571 lines
15 KiB
JavaScript
571 lines
15 KiB
JavaScript
/**
|
|
* This class lets you encode animated GIF files
|
|
* Base class : http://www.java2s.com/Code/Java/2D-Graphics-GUI/AnimatedGifEncoder.htm
|
|
* @author Kevin Weiner (original Java version - kweiner@fmsware.com)
|
|
* @author Thibault Imbert (AS3 version - bytearray.org)
|
|
* @version 0.1 AS3 implementation
|
|
*/
|
|
|
|
|
|
//import flash.utils.ByteArray;
|
|
//import flash.display.BitmapData;
|
|
//import flash.display.Bitmap;
|
|
//import org.bytearray.gif.encoder.NeuQuant
|
|
//import flash.net.URLRequestHeader;
|
|
//import flash.net.URLRequestMethod;
|
|
//import flash.net.URLRequest;
|
|
//import flash.net.navigateToURL;
|
|
|
|
GIFEncoder = function()
|
|
{
|
|
for(var i = 0, chr = {}; i < 256; i++)
|
|
chr[i] = String.fromCharCode(i);
|
|
|
|
function ByteArray(){
|
|
this.bin = [];
|
|
}
|
|
|
|
ByteArray.prototype.getData = function(){
|
|
|
|
for(var v = '', l = this.bin.length, i = 0; i < l; i++)
|
|
v += chr[this.bin[i]];
|
|
return v;
|
|
}
|
|
ByteArray.prototype.writeByte = function(val){
|
|
this.bin.push(val);
|
|
}
|
|
ByteArray.prototype.writeUTFBytes = function(string){
|
|
for(var l = string.length, i = 0; i < l; i++)
|
|
this.writeByte(string.charCodeAt(i));
|
|
}
|
|
ByteArray.prototype.writeBytes = function(array, offset, length){
|
|
for(var l = length || array.length, i = offset||0; i < l; i++)
|
|
this.writeByte(array[i]);
|
|
}
|
|
|
|
var exports = {};
|
|
/*private*/ var width/*int*/ // image size
|
|
/*private*/ var height/*int*/;
|
|
/*private*/ var transparent/***/ = null; // transparent color if given
|
|
/*private*/ var transIndex/*int*/; // transparent index in color table
|
|
/*private*/ var repeat/*int*/ = -1; // no repeat
|
|
/*private*/ var delay/*int*/ = 0; // frame delay (hundredths)
|
|
/*private*/ var started/*Boolean*/ = false; // ready to output frames
|
|
/*private*/ var out/*ByteArray*/;
|
|
/*private*/ var image/*Bitmap*/; // current frame
|
|
/*private*/ var pixels/*ByteArray*/; // BGR byte array from frame
|
|
/*private*/ var indexedPixels/*ByteArray*/ // converted frame indexed to palette
|
|
/*private*/ var colorDepth/*int*/; // number of bit planes
|
|
/*private*/ var colorTab/*ByteArray*/; // RGB palette
|
|
/*private*/ var usedEntry/*Array*/ = new Array; // active palette entries
|
|
/*private*/ var palSize/*int*/ = 7; // color table size (bits-1)
|
|
/*private*/ var dispose/*int*/ = -1; // disposal code (-1 = use default)
|
|
/*private*/ var closeStream/*Boolean*/ = false; // close stream when finished
|
|
/*private*/ var firstFrame/*Boolean*/ = true;
|
|
/*private*/ var sizeSet/*Boolean*/ = false; // if false, get size from first frame
|
|
/*private*/ var sample/*int*/ = 10; // default sample interval for quantizer
|
|
|
|
/**
|
|
* Sets the delay time between each frame, or changes it for subsequent frames
|
|
* (applies to last frame added)
|
|
* int delay time in milliseconds
|
|
* @param ms
|
|
*/
|
|
|
|
var setDelay = exports.setDelay = function setDelay(ms/*int*/)/*void*/
|
|
{
|
|
|
|
delay = Math.round(ms / 10);
|
|
|
|
}
|
|
|
|
/**
|
|
* Sets the GIF frame disposal code for the last added frame and any
|
|
*
|
|
* subsequent frames. Default is 0 if no transparent color has been set,
|
|
* otherwise 2.
