997 lines
36 KiB
JavaScript
997 lines
36 KiB
JavaScript
/*
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SuperGif
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Example usage:
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<img src="./example1_preview.gif" rel:animated_src="./example1.gif" width="360" height="360" rel:auto_play="1" />
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<script type="text/javascript">
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$$('img').each(function (img_tag) {
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if (/.*\.gif/.test(img_tag.src)) {
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var rub = new SuperGif({ gif: img_tag } );
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rub.load();
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}
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});
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</script>
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Image tag attributes:
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rel:animated_src - If this url is specified, it's loaded into the player instead of src.
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This allows a preview frame to be shown until animated gif data is streamed into the canvas
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rel:auto_play - Defaults to 1 if not specified. If set to zero, a call to the play() method is needed
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Constructor options args
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gif Required. The DOM element of an img tag.
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loop_mode Optional. Setting this to false will force disable looping of the gif.
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auto_play Optional. Same as the rel:auto_play attribute above, this arg overrides the img tag info.
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max_width Optional. Scale images over max_width down to max_width. Helpful with mobile.
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on_end Optional. Add a callback for when the gif reaches the end of a single loop (one iteration). The first argument passed will be the gif HTMLElement.
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loop_delay Optional. The amount of time to pause (in ms) after each single loop (iteration).
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draw_while_loading Optional. Determines whether the gif will be drawn to the canvas whilst it is loaded.
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show_progress_bar Optional. Only applies when draw_while_loading is set to true.
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Instance methods
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// loading
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load( callback ) Loads the gif specified by the src or rel:animated_src sttributie of the img tag into a canvas element and then calls callback if one is passed
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load_url( src, callback ) Loads the gif file specified in the src argument into a canvas element and then calls callback if one is passed
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// play controls
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play - Start playing the gif
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pause - Stop playing the gif
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move_to(i) - Move to frame i of the gif
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move_relative(i) - Move i frames ahead (or behind if i < 0)
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// getters
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get_canvas The canvas element that the gif is playing in. Handy for assigning event handlers to.
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get_playing Whether or not the gif is currently playing
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get_loading Whether or not the gif has finished loading/parsing
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get_auto_play Whether or not the gif is set to play automatically
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get_length The number of frames in the gif
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get_current_frame The index of the currently displayed frame of the gif
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For additional customization (viewport inside iframe) these params may be passed:
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c_w, c_h - width and height of canvas
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vp_t, vp_l, vp_ w, vp_h - top, left, width and height of the viewport
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A bonus: few articles to understand what is going on
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http://enthusiasms.org/post/16976438906
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http://www.matthewflickinger.com/lab/whatsinagif/bits_and_bytes.asp
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http://humpy77.deviantart.com/journal/Frame-Delay-Times-for-Animated-GIFs-214150546
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*/
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(function (root, factory) {
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if (typeof define === 'function' && define.amd) {
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define([], factory);
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} else if (typeof exports === 'object') {
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module.exports = factory();
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} else {
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root.SuperGif = factory();
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}
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}(this, function () {
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// Generic functions
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var bitsToNum = function (ba) {
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return ba.reduce(function (s, n) {
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return s * 2 + n;
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}, 0);
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};
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var byteToBitArr = function (bite) {
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var a = [];
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for (var i = 7; i >= 0; i--) {
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a.push( !! (bite & (1 << i)));
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}
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return a;
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};
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// Stream
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/**
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* @constructor
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*/
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// Make compiler happy.
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var Stream = function (data) {
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this.data = data;
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this.len = this.data.length;
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this.pos = 0;
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this.readByte = function () {
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if (this.pos >= this.data.length) {
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throw new Error('Attempted to read past end of stream.');
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}
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if (data instanceof Uint8Array)
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return data[this.pos++];
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else
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return data.charCodeAt(this.pos++) & 0xFF;
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};
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this.readBytes = function (n) {
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var bytes = [];
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for (var i = 0; i < n; i++) {
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bytes.push(this.readByte());
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}
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return bytes;
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};
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this.read = function (n) {
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var s = '';
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for (var i = 0; i < n; i++) {
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s += String.fromCharCode(this.readByte());
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}
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return s;
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};
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this.readUnsigned = function () { // Little-endian.
