Merge pull request #673 from danvk/track-code-size
[dygraphs.git] / src / plugins / axes.js
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1/**
2 * @license
3 * Copyright 2012 Dan Vanderkam (danvdk@gmail.com)
4 * MIT-licensed (http://opensource.org/licenses/MIT)
5 */
6
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7/*global Dygraph:false */
8
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9Dygraph.Plugins.Axes = (function() {
10
e0269a3d 11'use strict';
13f8b047 12
f8540c66 13/*
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14Bits of jankiness:
15- Direct layout access
16- Direct area access
17- Should include calculation of ticks, not just the drawing.
18
b67b868c 19Options left to make axis-friendly.
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20 ('drawAxesAtZero')
21 ('xAxisHeight')
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22*/
23
24/**
25 * Draws the axes. This includes the labels on the x- and y-axes, as well
26 * as the tick marks on the axes.
27 * It does _not_ draw the grid lines which span the entire chart.
28 */
29var axes = function() {
30 this.xlabels_ = [];
31 this.ylabels_ = [];
32};
33
34axes.prototype.toString = function() {
e0269a3d 35 return 'Axes Plugin';
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36};
37
38axes.prototype.activate = function(g) {
39 return {
40 layout: this.layout,
41 clearChart: this.clearChart,
98eb4713 42 willDrawChart: this.willDrawChart
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43 };
44};
45
46axes.prototype.layout = function(e) {
47 var g = e.dygraph;
48
7f6a7190 49 if (g.getOptionForAxis('drawAxis', 'y')) {
e0269a3d 50 var w = g.getOptionForAxis('axisLabelWidth', 'y') + 2 * g.getOptionForAxis('axisTickSize', 'y');
0cd1ad15 51 e.reserveSpaceLeft(w);
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52 }
53
7f6a7190 54 if (g.getOptionForAxis('drawAxis', 'x')) {
f8540c66 55 var h;
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56 // NOTE: I think this is probably broken now, since g.getOption() now
57 // hits the dictionary. (That is, g.getOption('xAxisHeight') now always
58 // has a value.)
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59 if (g.getOption('xAxisHeight')) {
60 h = g.getOption('xAxisHeight');
61 } else {
e0269a3d 62 h = g.getOptionForAxis('axisLabelFontSize', 'x') + 2 * g.getOptionForAxis('axisTickSize', 'x');
f8540c66 63 }
0cd1ad15 64 e.reserveSpaceBottom(h);
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65 }
66
67 if (g.numAxes() == 2) {
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68 if (g.getOptionForAxis('drawAxis', 'y2')) {
69 var w = g.getOptionForAxis('axisLabelWidth', 'y2') + 2 * g.getOptionForAxis('axisTickSize', 'y2');
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70 e.reserveSpaceRight(w);
71 }
f8540c66 72 } else if (g.numAxes() > 2) {
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73 g.error('Only two y-axes are supported at this time. (Trying ' +
74 'to use ' + g.numAxes() + ')');
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75 }
76};
77
78axes.prototype.detachLabels = function() {
79 function removeArray(ary) {
80 for (var i = 0; i < ary.length; i++) {
81 var el = ary[i];
82 if (el.parentNode) el.parentNode.removeChild(el);
83 }
84 }
85
86 removeArray(this.xlabels_);
87 removeArray(this.ylabels_);
88 this.xlabels_ = [];
89 this.ylabels_ = [];
90};
91
92axes.prototype.clearChart = function(e) {
f8540c66 93 this.detachLabels();
42a9ebb8 94};
f8540c66 95
98eb4713 96axes.prototype.willDrawChart = function(e) {
f8540c66 97 var g = e.dygraph;
7f6a7190 98
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99 if (!g.getOptionForAxis('drawAxis', 'x') &&
100 !g.getOptionForAxis('drawAxis', 'y') &&
101 !g.getOptionForAxis('drawAxis', 'y2')) {
102 return;
103 }
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104
105 // Round pixels to half-integer boundaries for crisper drawing.
106 function halfUp(x) { return Math.round(x) + 0.5; }
107 function halfDown(y){ return Math.round(y) - 0.5; }
108
109 var context = e.drawingContext;
110 var containerDiv = e.canvas.parentNode;
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111 var canvasWidth = g.width_; // e.canvas.width is affected by pixel ratio.
