npm_modules: Fork bower_components into Polymer 0.4.0 and 0.5.0 versions

bower_components/gif.js/src/GIFEncoder.js

-/*
-  GIFEncoder.js
-
-  Authors
-  Kevin Weiner (original Java version - kweiner@fmsware.com)
-  Thibault Imbert (AS3 version - bytearray.org)
-  Johan Nordberg (JS version - code@johan-nordberg.com)
-*/
-
-var NeuQuant = require('./TypedNeuQuant.js');
-var LZWEncoder = require('./LZWEncoder.js');
-
-function ByteArray() {
-  this.page = -1;
-  this.pages = [];
-  this.newPage();
-}
-
-ByteArray.pageSize = 4096;
-ByteArray.charMap = {};
-
-for (var i = 0; i < 256; i++)
-  ByteArray.charMap[i] = String.fromCharCode(i);
-
-ByteArray.prototype.newPage = function() {
-  this.pages[++this.page] = new Uint8Array(ByteArray.pageSize);
-  this.cursor = 0;
-};
-
-ByteArray.prototype.getData = function() {
-  var rv = '';
-  for (var p = 0; p < this.pages.length; p++) {
-    for (var i = 0; i < ByteArray.pageSize; i++) {
-      rv += ByteArray.charMap[this.pages[p][i]];
-    }
-  }
-  return rv;
-};
-
-ByteArray.prototype.writeByte = function(val) {
-  if (this.cursor >= ByteArray.pageSize) this.newPage();
-  this.pages[this.page][this.cursor++] = 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]);
-};
-
-function GIFEncoder(width, height) {
-  // image size
-  this.width = ~~width;
-  this.height = ~~height;
-
-  // transparent color if given
-  this.transparent = null;
-
-  // transparent index in color table
-  this.transIndex = 0;
-
-  // -1 = no repeat, 0 = forever. anything else is repeat count
-  this.repeat = -1;
-
-  // frame delay (hundredths)
-  this.delay = 0;
-
-  this.image = null; // current frame
-  this.pixels = null; // BGR byte array from frame
-  this.indexedPixels = null; // converted frame indexed to palette
-  this.colorDepth = null; // number of bit planes
-  this.colorTab = null; // RGB palette
-  this.usedEntry = new Array(); // active palette entries
-  this.palSize = 7; // color table size (bits-1)
-  this.dispose = -1; // disposal code (-1 = use default)
-  this.firstFrame = true;
-  this.sample = 10; // default sample interval for quantizer
-
-  this.out = new ByteArray();
-}
-
-/*
-  Sets the delay time between each frame, or changes it for subsequent frames
-  (applies to last frame added)
-*/
-GIFEncoder.prototype.setDelay = function(milliseconds) {
-  this.delay = Math.round(milliseconds / 10);
-};
-
-/*
-  Sets frame rate in frames per second.
-*/
-GIFEncoder.prototype.setFrameRate = function(fps) {
-  this.delay = Math.round(100 / fps);
-};
-
-/*
-  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.
-*/
-GIFEncoder.prototype.setDispose = function(disposalCode) {
-  if (disposalCode >= 0) this.dispose = disposalCode;
-};
-
-/*
-  Sets the number of times the set of GIF frames should be played.
-
-  -1 = play once
-  0 = repeat indefinitely
-
-  Default is -1
-
-  Must be invoked before the first image is added
-*/
-
-GIFEncoder.prototype.setRepeat = function(repeat) {
-  this.repeat = repeat;
-};
-
-/*
-  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.
-*/
-GIFEncoder.prototype.setTransparent = function(color) {
-  this.transparent = color;
-};
-
-/*
-  Adds next GIF frame. The frame is not written immediately, but is
-  actually deferred until the next frame is received so that timing
-  data can be inserted.  Invoking finish() flushes all frames.
-*/
-GIFEncoder.prototype.addFrame = function(imageData) {
-  this.image = imageData;
-
-  this.getImagePixels(); // convert to correct format if necessary
-  this.analyzePixels(); // build color table & map pixels
-
-  if (this.firstFrame) {
-    this.writeLSD(); // logical screen descriptior
-    this.writePalette(); // global color table
-    if (this.repeat >= 0) {
-      // use NS app extension to indicate reps
-      this.writeNetscapeExt();
-    }
-  }
-
-  this.writeGraphicCtrlExt(); // write graphic control extension
-  this.writeImageDesc(); // image descriptor
-  if (!this.firstFrame) this.writePalette(); // local color table
-  this.writePixels(); // encode and write pixel data
-
-  this.firstFrame = false;
-};
-
-/*
-  Adds final trailer to the GIF stream, if you don't call the finish method
-  the GIF stream will not be valid.
-*/
-GIFEncoder.prototype.finish = function() {
-  this.out.writeByte(0x3b); // gif trailer
-};
-
-/*
-  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.
-*/
-GIFEncoder.prototype.setQuality = function(quality) {
-  if (quality < 1) quality = 1;
-  this.sample = quality;
-};
-
-/*
-  Writes GIF file header
-*/
-GIFEncoder.prototype.writeHeader = function() {
-  this.out.writeUTFBytes("GIF89a");
-};
-
-/*
-  Analyzes current frame colors and creates color map.
