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GIFEncoder from jsgif
Acest script nu ar trebui instalat direct. Aceasta este o bibliotecă pentru alte scripturi care este inclusă prin directiva meta a // @require https://update.greasyfork.org/scripts/428487/1028787/gif-encoder.js
/**
* 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)
* @author Kevin Kwok (JavaScript version - https://github.com/antimatter15/jsgif)
* @version 0.1 AS3 implementation
*/
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 = {};
var width; // image size
var height;
var transparent = null; // transparent color if given
var transIndex; // transparent index in color table
var repeat = -1; // no repeat
var delay = 0; // frame delay (hundredths)
var started = false; // ready to output frames
var out;
var image; // current frame
var pixels; // BGR byte array from frame
var indexedPixels; // converted frame indexed to palette
var colorDepth; // number of bit planes
var colorTab; // RGB palette
var usedEntry = []; // active palette entries
var palSize = 7; // color table size (bits-1)
var dispose = -1; // disposal code (-1 = use default)
var closeStream = false; // close stream when finished
var firstFrame = true;
var sizeSet = false; // if false, get size from first frame
var sample = 10; // default sample interval for quantizer
var comment = "Generated by jsgif (https://github.com/antimatter15/jsgif/)"; // default comment for generated gif
/**
* 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) {
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) {
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) {
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) {
transparent = c;
};
/**
* Sets the comment for the block comment
* @param
* string to be insterted as comment
*/
var setComment = exports.setComment = function setComment(c) {
comment = 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, is_imageData) {
if ((im === null) || !started || out === null) {
throw new Error("Please call start method before calling addFrame");
}
var ok = 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 {
if(im instanceof ImageData) {
image = im.data;
if(!sizeset || width!=im.width || height!=im.height) {
setSize(im.width,im.height);
} else {
}
} else if(im instanceof Uint8ClampedArray) {
if(im.length==(width*height*4)) {
image=im;
} else {
console.log("Please set the correct size: ImageData length mismatch");
ok=false;
}
} else {
console.log("Please provide correct input");
ok=false;
}
}
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
if (comment !== '') {
writeCommentExt(); // write comment extension
}
writeImageDesc(); // image descriptor
if (!firstFrame) writePalette(); // local color table
writePixels(); // encode and write pixel data
firstFrame = false;
} catch (e) {
ok = false;
}
return ok;
};
/**
* @description: Downloads the encoded gif with the given name
* No need of any conversion from the stream data (out) to base64
* Solves the issue of large file sizes when there are more frames
* and does not involve in creation of any temporary data in the process
* so no wastage of memory, and speeds up the process of downloading
* to just calling this function.
* @parameter {String} filename filename used for downloading the gif
*/
var download = exports.download = function download(filename) {
if(out===null || closeStream==false) {
console.log("Please call start method and add frames and call finish method before calling download");
} else {
filename= filename !== undefined ? ( filename.endsWith(".gif")? filename: filename+".gif" ): "download.gif";
var templink = document.createElement("a");
templink.download=filename;
templink.href= URL.createObjectURL(new Blob([new Uint8Array(out.bin)], {type : "image/gif" } ));
templink.click();
}
}
/**
* 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() {
if (!started) return false;
var ok = true;
started = false;
try {
out.writeByte(0x3b); // gif trailer
closeStream=true;
} catch (e) {
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() {
// 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) {
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) {
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, h) {
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() {
reset();
var ok = true;
closeStream = false;
out = new ByteArray();
try {
out.writeUTFBytes("GIF89a"); // header
} catch (e) {
ok = false;
}
return started = ok;
};
var cont = exports.cont = function cont() {
reset();
var ok = true;
closeStream = false;
out = new ByteArray();
return started = ok;
};
/**
* Analyzes image colors and creates color map.
*/
var analyzePixels = function analyzePixels() {
var len = pixels.length;
var nPix = len / 3;
indexedPixels = [];
var nq = new NeuQuant(pixels, len, sample);
// initialize quantizer
colorTab = nq.process(); // create reduced palette
// map image pixels to new palette
var k = 0;
for (var j = 0; j < nPix; j++) {
var index = 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);
}
};
/**
* Returns index of palette color closest to c
*/
var findClosest = function findClosest(c) {
if (colorTab === null) return -1;
var r = (c & 0xFF0000) >> 16;
var g = (c & 0x00FF00) >> 8;
var b = (c & 0x0000FF);
var minpos = 0;
var dmin = 256 * 256 * 256;
var len = colorTab.length;
for (var i = 0; i < len;) {
var dr = r - (colorTab[i++] & 0xff);
var dg = g - (colorTab[i++] & 0xff);
var db = b - (colorTab[i] & 0xff);
var d = dr * dr + dg * dg + db * db;
var index = 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() {
var w = width;
var h = height;
pixels = [];
var data = image;
var count = 0;
for (var i = 0; i < h; i++) {
for (var j = 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() {
out.writeByte(0x21); // extension introducer
out.writeByte(0xf9); // GCE label
out.writeByte(4); // data block size
var transp;
var disp;
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 Comment Extention
*/
var writeCommentExt = function writeCommentExt() {
out.writeByte(0x21); // extension introducer
out.writeByte(0xfe); // comment label
out.writeByte(comment.length); // Block Size (s)
out.writeUTFBytes(comment);
out.writeByte(0); // block terminator
};
/**
* Writes Image Descriptor
*/
var writeImageDesc = function writeImageDesc() {
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() {
// 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() {
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() {
out.writeBytes(colorTab);
var n = (3 * 256) - colorTab.length;
for (var i = 0; i < n; i++) out.writeByte(0);
};
var WriteShort = function WriteShort(pValue) {
out.writeByte(pValue & 0xFF);
out.writeByte((pValue >> 8) & 0xFF);
};
/**
* Encodes and writes pixel data
*/
var writePixels = function writePixels() {
var myencoder = new LZWEncoder(width, height, indexedPixels, colorDepth);
myencoder.encode(out);
};
/**
* Retrieves the GIF stream
*/
var stream = exports.stream = function stream() {
return out;
};
var setProperties = exports.setProperties = function setProperties(has_start, is_first) {
started = has_start;
firstFrame = is_first;
};
return exports;
};