DefineBitsJPEG3.java

/*
 * JSwiff is an open source Java API for Macromedia Flash file generation
 * and manipulation
 *
 * Copyright (C) 2004-2005 Ralf Terdic (contact@jswiff.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.jswiff.swfrecords.tags;

import com.jswiff.io.InputBitStream;
import com.jswiff.io.OutputBitStream;

import java.io.IOException;


/**
 * Defines a bitmap character with JPEG compression. Unlike
 * <code>DefineBitsJPEG2</code>, this tag adds alpha channel (transparency)
 * support. As transparency is not a standard feature in JPEG images, the
 * alpha channel information is encoded separately from the JPEG data.
 *
 * @since SWF 3
 */
public final class DefineBitsJPEG3 extends DefinitionTag {
	private byte[] jpegData;
	private byte[] bitmapAlphaData;

	/**
	 * Creates a new DefineBitsJPEG3 tag.
	 *
	 * @param characterId character ID of the bitmap
	 * @param jpegData JPEG data (image and encoding)
	 * @param bitmapAlphaData alpha channel data (ZLIB-compressed)
	 */
	public DefineBitsJPEG3(
		int characterId, byte[] jpegData, byte[] bitmapAlphaData) {
		code					 = TagConstants.DEFINE_BITS_JPEG_3;
		this.characterId		 = characterId;
		this.jpegData			 = jpegData;
		this.bitmapAlphaData     = bitmapAlphaData;
	}

	DefineBitsJPEG3() {
		// empty
	}

	/**
	 * Sets the ZLIB-compressed alpha channel data.
	 *
	 * @param bitmapAlphaData alpha channel data
	 */
	public void setBitmapAlphaData(byte[] bitmapAlphaData) {
		this.bitmapAlphaData = bitmapAlphaData;
	}

	/**
	 * Returns the ZLIB-compressed alpha channel data.
	 *
	 * @return alpha channel data
	 */
	public byte[] getBitmapAlphaData() {
		return bitmapAlphaData;
	}

	/**
	 * Sets the byte array containing the image data.
	 *
	 * @param jpegData image data
	 */
	public void setJpegData(byte[] jpegData) {
		this.jpegData = jpegData;
	}

	/**
	 * Returns the JPEG data contained in the tag.
	 *
	 * @return JPEG data (image and encoding)
	 */
	public byte[] getJpegData() {
		return jpegData;
	}

	protected void writeData(OutputBitStream outStream)
		throws IOException {
		forceLongHeader = true;
		outStream.writeUI16(characterId);
		outStream.writeUI32(jpegData.length); // alphaDataOffset
		outStream.writeBytes(jpegData);
		outStream.writeBytes(bitmapAlphaData);
	}

	void setData(byte[] data) throws IOException {
		InputBitStream inStream = new InputBitStream(data);
		characterId = inStream.readUI16();
		int alphaDataOffset = (int) inStream.readUI32();
		jpegData = new byte[alphaDataOffset];
		System.arraycopy(data, 6, jpegData, 0, alphaDataOffset);
		int alphaDataSize = data.length - 6 - alphaDataOffset;
		bitmapAlphaData = new byte[alphaDataSize];
		System.arraycopy(
			data, 6 + alphaDataOffset, bitmapAlphaData, 0, alphaDataSize);
	}
}