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var a = this.readBytes(2);
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return (a[1] << 8) + a[0];
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};
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};
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var lzwDecode = function (minCodeSize, data) {
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// TODO: Now that the GIF parser is a bit different, maybe this should get an array of bytes instead of a String?
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var pos = 0; // Maybe this streaming thing should be merged with the Stream?
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var readCode = function (size) {
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var code = 0;
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for (var i = 0; i < size; i++) {
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if (data.charCodeAt(pos >> 3) & (1 << (pos & 7))) {
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code |= 1 << i;
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}
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pos++;
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}
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return code;
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};
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var output = [];
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var clearCode = 1 << minCodeSize;
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var eoiCode = clearCode + 1;
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var codeSize = minCodeSize + 1;
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var dict = [];
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var clear = function () {
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dict = [];
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codeSize = minCodeSize + 1;
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for (var i = 0; i < clearCode; i++) {
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dict[i] = [i];
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}
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dict[clearCode] = [];
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dict[eoiCode] = null;
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};
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var code;
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var last;
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while (true) {
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last = code;
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code = readCode(codeSize);
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if (code === clearCode) {
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clear();
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continue;
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}
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if (code === eoiCode) break;
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if (code < dict.length) {
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if (last !== clearCode) {
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dict.push(dict[last].concat(dict[code][0]));
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}
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}
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else {
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if (code !== dict.length) throw new Error('Invalid LZW code.');
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dict.push(dict[last].concat(dict[last][0]));
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}
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output.push.apply(output, dict[code]);
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if (dict.length === (1 << codeSize) && codeSize < 12) {
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// If we're at the last code and codeSize is 12, the next code will be a clearCode, and it'll be 12 bits long.
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codeSize++;
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}
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}
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// I don't know if this is technically an error, but some GIFs do it.
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//if (Math.ceil(pos / 8) !== data.length) throw new Error('Extraneous LZW bytes.');
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return output;
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};
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// The actual parsing; returns an object with properties.
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var parseGIF = function (st, handler) {
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handler || (handler = {});
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// LZW (GIF-specific)
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var parseCT = function (entries) { // Each entry is 3 bytes, for RGB.
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var ct = [];
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for (var i = 0; i < entries; i++) {
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ct.push(st.readBytes(3));
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}
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return ct;
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};
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var readSubBlocks = function () {
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var size, data;
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data = '';
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do {
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size = st.readByte();
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data += st.read(size);
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} while (size !== 0);
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return data;
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};
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var parseHeader = function () {
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var hdr = {};
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hdr.sig = st.read(3);
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hdr.ver = st.read(3);
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if (hdr.sig !== 'GIF') throw new Error('Not a GIF file.'); // XXX: This should probably be handled more nicely.
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hdr.width = st.readUnsigned();
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hdr.height = st.readUnsigned();
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var bits = byteToBitArr(st.readByte());
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hdr.gctFlag = bits.shift();
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hdr.colorRes = bitsToNum(bits.splice(0, 3));
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hdr.sorted = bits.shift();
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hdr.gctSize = bitsToNum(bits.splice(0, 3));
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hdr.bgColor = st.readByte();
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hdr.pixelAspectRatio = st.readByte(); // if not 0, aspectRatio = (pixelAspectRatio + 15) / 64
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if (hdr.gctFlag) {
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hdr.gct = parseCT(1 << (hdr.gctSize + 1));
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}
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handler.hdr && handler.hdr(hdr);
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};
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var parseExt = function (block) {
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var parseGCExt = function (block) {
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var blockSize = st.readByte(); // Always 4
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var bits = byteToBitArr(st.readByte());
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block.reserved = bits.splice(0, 3); // Reserved; should be 000.
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block.disposalMethod = bitsToNum(bits.splice(0, 3));
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block.userInput = bits.shift();
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block.transparencyGiven = bits.shift();
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block.delayTime = st.readUnsigned();
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block.transparencyIndex = st.readByte();
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block.terminator = st.readByte();
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handler.gce && handler.gce(block);
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};
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var parseComExt = function (block) {
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block.comment = readSubBlocks();
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handler.com && handler.com(block);
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};
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var parsePTExt = function (block) {
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// No one *ever* uses this. If you use it, deal with parsing it yourself.
