gif_decoder

package com.bumptech.glide.gifdecoder; /** * Copyright (c) 2013 Xcellent Creations, Inc. * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ import android.graphics.Bitmap; import android.util.Log; import com.bumptech.glide.Resource; import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool; import com.bumptech.glide.load.resource.bitmap.BitmapResource; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.nio.ByteBuffer; import java.nio.ByteOrder; /** * Reads frame data from a GIF image source and decodes it into individual frames * for animation purposes. Image data can be read from either and InputStream source * or a byte[]. * * This class is optimized for running animations with the frames, there * are no methods to get individual frame images, only to decode the next frame in the * animation sequence. Instead, it lowers its memory footprint by only housing the minimum * data necessary to decode the next frame in the animation sequence. * * The animation must be manually moved forward using {@link #advance()} before requesting the next * frame. This method must also be called before you request the first frame or an error will * occur. * * Implementation adapted from sample code published in Lyons. (2004). <em>Java for Programmers</em>, * republished under the MIT Open Source License */ public class GifDecoder { private static final String TAG = GifDecoder.class.getSimpleName(); /** * File read status: No errors. */ public static final int STATUS_OK = 0; /** * File read status: Error decoding file (may be partially decoded) */ public static final int STATUS_FORMAT_ERROR = 1; /** * File read status: Unable to open source. */ public static final int STATUS_OPEN_ERROR = 2; /** * max decoder pixel stack size */ private static final int MAX_STACK_SIZE = 4096; /** * GIF Disposal Method meaning take no action */ private static final int DISPOSAL_UNSPECIFIED = 0; /** * GIF Disposal Method meaning leave canvas from previous frame */ private static final int DISPOSAL_NONE = 1; /** * GIF Disposal Method meaning clear canvas to background color */ private static final int DISPOSAL_BACKGROUND = 2; /** * GIF Disposal Method meaning clear canvas to frame before last */ private static final int DISPOSAL_PREVIOUS = 3; //Global File Header values and parsing flags private int[] act; // active color table // Raw GIF data from input source private ByteBuffer rawData; // Raw data read working array private byte[] block = new byte[256]; // current data block // LZW decoder working arrays private short[] prefix; private byte[] suffix; private byte[] pixelStack; private byte[] mainPixels; private int[] mainScratch; private int framePointer = -1; private BitmapPool bitmapPool; private Bitmap currentImage; private byte[] data; private GifHeader header; private String id; public GifDecoder(BitmapPool bitmapPool) { this.bitmapPool = bitmapPool; header = new GifHeader(); } public int getWidth() { return header.width; } public int getHeight() { return header.height; } public boolean isTransparent() { return header.isTransparent; } public int getGifByteSize() { return data.length; } public byte[] getData() { return data; } public int getDecodedFramesByteSizeSum() { // 4 == ARGB_8888, 2 == RGB_565 return header.frameCount * header.width * header.height * (header.isTransparent ? 4 : 2); } /** * Move the animation frame counter forward */ public void advance() { framePointer = (framePointer + 1) % header.frameCount; } /** * Gets display duration for specified frame. * * @param n int index of frame * @return delay in milliseconds */ public int getDelay(int n) { int delay = -1; if ((n >= 0) && (n < header.frameCount)) { delay = header.frames.get(n).delay; } return delay; } /** * Gets display duration for the upcoming frame */ public int getNextDelay() { if (header.frameCount <= 0 || framePointer < 0) { return -1; } return getDelay(framePointer); } /** * Gets the number of frames read from file. * * @return frame count */ public int getFrameCount() { return header.frameCount; } /** * Gets the current index of the animation frame, or -1 if animation hasn't not yet started * * @return frame index */ public int getCurrentFrameIndex() { return framePointer; } /** * Gets the "Netscape" iteration count, if any. A count of 0 means repeat indefinitiely. * * @return iteration count if one was specified, else 1. */ public int getLoopCount() { return header.loopCount; } public String getId() { return id; } /** * Get the next frame in the animation sequence. * * @return Bitmap representation of frame */ public Resource<Bitmap> getNextFrame() { if (header.frameCount <= 0 || framePointer < 0 ) { return null; } GifFrame frame = header.frames.get(framePointer); //Set the appropriate color table if (frame.lct == null) { act = header.gct; } else { act = frame.lct; if (header.bgIndex == frame.transIndex) { header.bgColor = 0; } } int save = 0; if (frame.transparency) { save = act[frame.transIndex]; act[frame.transIndex] = 0; // set transparent color if specified } if (act == null) { Log.w(TAG, "No Valid Color Table"); header.status = STATUS_FORMAT_ERROR; // no color table defined return null; } Bitmap result = setPixels(framePointer); // transfer pixel data to image currentImage = result; // Reset the transparent pixel in the color table if (frame.transparency) { act[frame.transIndex] = save; } return new BitmapResource(result, bitmapPool); } /** * Reads GIF image from stream * * @param is containing GIF file. * @return read status code (0 = no errors) */ public int read(InputStream is, int contentLength) { if (is != null) { try { int capacity = (contentLength > 0) ? (contentLength + 4096) : 16384; ByteArrayOutputStream buffer = new ByteArrayOutputStream(capacity); int nRead; byte[] data = new byte[16384];