|
|
* @param code
|
|
* int disposal code.
|
|
*/
|
|
|
|
var setDispose = exports.setDispose = function setDispose(code/*int*/)/*void*/
|
|
{
|
|
|
|
if (code >= 0) dispose = code;
|
|
|
|
}
|
|
|
|
/**
|
|
* Sets the number of times the set of GIF frames should be played. Default is
|
|
* 1; 0 means play indefinitely. Must be invoked before the first image is
|
|
* added.
|
|
*
|
|
* @param iter
|
|
* int number of iterations.
|
|
* @return
|
|
*/
|
|
|
|
var setRepeat = exports.setRepeat = function setRepeat(iter/*int*/)/*void*/
|
|
{
|
|
|
|
if (iter >= 0) repeat = iter;
|
|
|
|
}
|
|
|
|
/**
|
|
* Sets the transparent color for the last added frame and any subsequent
|
|
* frames. Since all colors are subject to modification in the quantization
|
|
* process, the color in the final palette for each frame closest to the given
|
|
* color becomes the transparent color for that frame. May be set to null to
|
|
* indicate no transparent color.
|
|
* @param
|
|
* Color to be treated as transparent on display.
|
|
*/
|
|
|
|
var setTransparent = exports.setTransparent = function setTransparent(c/*Number*/)/*void*/
|
|
{
|
|
|
|
transparent = c;
|
|
|
|
}
|
|
|
|
/**
|
|
* The addFrame method takes an incoming BitmapData object to create each frames
|
|
* @param
|
|
* BitmapData object to be treated as a GIF's frame
|
|
*/
|
|
|
|
var addFrame = exports.addFrame = function addFrame(im/*BitmapData*/, is_imageData)/*Boolean*/
|
|
{
|
|
|
|
if ((im == null) || !started || out == null)
|
|
{
|
|
throw new Error ("Please call start method before calling addFrame");
|
|
return false;
|
|
}
|
|
|
|
var ok/*Boolean*/ = true;
|
|
|
|
try {
|
|
if(!is_imageData){
|
|
image = im.getImageData(0,0, im.canvas.width, im.canvas.height).data;
|
|
if (!sizeSet) setSize(im.canvas.width, im.canvas.height);
|
|
}else{
|
|
image = im;
|
|
}
|
|
getImagePixels(); // convert to correct format if necessary
|
|
analyzePixels(); // build color table & map pixels
|
|
|
|
if (firstFrame)
|
|
{
|
|
writeLSD(); // logical screen descriptior
|
|
writePalette(); // global color table
|
|
if (repeat >= 0)
|
|
{
|
|
// use NS app extension to indicate reps
|
|
writeNetscapeExt();
|
|
}
|
|
}
|
|
|
|
writeGraphicCtrlExt(); // write graphic control extension
|
|
writeImageDesc(); // image descriptor
|
|
if (!firstFrame) writePalette(); // local color table
|
|
writePixels(); // encode and write pixel data
|
|
firstFrame = false;
|
|
} catch (e/*Error*/) {
|
|
ok = false;
|
|
}
|
|
|
|
return ok;
|
|
|
|
}
|
|
|
|
/**
|
|
* Adds final trailer to the GIF stream, if you don't call the finish method
|
|
* the GIF stream will not be valid.
|
|
*/
|
|
|
|
var finish = exports.finish = function finish()/*Boolean*/
|
|
{
|
|
if (!started) return false;
|
|
var ok/*Boolean*/ = true;
|
|
started = false;
|
|
try {
|
|
out.writeByte(0x3b); // gif trailer
|
|
} catch (e/*Error*/) {
|
|
ok = false;
|
|
}
|
|
|
|
return ok;
|
|
|
|
}
|
|
|
|
/**
|
|
* Resets some members so that a new stream can be started.
