111 lines
3.7 KiB
HTML
111 lines
3.7 KiB
HTML
<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>libwebp 压缩图片的 wasm 实现</title>
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</head>
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<body>
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WebP 图：
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<span>压缩：<span id="webpSize"></span></span>
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<img id="webpImage" alt="WebP Image">
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<br>
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<br>
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<!-- <button onclick="clickIt()">strat4次</button> -->
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<div id="result"></div>
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</body>
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<script>
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function base64ToArrayBuffer(base64) {
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var binaryString = atob(base64);
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var len = binaryString.length;
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var bytes = new Uint8Array(len);
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for (var i = 0; i < len; i++) {
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bytes[i] = binaryString.charCodeAt(i);
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}
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// 返回 ArrayBuffer
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return bytes.buffer;
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}
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// 将 WASM 生成的二进制数据转换成 Base64
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function arrayBufferToBase64(buffer) {
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let binary = '';
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let len = buffer.byteLength;
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for (let i = 0; i < len; i++) {
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binary += String.fromCharCode(buffer[i]);
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}
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return btoa(binary); // 使用 JavaScript 的 btoa() 函数
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}
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var fileurl = './image.png'
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// 初始化 WebAssembly 模块
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var Module = {
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onRuntimeInitialized: function () {
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// let baseData= document.getElementById("base64Image").src;
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// baseData=baseData.split(",")[1];
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// let buffer = base64ToArrayBuffer(baseData);
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// decodeToWebpp(buffer);
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// document.getElementById("base64Image").src = fileurl;
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decodeIt();
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},
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onAbort:(e)=>{
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alert(e);
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}
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};
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function clickIt(ti=4){
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for(var i=0;i<ti;i++){
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decodeIt(`./${i+1}.jpg`);
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}
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}
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var startTime=0;
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function decodeIt(url) {
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if (!url) {
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url = fileurl;
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}
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fetch(url).then(response => response.arrayBuffer()).then(buffer => {
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startTime=Date.now();
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decodeToWebpp(buffer);
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})
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}
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function decodeToWebpp(buffer) {
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// 显示原始图片大小
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let size = (buffer.byteLength / 1024).toFixed(2);
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// 转换图像为 Uint8Array
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var inputData = new Uint8Array(buffer);
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// 分配内存以存储输出 WebP 大小
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var outputSizePtr = Module._malloc(4); // 存储输出大小的指针
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// 设置目标宽高和质量因子
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var targetWidth = 300; // 目标宽度
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var targetHeight = 300; // 目标高度
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var qualityFactor = 50 // 压缩质量 (0 - 100)
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var inputDataPtr = Module._malloc(inputData.length);
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Module.HEAPU8.set(inputData, inputDataPtr);
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var webpPtr = Module._convert_image_to_webp(inputDataPtr, inputData.length, targetWidth, targetHeight, qualityFactor, outputSizePtr);
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// 调用 WebAssembly 函数进行图像转换，返回 WebP 数据指针
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// 获取 WebP 数据大小
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var outputSize = Module.getValue(outputSizePtr, 'i32');
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// 从 WebAssembly 内存中读取 WebP 数据
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var webpData = new Uint8Array(Module.HEAPU8.buffer, webpPtr, outputSize);
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document.getElementById('result').innerText+=' '+(Date.now()-startTime) +'ms';
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// 显示 WebP 图片大小
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document.getElementById("webpSize").textContent =`${size}KB => ${(outputSize / 1024).toFixed(2)}KB`;
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// 将 WebP 数据转换为 base64，并显示
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let img = document.getElementById("webpImage");
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img.src = "data:image/webp;base64," + arrayBufferToBase64(webpData);
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// 使用完成后释放内存
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Module._free(outputSizePtr);
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Module._free(webpPtr);
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Module._free(inputDataPtr);
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}
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</script>
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<script src="convert_image_to_webp.js"></script> |