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https://github.com/webmproject/libwebp.git
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f88666eb47
after:24d7f9cbSwitch code to SDL2. fixes: webp_wasm.js:1 Uncaught TypeError: Cannot read properties of null (reading 'addEventListener') at Object.registerOrRemoveHandler (webp_wasm.js:1:101330) at registerMouseEventCallback (webp_wasm.js:1:154227) at _emscripten_set_mousemove_callback_on_thread (webp_wasm.js:1:155015) ... The SDL2 port forces the canvas id to '#canvas':324df6865a/src/video/emscripten/SDL_emscriptenvideo.c (L210)This change maps '#output_canvas' to this entry in specialHTMLTargets[]: https://emscripten.org/docs/api_reference/html5.h.html https://github.com/libsdl-org/SDL/issues/5260 & https://github.com/emscripten-ports/SDL2/issues/130 may also be related. Change-Id: I26f4aa22b9d68b0fc45b83edfe6fe074b59a82a7 Test: emscripten 3.1.16
78 lines
2.1 KiB
HTML
78 lines
2.1 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</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" src="./webp.js"></script>
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<script type="text/javascript">
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'use strict';
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// main wrapper for the function decoding a WebP into a canvas object
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var WebpToCanvas;
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function init() {
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WebpToCanvas = Module.cwrap('WebPToSDL', 'number', ['array', 'number']);
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}
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window.onload = init;
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function decode(webp_data, canvas_id) {
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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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// Map this canvas to the default selector used by emscripten/SDL2.
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specialHTMLTargets["#canvas"] = Module.canvas;
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// decode and measure timing
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var start = new Date();
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var ret = WebpToCanvas(webp_data, webp_data.length);
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var end = new Date();
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var speed_result = document.getElementById('timing');
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// display timing result
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if (speed_result != null) {
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var decode_time = end - start;
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speed_result.innerHTML = '<p>decoding time: ' + decode_time +' ms.</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>
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<p>
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<strong>WebP in JavaScript demo</strong> -
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</p>
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<p>
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WebP decoder in JavaScript, 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!" name="./test_webp_js.webp"
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onclick="loadfile(this.name, '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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