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var blockSize = st.readByte(); // Always 12
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block.ptHeader = st.readBytes(12);
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block.ptData = readSubBlocks();
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handler.pte && handler.pte(block);
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};
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var parseAppExt = function (block) {
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var parseNetscapeExt = function (block) {
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var blockSize = st.readByte(); // Always 3
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block.unknown = st.readByte(); // ??? Always 1? What is this?
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block.iterations = st.readUnsigned();
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block.terminator = st.readByte();
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handler.app && handler.app.NETSCAPE && handler.app.NETSCAPE(block);
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};
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var parseUnknownAppExt = function (block) {
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block.appData = readSubBlocks();
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// FIXME: This won't work if a handler wants to match on any identifier.
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handler.app && handler.app[block.identifier] && handler.app[block.identifier](block);
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};
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var blockSize = st.readByte(); // Always 11
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block.identifier = st.read(8);
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block.authCode = st.read(3);
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switch (block.identifier) {
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case 'NETSCAPE':
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parseNetscapeExt(block);
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break;
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default:
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parseUnknownAppExt(block);
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break;
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}
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};
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var parseUnknownExt = function (block) {
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block.data = readSubBlocks();
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handler.unknown && handler.unknown(block);
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};
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block.label = st.readByte();
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switch (block.label) {
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case 0xF9:
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block.extType = 'gce';
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parseGCExt(block);
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break;
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case 0xFE:
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block.extType = 'com';
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parseComExt(block);
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break;
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case 0x01:
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block.extType = 'pte';
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parsePTExt(block);
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break;
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case 0xFF:
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block.extType = 'app';
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parseAppExt(block);
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break;
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default:
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block.extType = 'unknown';
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parseUnknownExt(block);
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break;
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}
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};
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var parseImg = function (img) {
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var deinterlace = function (pixels, width) {
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// Of course this defeats the purpose of interlacing. And it's *probably*
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// the least efficient way it's ever been implemented. But nevertheless...
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var newPixels = new Array(pixels.length);
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var rows = pixels.length / width;
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var cpRow = function (toRow, fromRow) {
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var fromPixels = pixels.slice(fromRow * width, (fromRow + 1) * width);
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newPixels.splice.apply(newPixels, [toRow * width, width].concat(fromPixels));
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};
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// See appendix E.
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var offsets = [0, 4, 2, 1];
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var steps = [8, 8, 4, 2];
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var fromRow = 0;
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for (var pass = 0; pass < 4; pass++) {
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for (var toRow = offsets[pass]; toRow < rows; toRow += steps[pass]) {
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cpRow(toRow, fromRow)
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fromRow++;
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}
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}
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return newPixels;
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};
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img.leftPos = st.readUnsigned();
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img.topPos = st.readUnsigned();
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img.width = st.readUnsigned();
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img.height = st.readUnsigned();
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var bits = byteToBitArr(st.readByte());
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img.lctFlag = bits.shift();
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img.interlaced = bits.shift();
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img.sorted = bits.shift();
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img.reserved = bits.splice(0, 2);
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img.lctSize = bitsToNum(bits.splice(0, 3));
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if (img.lctFlag) {
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img.lct = parseCT(1 << (img.lctSize + 1));
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}
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img.lzwMinCodeSize = st.readByte();
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var lzwData = readSubBlocks();
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img.pixels = lzwDecode(img.lzwMinCodeSize, lzwData);
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if (img.interlaced) { // Move
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img.pixels = deinterlace(img.pixels, img.width);
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}
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handler.img && handler.img(img);
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};
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var parseBlock = function () {
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var block = {};
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block.sentinel = st.readByte();
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switch (String.fromCharCode(block.sentinel)) { // For ease of matching
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case '!':
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block.type = 'ext';
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parseExt(block);
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break;
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case ',':
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block.type = 'img';
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parseImg(block);
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break;
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case ';':
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block.type = 'eof';
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handler.eof && handler.eof(block);
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break;
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default:
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throw new Error('Unknown block: 0x' + block.sentinel.toString(16)); // TODO: Pad this with a 0.