112 var canvasHeight = g.height_;
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113
114 var label, x, y, tick, i;
115
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116 var makeLabelStyle = function(axis) {
117 return {
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118 position: 'absolute',
119 fontSize: g.getOptionForAxis('axisLabelFontSize', axis) + 'px',
48dc3815 120 zIndex: 10,
3a84670d 121 color: g.getOptionForAxis('axisLabelColor', axis),
e0269a3d 122 width: g.getOptionForAxis('axisLabelWidth', axis) + 'px',
48dc3815 123 // height: g.getOptionForAxis('axisLabelFontSize', 'x') + 2 + "px",
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124 lineHeight: 'normal', // Something other than "normal" line-height screws up label positioning.
125 overflow: 'hidden'
48dc3815 126 };
83b0c192 127 };
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128
129 var labelStyles = {
130 x : makeLabelStyle('x'),
131 y : makeLabelStyle('y'),
83b0c192 132 y2 : makeLabelStyle('y2')
f8540c66 133 };
48dc3815 134
f8540c66 135 var makeDiv = function(txt, axis, prec_axis) {
48dc3815 136 /*
7e1d5659 137 * This seems to be called with the following three sets of axis/prec_axis:
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138 * x: undefined
139 * y: y1
140 * y: y2
141 */
e0269a3d 142 var div = document.createElement('div');
48dc3815 143 var labelStyle = labelStyles[prec_axis == 'y2' ? 'y2' : axis];
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144 for (var name in labelStyle) {
145 if (labelStyle.hasOwnProperty(name)) {
146 div.style[name] = labelStyle[name];
147 }
148 }
e0269a3d 149 var inner_div = document.createElement('div');
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150 inner_div.className = 'dygraph-axis-label' +
151 ' dygraph-axis-label-' + axis +
152 (prec_axis ? ' dygraph-axis-label-' + prec_axis : '');
153 inner_div.innerHTML = txt;
154 div.appendChild(inner_div);
155 return div;
156 };
157
158 // axis lines
159 context.save();
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160
161 var layout = g.layout_;
162 var area = e.dygraph.plotter_.area;
163
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164 // Helper for repeated axis-option accesses.
165 var makeOptionGetter = function(axis) {
166 return function(option) {
167 return g.getOptionForAxis(option, axis);
168 };
169 };
170
7f6a7190 171 if (g.getOptionForAxis('drawAxis', 'y')) {
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172 if (layout.yticks && layout.yticks.length > 0) {
173 var num_axes = g.numAxes();
e0269a3d 174 var getOptions = [makeOptionGetter('y'), makeOptionGetter('y2')];
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175 for (i = 0; i < layout.yticks.length; i++) {
176 tick = layout.yticks[i];
e0269a3d 177 if (typeof(tick) == 'function') return; // <-- when would this happen?
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178 x = area.x;
179 var sgn = 1;
180 var prec_axis = 'y1';
e0269a3d 181 var getAxisOption = getOptions[0];
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182 if (tick[0] == 1) { // right-side y-axis
183 x = area.x + area.w;
184 sgn = -1;
185 prec_axis = 'y2';
e0269a3d 186 getAxisOption = getOptions[1];
f8540c66 187 }
e0269a3d 188 var fontSize = getAxisOption('axisLabelFontSize');
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189 y = area.y + tick[1] * area.h;
190
191 /* Tick marks are currently clipped, so don't bother drawing them.
192 context.beginPath();
193 context.moveTo(halfUp(x), halfDown(y));
194 context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y));
195 context.closePath();
196 context.stroke();
197 */
198
199 label = makeDiv(tick[2], 'y', num_axes == 2 ? prec_axis : null);
48dc3815 200 var top = (y - fontSize / 2);
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201 if (top < 0) top = 0;
202
48dc3815 203 if (top + fontSize + 3 > canvasHeight) {
e0269a3d 204 label.style.bottom = '0';
f8540c66 205 } else {
e0269a3d 206 label.style.top = top + 'px';
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207 }
208 if (tick[0] === 0) {
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209 label.style.left = (area.x - getAxisOption('axisLabelWidth') - getAxisOption('axisTickSize')) + 'px';
210 label.style.textAlign = 'right';
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211 } else if (tick[0] == 1) {
212 label.style.left = (area.x + area.w +
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213 getAxisOption('axisTickSize')) + 'px';
214 label.style.textAlign = 'left';
f8540c66 215 }
e0269a3d 216 label.style.width = getAxisOption('axisLabelWidth') + 'px';
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217 containerDiv.appendChild(label);
218 this.ylabels_.push(label);
219 }
220
221 // The lowest tick on the y-axis often overlaps with the leftmost
222 // tick on the x-axis. Shift the bottom tick up a little bit to
223 // compensate if necessary.
