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