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}
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if (block.type !== 'eof') setTimeout(parseBlock, 0);
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};
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var parse = function () {
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parseHeader();
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setTimeout(parseBlock, 0);
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};
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parse();
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};
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var SuperGif = function ( opts ) {
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var options = {
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//viewport position
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vp_l: 0,
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vp_t: 0,
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vp_w: null,
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vp_h: null,
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//canvas sizes
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c_w: null,
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c_h: null
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};
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for (var i in opts ) { options[i] = opts[i] }
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if (options.vp_w && options.vp_h) options.is_vp = true;
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var stream;
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var hdr;
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var loadError = null;
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var loading = false;
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var transparency = null;
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var delay = null;
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var disposalMethod = null;
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var disposalRestoreFromIdx = null;
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var lastDisposalMethod = null;
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var frame = null;
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var lastImg = null;
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var playing = true;
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var forward = true;
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var ctx_scaled = false;
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var frames = [];
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var frameOffsets = []; // elements have .x and .y properties
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var gif = options.gif;
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if (typeof options.auto_play == 'undefined')
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options.auto_play = (!gif.getAttribute('rel:auto_play') || gif.getAttribute('rel:auto_play') == '1');
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var onEndListener = (options.hasOwnProperty('on_end') ? options.on_end : null);
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var loopDelay = (options.hasOwnProperty('loop_delay') ? options.loop_delay : 0);
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var overrideLoopMode = (options.hasOwnProperty('loop_mode') ? options.loop_mode : 'auto');
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var drawWhileLoading = (options.hasOwnProperty('draw_while_loading') ? options.draw_while_loading : true);
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var showProgressBar = drawWhileLoading ? (options.hasOwnProperty('show_progress_bar') ? options.show_progress_bar : true) : false;
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var progressBarHeight = (options.hasOwnProperty('progressbar_height') ? options.progressbar_height : 25);
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var progressBarBackgroundColor = (options.hasOwnProperty('progressbar_background_color') ? options.progressbar_background_color : 'rgba(255,255,255,0.4)');
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var progressBarForegroundColor = (options.hasOwnProperty('progressbar_foreground_color') ? options.progressbar_foreground_color : 'rgba(255,0,22,.8)');
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var clear = function () {
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transparency = null;
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delay = null;
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lastDisposalMethod = disposalMethod;
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disposalMethod = null;
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frame = null;
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};
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// XXX: There's probably a better way to handle catching exceptions when
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// callbacks are involved.
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var doParse = function () {
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try {
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parseGIF(stream, handler);
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}
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catch (err) {
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doLoadError('parse');
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}
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};
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var doText = function (text) {
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toolbar.innerHTML = text; // innerText? Escaping? Whatever.
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toolbar.style.visibility = 'visible';
