xmpp.chapril.org-conversejs/src/shared/gif/index.js

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/**
* @copyright Shachaf Ben-Kiki, JC Brand
* @description
* Started as a fork of Shachaf Ben-Kiki's jsgif library
* https://github.com/shachaf/jsgif
* @license MIT License
*/
import Stream from './stream.js';
import { getOpenPromise } from '@converse/openpromise';
import { parseGIF } from './utils.js';
const DELAY_FACTOR = 10;
export default class ConverseGif {
/**
* Creates a new ConverseGif instance
* @param { HTMLElement } el
* @param { Object } [options]
* @param { Number } [options.width] - The width, in pixels, of the canvas
* @param { Number } [options.height] - The height, in pixels, of the canvas
* @param { Boolean } [options.loop=true] - Setting this to `true` will enable looping of the gif
* @param { Boolean } [options.autoplay=true] - Same as the rel:autoplay attribute above, this arg overrides the img tag info.
* @param { Number } [options.max_width] - Scale images over max_width down to max_width. Helpful with mobile.
* @param { Function } [options.onIterationEnd] - 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.
* @param { Boolean } [options.show_progress_bar=true]
* @param { String } [options.progress_bg_color='rgba(0,0,0,0.4)']
* @param { String } [options.progress_color='rgba(255,0,22,.8)']
* @param { Number } [options.progress_bar_height=5]
*/
constructor (el, opts) {
this.options = Object.assign({
width: null,
height: null,
autoplay: true,
loop: true,
show_progress_bar: true,
progress_bg_color: 'rgba(0,0,0,0.4)',
progress_color: 'rgba(255,0,22,.8)',
progress_bar_height: 5
},
opts
);
this.el = el;
this.gif_el = el.querySelector('img');
this.canvas = el.querySelector('canvas');
this.ctx = this.canvas.getContext('2d');
// It's good practice to pre-render to an offscreen canvas
this.offscreenCanvas = document.createElement('canvas');
this.ctx_scaled = false;
this.disposal_method = null;
this.disposal_restore_from_idx = null;
this.frame = null;
this.frame_offsets = []; // elements have .x and .y properties
this.frames = [];
this.last_disposal_method = null;
this.last_img = null;
this.load_error = null;
this.playing = this.options.autoplay;
this.transparency = null;
this.frame_delay = null;
this.frame_idx = 0;
this.iteration_count = 0;
this.start = null;
this.initialize();
}
async initialize () {
if (this.options.width && this.options.height) {
this.setSizes(this.options.width, this.options.height);
}
const data = await this.fetchGIF(this.gif_el.src);
requestAnimationFrame(() => this.startParsing(data));
}
initPlayer () {
if (this.load_error) return;
if (!(this.options.width && this.options.height)) {
this.ctx.scale(this.getCanvasScale(), this.getCanvasScale());
}
// Show the first frame
this.frame_idx = 0;
this.putFrame(this.frame_idx);
if (this.options.autoplay) {
const delay = (this.frames[this.frame_idx]?.delay ?? 0) * DELAY_FACTOR;
setTimeout(() => this.play(), delay);
}
}
/**
* Gets the index of the frame "up next"
* @returns {number}
*/
getNextFrameNo () {
if (this.frames.length === 0) {
return 0;
}
return (this.frame_idx + 1 + this.frames.length) % this.frames.length;
}
/**
* Called once we've looped through all frames in the GIF
* @returns { Boolean } - Returns `true` if the GIF is now paused (i.e. further iterations are not desired)
*/
onIterationEnd () {
this.iteration_count++;
this.options.onIterationEnd?.(this);
if (!this.options.loop) {
this.pause();
return true;
}
return false;
}
/**
* Inner callback for the `requestAnimationFrame` function.
*
* This method gets wrapped by an arrow function so that the `previous_timestamp` and
* `frame_delay` parameters can also be passed in. The `timestamp`
* parameter comes from `requestAnimationFrame`.
*
* The purpose of this method is to call `putFrame` with the right delay
* in order to render the GIF animation.
*
* Note, this method will cause the *next* upcoming frame to be rendered,
* not the current one.
