Javascript nodejs画布:给定的图像尚未完成加载
我得到了这个错误:Javascript nodejs画布:给定的图像尚未完成加载,javascript,node.js,canvas,node-canvas,Javascript,Node.js,Canvas,Node Canvas,我得到了这个错误: ctx.drawImage(avatar, 50, 50 ); ^ Error: Image given has not completed loading at Request.request.get 尝试执行此操作时: app.get('/test', (req, res) => { let Canvas = require('canvas') , Image = Canvas.Image
ctx.drawImage(avatar, 50, 50 );
^
Error: Image given has not completed loading
at Request.request.get
尝试执行此操作时:
app.get('/test', (req, res) => {
let Canvas = require('canvas')
, Image = Canvas.Image
, canvas = new Canvas(500, 500)
, ctx = canvas.getContext('2d');
let request = require('request');
let avatar = new Image;
request.get('http://s.4pda.to/pKugVJ7TmgG1Tg5z0SsVLfRCUqTAz2oqz1lz2z2co.jpg', (err, res) => {
avatar.src = res;
ctx.drawImage(avatar, 50, 50 );
});
ctx.font = '30px Impact';
ctx.rotate(.1);
ctx.fillText("Awesome!", 50, 100);
let te = ctx.measureText('Awesome!');
ctx.strokeStyle = 'rgba(0,0,0,0.5)';
ctx.beginPath();
ctx.stroke();
res.setHeader('Content-Type', 'image/png');
canvas.pngStream().pipe(res)
});
我使用的是node 8.3.0、node canvas 1.6.6、mac os x 10.12.6。
我已经尝试过重新安装和重建cairo、jpg/png libs、pixman、node canvas,但没有帮助 任何对此进行研究的人,请参见LinusU于2017年8月13日发表的评论: 从那里抄袭,他建议这样一种方法来加载图像,并等待加载:
function loadImage (url) {
return new Promise((resolve, reject) => {
const img = new Canvas.Image()
img.onload = () => resolve(img)
img.onerror = () => reject(new Error('Failed to load image'))
request.get(url, (err, res) => {
if (err) return reject(err)
img.src = res.body
})
})
}
这对我很有效