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@@ -1,15 +1,15 @@
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export function resize(base64, callback) {
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const w = 1440
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- var newImage = new Image()
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- var quality = 0.8 //压缩系数
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+ let newImage = new Image()
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+ let quality = 0.8 //压缩系数
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newImage.src = base64
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newImage.setAttribute('crossOrigin', 'Anonymous')
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- var imgWidth, imgHeight
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+ let imgWidth, imgHeight
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newImage.onload = function () {
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imgWidth = this.width
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imgHeight = this.height
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- var canvas = document.createElement('canvas')
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- var ctx = canvas.getContext('2d')
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+ let canvas = document.createElement('canvas')
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+ let ctx = canvas.getContext('2d')
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if (Math.max(imgWidth, imgHeight) > w) {
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if (imgWidth > imgHeight) {
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canvas.width = w
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@@ -25,16 +25,11 @@ export function resize(base64, callback) {
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}
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ctx.clearRect(0, 0, canvas.width, canvas.height)
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ctx.drawImage(this, 0, 0, canvas.width, canvas.height)
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- var base64 = canvas.toDataURL('image/jpeg', quality) // 执行压缩
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+ let base64 = canvas.toDataURL('image/jpeg', quality) // 执行压缩
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while (base64.length / 1024 > 500) {
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quality -= 0.01
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base64 = canvas.toDataURL('image/jpeg', quality)
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}
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- // 防止最后一次压缩低于最低尺寸，只要quality递减合理，无需考虑
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- // while (base64.length / 1024 < 50) {
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- // quality += 0.001;
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- // base64 = canvas.toDataURL("image/jpeg", quality);
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- // }
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- callback(base64) //必须通过回调函数返回，否则无法及时拿到该值
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+ callback(base64)
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}
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}
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