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[dygraphs.git] / dygraph-canvas.js
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1// Copyright 2006 Dan Vanderkam (danvdk@gmail.com)
2// All Rights Reserved.
3
4/**
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5 * @fileoverview Based on PlotKit, but modified to meet the needs of dygraphs.
6 * In particular, support for:
7 * - grid overlays
8 * - error bars
9 * - dygraphs attribute system
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10 */
11
6a1aa64f 12/**
3df0ccf0 13 * Creates a new DygraphLayout object.
6a1aa64f 14 * @param {Object} options Options for PlotKit.Layout
285a6bda 15 * @return {Object} The DygraphLayout object
6a1aa64f 16 */
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17DygraphLayout = function(dygraph, options) {
18 this.dygraph_ = dygraph;
19 this.options = {}; // TODO(danvk): remove, use attr_ instead.
20 MochiKit.Base.update(this.options, options ? options : {});
21 this.datasets = new Array();
6a1aa64f 22};
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23
24DygraphLayout.prototype.attr_ = function(name) {
25 return this.dygraph_.attr_(name);
26};
27
28DygraphLayout.prototype.addDataset = function(setname, set_xy) {
29 this.datasets[setname] = set_xy;
30};
31
32DygraphLayout.prototype.evaluate = function() {
33 this._evaluateLimits();
34 this._evaluateLineCharts();
35 this._evaluateLineTicks();
36};
37
38DygraphLayout.prototype._evaluateLimits = function() {
39 this.minxval = this.maxxval = null;
40 for (var name in this.datasets) {
41 var series = this.datasets[name];
42 var x1 = series[0][0];
43 if (!this.minxval || x1 < this.minxval) this.minxval = x1;
44
45 var x2 = series[series.length - 1][0];
46 if (!this.maxxval || x2 > this.maxxval) this.maxxval = x2;
47 }
48 this.xrange = this.maxxval - this.minxval;
49 this.xscale = (this.xrange != 0 ? 1/this.xrange : 1.0);
50
51 this.minyval = this.options.yAxis[0];
52 this.maxyval = this.options.yAxis[1];
53 this.yrange = this.maxyval - this.minyval;
54 this.yscale = (this.yrange != 0 ? 1/this.yrange : 1.0);
55};
56
57DygraphLayout.prototype._evaluateLineCharts = function() {
58 // add all the rects
59 this.points = new Array();
60 for (var setName in this.datasets) {
61 var dataset = this.datasets[setName];
62 for (var j = 0; j < dataset.length; j++) {
63 var item = dataset[j];
64 var point = {
65 x: ((parseFloat(item[0]) - this.minxval) * this.xscale),
66 y: 1.0 - ((parseFloat(item[1]) - this.minyval) * this.yscale),
67 xval: parseFloat(item[0]),
68 yval: parseFloat(item[1]),
69 name: setName
70 };
71
72 // limit the x, y values so they do not overdraw
73 if (point.y <= 0.0) {
74 point.y = 0.0;
75 }
76 if (point.y >= 1.0) {
77 point.y = 1.0;
78 }
79 if ((point.x >= 0.0) && (point.x <= 1.0)) {
80 this.points.push(point);
81 }
82 }
83 }
84};
85
86DygraphLayout.prototype._evaluateLineTicks = function() {
87 this.xticks = new Array();
88 for (var i = 0; i < this.options.xTicks.length; i++) {
89 var tick = this.options.xTicks[i];
90 var label = tick.label;
91 var pos = this.xscale * (tick.v - this.minxval);
92 if ((pos >= 0.0) && (pos <= 1.0)) {
93 this.xticks.push([pos, label]);
94 }
95 }
96
97 this.yticks = new Array();
98 for (var i = 0; i < this.options.yTicks.length; i++) {
99 var tick = this.options.yTicks[i];
100 var label = tick.label;
101 var pos = 1.0 - (this.yscale * (tick.v - this.minyval));
102 if ((pos >= 0.0) && (pos <= 1.0)) {
103 this.yticks.push([pos, label]);
104 }
105 }
106};
107
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108
109/**
110 * Behaves the same way as PlotKit.Layout, but also copies the errors
111 * @private
112 */
285a6bda 113DygraphLayout.prototype.evaluateWithError = function() {
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114 this.evaluate();
115 if (!this.options.errorBars) return;
116
117 // Copy over the error terms
118 var i = 0; // index in this.points
119 for (var setName in this.datasets) {
120 var j = 0;
121 var dataset = this.datasets[setName];
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122 for (var j = 0; j < dataset.length; j++, i++) {
123 var item = dataset[j];
124 var xv = parseFloat(item[0]);
125 var yv = parseFloat(item[1]);
126
127 if (xv == this.points[i].xval &&
128 yv == this.points[i].yval) {
129 this.points[i].errorMinus = parseFloat(item[2]);
130 this.points[i].errorPlus = parseFloat(item[3]);
131 }
132 }
133 }
134};
135
136/**
137 * Convenience function to remove all the data sets from a graph
138 */
285a6bda 139DygraphLayout.prototype.removeAllDatasets = function() {
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140 delete this.datasets;
141 this.datasets = new Array();
142};
143
144/**
145 * Change the values of various layout options
146 * @param {Object} new_options an associative array of new properties
147 */
285a6bda 148DygraphLayout.prototype.updateOptions = function(new_options) {
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149 MochiKit.Base.update(this.options, new_options ? new_options : {});
150};
151
152// Subclass PlotKit.CanvasRenderer to add:
153// 1. X/Y grid overlay
154// 2. Ability to draw error bars (if required)
155
156/**
157 * Sets some PlotKit.CanvasRenderer options
158 * @param {Object} element The canvas to attach to
285a6bda 159 * @param {Layout} layout The DygraphLayout object for this graph.
