org.eclipse.swt.internal.image.PngPlteChunk Maven / Gradle / Ivy

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The osx x86_64 swt jar as available in the Eclipse 4.6 (Neon) release for OSX. It is suitable for use with jface and other dependencies available from maven central in the org.eclipse.scout.sdk.deps group. The sources is copied from swt-4.6-cocoa-macosx-x86_64.zip from http://download.eclipse.org/eclipse/downloads/drops4/R-4.6-201606061100/ and javadoc is generated from sources.

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/*******************************************************************************
 * Copyright (c) 2000, 2011 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
 *******************************************************************************/
package org.eclipse.swt.internal.image;


import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;

class PngPlteChunk extends 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;
}

@Override
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.
 */
@Override
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)
	{
		SWT.error(SWT.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()) SWT.error(SWT.ERROR_INVALID_IMAGE);

	// Palette chunks' data fields must be event multiples
	// of 3. Each 3-byte group represents an RGB value.
	if (getLength() % 3 != 0) SWT.error(SWT.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) {
		SWT.error(SWT.ERROR_INVALID_IMAGE);
	}

	// Palettes cannot have more than 256 entries.
	if (256 < paletteSize) SWT.error(SWT.ERROR_INVALID_IMAGE);
}

@Override
void contributeToString(StringBuffer buffer) {
	buffer.append("\n\tPalette size:");
	buffer.append(paletteSize);
}

}