433 lines
16 KiB
JavaScript
433 lines
16 KiB
JavaScript
import log from '@converse/headless/log.js';
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import { getOpenPromise } from '@converse/openpromise';
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import { parseGIF, decompressFrames } from 'gifuct-js';
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export default class ConverseGif {
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/**
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* Creates a new ConverseGif instance
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* @param { import('lit').LitElement } el
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* @param { Object } [options]
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* @param { Number } [options.width] - The width, in pixels, of the canvas
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* @param { Number } [options.height] - The height, in pixels, of the canvas
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* @param { Boolean } [options.loop=true] - Setting this to `true` will enable looping of the gif
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* @param { Boolean } [options.autoplay=true] - Same as the rel:autoplay attribute above, this arg overrides the img tag info.
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* @param { Number } [options.max_width] - Scale images over max_width down to max_width. Helpful with mobile.
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* @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.
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* @param { Boolean } [options.show_progress_bar=true]
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* @param { String } [options.progress_bg_color='rgba(0,0,0,0.4)']
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* @param { String } [options.progress_color='rgba(255,0,22,.8)']
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* @param { Number } [options.progress_bar_height=5]
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*/
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constructor (el, opts) {
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this.options = Object.assign(
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{
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width: null,
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height: null,
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autoplay: true,
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loop: true,
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show_progress_bar: true,
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progress_bg_color: 'rgba(0,0,0,0.4)',
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progress_color: 'rgba(255,0,22,.8)',
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progress_bar_height: 5,
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},
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opts
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);
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this.el = el;
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this.gif_el = el.querySelector('img');
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this.canvas = el.querySelector('canvas');
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this.ctx = this.canvas.getContext('2d');
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// Offscreen canvas with full gif
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this.offscreenCanvas = document.createElement('canvas');
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// Offscreen canvas for patches
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this.patchCanvas = document.createElement('canvas');
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this.ctx_scaled = false;
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this.frames = [];
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this.load_error = null;
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this.playing = this.options.autoplay;
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this.frame_idx = 0;
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this.iteration_count = 0;
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this.start = null;
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this.hovering = null;
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this.frameImageData = null;
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this.disposal_restore_from_idx = null;
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this.initialize();
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}
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async initialize () {
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if (this.options.width && this.options.height) {
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this.setSizes(this.options.width, this.options.height);
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}
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const data = await this.fetchGIF(this.gif_el.src);
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requestAnimationFrame(() => this.handleGIFResponse(data));
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}
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initPlayer () {
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if (this.load_error) return;
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if (!(this.options.width && this.options.height)) {
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this.ctx.scale(this.getCanvasScale(), this.getCanvasScale());
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}
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// Show the first frame
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this.frame_idx = 0;
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this.renderImage();
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if (this.options.autoplay) {
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const delay = this.frames[this.frame_idx]?.delay ?? 0;
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setTimeout(() => this.play(), delay);
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}
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}
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/**
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* Gets the index of the frame "up next"
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* @returns {number}
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*/
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getNextFrameNo () {
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if (this.frames.length === 0) {
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return 0;
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}
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return (this.frame_idx + 1 + this.frames.length) % this.frames.length;
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}
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/**
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* Called once we've looped through all frames in the GIF
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* @returns { Boolean } - Returns `true` if the GIF is now paused (i.e. further iterations are not desired)
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*/
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onIterationEnd () {
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this.iteration_count++;
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this.options.onIterationEnd?.(this);
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if (!this.options.loop) {
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this.pause();
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return true;
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}
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return false;
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}
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/**
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* Inner callback for the `requestAnimationFrame` function.
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*
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* This method gets wrapped by an arrow function so that the `previous_timestamp` and
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* `frame_delay` parameters can also be passed in. The `timestamp`
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* parameter comes from `requestAnimationFrame`.
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*
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* The purpose of this method is to call `renderImage` with the right delay
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* in order to render the GIF animation.
