图片处理

Canvas 中的图片处理

async function getCanvasFromImageUrl(imgUrl) {
const img = new Image();
img.crossOrigin = 'Anonymous';
img.src = imgUrl;
return new Promise((resolve, reject) => {
img.onload = () => {
const canvas = document.createElement('canvas');
canvas.width = img.width;
canvas.height = img.height;
const ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0);
resolve(canvas);
};
img.onerror = err => {
reject(err);
};
});
}