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};
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var setSizes = function(w, h) {
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canvas.width = w * get_canvas_scale();
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canvas.height = h * get_canvas_scale();
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toolbar.style.minWidth = ( w * get_canvas_scale() ) + 'px';
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tmpCanvas.width = w;
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tmpCanvas.height = h;
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tmpCanvas.style.width = w + 'px';
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tmpCanvas.style.height = h + 'px';
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tmpCanvas.getContext('2d', { willReadFrequently: true }).setTransform(1, 0, 0, 1, 0, 0);
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};
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var setFrameOffset = function(frame, offset) {
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if (!frameOffsets[frame]) {
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frameOffsets[frame] = offset;
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return;
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}
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if (typeof offset.x !== 'undefined') {
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frameOffsets[frame].x = offset.x;
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}
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if (typeof offset.y !== 'undefined') {
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frameOffsets[frame].y = offset.y;
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}
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};
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var doShowProgress = function (pos, length, draw) {
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if (draw && showProgressBar) {
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var height = progressBarHeight;
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var left, mid, top, width;
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if (options.is_vp) {
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if (!ctx_scaled) {
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top = (options.vp_t + options.vp_h - height);
|
|
height = height;
|
|
left = options.vp_l;
|
|
mid = left + (pos / length) * options.vp_w;
|
|
width = canvas.width;
|
|
} else {
|
|
top = (options.vp_t + options.vp_h - height) / get_canvas_scale();
|
|
height = height / get_canvas_scale();
|
|
left = (options.vp_l / get_canvas_scale() );
|
|
mid = left + (pos / length) * (options.vp_w / get_canvas_scale());
|
|
width = canvas.width / get_canvas_scale();
|
|
}
|
|
//some debugging, draw rect around viewport
|
|
if (false) {
|
|
if (!ctx_scaled) {
|
|
var l = options.vp_l, t = options.vp_t;
|
|
var w = options.vp_w, h = options.vp_h;
|
|
} else {
|
|
var l = options.vp_l/get_canvas_scale(), t = options.vp_t/get_canvas_scale();
|
|
var w = options.vp_w/get_canvas_scale(), h = options.vp_h/get_canvas_scale();
|
|
}
|
|
ctx.rect(l,t,w,h);
|
|
ctx.stroke();
|
|
}
|
|
}
|
|
else {
|
|
top = (canvas.height - height) / (ctx_scaled ? get_canvas_scale() : 1);
|
|
mid = ((pos / length) * canvas.width) / (ctx_scaled ? get_canvas_scale() : 1);
|
|
width = canvas.width / (ctx_scaled ? get_canvas_scale() : 1 );
|
|
height /= ctx_scaled ? get_canvas_scale() : 1;
|
|
}
|
|
|
|
ctx.fillStyle = progressBarBackgroundColor;
|
|
ctx.fillRect(mid, top, width - mid, height);
|
|
|
|
ctx.fillStyle = progressBarForegroundColor;
|
|
ctx.fillRect(0, top, mid, height);
|
|
}
|
|
};
|
|
|
|
var doLoadError = function (originOfError) {
|
|
var drawError = function () {
|
|
ctx.fillStyle = 'black';
|
|
ctx.fillRect(0, 0, options.c_w ? options.c_w : hdr.width, options.c_h ? options.c_h : hdr.height);
|
|
ctx.strokeStyle = 'red';
|
|
ctx.lineWidth = 3;
|
|
ctx.moveTo(0, 0);
|
|
ctx.lineTo(options.c_w ? options.c_w : hdr.width, options.c_h ? options.c_h : hdr.height);
|
|
ctx.moveTo(0, options.c_h ? options.c_h : hdr.height);
|
|
ctx.lineTo(options.c_w ? options.c_w : hdr.width, 0);
|
|
ctx.stroke();
|
|
};
|
|
|
|
loadError = originOfError;
|
|
hdr = {
|
|
width: gif.width,
|
|
height: gif.height
|
|
}; // Fake header.
|
|
frames = [];
|
|
drawError();
|
|
};
|
|
|
|
var doHdr = function (_hdr) {
|
|
hdr = _hdr;
|
|
setSizes(hdr.width, hdr.height)
|
|
};
|
|
|
|
var doGCE = function (gce) {
|
|
pushFrame();
|
|
clear();
|
|
transparency = gce.transparencyGiven ? gce.transparencyIndex : null;
|
|
delay = gce.delayTime;
|
|
disposalMethod = gce.disposalMethod;
|
|
// We don't have much to do with the rest of GCE.
|
|
};
|
|
|
|
var pushFrame = function () {
|
|
if (!frame) return;
|
|
frames.push({
|
|
data: frame.getImageData(0, 0, hdr.width, hdr.height),
|
|
delay: delay
|
|
});
|
|
frameOffsets.push({ x: 0, y: 0 });
|
|
};
|
|
|
|
var doImg = function (img) {
|
|
if (!frame) frame = tmpCanvas.getContext('2d', { willReadFrequently: true });
|
|
|
|
var currIdx = frames.length;
|
|
|
|
//ct = color table, gct = global color table
|
|
var ct = img.lctFlag ? img.lct : hdr.gct; // TODO: What if neither exists?
|
|
|
|
/*
|
|
Disposal method indicates the way in which the graphic is to
|
|
be treated after being displayed.
|
|
|
|
Values : 0 - No disposal specified. The decoder is
|
|
not required to take any action.
|
|
1 - Do not dispose. The graphic is to be left
|
|
in place.
|
|
2 - Restore to background color. The area used by the
|
|
graphic must be restored to the background color.
|
|
3 - Restore to previous. The decoder is required to
|
|
restore the area overwritten by the graphic with
|
|
what was there prior to rendering the graphic.
|
|
|
|
Importantly, "previous" means the frame state
|
|
after the last disposal of method 0, 1, or 2.