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*
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* Note, this method will cause the *next* upcoming frame to be rendered,
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* not the current one.
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*
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* This means `this.frame_idx` will be incremented before calling `this.renderImage`, so
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* `renderImage(0)` needs to be called *before* this method, otherwise the
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* animation will incorrectly start from frame #1 (this is done in `initPlayer`).
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*
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* @param { DOMHighResTimeStamp } timestamp - The timestamp as returned by `requestAnimationFrame`
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* @param { DOMHighResTimeStamp } previous_timestamp - The timestamp from the previous iteration of this method.
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* We need this in order to calculate whether we have waited long enough to
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* show the next frame.
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* @param { Number } frame_delay - The delay (in 1/100th of a second)
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* before the currently being shown frame should be replaced by a new one.
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*/
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onAnimationFrame (timestamp, previous_timestamp, frame_delay) {
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if (!this.playing) {
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return;
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}
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if (timestamp - previous_timestamp < frame_delay) {
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this.hovering ? this.drawPauseIcon() : this.renderImage();
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// We need to wait longer
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requestAnimationFrame((ts) => this.onAnimationFrame(ts, previous_timestamp, frame_delay));
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return;
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}
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const next_frame = this.getNextFrameNo();
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if (next_frame === 0 && this.onIterationEnd()) {
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return;
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}
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this.frame_idx = next_frame;
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this.renderImage();
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const delay = this.frames[this.frame_idx]?.delay || 8;
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requestAnimationFrame((ts) => this.onAnimationFrame(ts, timestamp, delay));
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}
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setSizes (w, h) {
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this.canvas.width = w * this.getCanvasScale();
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this.canvas.height = h * this.getCanvasScale();
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this.offscreenCanvas.width = w;
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this.offscreenCanvas.height = h;
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this.offscreenCanvas.style.width = w + 'px';
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this.offscreenCanvas.style.height = h + 'px';
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this.offscreenCanvas.getContext('2d').setTransform(1, 0, 0, 1, 0, 0);
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}
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doShowProgress (pos, length, draw) {
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if (draw && this.options.show_progress_bar) {
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let height = this.options.progress_bar_height;
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const top = (this.canvas.height - height) / (this.ctx_scaled ? this.getCanvasScale() : 1);
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const mid = ((pos / length) * this.canvas.width) / (this.ctx_scaled ? this.getCanvasScale() : 1);
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const width = this.canvas.width / (this.ctx_scaled ? this.getCanvasScale() : 1);
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height /= this.ctx_scaled ? this.getCanvasScale() : 1;
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this.ctx.fillStyle = this.options.progress_bg_color;
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this.ctx.fillRect(mid, top, width - mid, height);
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this.ctx.fillStyle = this.options.progress_color;
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this.ctx.fillRect(0, top, mid, height);
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}
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}
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/**
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* Starts parsing the GIF stream data by calling `parseGIF` and passing in
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* a map of handler functions.
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* @param {ArrayBuffer} data - The GIF file data, as returned by the server
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*/
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handleGIFResponse (data) {
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try {
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const gif = parseGIF(data);
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this.hdr = gif.header;
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this.lsd = gif.lsd;
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this.setSizes(this.options.width ?? this.lsd.width, this.options.height ?? this.lsd.height);
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this.frames = decompressFrames(gif, true);
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} catch (err) {
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this.showError();
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}
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this.initPlayer();
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!this.options.autoplay && this.drawPlayIcon();
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}
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drawError () {
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this.ctx.fillStyle = 'black';
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this.ctx.fillRect(0, 0, this.options.width, this.options.height);
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this.ctx.strokeStyle = 'red';
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this.ctx.lineWidth = 3;
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this.ctx.moveTo(0, 0);
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this.ctx.lineTo(this.options.width, this.options.height);
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this.ctx.moveTo(0, this.options.height);
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this.ctx.lineTo(this.options.width, 0);
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this.ctx.stroke();
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}
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showError () {
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this.load_error = true;
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this.hdr = {
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width: this.gif_el.width,
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height: this.gif_el.height,
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}; // Fake header.
