{"id":154306,"date":"2024-05-08T11:30:03","date_gmt":"2024-05-08T03:30:03","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/154306.html"},"modified":"2024-05-08T11:30:06","modified_gmt":"2024-05-08T03:30:06","slug":"%e5%9c%a8-javascript-%e4%b8%ad%ef%bc%8c%e5%a6%82%e4%bd%95%e5%a4%84%e7%90%86%e6%9c%ac%e5%9c%b0%e5%9b%be%e7%89%87%e5%b9%b6%e8%8e%b7%e5%8f%96%e5%85%b6%e4%ba%8c%e8%bf%9b%e5%88%b6%e6%95%b0%e6%8d%ae","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/154306.html","title":{"rendered":"\u5728 JavaScript \u4e2d\uff0c\u5982\u4f55\u5904\u7406\u672c\u5730\u56fe\u7247\u5e76\u83b7\u53d6\u5176\u4e8c\u8fdb\u5236\u6570\u636e"},"content":{"rendered":"

\"\u5728<\/p>\n

\u5904\u7406\u672c\u5730\u56fe\u7247\u5e76\u83b7\u53d6\u5176\u4e8c\u8fdb\u5236\u6570\u636e\u5728JavaScript\u4e2d\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u4efb\u52a1\uff0c\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528FileReader<\/code>\u5bf9\u8c61\u3001\u5229\u7528Canvas<\/code>\u5143\u7d20\u6216\u4f7f\u7528fetch<\/code>\u548cblob<\/code>\u7b49\u591a\u79cd\u65b9\u6cd5\u5b9e\u73b0\u3002\u9996\u5148\uff0c\u901a\u8fc7HTML\u7684<input><\/code>\u6807\u7b7e\u4e0a\u4f20\u56fe\u7247\u6587\u4ef6\uff1b\u63a5\u7740\uff0c\u4f7f\u7528FileReader<\/code>\u5bf9\u8c61\u7684readAsArrayBuffer<\/code>\u65b9\u6cd5\u6765\u8bfb\u53d6\u6587\u4ef6\u5185\u5bb9\u5e76\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\u3002<\/strong><\/p>\n<\/p>\n

\u5728\u4f7f\u7528FileReader<\/code>\u5bf9\u8c61\u65f6\uff0c\u7528\u6237\u53ef\u4ee5\u901a\u8fc7<input type="file"><\/code>\u9009\u62e9\u672c\u5730\u56fe\u7247\uff0c\u7136\u540eJavaScript\u901a\u8fc7FileReader API\u8bfb\u53d6\u6587\u4ef6\u5185\u5bb9\u3002\u5982\u4f7f\u7528readAsDataURL<\/code>\u65b9\u6cd5\uff0c\u53ef\u4ee5\u5c06\u6587\u4ef6\u5185\u5bb9\u8f6c\u5316\u4e3abase64\u7f16\u7801\u7684\u5b57\u7b26\u4e32\uff0c\u800creadAsArrayBuffer<\/code>\u65b9\u6cd5\u5219\u53ef\u4ee5\u83b7\u53d6\u539f\u59cb\u7684\u4e8c\u8fdb\u5236\u6570\u636e\u3002\u5982\u679c\u56fe\u7247\u9700\u8981\u5728\u4e0a\u4f20\u524d\u8fdb\u884c\u526a\u88c1\u6216\u8c03\u6574\u5927\u5c0f\uff0c\u5219\u53ef\u4f7f\u7528Canvas<\/code>\u5143\u7d20\u3002Canvas<\/code>\u53ef\u4ee5\u8bfb\u53d6\u56fe\u7247\u5185\u5bb9\u5e76\u652f\u6301\u56fe\u50cf\u5904\u7406\uff0c\u4e4b\u540e\u53ef\u901a\u8fc7toBlob<\/code>\u65b9\u6cd5\u6216toDataURL<\/code>\u65b9\u6cd5\u83b7\u53d6\u5904\u7406\u540e\u7684\u56fe\u7247\u4e8c\u8fdb\u5236\u6570\u636e\u6216base64\u7f16\u7801\u3002\u6b64\u5916\uff0cfetch<\/code> API\u7ed3\u5408blob<\/code>\u4e5f\u53ef\u7528\u4e8e\u83b7\u53d6\u7f51\u7edc\u56fe\u7247\u8d44\u6e90\u7684\u4e8c\u8fdb\u5236\u6570\u636e\u3002<\/p>\n<\/p>\n

