canvas画视频截图

Question

报错Failed to execute 'drawImage' on 'CanvasRenderingContext2D': The provided value is not of type '(CSSImageValue or HTMLImageElement or SVGImageElement or HTMLVideoElement or HTMLCanvasElement or ImageBitmap or OffscreenCanvas)'

求问什么意思

var canvas = document.getElementById('canvas');

var video = document.getElementById('video');
var canvasimg = document.getElementById('canvasimg');
canvas.getContext('2d').drawImage(video, 0, 0, 300, 100);
canvasimg.crossOrigin="anonymous"; 
canvasimg.src = canvas.toDataURL("image/png");

Answer 1

试一下代码写完整，我也没试过少写会怎样：

var context = canvas.getContext('2d');
context.drawImage(oImg, 0, 0,originWidth,originHeight,0,0, targetWidth, targetHeight);