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this.frames = [];
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this.drawError();
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this.el.requestUpdate();
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}
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manageDisposal (i) {
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if (i <= 0) return;
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const offscreenContext = this.offscreenCanvas.getContext('2d');
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const disposal = this.frames[i - 1].disposalType;
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/*
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* Disposal method indicates the way in which the graphic is to
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* be treated after being displayed.
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*
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* Values : 0 - No disposal specified. The decoder is
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* not required to take any action.
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* 1 - Do not dispose. The graphic is to be left
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* in place.
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* 2 - Restore to background color. The area used by the
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* graphic must be restored to the background color.
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* 3 - Restore to previous. The decoder is required to
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* restore the area overwritten by the graphic with
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* what was there prior to rendering the graphic.
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*
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* Importantly, "previous" means the frame state
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* after the last disposal of method 0, 1, or 2.
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*/
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if (i > 1) {
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if (disposal === 3) {
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// eslint-disable-next-line no-eq-null
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if (this.disposal_restore_from_idx != null) {
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offscreenContext.putImageData(this.frames[this.disposal_restore_from_idx].data, 0, 0);
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}
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} else {
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this.disposal_restore_from_idx = i - 1;
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}
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}
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if (disposal === 2) {
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// Restore to background color
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// Browser implementations historically restore to transparent; we do the same.
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// http://www.wizards-toolkit.org/discourse-server/viewtopic.php?f=1&t=21172#p86079
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offscreenContext.clearRect(
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this.last_frame.dims.left,
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this.last_frame.dims.top,
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this.last_frame.dims.width,
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this.last_frame.dims.height
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);
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}
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}
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/**
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* Draws a gif frame at a specific index inside the canvas.
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* @param {boolean} show_pause_on_hover - The frame index
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*/
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renderImage (show_pause_on_hover = true) {
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if (!this.frames.length) return;
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let i = this.frame_idx;
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i = parseInt(i.toString(), 10);
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if (i > this.frames.length - 1 || i < 0) {
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i = 0;
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}
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this.manageDisposal(i);
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const frame = this.frames[i];
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const patchContext = this.patchCanvas.getContext('2d');
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const offscreenContext = this.offscreenCanvas.getContext('2d');
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const dims = frame.dims;
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if (
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!this.frameImageData ||
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dims.width != this.frameImageData.width ||
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dims.height != this.frameImageData.height
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) {
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this.patchCanvas.width = dims.width;
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this.patchCanvas.height = dims.height;
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this.frameImageData = patchContext.createImageData(dims.width, dims.height);
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}
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// set the patch data as an override
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this.frameImageData.data.set(frame.patch);
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// draw the patch back over the canvas
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patchContext.putImageData(this.frameImageData, 0, 0);
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offscreenContext.drawImage(this.patchCanvas, dims.left, dims.top);
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const imageData = offscreenContext.getImageData(0, 0, this.offscreenCanvas.width, this.offscreenCanvas.height);
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this.ctx.putImageData(imageData, 0, 0);
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this.ctx.drawImage(this.canvas, 0, 0, this.canvas.width, this.canvas.height);
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if (show_pause_on_hover && this.hovering) {
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this.drawPauseIcon();
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}
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this.last_frame = frame;
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}
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/**
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* Start playing the gif
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*/
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play () {
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this.playing = true;
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requestAnimationFrame((ts) => this.onAnimationFrame(ts, 0, 0));
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}
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/**
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* Pause the gif
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*/
