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