neihangif/server/index.js

const Koa = require('koa')
const Router = require('koa-router');
const serve = require('koa-static')
const app = new Koa()
const router = new Router()
const gifInfo = require('./config/gifInfo');
const gifEncoder = require('gifencoder');
const Canvas = require('canvas');
const fs = require('fs');
const path = require('path')

router.get('/getgif', async (context, next) => {
	let start = Date.now();
	let query = context.query;
	let task = query.task
	let textArr = query.text.split(",")
	let target = gifInfo[task]
	if(target) {
		textArr.forEach((n, i) => {
			target.textArr[i].text = n
		})
		
		var ctxW = target.width;
		var ctxH = target.height;
		var encoder = new gifEncoder(ctxW, ctxH);

		console.log(`正在生成gif...`);

		encoder.createReadStream().pipe(fs.createWriteStream(`dist/${task}.gif`));
		encoder.start();
		encoder.setRepeat(0);
		encoder.setDelay(1);
		encoder.setQuality(10);

		var canvas = new Canvas(ctxW, ctxH);
		var ctx = canvas.getContext('2d');

		function drawText(ctx, text, x, y) {
			ctx.fillStyle = "#ffffff";
			ctx.font = "16px Arial";
			ctx.textAlign = "center";
			ctx.fillText(text, x, y)
		}

		var imgObj = new Canvas.Image()
		for (let i = 0; i <= target.size; i++) {
			imgObj.src = `res/${task}/image-${i}.png`
			ctx.drawImage(imgObj, 0, 0, ctxW, ctxH)

			target.textArr.forEach(n => {
				if(i >= n.arr[0] && i < n.arr[1]) {
					drawText(ctx, n.text, ctxW / 2, ctxH - 6)
				}
			})

			encoder.addFrame(ctx)
		}
		encoder.finish()

		let ms = Date.now() - start;
		console.log(`成功生成，耗时：${ms}ms`);

		context.body = {
			gifurl: `${task}.gif`
		}
		// next()
	}
	
});

app.use(serve(__dirname + '/dist'));
  
app.use(router.routes())
app.use(router.allowedMethods())

const http = require('http');
http.createServer(app.callback()).listen(4008);

console.log(`start server, listen: 4008`);