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1 /* | |
2 Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
3 Use of this source code is governed by a BSD-style license that can be | |
4 found in the LICENSE file. | |
5 */ | |
6 | |
7 /** | |
8 * @fileoverview Class and functions to handle positioning of plot data points. | |
9 */ | |
10 | |
11 /** | |
12 * Class that handles plot data positioning. | |
13 * @constructor | |
14 * @param {Array.<Array.<Array.<number>>>>} plotData Data that will be plotted. | |
15 * It is an array of lines, where each line is an array of points, and each | |
16 * point is a length-2 array representing an (x, y) pair. | |
17 */ | |
18 function Coordinates(plotData) { | |
19 this.plotData = plotData; | |
20 | |
21 height = window.innerHeight - 16; | |
22 width = window.innerWidth - 16; | |
23 | |
24 this.widthMax = width; | |
25 this.heightMax = Math.min(400, height - 85); | |
26 | |
27 this.processValues_('x'); | |
28 this.processValues_('y'); | |
29 } | |
30 | |
31 /** | |
32 * Determines the min/max x or y values in the plot, accounting for some extra | |
33 * buffer space. | |
34 * @param {string} type The type of value to process, either 'x' or 'y'. | |
35 */ | |
36 Coordinates.prototype.processValues_ = function (type) { | |
37 var merged = []; | |
38 for (var i = 0; i < this.plotData.length; i++) | |
39 for (var j = 0; j < this.plotData[i].length; j++) { | |
40 if (type == 'x') | |
41 merged.push(parseFloat(this.plotData[i][j][0])); // Index 0 is x value. | |
42 else | |
43 merged.push(parseFloat(this.plotData[i][j][1])); // Index 1 is y value. | |
44 } | |
45 | |
46 min = merged[0]; | |
47 max = merged[0]; | |
48 for (var i = 1; i < merged.length; ++i) { | |
49 if (isNaN(min) || merged[i] < min) | |
50 min = merged[i]; | |
51 if (isNaN(max) || merged[i] > max) | |
52 max = merged[i]; | |
53 } | |
54 | |
55 var bufferSpace = 0.02 * (max - min); | |
56 | |
57 if (type == 'x') { | |
58 this.xBufferSpace_ = bufferSpace; | |
59 this.xMinValue_ = min; | |
60 this.xMaxValue_ = max; | |
61 } else { | |
62 this.yBufferSpace_ = bufferSpace; | |
63 this.yMinValue_ = min; | |
64 this.yMaxValue_ = max; | |
65 } | |
66 }; | |
67 | |
68 /** | |
69 * Difference between horizontal upper and lower limit values. | |
70 * @return {number} The x value range. | |
71 */ | |
72 Coordinates.prototype.xValueRange = function() { | |
73 return this.xUpperLimitValue() - this.xLowerLimitValue(); | |
74 }; | |
75 | |
76 /** | |
77 * Difference between vertical upper and lower limit values. | |
78 * @return {number} The y value range. | |
79 */ | |
80 Coordinates.prototype.yValueRange = function() { | |
81 return this.yUpperLimitValue() - this.yLowerLimitValue(); | |
82 }; | |
83 | |
84 /** | |
85 * Converts horizontal data value to pixel value on canvas. | |
86 * @param {number} value The x data value. | |
87 * @return {number} The corresponding x pixel value on the canvas. | |
88 */ | |
89 Coordinates.prototype.xPixel = function(value) { | |
90 return this.widthMax * | |
91 ((value - this.xLowerLimitValue()) / this.xValueRange()); | |
92 }; | |
93 | |
94 /** | |
95 * Converts vertical data value to pixel value on canvas. | |
96 * @param {number} value The y data value. | |
97 * @return {number} The corresponding y pixel value on the canvas. | |
98 */ | |
99 Coordinates.prototype.yPixel = function(value) { | |
100 if (this.yValueRange() == 0) { | |
101 // Completely horizontal lines should be centered horizontally. | |
102 return this.heightMax / 2; | |
103 } else { | |
104 return this.heightMax - | |
105 (this.heightMax * | |
106 (value - this.yLowerLimitValue()) / this.yValueRange()); | |
107 } | |
108 }; | |
109 | |
110 /** | |
111 * Converts x point on canvas to data value it represents. | |
112 * @param {number} position The x pixel value on the canvas. | |
113 * @return {number} The corresponding x data value. | |
114 */ | |
115 Coordinates.prototype.xValue = function(position) { | |
116 return this.xLowerLimitValue() + | |
117 (position / this.widthMax * this.xValueRange()); | |
118 }; | |
119 | |
120 /** | |
121 * Converts y point on canvas to data value it represents. | |
122 * @param {number} position The y pixel value on the canvas. | |
123 * @return {number} The corresponding y data value. | |
124 */ | |
125 Coordinates.prototype.yValue = function(position) { | |
126 var ratio = this.heightMax / (this.heightMax - position); | |
127 return this.yLowerLimitValue() + (this.yValueRange() / ratio); | |
128 }; | |
129 | |
130 /** | |
131 * Returns the minimum x value of all the data points. | |
132 * @return {number} The minimum x value of all the data points. | |
133 */ | |
134 Coordinates.prototype.xMinValue = function() { | |
135 return this.xMinValue_; | |
136 }; | |
137 | |
138 /** | |
139 * Returns the maximum x value of all the data points. | |
140 * @return {number} The maximum x value of all the data points. | |
141 */ | |
142 Coordinates.prototype.xMaxValue = function() { | |
143 return this.xMaxValue_; | |
144 }; | |
145 | |
146 /** | |
147 * Returns the minimum y value of all the data points. | |
148 * @return {number} The minimum y value of all the data points. | |
149 */ | |
150 Coordinates.prototype.yMinValue = function() { | |
151 return this.yMinValue_; | |
152 }; | |
153 | |
154 /** | |
155 * Returns the maximum y value of all the data points. | |
156 * @return {number} The maximum y value of all the data points. | |
157 */ | |
158 Coordinates.prototype.yMaxValue = function() { | |
159 return this.yMaxValue_; | |
160 }; | |
161 | |
162 /** | |
163 * Returns the x value at the lower limit of the bounding box of the canvas. | |
164 * @return {number} The x value at the lower limit of the bounding box of | |
165 * the canvas. | |
166 */ | |
167 Coordinates.prototype.xLowerLimitValue = function() { | |
168 return this.xMinValue_ - this.xBufferSpace_; | |
169 }; | |
170 | |
171 /** | |
172 * Returns the x value at the upper limit of the bounding box of the canvas. | |
173 * @return {number} The x value at the upper limit of the bounding box of | |
174 * the canvas. | |
175 */ | |
176 Coordinates.prototype.xUpperLimitValue = function() { | |
177 return this.xMaxValue_ + this.xBufferSpace_; | |
178 }; | |
179 | |
180 /** | |
181 * Returns the y value at the lower limit of the bounding box of the canvas. | |
182 * @return {number} The y value at the lower limit of the bounding box of | |
183 * the canvas. | |
184 */ | |
185 Coordinates.prototype.yLowerLimitValue = function() { | |
186 return this.yMinValue_ - this.yBufferSpace_; | |
187 }; | |
188 | |
189 /** | |
190 * Returns the y value at the upper limit of the bounding box of the canvas. | |
191 * @return {number} The y value at the upper limit of the bounding box of | |
192 * the canvas. | |
193 */ | |
194 Coordinates.prototype.yUpperLimitValue = function() { | |
195 return this.yMaxValue_ + this.yBufferSpace_; | |
196 }; | |
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