|
|
*/
|
|
if (currIdx > 0) {
|
|
if (lastDisposalMethod === 3) {
|
|
// Restore to previous
|
|
// If we disposed every frame including first frame up to this point, then we have
|
|
// no composited frame to restore to. In this case, restore to background instead.
|
|
if (disposalRestoreFromIdx !== null) {
|
|
frame.putImageData(frames[disposalRestoreFromIdx].data, 0, 0);
|
|
} else {
|
|
frame.clearRect(lastImg.leftPos, lastImg.topPos, lastImg.width, lastImg.height);
|
|
}
|
|
} else {
|
|
disposalRestoreFromIdx = currIdx - 1;
|
|
}
|
|
|
|
if (lastDisposalMethod === 2) {
|
|
// Restore to background color
|
|
// Browser implementations historically restore to transparent; we do the same.
|
|
// http://www.wizards-toolkit.org/discourse-server/viewtopic.php?f=1&t=21172#p86079
|
|
frame.clearRect(lastImg.leftPos, lastImg.topPos, lastImg.width, lastImg.height);
|
|
}
|
|
}
|
|
// else, Undefined/Do not dispose.
|
|
// frame contains final pixel data from the last frame; do nothing
|
|
|
|
//Get existing pixels for img region after applying disposal method
|
|
var imgData = frame.getImageData(img.leftPos, img.topPos, img.width, img.height);
|
|
|
|
//apply color table colors
|
|
img.pixels.forEach(function (pixel, i) {
|
|
// imgData.data === [R,G,B,A,R,G,B,A,...]
|
|
if (pixel !== transparency) {
|
|
imgData.data[i * 4 + 0] = ct[pixel][0];
|
|
imgData.data[i * 4 + 1] = ct[pixel][1];
|
|
imgData.data[i * 4 + 2] = ct[pixel][2];
|
|
imgData.data[i * 4 + 3] = 255; // Opaque.
|
|
}
|
|
});
|
|
|
|
frame.putImageData(imgData, img.leftPos, img.topPos);
|
|
|
|
if (!ctx_scaled) {
|
|
ctx.scale(get_canvas_scale(),get_canvas_scale());
|
|
ctx_scaled = true;
|
|
}
|
|
|
|
// We could use the on-page canvas directly, except that we draw a progress
|
|
// bar for each image chunk (not just the final image).
|
|
if (drawWhileLoading) {
|
|
ctx.drawImage(tmpCanvas, 0, 0);
|
|
drawWhileLoading = options.auto_play;
|
|
}
|
|
|
|
lastImg = img;
|
|
};
|
|
|
|
var player = (function () {
|
|
var i = -1;
|
|
var iterationCount = 0;
|
|
|
|
var showingInfo = false;
|
|
var pinned = false;
|
|
|
|
/**
|
|
* Gets the index of the frame "up next".
|
|
* @returns {number}
|
|
*/
|
|
var getNextFrameNo = function () {
|
|
var delta = (forward ? 1 : -1);
|
|
return (i + delta + frames.length) % frames.length;
|
|
};
|
|
|
|
var stepFrame = function (amount) { // XXX: Name is confusing.
|
|
i = i + amount;
|
|
|
|
putFrame();
|
|
};
|
|
|
|
var step = (function () {
|
|
var stepping = false;
|
|
|
|
var completeLoop = function () {
|
|
if (onEndListener !== null)
|
|
onEndListener(gif);
|
|
iterationCount++;
|
|
|
|
if (overrideLoopMode !== false || iterationCount < 0) {
|
|
doStep();
|
|
} else {
|
|
stepping = false;
|
|
playing = false;
|
|
}
|
|
};
|
|
|
|
var doStep = function () {
|
|
stepping = playing;
|
|
if (!stepping) return;
|
|
|
|
stepFrame(1);
|
|
var delay = frames[i].delay * 10;
|
|
if (!delay) delay = 100; // FIXME: Should this even default at all? What should it be?