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pause () {
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this.playing = false;
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requestAnimationFrame(() => this.drawPlayIcon());
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}
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drawPauseIcon () {
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if (!this.playing) return;
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// Clear the potential play button by re-rendering the current frame
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this.renderImage(false);
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// Draw dark overlay
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this.ctx.fillStyle = 'rgb(0, 0, 0, 0.25)';
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this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height);
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const icon_size = this.canvas.height * 0.1;
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// Draw bars
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this.ctx.lineWidth = this.canvas.height * 0.04;
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this.ctx.beginPath();
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this.ctx.moveTo(this.canvas.width / 2 - icon_size / 2, this.canvas.height / 2 - icon_size);
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this.ctx.lineTo(this.canvas.width / 2 - icon_size / 2, this.canvas.height / 2 + icon_size);
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this.ctx.fillStyle = 'rgb(200, 200, 200, 0.75)';
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this.ctx.stroke();
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this.ctx.beginPath();
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this.ctx.moveTo(this.canvas.width / 2 + icon_size / 2, this.canvas.height / 2 - icon_size);
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this.ctx.lineTo(this.canvas.width / 2 + icon_size / 2, this.canvas.height / 2 + icon_size);
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this.ctx.fillStyle = 'rgb(200, 200, 200, 0.75)';
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this.ctx.stroke();
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// Draw circle
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this.ctx.lineWidth = this.canvas.height * 0.02;
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this.ctx.strokeStyle = 'rgb(200, 200, 200, 0.75)';
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this.ctx.beginPath();
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this.ctx.arc(this.canvas.width / 2, this.canvas.height / 2, icon_size * 1.5, 0, 2 * Math.PI);
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this.ctx.stroke();
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}
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drawPlayIcon () {
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if (this.playing) return;
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// Clear the potential pause button by re-rendering the current frame
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this.renderImage(false);
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// Draw dark overlay
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this.ctx.fillStyle = 'rgb(0, 0, 0, 0.25)';
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this.ctx.fillRect(0, 0, this.canvas.width, this.canvas.height);
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// Draw triangle
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const triangle_size = this.canvas.height * 0.1;
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const region = new Path2D();
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region.moveTo(this.canvas.width / 2 + triangle_size, this.canvas.height / 2); // start at the pointy end
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region.lineTo(this.canvas.width / 2 - triangle_size / 2, this.canvas.height / 2 + triangle_size);
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region.lineTo(this.canvas.width / 2 - triangle_size / 2, this.canvas.height / 2 - triangle_size);
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region.closePath();
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this.ctx.fillStyle = 'rgb(200, 200, 200, 0.75)';
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this.ctx.fill(region);
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// Draw circle
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const circle_size = triangle_size * 1.5;
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this.ctx.lineWidth = this.canvas.height * 0.02;
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this.ctx.strokeStyle = 'rgb(200, 200, 200, 0.75)';
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this.ctx.beginPath();
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this.ctx.arc(this.canvas.width / 2, this.canvas.height / 2, circle_size, 0, 2 * Math.PI);
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this.ctx.stroke();
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}
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getCanvasScale () {
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let scale;
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if (this.options.max_width && this.hdr && this.lsd.width > this.options.max_width) {
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scale = this.options.max_width / this.lsd.width;
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} else {
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scale = 1;
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}
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return scale;
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}
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/**
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* Makes an HTTP request to fetch a GIF
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* @param { String } url
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* @returns { Promise<ArrayBuffer> } Returns a promise which resolves with the response data.
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*/
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fetchGIF (url) {
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const promise = getOpenPromise();
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const h = new XMLHttpRequest();
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h.open('GET', url, true);
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h.responseType = 'arraybuffer';
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h?.overrideMimeType('text/plain; charset=x-user-defined');
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h.onload = () => {
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if (h.status != 200) {
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this.showError();
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return promise.reject();
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}
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promise.resolve(h.response);
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};
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h.onprogress = (e) => e.lengthComputable && this.doShowProgress(e.loaded, e.total, true);
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h.onerror = (e) => {
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log.error(e);
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this.showError();
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};
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h.send();
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return promise;
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}
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}
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