|
|
* This method is actually called by the start method
|
|
*/
|
|
|
|
var reset = function reset ( )/*void*/
|
|
{
|
|
|
|
// reset for subsequent use
|
|
transIndex = 0;
|
|
image = null;
|
|
pixels = null;
|
|
indexedPixels = null;
|
|
colorTab = null;
|
|
closeStream = false;
|
|
firstFrame = true;
|
|
|
|
}
|
|
|
|
/**
|
|
* * Sets frame rate in frames per second. Equivalent to
|
|
* <code>setDelay(1000/fps)</code>.
|
|
* @param fps
|
|
* float frame rate (frames per second)
|
|
*/
|
|
|
|
var setFrameRate = exports.setFrameRate = function setFrameRate(fps/*Number*/)/*void*/
|
|
{
|
|
|
|
if (fps != 0xf) delay = Math.round(100/fps);
|
|
|
|
}
|
|
|
|
/**
|
|
* Sets quality of color quantization (conversion of images to the maximum 256
|
|
* colors allowed by the GIF specification). Lower values (minimum = 1)
|
|
* produce better colors, but slow processing significantly. 10 is the
|
|
* default, and produces good color mapping at reasonable speeds. Values
|
|
* greater than 20 do not yield significant improvements in speed.
|
|
* @param quality
|
|
* int greater than 0.
|
|
* @return
|
|
*/
|
|
|
|
var setQuality = exports.setQuality = function setQuality(quality/*int*/)/*void*/
|
|
{
|
|
|
|
if (quality < 1) quality = 1;
|
|
sample = quality;
|
|
|
|
}
|
|
|
|
/**
|
|
* Sets the GIF frame size. The default size is the size of the first frame
|
|
* added if this method is not invoked.
|
|
* @param w
|
|
* int frame width.
|
|
* @param h
|
|
* int frame width.
|
|
*/
|
|
|
|
var setSize = exports.setSize = function setSize(w/*int*/, h/*int*/)/*void*/
|
|
{
|
|
|
|
if (started && !firstFrame) return;
|
|
width = w;
|
|
height = h;
|
|
if (width < 1)width = 320;
|
|
if (height < 1)height = 240;
|
|
sizeSet = true
|
|
|
|
}
|
|
|
|
/**
|
|
* Initiates GIF file creation on the given stream.
|
|
* @param os
|
|
* OutputStream on which GIF images are written.
|
|
* @return false if initial write failed.
|
|
*
|
|
*/
|
|
|
|
var start = exports.start = function start()/*Boolean*/
|
|
{
|
|
|
|
reset();
|
|
var ok/*Boolean*/ = true;
|
|
closeStream = false;
|
|
out = new ByteArray;
|
|
try {
|
|
out.writeUTFBytes("GIF89a"); // header
|
|
} catch (e/*Error*/) {
|
|
ok = false;
|
|
}
|
|
|
|
return started = ok;
|
|
|
|
}
|
|
|
|
var cont = exports.cont = function cont()/*Boolean*/
|
|
{
|
|
|
|
reset();
|
|
var ok/*Boolean*/ = true;
|
|
closeStream = false;
|
|
out = new ByteArray;
|
|
|
|
return started = ok;
|
|
|
|
}
|
|
|
|
/**
|
|
* Analyzes image colors and creates color map.