\u4e00\u3001\u4f7f\u7528 HTML \u548c FileReader \u8bfb\u53d6\u56fe\u7247\u6587\u4ef6<\/h3>\n<\/p>\n

HTML\u9875\u9762\u8bbe\u7f6e<\/strong><\/p>\n<\/p>\n

\u5728\u7f51\u9875\u4e0a\uff0c\u901a\u5e38\u4f7f\u7528input\u6807\u7b7e\u6765\u8ba9\u7528\u6237\u9009\u62e9\u8981\u4e0a\u4f20\u7684\u672c\u5730\u56fe\u7247\u6587\u4ef6\u3002<\/p>\n<\/p>\n

<input type="file" id="imageInput" accept="image\/*"><\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8bfb\u53d6\u56fe\u7247\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e<\/strong><\/p>\n<\/p>\n
\u5f53\u7528\u6237\u9009\u62e9\u6587\u4ef6\u540e\uff0c\u53ef\u4ee5\u4f7f\u7528FileReader<\/code>\u7684readAsArrayBuffer<\/code>\u65b9\u6cd5\u8bfb\u53d6\u6587\u4ef6\u7684\u5185\u5bb9\u3002<\/p>\n<\/p>\n
document.getElementById('imageInput').addEventListener('change', function(event) {<\/p>\n
    const file = event.target.files[0];<\/p>\n
    if (file) {<\/p>\n
        const reader = new FileReader();<\/p>\n
        reader.onload = function(evt) {<\/p>\n
            const arrayBuffer = evt.target.result;<\/p>\n
            \/\/ \u5904\u7406arrayBuffer\u5373\u4e3a\u56fe\u7247\u7684\u4e8c\u8fdb\u5236\u6570\u636e<\/p>\n
        };<\/p>\n
        reader.readAsArrayBuffer(file);<\/p>\n
    }<\/p>\n
});<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e8c\u3001\u4f7f\u7528 Canvas \u5904\u7406\u548c\u83b7\u53d6\u56fe\u7247\u6570\u636e<\/h3>\n<\/p>\n
\u7ed8\u5236\u56fe\u7247\u5230Canvas<\/strong><\/p>\n<\/p>\n
\u9996\u5148\uff0c\u9700\u8981\u5c06\u672c\u5730\u56fe\u7247\u7ed8\u5236\u5230Canvas\u4e0a\uff0c\u5728\u7ed8\u5236\u4e4b\u524d\uff0c\u9700\u8981\u7b49\u5f85\u56fe\u7247\u52a0\u8f7d\u5b8c\u6210\u3002<\/p>\n<\/p>\n
function handleImage(file) {<\/p>\n
    const img = new Image();<\/p>\n
    img.onload = function() {<\/p>\n
        const canvas = document.createElement('canvas');<\/p>\n
        canvas.width = img.width;<\/p>\n
        canvas.height = img.height;<\/p>\n
        const ctx = canvas.getContext('2d');<\/p>\n
        ctx.drawImage(img, 0, 0);<\/p>\n
        \/\/ \u63a5\u4e0b\u6765\u53ef\u4ee5\u5bf9Canvas\u8fdb\u884c\u64cd\u4f5c<\/p>\n
    };<\/p>\n
    img.src = URL.createObjectURL(file);<\/p>\n
}<\/p>\n
document.getElementById('imageInput').addEventListener('change', function(event) {<\/p>\n
    const file = event.target.files[0];<\/p>\n
    if (file) {<\/p>\n
        handleImage(file);<\/p>\n
    }<\/p>\n
});<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u901a\u8fc7Canvas\u83b7\u53d6\u4e8c\u8fdb\u5236\u6570\u636e<\/strong><\/p>\n<\/p>\n
\u5b8c\u6210\u56fe\u50cf\u5904\u7406\u540e\uff0c\u53ef\u4ee5\u4f7f\u7528toBlob<\/code>\u65b9\u6cd5\u83b7\u53d6\u56fe\u50cf\u7684\u4e8c\u8fdb\u5236\u6570\u636e\u3002<\/p>\n<\/p>\n
canvas.toBlob(function(blob) {<\/p>\n
    \/\/ \u6b64\u5904\u7684blob\u5373\u4e3a\u56fe\u7247\u7684\u4e8c\u8fdb\u5236\u6570\u636e<\/p>\n
}, 'image\/png');<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001\u4f7f\u7528 fetch \u548c Blob \u83b7\u53d6\u7f51\u7edc\u56fe\u7247\u7684\u4e8c\u8fdb\u5236\u6570\u636e<\/h3>\n<\/p>\n
