295 lines
9 KiB
JavaScript
295 lines
9 KiB
JavaScript
const _ = require('lodash');
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const fs = require('fs');
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const got = require('got');
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const Canvas = require('canvas');
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const streamBuffers = require('stream-buffers');
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const mime = require('mime-types');
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const { GifReader } = require('omggif');
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const GifEncoder = require('gifencoder');
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const { createCanvas } = Canvas;
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const { Image } = Canvas;
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function loadFromUri(uri) {
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if (uri.startsWith('http')) {
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return got(uri, { encoding: null }).then(res => ({
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type: res.headers['content-type'],
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data: res.body
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}));
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}
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return new Promise((resolve, reject) => {
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fs.readFile(uri, (err, data) => {
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if (err) reject(err);
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resolve({
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type: mime.lookup(uri),
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data
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});
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});
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});
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}
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function _drawImage(ctx, img, x, y, args = {}) {
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if (args.transform || args.attributes) {
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ctx.save();
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if (args.transform) {
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_.each(args.transform, (val, prop) => {
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console.log(`Transforming ${prop} by ${val}`);
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ctx[prop](...val);
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});
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}
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if (args.attributes) {
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_.each(args.attributes, (val, prop) => {
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console.log(`Setting ${prop} to ${val}`);
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ctx[prop] = val;
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});
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}
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}
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if (args.sx !== undefined || args.sy !== undefined || args.swidth !== undefined || args.sheight !== undefined) {
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ctx.drawImage(img, args.sx, args.sy, args.swidth, args.sheight, x, y, args.width || args.swidth, args.height || args.sheight);
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} else {
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ctx.drawImage(img, x, y, args.width, args.height);
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}
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if (args.transform || args.attributes) {
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ctx.restore();
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}
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}
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class ImageEx {
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constructor(uri) {
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this.uri = uri;
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this.frames = null;
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this.loaded = loadFromUri(uri).then(result => {
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this.type = result.type;
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this.data = result.data;
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if (this.type === 'image/gif') {
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console.log(uri, 'loaded');
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this.initGif();
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} else {
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this.initStatic();
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}
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return this;
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});
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}
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initGif() {
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const reader = new GifReader(new Uint8Array(this.data));
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this.width = reader.width;
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this.height = reader.height;
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console.log('Decoding frames');
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this.frames = this.decodeFrames(reader);
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console.log('Frames decoded!');
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this.renderAllFrames();
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return this;
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}
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initStatic() {
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const img = new Image();
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img.src = this.data;
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this.width = img.width;
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this.height = img.height;
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const canvas = createCanvas(this.width, this.height);
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const ctx = canvas.getContext('2d');
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ctx.drawImage(img, 0, 0);
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this.frames = [{
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actualOffset: 0,
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actualDelay: Infinity,
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delay: Infinity,
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canvas
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}];
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}
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decodeFrames(reader) {
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const frames = [];
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let offset = 0;
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for (let i = 0; i < reader.numFrames(); ++i) {
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const frameInfo = reader.frameInfo(i);
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frameInfo.pixels = new Uint8ClampedArray(reader.width * reader.height * 4);
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reader.decodeAndBlitFrameRGBA(i, frameInfo.pixels);
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frameInfo.buffer = this.createBufferCanvas(frameInfo, this.width, this.height);
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frameInfo.actualOffset = offset;
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frameInfo.actualDelay = Math.max(frameInfo.delay * 10, 20);
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offset += frameInfo.actualDelay;
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frames.push(frameInfo);
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}
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this.totalDuration = offset;
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return frames;
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}
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renderAllFrames() {
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let disposeFrame = null;
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const canvas = createCanvas(this.width, this.height);
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const ctx = canvas.getContext('2d');
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let saved;
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for (let i = 0; i < this.frames.length; ++i) {
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const frame = this.frames[i];
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console.log('Rendering frame', frame);
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if (typeof disposeFrame === 'function') disposeFrame();
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switch (frame.disposal) {
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case 2:
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disposeFrame = () => ctx.clearRect(0, 0, canvas.width, canvas.height);
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break;
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case 3:
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saved = ctx.getImageData(0, 0, canvas.width, canvas.height);
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disposeFrame = () => ctx.putImageData(saved, 0, 0); // eslint-disable-line no-loop-func
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break;
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default:
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this.disposeFrame = null;
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}
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// draw current frame
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ctx.drawImage(frame.buffer, frame.x, frame.y);
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const frameCanvas = createCanvas(this.width, this.height);
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const frameCtx = frameCanvas.getContext('2d');
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frameCtx.drawImage(canvas, 0, 0);
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frame.canvas = frameCanvas;
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}
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}
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createBufferCanvas(frame, width, height) {