*
* This means `this.frame_idx` will be incremented before calling `this.putFrame`, so
* `putFrame(0)` needs to be called *before* this method, otherwise the
* animation will incorrectly start from frame #1 (this is done in `initPlayer`).
*
* @param { DOMHighRestTimestamp } timestamp - The timestamp as returned by `requestAnimationFrame`
* @param { DOMHighRestTimestamp } previous_timestamp - The timestamp from the previous iteration of this method.
* We need this in order to calculate whether we have waited long enough to
* show the next frame.
* @param { Number } frame_delay - The delay (in 1/100th of a second)
* before the currently being shown frame should be replaced by a new one.
*/
onAnimationFrame (timestamp, previous_timestamp, frame_delay) {
if (!this.playing) {
return;
}
if ((timestamp - previous_timestamp) < frame_delay) {
this.hovering ? this.drawPauseIcon() : this.putFrame(this.frame_idx);
// We need to wait longer
requestAnimationFrame(ts => this.onAnimationFrame(ts, previous_timestamp, frame_delay));
return;
}
const next_frame = this.getNextFrameNo();
if (next_frame === 0 && this.onIterationEnd()) {
return;
}
this.frame_idx = next_frame;
this.putFrame(this.frame_idx);
const delay = (this.frames[this.frame_idx]?.delay || 8) * DELAY_FACTOR;
requestAnimationFrame(ts => this.onAnimationFrame(ts, timestamp, delay));
}
setSizes (w, h) {
this.canvas.width = w * this.getCanvasScale();
this.canvas.height = h * this.getCanvasScale();
this.offscreenCanvas.width = w;
this.offscreenCanvas.height = h;
this.offscreenCanvas.style.width = w + 'px';
this.offscreenCanvas.style.height = h + 'px';
this.offscreenCanvas.getContext('2d').setTransform(1, 0, 0, 1, 0, 0);
}
setFrameOffset (frame, offset) {
if (!this.frame_offsets[frame]) {
this.frame_offsets[frame] = offset;
return;
}
if (typeof offset.x !== 'undefined') {
this.frame_offsets[frame].x = offset.x;
}
if (typeof offset.y !== 'undefined') {
this.frame_offsets[frame].y = offset.y;
}
}
doShowProgress (pos, length, draw) {
if (draw && this.options.show_progress_bar) {
let height = this.options.progress_bar_height;
const top = (this.canvas.height - height) / (this.ctx_scaled ? this.getCanvasScale() : 1);
const mid = ((pos / length) * this.canvas.width) / (this.ctx_scaled ? this.getCanvasScale() : 1);
const width = this.canvas.width / (this.ctx_scaled ? this.getCanvasScale() : 1);
height /= this.ctx_scaled ? this.getCanvasScale() : 1;
this.ctx.fillStyle = this.options.progress_bg_color;
this.ctx.fillRect(mid, top, width - mid, height);
this.ctx.fillStyle = this.options.progress_color;
this.ctx.fillRect(0, top, mid, height);
}
}
/**
* Starts parsing the GIF stream data by calling `parseGIF` and passing in
* a map of handler functions.
* @param { String } data - The GIF file data, as returned by the server
*/
startParsing (data) {
const stream = new Stream(data);
/**
* @typedef { Object } GIFParserHandlers
* A map of callback functions passed `parseGIF`. These functions are
* called as various parts of the GIF file format are parsed.
* @property { Function } hdr - Callback to handle the GIF header data
* @property { Function } gce - Callback to handle the GIF Graphic Control Extension data
* @property { Function } com - Callback to handle the comment extension block
* @property { Function } img - Callback to handle image data
* @property { Function } eof - Callback once the end of file has been reached
*/
const handler = {
'hdr': this.withProgress(stream, header => this.handleHeader(header)),
'gce': this.withProgress(stream, gce => this.handleGCE(gce)),
'com': this.withProgress(stream, ),
'img': this.withProgress(stream, img => this.doImg(img), true),
'eof': () => this.handleEOF(stream)
};
try {
parseGIF(stream, handler);
} catch (err) {
this.showError('parse');
}
}
drawError () {
this.ctx.fillStyle = 'black';
this.ctx.fillRect(
0,
0,
this.options.width ? this.options.width : this.hdr.width,
this.options.height ? this.options.height : this.hdr.height
);
this.ctx.strokeStyle = 'red';
this.ctx.lineWidth = 3;
this.ctx.moveTo(0, 0);
this.ctx.lineTo(
this.options.width ? this.options.width : this.hdr.width,
this.options.height ? this.options.height : this.hdr.height
);
this.ctx.moveTo(0, this.options.height ? this.options.height : this.hdr.height);
this.ctx.lineTo(this.options.width ? this.options.width : this.hdr.width, 0);
this.ctx.stroke();
}
showError (errtype) {
this.load_error = errtype;
this.hdr = {
width: this.gif_el.width,
height: this.gif_el.height,
}; // Fake header.
