of 3. Each 3-byte group represents an RGB value.
+    if (getLength() % 3 !is 0) DWT.error(DWT.ERROR_INVALID_IMAGE);  
+    
+    // Palettes cannot have more entries than 2^bitDepth
+    // where bitDepth is the bit depth of the image given
+    // in the IHDR chunk.
+    if (1 << headerChunk.getBitDepth() < paletteSize) {
+        DWT.error(DWT.ERROR_INVALID_IMAGE);
+    }
+    
+    // Palettes cannot have more than 256 entries.
+    if (256 < paletteSize) DWT.error(DWT.ERROR_INVALID_IMAGE);
+}
+
+void contributeToString(StringBuffer buffer) {
+    buffer.append("\n\tPalette size:");
+    buffer.append(paletteSize);
+}
+
+}