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const canvas = createCanvas(frame.width, frame.height);
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const ctx = canvas.getContext('2d');
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const imageData = ctx.createImageData(width, height);
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imageData.data.set(frame.pixels);
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ctx.putImageData(imageData, -frame.x, -frame.y);
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return canvas;
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}
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drawFrame(ctx, frameNum, x, y, args = {}) {
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_drawImage(ctx, this.frames[frameNum].canvas, x, y, args);
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}
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}
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class CanvasEx {
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constructor(width, height) {
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this.width = Math.round(width);
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this.height = Math.round(height);
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this.frames = [];
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this.totalDuration = Infinity;
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}
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setDelay(frame, actualDelay, delay) {
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if (!Number.isFinite(this.totalDuration)) this.totalDuration = 0;
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else if (Number.isFinite(frame.actualDelay)) this.totalDuration -= frame.actualDelay || 0;
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if ((actualDelay === undefined || actualDelay === null)
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&& (delay === undefined || delay === null)) throw new Error('Delay has to be set!');
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if (!Number.isNaN(delay) && delay <= 1) {
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delay = 10;
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}
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frame.delay = delay || Math.max(Math.round(actualDelay / 10), 2);
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frame.actualDelay = actualDelay || Math.max(delay * 10, 20);
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this.totalDuration += frame.actualDelay;
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}
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addFrame(actualDelay, delay) {
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const canvas = createCanvas(this.width, this.height);
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const frame = {
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actualOffset: this.totalDuration,
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canvas,
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ctx: canvas.getContext('2d')
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};
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this.setDelay(frame, actualDelay, delay);
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this.totalDuration += frame.actualDelay;
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this.frames.push(frame);
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}
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drawImage(img, x, y, args = {}) {
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if (img.frames && img.frames.length > 1) {
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if (this.frames.length > 1) throw new Error('Cannot render animations onto animated canvases!');
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this.totalDuration = 0;
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// we are drawing an animated image onto a static one.
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// for each frame in the image, create a frame on this one, cloning the original picture (if any),
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// render the original on each frame, and draw the frame on top.
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// if this canvas already has a frame, update the duration
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if (this.frames.length > 0) this.setDelay(this.frames[0], null, img.frames[0].delay);
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for (let i = this.frames.length; i < img.frames.length; ++i) {
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const frame = img.frames[i];
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this.addFrame(null, frame.delay);
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if (this.frames.length > 0) {
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this.frames[i].ctx.antialias = 'none';
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_drawImage(this.frames[i].ctx, this.frames[0].canvas, 0, 0, { width: this.width, height: this.height });
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this.frames[i].ctx.antialias = 'default';
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}
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}
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for (let i = 0; i < img.frames.length; ++i) {
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// draw the i-th source frame to the i-th target frame
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img.drawFrame(this.frames[i].ctx, i, x, y, args);
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}
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} else {
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// we are drawing a static image on top of a (possibly animated) image.
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// for each frame, just draw, nothing fancy.
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if (img.frames) { // eslint-disable-line no-lonely-if
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// the image cant have more than one frame, and if it has 0, we dont need to do anything at all
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if (img.frames.length === 1) {
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// if theres no frames at all, add one
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if (this.frames.length === 0) {
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this.addFrame(Infinity);
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}
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for (let i = 0; i < this.frames.length; ++i) {
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img.drawFrame(this.frames[i].ctx, 0, x, y, args);
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}
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}
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} else {
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for (let i = 0; i < this.frames.length; ++i) {
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_drawImage(this.frames[i].ctx, img, x, y, args);
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}
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}
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}
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}
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drawFrame(ctx, frameNum, x, y, args = {}) {
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_drawImage(ctx, this.frames[frameNum].canvas, x, y, args);
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}
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export(outStream) {
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if (this.frames.length > 1) {
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if (outStream.setHeader) outStream.setHeader('Content-Type', 'image/gif');
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const gif = new GifEncoder(this.width, this.height);
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gif.createReadStream().pipe(outStream);
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// gif.setTransparent(0xfefe01);
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gif.setRepeat(0);
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gif.start();
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for (let i = 0; i < this.frames.length; ++i) {
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const frame = this.frames[i];
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gif.setDelay(frame.actualDelay);
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gif.addFrame(frame.ctx);
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}
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gif.finish();
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} else if (this.frames.length === 1) {
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if (outStream.setHeader) outStream.setHeader('Content-Type', 'image/png');
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const stream = this.frames[0].canvas.pngStream();
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stream.pipe(outStream);
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} else {
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throw new Error('No image data to be exported');
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}
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}
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toBuffer() {
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const buf = new streamBuffers.WritableStreamBuffer({
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initialSize: this.height * this.width * 4 * this.frames.length,
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incrementAmount: this.height * this.width * 4
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});
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this.export(buf);
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return new Promise(resolve => {
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buf.on('finish', () => {
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console.log('Render completed');
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resolve(buf.getContents());
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});
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});
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}
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}
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module.exports = {
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CanvasEx,
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ImageEx,
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_drawImage
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};
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