\u6709\u65f6\u9700\u8981\u5904\u7406\u7684\u4e0d\u662f\u672c\u5730\u56fe\u7247\u6587\u4ef6\uff0c\u800c\u662f\u7f51\u7edc\u4e0a\u7684\u56fe\u7247\u8d44\u6e90\u3002<\/p>\n<\/p>\n
\u83b7\u53d6\u7f51\u7edc\u56fe\u7247<\/strong><\/p>\n<\/p>\n
fetch('image-url')<\/p>\n
    .then(response => response.blob())<\/p>\n
    .then(blob => {<\/p>\n
        \/\/ \u6b64\u5904\u7684blob\u5c31\u662f\u56fe\u7247\u7684\u4e8c\u8fdb\u5236\u6570\u636e<\/p>\n
    });<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u8f6c\u6362Blob\u4e3a\u5176\u4ed6\u683c\u5f0f<\/strong><\/p>\n<\/p>\n
\u5982\u679c\u9700\u8981\u5c06\u7f51\u7edc\u56fe\u7247\u8f6c\u6362\u4e3aArrayBuffer\u6216\u5176\u4ed6\u683c\u5f0f\uff0c\u53ef\u4ee5\u4f7f\u7528FileReader<\/code>\u3002<\/p>\n<\/p>\n
function blobToArrayBuffer(blob) {<\/p>\n
    const reader = new FileReader();<\/p>\n
    reader.onload = function(evt) {<\/p>\n
        const arrayBuffer = evt.target.result;<\/p>\n
        \/\/ \u4f7f\u7528arrayBuffer<\/p>\n
    };<\/p>\n
    reader.readAsArrayBuffer(blob);<\/p>\n
}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001\u5904\u7406\u8de8\u57df\u95ee\u9898<\/h3>\n<\/p>\n
\u5728\u83b7\u53d6\u975e\u540c\u6e90\u7f51\u7edc\u56fe\u7247\u4e8c\u8fdb\u5236\u6570\u636e\u65f6\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u8de8\u57df\u9650\u5236\u95ee\u9898\u3002<\/p>\n<\/p>\n
CORS\u89e3\u51b3\u8de8\u57df\u95ee\u9898<\/strong><\/p>\n<\/p>\n
\u9700\u8981\u670d\u52a1\u5668\u7aef\u914d\u7f6e\u9002\u5f53\u7684CORS\u7b56\u7565\uff0c\u786e\u4fdd\u56fe\u7247\u8d44\u6e90\u7684\u63d0\u4f9b\u65b9\u5141\u8bb8\u8de8\u57df\u4f7f\u7528\u3002<\/p>\n<\/p>\n
fetch('image-url', {<\/p>\n
    mode: 'cors', \/\/ \u6307\u5b9a\u8bf7\u6c42\u6a21\u5f0f\u4e3aCORS<\/p>\n
    headers: {<\/p>\n
        'Access-Control-Allow-Origin': '*'<\/p>\n
    }<\/p>\n
})<\/p>\n
.then(response => response.blob())<\/p>\n
.then(blob => {<\/p>\n
    \/\/ \u83b7\u53d6\u4e8c\u8fdb\u5236\u6570\u636e<\/p>\n
});<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4ee5\u4e0a\u65b9\u6cd5\u4e2d\uff0cFileReader API\u63d0\u4f9b\u7684\u591a\u79cd\u8bfb\u53d6\u65b9\u6cd5\u548cCanvas\u7684\u4e30\u5bcc\u56fe\u50cf\u5904\u7406\u529f\u80fd\uff0c\u4ee5\u53ca\u73b0\u4ee3\u6d4f\u89c8\u5668\u7684Fetch API\uff0c\u90fd\u53ef\u4ee5\u5e2e\u52a9\u5f00\u53d1\u8005\u5b8c\u6210\u4ece\u672c\u5730\u6587\u4ef6\u8bfb\u53d6\u3001\u5904\u7406\u56fe\u7247\u5e76\u83b7\u53d6\u5176\u4e8c\u8fdb\u5236\u6570\u636e\u7684\u4efb\u52a1\u3002\u5173\u952e\u5728\u4e8e\u6839\u636e\u5177\u4f53\u9700\u6c42\u9009\u62e9\u5408\u9002\u7684\u6280\u672f\u8def\u5f84\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
\u5982\u4f55\u5728 JavaScript \u4e2d\u8bfb\u53d6\u672c\u5730\u56fe\u7247\u7684\u4e8c\u8fdb\u5236\u6570\u636e\uff1f<\/strong>
