libbpg-0.9.3

post.js

@@ -0,0 +1,168 @@
+/*
+ * BPG Javascript decoder
+ *
+ * Copyright (c) 2014 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+window['BPGDecoder'] = function(ctx) {
+    this.ctx = ctx;
+    this['imageData'] = null;
+    this['onload'] = null;
+}
+
+window['BPGDecoder'].prototype = {
+
+malloc: Module['cwrap']('malloc', 'number', [ 'number' ]),
+
+free: Module['cwrap']('free', 'void', [ 'number' ]),
+
+bpg_decoder_open: Module['cwrap']('bpg_decoder_open', 'number', [ ]),
+
+bpg_decoder_decode: Module['cwrap']('bpg_decoder_decode', 'number', [ 'number', 'array', 'number' ]),
+
+bpg_decoder_get_info: Module['cwrap']('bpg_decoder_get_info', 'number', [ 'number', 'number' ]),
+
+bpg_decoder_start: Module['cwrap']('bpg_decoder_start', 'number', [ 'number', 'number' ]),
+
+bpg_decoder_get_line: Module['cwrap']('bpg_decoder_get_line', 'number', [ 'number', 'number' ]),
+
+bpg_decoder_close: Module['cwrap']('bpg_decoder_close', 'void', [ 'number' ] ),
+
+load: function(url) 
+{
+    var request = new XMLHttpRequest();
+    var this1 = this;
+
+    request.open("get", url, true);
+    request.responseType = "arraybuffer";
+    request.onload = function(event) {
+        this1._onload(request, event);
+    };
+    request.send();
+},
+
+_onload: function(request, event)
+{
+    var data = request.response;
+    var array = new Uint8Array(data);
+    var img, w, h, img_info_buf, cimg, p0, rgba_line, w4;
+    var heap8, heap32, dst, v, i, y, func;
+
+    //    console.log("loaded " + data.byteLength + " bytes");
+
+    img = this.bpg_decoder_open();
+
+    if (this.bpg_decoder_decode(img, array, array.length) < 0) {
+        console.log("could not decode image");
+        return;
+    }
+    
+    img_info_buf = this.malloc(9 * 4);
+    this.bpg_decoder_get_info(img, img_info_buf);
+    /* extract the image info */
+    heap32 = Module['HEAPU32'];
+    w = heap32[img_info_buf >> 2];
+    h = heap32[(img_info_buf + 4) >> 2];
+    this.free(img_info_buf);
+
+//    console.log("image " + w + " " + h);
+    
+    /* select RGBA32 output */
+    this.bpg_decoder_start(img, 1);
+
+    rgba_line = this.malloc(w * 4);
+    cimg = this.ctx.createImageData(w, h);
+    dst = cimg.data;
+    p0 = 0;
+    heap8 = Module['HEAPU8'];
+    w4 = w * 4;
+    for(y = 0; y < h; y++) {
+        this.bpg_decoder_get_line(img, rgba_line);
+        for(i = 0; i < w4; i = (i + 1) | 0) {
+            dst[p0] = heap8[(rgba_line + i) | 0] | 0;
+            p0 = (p0 + 1) | 0;
+        }
+    }
+
+    this.free(rgba_line);
+
+    this.bpg_decoder_close(img);
+
+    this['imageData'] = cimg;
+    
+    if (this['onload'])
+        this['onload']();
+}
+
+};
+
+window.onload = function() { 
+    var i, n, el, tab, tab1, url, dec, canvas, id, style, ctx, dw, dh;
+
+    /* put all images to load in a separate array */
+    tab = document.images;
+    n = tab.length;
+    tab1 = [];
+    for(i = 0; i < n; i++) {
+        el = tab[i];
+        url = el.src;
+        if (url.substr(-4,4).toLowerCase() == ".bpg") {
+            tab1[tab1.length] = el;
+        }
+    }
+
+    /* change the tags to canvas */
+    n = tab1.length;
+    for(i = 0; i < n; i++) {
+        el = tab1[i];
+        url = el.src;
+        canvas = document.createElement("canvas");
+
+        if (el.id)
+            canvas.id = el.id;
+        if (el.className)
+            canvas.className = el.className;
+
+        /* handle simple attribute cases to resize the canvas */
+        dw = el.getAttribute("width") | 0;
+        if (dw) {
+            canvas.style.width = dw + "px";
+        }
+        dh = el.getAttribute("height") | 0;
+        if (dh) {
+            canvas.style.height = dh + "px";
+        }
+
+        el.parentNode.replaceChild(canvas, el);
+
+        ctx = canvas.getContext("2d");
+        dec = new BPGDecoder(ctx);
+        dec.onload = (function(canvas, ctx) {
+            var imageData = this['imageData'];
+            /* resize the canvas to the image size */
+            canvas.width = imageData.width;
+            canvas.height = imageData.height;
+
+            /* draw the image */
+            ctx.putImageData(imageData, 0, 0);
+        }).bind(dec, canvas, ctx);
+        dec.load(url);
+    }
+};