Add color enhancer as a chromium accessibility extensions.

ui/accessibility/extensions/colorenhancer/src/cvd.js

Index: ui/accessibility/extensions/colorenhancer/src/cvd.js
diff --git a/ui/accessibility/extensions/colorenhancer/src/cvd.js b/ui/accessibility/extensions/colorenhancer/src/cvd.js
new file mode 100644
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+++ b/ui/accessibility/extensions/colorenhancer/src/cvd.js
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+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+
+// ======= Global state =======
+
+var storedDelta = 0;
+var storedSeverity = 0;
+var storedType = 'PROTANOMALY';
+var storedSimulate = false;
+var curFilter = 0;
+
+
+// ======= 3x3 matrix ops =======
+
+var identityMatrix3x3 = [
+  [1, 0, 0],
+  [0, 1, 0],
+  [0, 0, 1]
+];
+
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function add3x3(m1, m2) {
+    var result = [];
+    for (var i = 0; i < 3; i++) {
+        result[i] = [];
+        for (var j = 0; j < 3; j++) {
+            result[i].push(m1[i][j] + m2[i][j]);
+        }
+    }
+    return result;
+}
+
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function sub3x3(m1, m2) {
+    var result = [];
+    for (var i = 0; i < 3; i++) {
+        result[i] = [];
+        for (var j = 0; j < 3; j++) {
+            result[i].push(m1[i][j] - m2[i][j]);
+        }
+    }
+    return result;
+}
+
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function mul3x3(m1, m2) {
+    var result = [];
+    for (var i = 0; i < 3; i++) {
+        result[i] = [];
+        for (var j = 0; j < 3; j++) {
+            var sum = 0;
+            for (var k = 0; k < 3; k++) {
+                sum += m1[i][k] * m2[k][j];
+            }
+            result[i].push(sum);
+        }
+    }
+    return result;
+}
+
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function mul3x3Scalar(m, k) {
+    var result = [];
+    for (var i = 0; i < 3; i++) {
+        result[i] = [];
+        for (var j = 0; j < 3; j++) {
+            result[i].push(k * m[i][j]);
+        }
+    }
+    return result;
+}
+
+
+// ======= CVD parameters =======
+/**
+ * Parameters for simulating color vision deficiency.
+ * Source:
+ *     http://www.inf.ufrgs.br/~oliveira/pubs_files/CVD_Simulation/CVD_Simulation.html
+ * Original Research Paper:
+ *     http://www.inf.ufrgs.br/~oliveira/pubs_files/CVD_Simulation/Machado_Oliveira_Fernandes_CVD_Vis2009_final.pdf
+ *
+ * @enum {string}
+ */
+var cvdSimulationParams = {
+  PROTANOMALY: [
+    [0.4720, -1.2946, 0.9857],
+    [-0.6128, 1.6326, 0.0187],
+    [0.1407, -0.3380, -0.0044],
+    [-0.1420, 0.2488, 0.0044],
+    [0.1872, -0.3908, 0.9942],
+    [-0.0451, 0.1420, 0.0013],
+    [0.0222, -0.0253, -0.0004],
+    [-0.0290, -0.0201, 0.0006],
+    [0.0068, 0.0454, 0.9990]
+  ],
+  DEUTERANOMALY: [
+    [0.5442, -1.1454, 0.9818],
+    [-0.7091, 1.5287, 0.0238],
+    [0.1650, -0.3833, -0.0055],
+    [-0.1664, 0.4368, 0.0056],
+    [0.2178, -0.5327, 0.9927],
+    [-0.0514, 0.0958, 0.0017],
+    [0.0180, -0.0288, -0.0006],
+    [-0.0232, -0.0649, 0.0007],
+    [0.0052, 0.0360, 0.9998]
+  ],
+  TRITANOMALY: [
+    [0.4275, -0.0181, 0.9307],
+    [-0.2454, 0.0013, 0.0827],
+    [-0.1821, 0.0168, -0.0134],
+    [-0.1280, 0.0047, 0.0202],
+    [0.0233, -0.0398, 0.9728],
+    [0.1048, 0.0352, 0.0070],
+    [-0.0156, 0.0061, 0.0071],
+    [0.3841, 0.2947, 0.0151],
+    [-0.3685, -0.3008, 0.9778]
+  ]
+};
+
+
+// TODO(mustaq): A common matrix for all types? E.g. Kevin's experiment
+//   suggested: Mx[1][0] = 0.7+0.3*delta and Mx[2][0] = 0.7-0.3*delta
+/**
+ * TODO(mustaq): JsDoc
+ *
+ * @enum {string}
+ */
+var cvdCorrectionParams = {
+  PROTANOMALY: {
+    addendum: [
+      [-1.0, 0.0, 0.0],
+      [0.5, 1.0, 0.0],
+      [1.5, 0.0, 1.0]
+    ],
+    delta_factor: [
+      [0.0, 0.0, 0.0],
+      [1.0, 0.0, 0.0],
+      [-1.0, 0.0, 0.0]
+    ]
+  },
+  DEUTERANOMALY: {
+    addendum: [
+      [1.0, 0.5, 0.0],
+      [0.5, -1.0, 0.0],
+      [1.5, 1.5, 1.0]
+    ],
+    delta_factor: [
+      [0.0, 1.0, 0.0],
+      [0.0, 0.0, 0.0],
+      [0.0, -1.0, 0.0]
+    ]
+  },
+  TRITANOMALY: {
+    addendum: [
+      [1.0, 0.0, 1.5],
+      [0.0, 1.0, 0.5],
+      [0.0, 0.0, -1.0]
+    ],
+    delta_factor: [
+      [0.0, 0.0, -1.0],
+      [0.0, 0.0, 1.0],
+      [0.0, 0.0, 0.0]
+    ]
+  }
+};
+
+
+// =======  CVD matrix builders =======
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function getCvdSimulationMatrix(cvdType, severity) {
+  var cvdSimulationParam = cvdSimulationParams[cvdType];
+  var severity2 = severity * severity;
+  var matrix = [];
+  for (var i = 0; i < 3; i++) {
+    var row = [];
+    for (var j = 0; j < 3; j++) {
+      var paramRow = i*3+j;
+      var val = cvdSimulationParam[paramRow][0] * severity2
+              + cvdSimulationParam[paramRow][1] * severity
+              + cvdSimulationParam[paramRow][2];
+      row.push(val);
+    }
+    matrix.push(row);
+  }
+  return matrix;
+}
+
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function getCvdCorrectionMatrix(cvdType, delta) {
+  cvdCorrectionParam = cvdCorrectionParams[cvdType];
+  // TODO(mustaq): Perhaps nuke full-matrix operations after experiment.