|
|
*/
|
|
|
|
var analyzePixels = function analyzePixels()/*void*/
|
|
{
|
|
|
|
var len/*int*/ = pixels.length;
|
|
var nPix/*int*/ = len / 3;
|
|
indexedPixels = [];
|
|
var nq/*NeuQuant*/ = new NeuQuant(pixels, len, sample);
|
|
// initialize quantizer
|
|
colorTab = nq.process(); // create reduced palette
|
|
// map image pixels to new palette
|
|
var k/*int*/ = 0;
|
|
for (var j/*int*/ = 0; j < nPix; j++) {
|
|
var index/*int*/ = nq.map(pixels[k++] & 0xff, pixels[k++] & 0xff, pixels[k++] & 0xff);
|
|
usedEntry[index] = true;
|
|
indexedPixels[j] = index;
|
|
}
|
|
pixels = null;
|
|
colorDepth = 8;
|
|
palSize = 7;
|
|
// get closest match to transparent color if specified
|
|
if (transparent != null) {
|
|
transIndex = findClosest(transparent);
|
|
|
|
var r = colorTab[transIndex*3];
|
|
var g = colorTab[transIndex*3+1];
|
|
var b = colorTab[transIndex*3+2];
|
|
var trans_indices = [];
|
|
for (var i=0; i<colorTab.length; i+=3)
|
|
{
|
|
var index = i / 3;
|
|
if (!usedEntry[index]) continue;
|
|
if (colorTab[i] == r && colorTab[i+1] == g && colorTab[i+2] == b)
|
|
trans_indices.push(index);
|
|
}
|
|
for (var i=0; i<indexedPixels.length; i++) {
|
|
if (trans_indices.indexOf(indexedPixels[i]) >= 0) {
|
|
indexedPixels[i] = transIndex;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns index of palette color closest to c
|
|
*
|
|
*/
|
|
|
|
var findClosest = function findClosest(c/*Number*/)/*int*/
|
|
{
|
|
|
|
if (colorTab == null) return -1;
|
|
var r/*int*/ = (c & 0xFF0000) >> 16;
|
|
var g/*int*/ = (c & 0x00FF00) >> 8;
|
|
var b/*int*/ = (c & 0x0000FF);
|
|
var minpos/*int*/ = 0;
|
|
var dmin/*int*/ = 256 * 256 * 256;
|
|
var len/*int*/ = colorTab.length;
|
|
|
|
for (var i/*int*/ = 0; i < len;) {
|
|
var dr/*int*/ = r - (colorTab[i++] & 0xff);
|
|
var dg/*int*/ = g - (colorTab[i++] & 0xff);
|
|
var db/*int*/ = b - (colorTab[i] & 0xff);
|
|
var d/*int*/ = dr * dr + dg * dg + db * db;
|
|
var index/*int*/ = i / 3;
|
|
if (usedEntry[index] && (d < dmin)) {
|
|
dmin = d;
|
|
minpos = index;
|
|
}
|
|
i++;
|
|
}
|
|
return minpos;
|
|
|
|
}
|
|
|
|
/**
|
|
* Extracts image pixels into byte array "pixels
|
|
*/
|
|
|
|
var getImagePixels = function getImagePixels()/*void*/
|
|
{
|
|
|
|
var w/*int*/ = width;
|
|
var h/*int*/ = height;
|
|
pixels = [];
|
|
var data = image;
|
|
var count/*int*/ = 0;
|
|
|
|
for ( var i/*int*/ = 0; i < h; i++ )
|
|
{
|
|
|
|
for (var j/*int*/ = 0; j < w; j++ )
|
|
{
|
|
|
|
var b = (i*w*4)+j*4;
|
|
pixels[count++] = data[b];
|
|
pixels[count++] = data[b+1];
|
|
pixels[count++] = data[b+2];
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
* Writes Graphic Control Extension
|
|
*/
|
|
|
|
var writeGraphicCtrlExt = function writeGraphicCtrlExt()/*void*/
|
|
{
|
|
out.writeByte(0x21); // extension introducer
|
|
out.writeByte(0xf9); // GCE label
|
|
out.writeByte(4); // data block size
|
|
var transp/*int*/
|
|
var disp/*int*/;
|
|
if (transparent == null) {
|
|
transp = 0;
|
|
disp = 0; // dispose = no action
|
|
} else {
|
|
transp = 1;
|
|
disp = 2; // force clear if using transparent color
|
|
}
|
|
if (dispose >= 0) {
|
|
disp = dispose & 7; // user override