this.frames = [];
this.drawError();
this.el.requestUpdate();
}
handleHeader (header) {
this.hdr = header;
this.setSizes(
this.options.width ?? this.hdr.width,
this.options.height ?? this.hdr.height
);
}
/**
* Handler for GIF Graphic Control Extension (GCE) data
*/
handleGCE (gce) {
this.pushFrame();
this.clear();
this.frame_delay = gce.delayTime;
this.transparency = gce.transparencyGiven ? gce.transparencyIndex : null;
this.disposal_method = gce.disposalMethod;
}
/**
* Handler for when the end of the GIF's file has been reached
*/
handleEOF (stream) {
this.pushFrame();
this.doDecodeProgress(stream, false);
this.initPlayer();
!this.options.autoplay && this.drawPlayIcon();
}
pushFrame () {
if (!this.frame) return;
this.frames.push({
data: this.frame.getImageData(0, 0, this.hdr.width, this.hdr.height),
delay: this.frame_delay
});
this.frame_offsets.push({ x: 0, y: 0 });
}
doImg (img) {
this.frame = this.frame || this.offscreenCanvas.getContext('2d');
const currIdx = this.frames.length;
//ct = color table, gct = global color table
const ct = img.lctFlag ? img.lct : this.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 (this.last_disposal_method === 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 (this.disposal_restore_from_idx !== null) {
this.frame.putImageData(this.frames[this.disposal_restore_from_idx].data, 0, 0);
} else {
this.frame.clearRect(
this.last_img.leftPos,
this.last_img.topPos,
this.last_img.width,
this.last_img.height
);
}
} else {
this.disposal_restore_from_idx = currIdx - 1;
}
if (this.last_disposal_method === 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
this.frame.clearRect(
this.last_img.leftPos,
this.last_img.topPos,
this.last_img.width,
this.last_img.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
const imgData = this.frame.getImageData(img.leftPos, img.topPos, img.width, img.height);
//apply color table colors
img.pixels.forEach((pixel, i) => {
// imgData.data === [R,G,B,A,R,G,B,A,...]
if (pixel !== this.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.
}
});
this.frame.putImageData(imgData, img.leftPos, img.topPos);
if (!this.ctx_scaled) {
this.ctx.scale(this.getCanvasScale(), this.getCanvasScale());
this.ctx_scaled = true;
}
if (!this.last_img) {
// This is the first received image, so we draw it
this.ctx.drawImage(this.offscreenCanvas, 0, 0);
}
this.last_img = img;
}
/**
* Draws a gif frame at a specific index inside the canvas.
