mirror of
https://github.com/webmproject/libwebp.git
synced 2024-11-20 04:18:26 +01:00
85 lines
2.4 KiB
HTML
85 lines
2.4 KiB
HTML
<!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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<title>simple Javascript WebP decoding demo, using Web-Assembly (WASM)</title>
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<script type="text/javascript">
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var Module = {
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noInitialRun : true
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};
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</script>
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<script type="text/javascript">
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function init() {
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var xhr = new XMLHttpRequest();
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xhr.open('GET', 'webp_wasm.wasm', true);
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xhr.responseType = 'arraybuffer';
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xhr.onload = function() {
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Module.wasmBinary = xhr.response;
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var script = document.createElement('script');
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script.src = "webp_wasm.js";
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document.body.appendChild(script);
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};
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xhr.send(null);
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}
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function decode(webp_data, canvas_id) {
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var result;
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if (Module["asm"] != undefined) {
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// wrapper for the function decoding a WebP into a canvas object
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WebpToCanvas = Module.cwrap('WebpToSDL', 'number', ['array', 'number']);
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// get the canvas to decode into
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var canvas = document.getElementById(canvas_id);
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if (canvas == null) return;
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// clear previous picture (if any)
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Module.canvas = canvas;
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canvas.getContext('2d').clearRect(0, 0, canvas.width, canvas.height);
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// decode and measure timing
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start = new Date();
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var ret = WebpToCanvas(webp_data, webp_data.length);
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end = new Date();
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var decode_time = end - start;
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result = 'decoding time: ' + decode_time +' ms.';
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} else {
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result = "WASM module not finished loading! Please retry";
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}
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// display timing result
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speed_result = document.getElementById('timing');
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if (speed_result != null) {
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speed_result.innerHTML = '<p>'+ result + '</p>';
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}
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}
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function loadfile(filename, canvas_id) {
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var xhr = new XMLHttpRequest();
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xhr.open('GET', filename);
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xhr.responseType = 'arraybuffer';
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xhr.onreadystatechange = function() {
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if (xhr.readyState == 4 && xhr.status == 200) {
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var webp_data = new Uint8Array(xhr.response);
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decode(webp_data, canvas_id);
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}
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};
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xhr.send();
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}
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</script>
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</head>
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<body onload='init()'>
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<p>
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<strong>WebP demo using Web-Assembly</strong> -
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</p>
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<p>
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WASM version of the WebP decoder, using libwebp compiled with
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<a href="https://github.com/kripken/emscripten/wiki">Emscripten</a>.
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</p>
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<p id="image_buttons">
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<input type="button" value="test image!"
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onclick="loadfile('./test_webp_wasm.webp', 'output_canvas')">
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</p>
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<p id="timing">Timing: N/A</p>
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<canvas id="output_canvas">Your browser does not support canvas</canvas>
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</body>
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</html>
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