\n\u8981\u5728 JavaScript \u4e2d\u5904\u7406\u672c\u5730\u56fe\u7247\u5e76\u83b7\u53d6\u5176\u4e8c\u8fdb\u5236\u6570\u636e\uff0c\u53ef\u4ee5\u4f7f\u7528 FileReader \u5bf9\u8c61\u7684 readAsArrayBuffer \u6216\u8005 readAsDataURL \u65b9\u6cd5\u3002\u901a\u8fc7\u9009\u62e9\u6587\u4ef6\u4e0a\u4f20\u63a7\u4ef6\u6216\u8005\u62d6\u653e\u4e8b\u4ef6\uff0c\u83b7\u53d6\u5230\u56fe\u7247\u6587\u4ef6\u5bf9\u8c61\u540e\uff0c\u53ef\u4ee5\u4f7f\u7528 FileReader \u5bf9\u8c61\u5c06\u5176\u8bfb\u53d6\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\u6216\u8005\u6570\u636eURL\uff0c\u5e76\u8fdb\u884c\u8fdb\u4e00\u6b65\u5904\u7406\u3002<\/p>\n
\u5982\u4f55\u5c06\u672c\u5730\u56fe\u7247\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\u5728 JavaScript \u4e2d\u8fdb\u884c\u64cd\u4f5c\uff1f<\/strong>
\n\u8981\u5c06\u672c\u5730\u56fe\u7247\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\u5728 JavaScript \u4e2d\u8fdb\u884c\u64cd\u4f5c\uff0c\u53ef\u4ee5\u4f7f\u7528 FileReader \u5bf9\u8c61\u7684 readAsArrayBuffer \u65b9\u6cd5\u3002\u9996\u5148\uff0c\u83b7\u53d6\u5230\u7528\u6237\u9009\u62e9\u7684\u56fe\u7247\u6587\u4ef6\u5bf9\u8c61\uff0c\u7136\u540e\u521b\u5efa\u4e00\u4e2a\u65b0\u7684 FileReader \u5bf9\u8c61\u3002\u4f7f\u7528 readAsArrayBuffer \u65b9\u6cd5\uff0c\u5c06\u56fe\u7247\u6587\u4ef6\u8bfb\u53d6\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\u3002\u4e00\u65e6\u8bfb\u53d6\u5b8c\u6210\uff0c\u53ef\u4ee5\u5728 onload \u4e8b\u4ef6\u4e2d\u83b7\u53d6\u5230\u4e8c\u8fdb\u5236\u6570\u636e\u3002<\/p>\n
\u5982\u4f55\u901a\u8fc7 JavaScript \u5904\u7406\u672c\u5730\u56fe\u7247\u5e76\u5c06\u5176\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\uff1f<\/strong>
\n\u8981\u901a\u8fc7 JavaScript \u5904\u7406\u672c\u5730\u56fe\u7247\u5e76\u5c06\u5176\u8f6c\u6362\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\uff0c\u53ef\u4ee5\u4f7f\u7528 FileReader \u5bf9\u8c61\u7684 readAsArrayBuffer \u65b9\u6cd5\u3002\u9996\u5148\uff0c\u83b7\u53d6\u7528\u6237\u9009\u62e9\u6216\u62d6\u653e\u7684\u56fe\u7247\u6587\u4ef6\u5bf9\u8c61\u3002\u7136\u540e\uff0c\u521b\u5efa\u4e00\u4e2a\u65b0\u7684 FileReader \u5bf9\u8c61\uff0c\u4f7f\u7528 readAsArrayBuffer \u65b9\u6cd5\u8bfb\u53d6\u56fe\u7247\u6587\u4ef6\u4e3a\u4e8c\u8fdb\u5236\u6570\u636e\u3002\u6700\u540e\uff0c\u5728 FileReader \u7684 onload \u4e8b\u4ef6\u4e2d\uff0c\u53ef\u4ee5\u83b7\u53d6\u5230\u8bfb\u53d6\u5b8c\u6210\u7684\u4e8c\u8fdb\u5236\u6570\u636e\uff0c\u8fdb\u884c\u8fdb\u4e00\u6b65\u7684\u5904\u7406\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u5904\u7406\u672c\u5730\u56fe\u7247\u5e76\u83b7\u53d6\u5176\u4e8c\u8fdb\u5236\u6570\u636e\u5728JavaScript\u4e2d\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u4efb\u52a1\uff0c\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528FileReader\u5bf9\u8c61\u3001 […]","protected":false},"author":3,"featured_media":154311,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/154306"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=154306"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/154306\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/154311"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=154306"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=154306"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=154306"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}