224 var bottomTick = this.ylabels_[0];
48dc3815 225 // Interested in the y2 axis also?
e0269a3d 226 var fontSize = g.getOptionForAxis('axisLabelFontSize', 'y');
f8540c66 227 var bottom = parseInt(bottomTick.style.top, 10) + fontSize;
beeabac2 228 if (bottom > canvasHeight - fontSize) {
f8540c66 229 bottomTick.style.top = (parseInt(bottomTick.style.top, 10) -
e0269a3d 230 fontSize / 2) + 'px';
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231 }
232 }
233
234 // draw a vertical line on the left to separate the chart from the labels.
235 var axisX;
236 if (g.getOption('drawAxesAtZero')) {
beeabac2 237 var r = g.toPercentXCoord(0);
33e96f11 238 if (r > 1 || r < 0 || isNaN(r)) r = 0;
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239 axisX = halfUp(area.x + r * area.w);
240 } else {
241 axisX = halfUp(area.x);
242 }
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243
244 context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y');
245 context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y');
246
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247 context.beginPath();
248 context.moveTo(axisX, halfDown(area.y));
249 context.lineTo(axisX, halfDown(area.y + area.h));
250 context.closePath();
251 context.stroke();
252
253 // if there's a secondary y-axis, draw a vertical line for that, too.
254 if (g.numAxes() == 2) {
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255 context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y2');
256 context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y2');
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257 context.beginPath();
258 context.moveTo(halfDown(area.x + area.w), halfDown(area.y));
259 context.lineTo(halfDown(area.x + area.w), halfDown(area.y + area.h));
260 context.closePath();
261 context.stroke();
262 }
263 }
264
7f6a7190 265 if (g.getOptionForAxis('drawAxis', 'x')) {
f8540c66 266 if (layout.xticks) {
e0269a3d 267 var getAxisOption = makeOptionGetter('x');
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268 for (i = 0; i < layout.xticks.length; i++) {
269 tick = layout.xticks[i];
270 x = area.x + tick[0] * area.w;
271 y = area.y + area.h;
272
273 /* Tick marks are currently clipped, so don't bother drawing them.
274 context.beginPath();
275 context.moveTo(halfUp(x), halfDown(y));
276 context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize')));
277 context.closePath();
278 context.stroke();
279 */
280
281 label = makeDiv(tick[1], 'x');
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282 label.style.textAlign = 'center';
283 label.style.top = (y + getAxisOption('axisTickSize')) + 'px';
f8540c66 284
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285 var left = (x - getAxisOption('axisLabelWidth')/2);
286 if (left + getAxisOption('axisLabelWidth') > canvasWidth) {
287 left = canvasWidth - getAxisOption('axisLabelWidth');
288 label.style.textAlign = 'right';
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289 }
290 if (left < 0) {
291 left = 0;
e0269a3d 292 label.style.textAlign = 'left';
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293 }
294
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295 label.style.left = left + 'px';
296 label.style.width = getAxisOption('axisLabelWidth') + 'px';
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297 containerDiv.appendChild(label);
298 this.xlabels_.push(label);
299 }
300 }
301
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302 context.strokeStyle = g.getOptionForAxis('axisLineColor', 'x');
303 context.lineWidth = g.getOptionForAxis('axisLineWidth', 'x');
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304 context.beginPath();
305 var axisY;
306 if (g.getOption('drawAxesAtZero')) {
307 var r = g.toPercentYCoord(0, 0);
308 if (r > 1 || r < 0) r = 1;
309 axisY = halfDown(area.y + r * area.h);
310 } else {
311 axisY = halfDown(area.y + area.h);
312 }
313 context.moveTo(halfUp(area.x), axisY);
314 context.lineTo(halfUp(area.x + area.w), axisY);
315 context.closePath();
316 context.stroke();
317 }
318
319 context.restore();
42a9ebb8 320};
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321
322return axes;
323})();