|
|
|
|
var nextFrameNo = getNextFrameNo();
|
|
if (nextFrameNo === 0) {
|
|
delay += loopDelay;
|
|
setTimeout(completeLoop, delay);
|
|
} else {
|
|
setTimeout(doStep, delay);
|
|
}
|
|
};
|
|
|
|
return function () {
|
|
if (!stepping) setTimeout(doStep, 0);
|
|
};
|
|
}());
|
|
|
|
var putFrame = function () {
|
|
var offset;
|
|
i = parseInt(i, 10);
|
|
|
|
if (i > frames.length - 1){
|
|
i = 0;
|
|
}
|
|
|
|
if (i < 0){
|
|
i = 0;
|
|
}
|
|
|
|
offset = frameOffsets[i];
|
|
|
|
tmpCanvas.getContext("2d", { willReadFrequently: true }).putImageData(frames[i].data, offset.x, offset.y);
|
|
ctx.globalCompositeOperation = "copy";
|
|
ctx.drawImage(tmpCanvas, 0, 0);
|
|
};
|
|
|
|
var play = function () {
|
|
playing = true;
|
|
step();
|
|
};
|
|
|
|
var pause = function () {
|
|
playing = false;
|
|
};
|
|
|
|
|
|
return {
|
|
init: function () {
|
|
if (loadError) return;
|
|
|
|
if ( ! (options.c_w && options.c_h) ) {
|
|
ctx.scale(get_canvas_scale(),get_canvas_scale());
|
|
}
|
|
|
|
if (options.auto_play) {
|
|
step();
|
|
}
|
|
else {
|
|
i = 0;
|
|
putFrame();
|
|
}
|
|
},
|
|
step: step,
|
|
play: play,
|
|
pause: pause,
|
|
playing: playing,
|
|
move_relative: stepFrame,
|
|
current_frame: function() { return i; },
|
|
length: function() { return frames.length },
|
|
move_to: function ( frame_idx ) {
|
|
i = frame_idx;
|
|
putFrame();
|
|
}
|
|
}
|
|
}());
|
|
|
|
var doDecodeProgress = function (draw) {
|
|
doShowProgress(stream.pos, stream.data.length, draw);
|
|
};
|
|
|
|
var doNothing = function () {};
|
|
/**
|
|
* @param{boolean=} draw Whether to draw progress bar or not; this is not idempotent because of translucency.
|
|
* Note that this means that the text will be unsynchronized with the progress bar on non-frames;
|
|
* but those are typically so small (GCE etc.) that it doesn't really matter. TODO: Do this properly.
|
|
*/
|
|
var withProgress = function (fn, draw) {
|
|
return function (block) {
|
|
fn(block);
|
|
doDecodeProgress(draw);
|
|
};
|
|
};
|
|
|
|
|
|
var handler = {
|
|
hdr: withProgress(doHdr),
|
|
gce: withProgress(doGCE),
|
|
com: withProgress(doNothing),
|
|
// I guess that's all for now.
|
|
app: {
|
|
// TODO: Is there much point in actually supporting iterations?
|
|
NETSCAPE: withProgress(doNothing)
|
|
},
|
|
img: withProgress(doImg, true),
|
|
eof: function (block) {
|
|
//toolbar.style.display = '';
|
|
pushFrame();
|
|
doDecodeProgress(false);
|
|
if ( ! (options.c_w && options.c_h) ) {
|
|
canvas.width = hdr.width * get_canvas_scale();
|
|
canvas.height = hdr.height * get_canvas_scale();
|
|
}
|
|
player.init();
|
|
loading = false;
|
|
if (load_callback) {
|
|
load_callback(gif);
|
|
}
|
|
|
|
}
|
|
};
|
|
|
|
var init = function () {
|
|
var parent = gif.parentNode;
|
|
|
|
var div = document.createElement('div');
|
|
canvas = document.createElement('canvas');
|
|
ctx = canvas.getContext('2d', { willReadFrequently: true });
|
|
toolbar = document.createElement('div');
|
|
|
|
tmpCanvas = document.createElement('canvas');
|
|
|
|
div.width = canvas.width = gif.width;
|
|
div.height = canvas.height = gif.height;
|
|
toolbar.style.minWidth = gif.width + 'px';
|
|
|
|
div.className = 'jsgif';
|
|
toolbar.className = 'jsgif_toolbar';
|
|
div.appendChild(canvas);
|
|
div.appendChild(toolbar);
|
|
|
|