|
|
}
|
|
disp <<= 2;
|
|
// packed fields
|
|
out.writeByte(0 | // 1:3 reserved
|
|
disp | // 4:6 disposal
|
|
0 | // 7 user input - 0 = none
|
|
transp); // 8 transparency flag
|
|
|
|
WriteShort(delay); // delay x 1/100 sec
|
|
out.writeByte(transIndex); // transparent color index
|
|
out.writeByte(0); // block terminator
|
|
|
|
}
|
|
|
|
/**
|
|
* Writes Image Descriptor
|
|
*/
|
|
|
|
var writeImageDesc = function writeImageDesc()/*void*/
|
|
{
|
|
|
|
out.writeByte(0x2c); // image separator
|
|
WriteShort(0); // image position x,y = 0,0
|
|
WriteShort(0);
|
|
WriteShort(width); // image size
|
|
WriteShort(height);
|
|
|
|
// packed fields
|
|
if (firstFrame) {
|
|
// no LCT - GCT is used for first (or only) frame
|
|
out.writeByte(0);
|
|
} else {
|
|
// specify normal LCT
|
|
out.writeByte(0x80 | // 1 local color table 1=yes
|
|
0 | // 2 interlace - 0=no
|
|
0 | // 3 sorted - 0=no
|
|
0 | // 4-5 reserved
|
|
palSize); // 6-8 size of color table
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Writes Logical Screen Descriptor
|
|
*/
|
|
|
|
var writeLSD = function writeLSD()/*void*/
|
|
{
|
|
|
|
// logical screen size
|
|
WriteShort(width);
|
|
WriteShort(height);
|
|
// packed fields
|
|
out.writeByte((0x80 | // 1 : global color table flag = 1 (gct used)
|
|
0x70 | // 2-4 : color resolution = 7
|
|
0x00 | // 5 : gct sort flag = 0
|
|
palSize)); // 6-8 : gct size
|
|
|
|
out.writeByte(0); // background color index
|
|
out.writeByte(0); // pixel aspect ratio - assume 1:1
|
|
|
|
}
|
|
|
|
/**
|
|
* Writes Netscape application extension to define repeat count.
|
|
*/
|
|
|
|
var writeNetscapeExt = function writeNetscapeExt()/*void*/
|
|
{
|
|
|
|
out.writeByte(0x21); // extension introducer
|
|
out.writeByte(0xff); // app extension label
|
|
out.writeByte(11); // block size
|
|
out.writeUTFBytes("NETSCAPE" + "2.0"); // app id + auth code
|
|
out.writeByte(3); // sub-block size
|
|
out.writeByte(1); // loop sub-block id
|
|
WriteShort(repeat); // loop count (extra iterations, 0=repeat forever)
|
|
out.writeByte(0); // block terminator
|
|
|
|
}
|
|
|
|
/**
|
|
* Writes color table
|
|
*/
|
|
|
|
var writePalette = function writePalette()/*void*/
|
|
{
|
|
out.writeBytes(colorTab);
|
|
var n/*int*/ = (3 * 256) - colorTab.length;
|
|
for (var i/*int*/ = 0; i < n; i++) out.writeByte(0);
|
|
|
|
}
|
|
|
|
var WriteShort = function WriteShort (pValue/*int*/)/*void*/
|
|
{
|
|
|
|
out.writeByte( pValue & 0xFF );
|
|
out.writeByte( (pValue >> 8) & 0xFF);
|
|
|
|
}
|
|
|
|
/**
|
|
* Encodes and writes pixel data
|
|
*/
|
|
|
|
var writePixels = function writePixels()/*void*/
|
|
{
|
|
|
|
var myencoder/*LZWEncoder*/ = new LZWEncoder(width, height, indexedPixels, colorDepth);
|
|
myencoder.encode(out);
|
|
|
|
}
|
|
|
|
/**
|
|
* retrieves the GIF stream
|
|
*/
|
|
var stream = exports.stream = function stream ( )/*ByteArray*/
|
|
{
|
|
|
|
return out;
|
|
|
|
}
|
|
|
|
var setProperties = exports.setProperties = function setProperties(has_start, is_first){
|
|
started = has_start;
|
|
firstFrame = is_first;
|
|
//out = new ByteArray; //??
|
|
}
|
|
|
|
return exports
|
|
|
|
}
|