1/*
2 * Copyright (c) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31var LOUPE_MAGNIFICATION_FACTOR = 10;
32
33function Loupe()
34{
35    this._node = $('loupe');
36    this._currentCornerX = -1;
37    this._currentCornerY = -1;
38
39    var self = this;
40
41    function handleOutputClick(event) { self._handleOutputClick(event); }
42    $('expected-image').addEventListener('click', handleOutputClick);
43    $('actual-image').addEventListener('click', handleOutputClick);
44    $('diff-canvas').addEventListener('click', handleOutputClick);
45
46    function handleLoupeClick(event) { self._handleLoupeClick(event); }
47    $('expected-loupe').addEventListener('click', handleLoupeClick);
48    $('actual-loupe').addEventListener('click', handleLoupeClick);
49    $('diff-loupe').addEventListener('click', handleLoupeClick);
50
51    function hide(event) { self.hide(); }
52    $('loupe-close').addEventListener('click', hide);
53}
54
55Loupe.prototype._handleOutputClick = function(event)
56{
57    // The -1 compensates for the border around the image/canvas.
58    this._showFor(event.offsetX - 1, event.offsetY - 1);
59};
60
61Loupe.prototype._handleLoupeClick = function(event)
62{
63    var deltaX = Math.floor(event.offsetX/LOUPE_MAGNIFICATION_FACTOR);
64    var deltaY = Math.floor(event.offsetY/LOUPE_MAGNIFICATION_FACTOR);
65
66    this._showFor(
67        this._currentCornerX + deltaX, this._currentCornerY + deltaY);
68}
69
70Loupe.prototype.hide = function()
71{
72    this._node.style.display = 'none';
73};
74
75Loupe.prototype._showFor = function(x, y)
76{
77    this._fillFromImage(x, y, 'expected', $('expected-image'));
78    this._fillFromImage(x, y, 'actual', $('actual-image'));
79    this._fillFromCanvas(x, y, 'diff', $('diff-canvas'));
80
81    this._node.style.display = '';
82};
83
84Loupe.prototype._fillFromImage = function(x, y, type, sourceImage)
85{
86    var tempCanvas = document.createElement('canvas');
87    tempCanvas.width = sourceImage.width;
88    tempCanvas.height = sourceImage.height;
89    var tempContext = tempCanvas.getContext('2d');
90
91    tempContext.drawImage(sourceImage, 0, 0);
92
93    this._fillFromCanvas(x, y, type, tempCanvas);
94};
95
96Loupe.prototype._fillFromCanvas = function(x, y, type, canvas)
97{
98    var context = canvas.getContext('2d');
99    var sourceImageData =
100        context.getImageData(0, 0, canvas.width, canvas.height);
101
102    var targetCanvas = $(type + '-loupe');
103    var targetContext = targetCanvas.getContext('2d');
104    targetContext.fillStyle = 'rgba(255, 255, 255, 1)';
105    targetContext.fillRect(0, 0, targetCanvas.width, targetCanvas.height);
106
107    var sourceXOffset = (targetCanvas.width/LOUPE_MAGNIFICATION_FACTOR - 1)/2;
108    var sourceYOffset = (targetCanvas.height/LOUPE_MAGNIFICATION_FACTOR - 1)/2;
109
110    function readPixelComponent(x, y, component) {
111        var offset = (y * sourceImageData.width + x) * 4 + component;
112        return sourceImageData.data[offset];
113    }
114
115    for (var i = -sourceXOffset; i <= sourceXOffset; i++) {
116        for (var j = -sourceYOffset; j <= sourceYOffset; j++) {
117            var sourceX = x + i;
118            var sourceY = y + j;
119
120            var sourceR = readPixelComponent(sourceX, sourceY, 0);
121            var sourceG = readPixelComponent(sourceX, sourceY, 1);
122            var sourceB = readPixelComponent(sourceX, sourceY, 2);
123            var sourceA = readPixelComponent(sourceX, sourceY, 3)/255;
124            sourceA = Math.round(sourceA * 10)/10;
125
126            var targetX = (i + sourceXOffset) * LOUPE_MAGNIFICATION_FACTOR;
127            var targetY = (j + sourceYOffset) * LOUPE_MAGNIFICATION_FACTOR;
128            var colorString =
129                sourceR + ', ' + sourceG + ', ' + sourceB + ', ' + sourceA;
130            targetContext.fillStyle = 'rgba(' + colorString + ')';
131            targetContext.fillRect(
132                targetX, targetY,
133                LOUPE_MAGNIFICATION_FACTOR, LOUPE_MAGNIFICATION_FACTOR);
134
135            if (i == 0 && j == 0) {
136                $('loupe-coordinate').textContent = sourceX + ', ' + sourceY;
137                $(type + '-loupe-color').textContent = colorString;
138            }
139        }
140    }
141
142    this._currentCornerX = x - sourceXOffset;
143    this._currentCornerY = y - sourceYOffset;
144};
145