parent.insertBefore(div, gif);
|
|
parent.removeChild(gif);
|
|
|
|
if (options.c_w && options.c_h) setSizes(options.c_w, options.c_h);
|
|
initialized=true;
|
|
};
|
|
|
|
var get_canvas_scale = function() {
|
|
var scale;
|
|
if (options.max_width && hdr && hdr.width > options.max_width) {
|
|
scale = options.max_width / hdr.width;
|
|
}
|
|
else {
|
|
scale = 1;
|
|
}
|
|
return scale;
|
|
}
|
|
|
|
var canvas, ctx, toolbar, tmpCanvas;
|
|
var initialized = false;
|
|
var load_callback = false;
|
|
|
|
var load_setup = function(callback) {
|
|
if (loading) return false;
|
|
if (callback) load_callback = callback;
|
|
else load_callback = false;
|
|
|
|
loading = true;
|
|
frames = [];
|
|
clear();
|
|
disposalRestoreFromIdx = null;
|
|
lastDisposalMethod = null;
|
|
frame = null;
|
|
lastImg = null;
|
|
|
|
return true;
|
|
}
|
|
|
|
return {
|
|
// play controls
|
|
play: player.play,
|
|
pause: player.pause,
|
|
move_relative: player.move_relative,
|
|
move_to: player.move_to,
|
|
|
|
// getters for instance vars
|
|
get_playing : function() { return playing },
|
|
get_canvas : function() { return canvas },
|
|
get_canvas_scale : function() { return get_canvas_scale() },
|
|
get_loading : function() { return loading },
|
|
get_auto_play : function() { return options.auto_play },
|
|
get_length : function() { return player.length() },
|
|
get_current_frame: function() { return player.current_frame() },
|
|
load_url: function(src,callback){
|
|
if (!load_setup(callback)) return;
|
|
var h = new XMLHttpRequest();
|
|
h.onreadystatechange = function() {
|
|
if (h.readyState == 4) {
|
|
if (h.status == 404) {
|
|
callback(404)
|
|
}
|
|
}
|
|
};
|
|
// new browsers (XMLHttpRequest2-compliant)
|
|
h.open('GET', src, true);
|
|
|
|
if ('overrideMimeType' in h) {
|
|
h.overrideMimeType('text/plain; charset=x-user-defined');
|
|
}
|
|
|
|
// old browsers (XMLHttpRequest-compliant)
|
|
else if ('responseType' in h) {
|
|
h.responseType = 'arraybuffer';
|
|
}
|
|
|
|
// IE9 (Microsoft.XMLHTTP-compliant)
|
|
else {
|
|
h.setRequestHeader('Accept-Charset', 'x-user-defined');
|
|
}
|
|
|
|
h.onloadstart = function() {
|
|
// Wait until connection is opened to replace the gif element with a canvas to avoid a blank img
|
|
if (!initialized) init();
|
|
};
|
|
h.onload = function(e) {
|
|
if (this.status != 200) {
|
|
doLoadError('xhr - response');
|
|
}
|
|
// emulating response field for IE9
|
|
if (!('response' in this)) {
|
|
this.response = new VBArray(this.responseText).toArray().map(String.fromCharCode).join('');
|
|
}
|
|
var data = this.response;
|
|
if (data.toString().indexOf("ArrayBuffer") > 0) {
|
|
data = new Uint8Array(data);
|
|
}
|
|
|
|
stream = new Stream(data);
|
|
setTimeout(doParse, 0);
|
|
};
|
|
h.onprogress = function (e) {
|
|
if (e.lengthComputable) doShowProgress(e.loaded, e.total, true);
|
|
};
|
|
h.onerror = function() { doLoadError('xhr'); };
|
|
h.send();
|
|
},
|
|
load: function (callback) {
|
|
this.load_url(gif.getAttribute('rel:animated_src') || gif.src,callback);
|
|
},
|
|
load_raw: function(arr, callback) {
|
|
if (!load_setup(callback)) return;
|
|
if (!initialized) init();
|
|
stream = new Stream(arr);
|
|
setTimeout(doParse, 0);
|
|
},
|
|
set_frame_offset: setFrameOffset
|
|
};
|
|
};
|
|
|
|
return SuperGif;
|
|
}));
|
|
|
|
|