+++ /dev/null
-<html>
- <head>
- <title>Compress colors using VQ</title>
- <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
- <style type="text/css">
- @import "../../../../dojo/resources/dojo.css";
- @import "../../../../dijit/tests/css/dijitTests.css";
-
- .pane { margin-top: 2em; }
- </style>
- <script type="text/javascript" src="../../../../dojo/dojo.js" djConfig="isDebug: true"></script>
- <script type="text/javascript">
- dojo.require("dojox.encoding.tests.compression.colors");
- dojo.require("dojox.encoding.compression.splay");
- dojo.require("dojox.encoding.bits");
-
- var colors = dojox.encoding.tests.compression.colors;
-
- var dist = function(a, b){
- var r = a[0] - b[0], g = a[1] - b[1], b = a[2] - b[2];
- return r * r + g * g + b * b;
- };
-
- var hexcolor = function(c){
- return "#" + (c[0] < 16 ? "0" : "") + c[0].toString(16) +
- (c[1] < 16 ? "0" : "") + c[1].toString(16) +
- (c[2] < 16 ? "0" : "") + c[2].toString(16);
- };
-
- var maxdist = function(a, b, maxdist){
- var r = Math.abs(a[0] - b[0]), g = Math.abs(a[1] - b[1]), b = Math.abs(a[2] - b[2]);
- ++maxdist[bits(r)];
- ++maxdist[bits(g)];
- ++maxdist[bits(b)];
- };
-
- var encodeColor = function(a, b, splay, stream){
- var r = a[0] - b[0], g = a[1] - b[1], b = a[2] - b[2];
- stream.putBits(r < 0 ? 1 : 0, 1);
- splay.encode(Math.abs(r), stream);
- stream.putBits(g < 0 ? 1 : 0, 1);
- splay.encode(Math.abs(g), stream);
- stream.putBits(b < 0 ? 1 : 0, 1);
- splay.encode(Math.abs(b), stream);
- };
-
- var bits = function(x){
- var w = 1;
- for(var v = 2; x >= v; v <<= 1, ++w);
- return w;
- };
-
- var runVQ = function(n){
- dojo.byId("status").innerHTML = "<em>Initializing...</em>";
- dojo.byId("report").innerHTML = "<em>Running VQ...</em>";
- var clusters = [];
- // select initial cluster centers
- var empty = {};
- for(var i in colors){
- if(i in empty){ continue; }
- clusters.push({center: colors[i]});
- if(clusters.length == n){ break; }
- }
- /*
- for(var i = 0; i < n; ++i){
- var r = Math.floor(Math.random() * 256), g = Math.floor(Math.random() * 256), b = Math.floor(Math.random() * 256);
- clusters.push({center: [r, g, b]});
- }
- */
- // do runs
- dojo.byId("status").innerHTML = "<div>Starting runs...</div>";
- var jitter = 0, niter = 1;
- do {
- // save previous centers
- var old_clusters = [];
- dojo.forEach(clusters, function(c){ old_clusters.push({center: c.center}); c.members = []; });
- // assign colors to clusters
- for(var i in colors){
- if(i in empty){ continue; }
- var c = colors[i], k = -1, kd = Number.MAX_VALUE;
- for(var j = 0; j < clusters.length; ++j){
- var jd = dist(clusters[j].center, c);
- if(jd < kd){ k = j, kd = jd; }
- }
- clusters[k].members.push(i);
- }
- // recalculate cluster centers
- for(var i = 0; i < clusters.length; ++i){
- if(!clusters[i].members.length){ continue; }
- var r = 0, g = 0, b = 0;
- dojo.forEach(clusters[i].members, function(name){
- var c = colors[name];
- r += c[0];
- g += c[1];
- b += c[2];
- });
- r = Math.round(r / clusters[i].members.length);
- g = Math.round(g / clusters[i].members.length);
- b = Math.round(b / clusters[i].members.length);
- clusters[i].center = [r, g, b];
- }
- // calculate the jitter
- jitter = 0;
- for(var i = 0; i < clusters.length; ++i){
- jitter = Math.max(jitter, dist(clusters[i].center, old_clusters[i].center));
- }
- var node = dojo.doc.createElement("div");
- node.innerHTML = "Run #" + niter + ", jitter = " + jitter;
- dojo.byId("status").appendChild(node);
- ++niter;
- }while(jitter > 1 && niter < 1000);
- // calculate the required number of bytes
- var output = new dojox.encoding.bits.OutputStream(),
- splay = new dojox.encoding.compression.Splay(256);
- for(var i = 0; i < clusters.length; ++i){
- var c = clusters[i], m = c.members, d = 0, ol = output.getWidth();
- output.putBits(c.center[0], 8);
- output.putBits(c.center[1], 8);
- output.putBits(c.center[2], 8);
- splay.reset();
- c.maxdist = [0, 0, 0, 0, 0, 0, 0, 0, 0];
- for(var j = 0; j < m.length; ++j){
- var color = colors[m[j]];
- maxdist(c.center, color, c.maxdist);
- encodeColor(c.center, color, splay, output);
- }
- c.bits = output.getWidth() - ol;
- }
- var node = dojo.doc.createElement("div");
- node.innerHTML = "Required " + Math.ceil(output.getWidth() / 8) + " bytes";
- dojo.byId("status").appendChild(node);
- // generate color tables
- var reps = [];
- for(var i = 0; i < clusters.length; ++i){
- var c = clusters[i], m = c.members;
- reps.push("<p>Cluster #" + i + " contains " + m.length + " members. Length histogram:");
- for(var j = 0; j < c.maxdist.length; ++j){
- if(c.maxdist[j]){
- reps.push(" " + j + "—" + c.maxdist[j]);
- }
- }
- reps.push(". It requires " + c.bits + " bits (" + Math.ceil(c.bits / 8) + " bytes) to be encoded.</p>");
- reps.push("<table>");
- var wd = dist([255,255,255], c.center), bd = dist([0,0,0], c.center);
- reps.push("<tr><td style='background: " + hexcolor(c.center) + "; color: " +
- (wd < bd ? "black" : "white") + "'><strong>CENTER</strong></td><td>" +
- c.center[0] + "</td><td>" + c.center[1] + "</td><td>" + c.center[2] + "</td></tr>");
- for(var j = 0; j < m.length; ++j){
- var color = colors[m[j]];
- wd = dist([255,255,255], color);
- bd = dist([0,0,0], color);
- reps.push("<tr><td style='background: " + m[j] + "; color: " +
- (wd < bd ? "black" : "white") + "'><strong>" + m[j] + "</strong></td><td>" +
- color[0] + "</td><td>" + color[1] + "</td><td>" + color[2] + "</td></tr>");
- }
- reps.push("</table>");
- }
- dojo.byId("report").innerHTML = reps.join("\n");
- };
-
- run = function(){
- var n = parseInt(dojo.byId("ncluster").value);
- runVQ(n);
- };
-
- dojo.addOnLoad(function(){
- dojo.connect(dojo.byId("run"), "onclick", run);
- });
- </script>
- </head>
- <body>
- <h1>Compress colors using VQ</h1>
- <p>Select desirable number of clusters: <select id="ncluster">
- <option value="1">1</option>
- <option value="2">2</option>
- <option value="4">4</option>
- <option value="8">8</option>
- <option value="16">16</option>
- <option value="32">32</option>
- <option value="64">64</option>
- </select> <button id="run">Run</button></p>
- <div id="status" class="pane"><em>No status yet.</em></div>
- <div id="report" class="pane"><em>No results yet.</em></div>
- </body>
-</html>
projects / eow / blobdiff