-*/
-GIFEncoder.prototype.analyzePixels = function() {
-  var len = this.pixels.length;
-  var nPix = len / 3;
-
-  this.indexedPixels = new Uint8Array(nPix);
-
-  var imgq = new NeuQuant(this.pixels, this.sample);
-  imgq.buildColormap(); // create reduced palette
-  this.colorTab = imgq.getColormap();
-
-  // map image pixels to new palette
-  var k = 0;
-  for (var j = 0; j < nPix; j++) {
-    var index = imgq.lookupRGB(
-      this.pixels[k++] & 0xff,
-      this.pixels[k++] & 0xff,
-      this.pixels[k++] & 0xff
-    );
-    this.usedEntry[index] = true;
-    this.indexedPixels[j] = index;
-  }
-
-  this.pixels = null;
-  this.colorDepth = 8;
-  this.palSize = 7;
-
-  // get closest match to transparent color if specified
-  if (this.transparent !== null) {
-    this.transIndex = this.findClosest(this.transparent);
-  }
-};
-
-/*
-  Returns index of palette color closest to c
-*/
-GIFEncoder.prototype.findClosest = function(c) {
-  if (this.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 = this.colorTab.length;
-
-  for (var i = 0; i < len;) {
-    var dr = r - (this.colorTab[i++] & 0xff);
-    var dg = g - (this.colorTab[i++] & 0xff);
-    var db = b - (this.colorTab[i] & 0xff);
-    var d = dr * dr + dg * dg + db * db;
-    var index = parseInt(i / 3);
-    if (this.usedEntry[index] && (d < dmin)) {
-      dmin = d;
-      minpos = index;
-    }
-    i++;
-  }
-
-  return minpos;
-};
-
-/*
-  Extracts image pixels into byte array pixels
-  (removes alphachannel from canvas imagedata)
-*/
-GIFEncoder.prototype.getImagePixels = function() {
-  var w = this.width;
-  var h = this.height;
-  this.pixels = new Uint8Array(w * h * 3);
-
-  var data = this.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;
-      this.pixels[count++] = data[b];
-      this.pixels[count++] = data[b+1];
-      this.pixels[count++] = data[b+2];
-    }
-  }
-};
-
-/*
-  Writes Graphic Control Extension
-*/
-GIFEncoder.prototype.writeGraphicCtrlExt = function() {
-  this.out.writeByte(0x21); // extension introducer
-  this.out.writeByte(0xf9); // GCE label
-  this.out.writeByte(4); // data block size
-
-  var transp, disp;
-  if (this.transparent === null) {
-    transp = 0;
-    disp = 0; // dispose = no action
-  } else {
-    transp = 1;
-    disp = 2; // force clear if using transparent color
-  }
-
-  if (this.dispose >= 0) {
-    disp = dispose & 7; // user override
-  }
-  disp <<= 2;
-
-  // packed fields
-  this.out.writeByte(
-    0 | // 1:3 reserved
-    disp | // 4:6 disposal
-    0 | // 7 user input - 0 = none
-    transp // 8 transparency flag
-  );
-
-  this.writeShort(this.delay); // delay x 1/100 sec
-  this.out.writeByte(this.transIndex); // transparent color index
-  this.out.writeByte(0); // block terminator
-};
-
-/*
-  Writes Image Descriptor
-*/
-GIFEncoder.prototype.writeImageDesc = function() {
-  this.out.writeByte(0x2c); // image separator
-  this.writeShort(0); // image position x,y = 0,0
-  this.writeShort(0);
-  this.writeShort(this.width); // image size
-  this.writeShort(this.height);
-
-  // packed fields
-  if (this.firstFrame) {
-    // no LCT - GCT is used for first (or only) frame
-    this.out.writeByte(0);
-  } else {
-    // specify normal LCT
-    this.out.writeByte(
-      0x80 | // 1 local color table 1=yes
-      0 | // 2 interlace - 0=no
-      0 | // 3 sorted - 0=no
-      0 | // 4-5 reserved
-      this.palSize // 6-8 size of color table
-    );
-  }
-};
-
-/*
-  Writes Logical Screen Descriptor
-*/
-GIFEncoder.prototype.writeLSD = function() {
-  // logical screen size
-  this.writeShort(this.width);
-  this.writeShort(this.height);
-
-  // packed fields
-  this.out.writeByte(
-    0x80 | // 1 : global color table flag = 1 (gct used)
-    0x70 | // 2-4 : color resolution = 7
-    0x00 | // 5 : gct sort flag = 0
-    this.palSize // 6-8 : gct size
-  );
-
-  this.out.writeByte(0); // background color index
-  this.out.writeByte(0); // pixel aspect ratio - assume 1:1
-};
-
-/*
-  Writes Netscape application extension to define repeat count.
-*/
-GIFEncoder.prototype.writeNetscapeExt = function() {
-  this.out.writeByte(0x21); // extension introducer
-  this.out.writeByte(0xff); // app extension label
-  this.out.writeByte(11); // block size
-  this.out.writeUTFBytes('NETSCAPE2.0'); // app id + auth code
-  this.out.writeByte(3); // sub-block size
-  this.out.writeByte(1); // loop sub-block id
-  this.writeShort(this.repeat); // loop count (extra iterations, 0=repeat forever)
-  this.out.writeByte(0); // block terminator
-};
-
-/*
-  Writes color table
-*/
-GIFEncoder.prototype.writePalette = function() {
-  this.out.writeBytes(this.colorTab);
-  var n = (3 * 256) - this.colorTab.length;
-  for (var i = 0; i < n; i++)
-    this.out.writeByte(0);
-};
-
-GIFEncoder.prototype.writeShort = function(pValue) {
-  this.out.writeByte(pValue & 0xFF);
-  this.out.writeByte((pValue >> 8) & 0xFF);
-};
-
-/*
-  Encodes and writes pixel data
-*/
-GIFEncoder.prototype.writePixels = function() {
-  var enc = new LZWEncoder(this.width, this.height, this.indexedPixels, this.colorDepth);
-  enc.encode(this.out);
-};
-
-/*
-  Retrieves the GIF stream
-*/
-GIFEncoder.prototype.stream = function() {
-  return this.out;
-};
-
-module.exports = GIFEncoder;