* @param { Number } i - The frame index
*/
putFrame (i, show_pause_on_hover=true) {
if (!this.frames.length) return
i = parseInt(i, 10);
if (i > this.frames.length - 1 || i < 0) {
i = 0;
}
const offset = this.frame_offsets[i];
this.offscreenCanvas.getContext('2d').putImageData(this.frames[i].data, offset.x, offset.y);
this.ctx.globalCompositeOperation = 'copy';
this.ctx.drawImage(this.offscreenCanvas, 0, 0);
if (show_pause_on_hover && this.hovering) {
this.drawPauseIcon();
}
}
clear () {
this.transparency = null;
this.last_disposal_method = this.disposal_method;
this.disposal_method = null;
this.frame = null;
}
/**
* Start playing the gif
*/
play () {
this.playing = true;
requestAnimationFrame(ts => this.onAnimationFrame(ts, 0, 0));
}
/**
* Pause the gif
*/
pause () {
this.playing = false;
requestAnimationFrame(() => this.drawPlayIcon())
}
drawPauseIcon () {
if (!this.playing) {
return;
}
// Clear the potential play button by re-rendering the current frame
this.putFrame(this.frame_idx, false);
this.ctx.globalCompositeOperation = 'source-over';
// Draw dark overlay
this.ctx.fillStyle = 'rgb(0, 0, 0, 0.25)';
this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height);
const icon_size = this.canvas.height*0.1;
// Draw bars
this.ctx.lineWidth = this.canvas.height*0.04;
this.ctx.beginPath();
this.ctx.moveTo(this.canvas.width/2-icon_size/2, this.canvas.height/2-icon_size);
this.ctx.lineTo(this.canvas.width/2-icon_size/2, this.canvas.height/2+icon_size);
this.ctx.fillStyle = 'rgb(200, 200, 200, 0.75)';
this.ctx.stroke();
this.ctx.beginPath();
this.ctx.moveTo(this.canvas.width/2+icon_size/2, this.canvas.height/2-icon_size);
this.ctx.lineTo(this.canvas.width/2+icon_size/2, this.canvas.height/2+icon_size);
this.ctx.fillStyle = 'rgb(200, 200, 200, 0.75)';
this.ctx.stroke();
// Draw circle
this.ctx.lineWidth = this.canvas.height*0.02;
this.ctx.strokeStyle = 'rgb(200, 200, 200, 0.75)';
this.ctx.beginPath();
this.ctx.arc(
this.canvas.width/2,
this.canvas.height/2,
icon_size*1.5,
0,
2*Math.PI
);
this.ctx.stroke();
}
drawPlayIcon () {
if (this.playing) {
return;
}
// Clear the potential pause button by re-rendering the current frame
this.putFrame(this.frame_idx, false);
this.ctx.globalCompositeOperation = 'source-over';
// Draw dark overlay
this.ctx.fillStyle = 'rgb(0, 0, 0, 0.25)';
this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height);
// Draw triangle
const triangle_size = this.canvas.height*0.1;
const region = new Path2D();
region.moveTo(this.canvas.width/2+triangle_size, this.canvas.height/2); // start at the pointy end
region.lineTo(this.canvas.width/2-triangle_size/2, this.canvas.height/2+triangle_size);
region.lineTo(this.canvas.width/2-triangle_size/2, this.canvas.height/2-triangle_size);
region.closePath();
this.ctx.fillStyle = 'rgb(200, 200, 200, 0.75)';
this.ctx.fill(region);
// Draw circle
const circle_size = triangle_size*1.5;
this.ctx.lineWidth = this.canvas.height*0.02;
this.ctx.strokeStyle = 'rgb(200, 200, 200, 0.75)';
this.ctx.beginPath();
this.ctx.arc(
this.canvas.width/2,
this.canvas.height/2,
circle_size,
0,
2*Math.PI
);
this.ctx.stroke();
}
doDecodeProgress (stream, draw) {
this.doShowProgress(stream.pos, stream.data.length, draw);
}
/**
* @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
*/
withProgress (stream, fn, draw) {
return block => {
fn?.(block);
this.doDecodeProgress(stream, draw);
};
}
getCanvasScale () {
let scale;
if (this.options.max_width && this.hdr && this.hdr.width > this.options.max_width) {
scale = this.options.max_width / this.hdr.width;
} else {
scale = 1;
}
return scale;
}
/**
* Makes an HTTP request to fetch a GIF
* @param { String } url
* @returns { Promise<String> } Returns a promise which resolves with the response data.
*/
fetchGIF (url) {
const promise = getOpenPromise();
const h = new XMLHttpRequest();
h.open('GET', url, true);
h?.overrideMimeType('text/plain; charset=x-user-defined');
h.onload = () => {
if (h.status != 200) {
this.showError('xhr - response');
return promise.reject();
}
promise.resolve(h.response);
};
h.onprogress = (e) => (e.lengthComputable && this.doShowProgress(e.loaded, e.total, true));
h.onerror = () => this.showError('xhr');
h.send();
return promise;
}
}