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67 lines
2.0 KiB
67 lines
2.0 KiB
3 years ago
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width,user-scalable=no,initial-scale=1,maximum-scale=1,minimum-scale=1" >
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<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate" />
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<meta http-equiv="Pragma" content="no-cache" />
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<meta http-equiv="Expires" content="0" />
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<title>Document</title>
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</head>
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<body>
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<div id="btn-image"
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style="border:1px solid gray;padding: 10px;">测试</div>
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<img src=""
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id="img_test"
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alt="">
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<script>
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const btn = document.querySelector('#btn-image')
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btn.onclick = () => {
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console.log(123);
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const input = document.createElement('input')
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input.setAttribute('type', 'file')
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input.setAttribute('accept', '*')
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input.onchange = (e) => {
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const file = e.target.files[0]
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const render = new FileReader() // 创建读取文件对象
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render.readAsDataURL(file) // 读取file文件,得到的结果为base64
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render.onload = function () {
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// result
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const renderImg = new Image()
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renderImg.src = render.result // 把读取到的base64图片设置给img的src属性
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renderImg.onload = function () {
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const imgWidth = renderImg.width
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const imgHeight = renderImg.height
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const canvas = document.createElement('canvas') // 如果不需要放在页面上,使用js创建该元素就可以了
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const canvasContent = canvas.getContext('2d')
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canvas.width = imgWidth
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canvas.height = imgHeight
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canvasContent.drawImage(renderImg, 0, 0, imgWidth, imgHeight) // 绘画到画布上
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const base64 = canvas.toDataURL(file.type, 1)
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console.log(base64);
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const domImg = document.querySelector('#img_test')
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domImg.src = base64
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}
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}
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}
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input.click()
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}
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</script>
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</body>
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</html>
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