+  return add3x3(cvdCorrectionParam['addendum'],
+                mul3x3Scalar(cvdCorrectionParam['delta_factor'], delta));
+}
+
+
+/**
+ * TODO(mustaq): JsDoc
+ */
+function getCvdMatrixAsString(cvdType, severity, delta, simulate) {
+  var effectiveMatrix = getCvdSimulationMatrix(cvdType, severity);
+
+  if (!simulate) {
+    var cvdCorrectionMatrix = getCvdCorrectionMatrix(cvdType, delta);
+    var tmpProduct = mul3x3(cvdCorrectionMatrix, effectiveMatrix);
+
+    effectiveMatrix = sub3x3(
+        add3x3(identityMatrix3x3, cvdCorrectionMatrix),
+        tmpProduct);
+  }
+
+  var outputRows = [];
+  for (var i = 0; i < 3; i++) {
+    outputRows.push(effectiveMatrix[i].join(' ') + ' 0 0');
+  }
+  // Add the alpha row
+  outputRows.push('0 0 0 1 0');
+  return outputRows.join(' ');
+}
+
+
+// ======= Page linker =======
+
+var svgDefaultMatrix =
+  '1 0 0 0 0 ' +
+  '0 1 0 0 0 ' +
+  '0 0 1 0 0 ' +
+  '0 0 0 1 0';
+
+var svgContent =
+  '<svg xmlns='http://www.w3.org/2000/svg' version='1.1'>' +
+  '  <defs>' +
+  '    <filter id='cvd_extension_0'>' +
+  '      <feColorMatrix id='cvd_filter_matrix_0' type='matrix' values='' +
+  svgDefaultMatrix + ''/>' +
+  '    </filter>' +
+  '    <filter id='cvd_extension_1'>' +
+  '      <feColorMatrix id='cvd_filter_matrix_1' type='matrix' values='' +
+  svgDefaultMatrix + ''/>' +
+  '    </filter>' +
+  '  </defs>' +
+  '</svg>';
+
+/**
+ * Checks for svg filter matrix presence and append to DOM if not present.
+ */
+function addSvgIfMissing() {
+  var wrap = document.getElementById('cvd_extension_svg_filter');
+  if (!wrap) {
+    wrap = document.createElement('span');
+    wrap.id = 'cvd_extension_svg_filter';
+    wrap.setAttribute('hidden', '');
+    wrap.innerHTML = svgContent;
+    document.body.appendChild(wrap);
+  }
+}
+
+
+/**
+ * Update matrix when config values change.
+ */
+function update() {
+  if (!document.body) {
+    document.addEventListener('DOMContentLoaded', update);
+    return;
+  }
+  addSvgIfMissing();
+  var next = 1 - curFilter;
+
+  debugPrint(
+      'Setting matrix#' + next + ' to ' +
+      getCvdMatrixAsString(
+          storedType, storedSeverity, storedDelta, storedSimulate));
+
+  var matrix = document.getElementById('cvd_filter_matrix_' + next);
+  matrix.setAttribute(
+      'values', getCvdMatrixAsString(
+          storedType, storedSeverity, storedDelta, storedSimulate));
+
+  var html = document.documentElement;
+  html.classList.remove('filter' + curFilter);
+  html.offsetTop;
+  html.classList.add('filter' + next);
+
+  curFilter = next;
+
+  // TODO(wnwen): Figure out whether this hack is still necessary.
+  window.scrollBy(0, 1);
+  window.scrollBy(0, -1);
+}
+
+
+/**
+ * Process request from background page.
+ */
+function onExtensionMessage(request) {
+  var changed = false;
+
+  if (request['delta'] !== undefined) {
+    var delta = request.delta;
+    if (storedDelta != delta) {
+      storedDelta = delta;
+      changed = true;
+    }
+  }
+
+  if (request['severity'] !== undefined) {
+    var severity = request.severity;
+    if (storedSeverity != severity) {
+      storedSeverity = severity;
+      changed = true;
+    }
+  }
+
+  if (request['type'] !== undefined) {
+    var type = request.type;
+    if (storedType != type) {
+      storedType = type;
+      changed = true;
+    }
+  }
+
+  if (request['simulate'] !== undefined) {
+    var simulate = request.simulate;
+    if (storedSimulate != simulate) {
+      storedSimulate = simulate;
+      changed = true;
+    }
+  }
+
+  if (changed)
+    update();
+}
+
+
+/**
+ * Prepare to process background messages and let it know to send initial
+ * values.
+ */
+(function initialize() {
+  chrome.extension.onRequest.addListener(onExtensionMessage);
+  chrome.extension.sendRequest({'init': true}, onExtensionMessage);
+})();