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160 * @param {Object} options Options to pass on to CanvasRenderer
161 */
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162DygraphCanvasRenderer = function(dygraph, element, layout, options) {
163 // TODO(danvk): remove options, just use dygraph.attr_.
9317362d 164 this.dygraph_ = dygraph;
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165
166 // default options
167 this.options = {
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168 "strokeWidth": 0.5,
169 "drawXAxis": true,
170 "drawYAxis": true,
171 "axisLineColor": "black",
172 "axisLineWidth": 0.5,
173 "axisTickSize": 3,
174 "axisLabelColor": "black",
175 "axisLabelFont": "Arial",
176 "axisLabelFontSize": 9,
177 "axisLabelWidth": 50,
178 "drawYGrid": true,
179 "drawXGrid": true,
180 "gridLineColor": "rgb(128,128,128)"
fbe31dc8 181 };
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182 MochiKit.Base.update(this.options, options);
183
fbe31dc8 184 this.layout = layout;
b0c3b730 185 this.element = element;
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186 this.container = this.element.parentNode;
187
188 // Stuff relating to Canvas on IE support
3df0ccf0 189 this.isIE = (/MSIE/.test(navigator.userAgent) && !window.opera);
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190
191 if (this.isIE && !isNil(G_vmlCanvasManager)) {
192 this.IEDelay = 0.5;
193 this.maxTries = 5;
194 this.renderDelay = null;
195 this.clearDelay = null;
196 this.element = G_vmlCanvasManager.initElement(this.element);
197 }
198
199 this.height = this.element.height;
200 this.width = this.element.width;
201
202 // --- check whether everything is ok before we return
203 if (!this.isIE && !(DygraphCanvasRenderer.isSupported(this.element)))
204 throw "Canvas is not supported.";
205
206 // internal state
207 this.xlabels = new Array();
208 this.ylabels = new Array();
209
210 this.area = {
211 x: this.options.yAxisLabelWidth + 2 * this.options.axisTickSize,
212 y: 0
213 };
214 this.area.w = this.width - this.area.x - this.options.rightGap;
215 this.area.h = this.height - this.options.axisLabelFontSize -
216 2 * this.options.axisTickSize;
217
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218 this.container.style.position = "relative";
219 this.container.style.width = this.width + "px";
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220};
221
222DygraphCanvasRenderer.prototype.clear = function() {
223 if (this.isIE) {
224 // VML takes a while to start up, so we just poll every this.IEDelay
225 try {
226 if (this.clearDelay) {
227 this.clearDelay.cancel();
228 this.clearDelay = null;
229 }
230 var context = this.element.getContext("2d");
231 }
232 catch (e) {
76171648 233 // TODO(danvk): this is broken, since MochiKit.Async is gone.
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234 this.clearDelay = MochiKit.Async.wait(this.IEDelay);
235 this.clearDelay.addCallback(bind(this.clear, this));
236 return;
237 }
238 }
239
240 var context = this.element.getContext("2d");
241 context.clearRect(0, 0, this.width, this.height);
242
2160ed4a 243 for (var i = 0; i < this.xlabels.length; i++) {
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244 var el = this.xlabels[i];
245 el.parentNode.removeChild(el);
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246 }
247 for (var i = 0; i < this.ylabels.length; i++) {
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248 var el = this.ylabels[i];
249 el.parentNode.removeChild(el);
2160ed4a 250 }
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251 this.xlabels = new Array();
252 this.ylabels = new Array();
253};
254
255
256DygraphCanvasRenderer.isSupported = function(canvasName) {
257 var canvas = null;
258 try {
21d3323f 259 if (typeof(canvasName) == 'undefined' || canvasName == null)
b0c3b730 260 canvas = document.createElement("canvas");
fbe31dc8 261 else
b0c3b730 262 canvas = canvasName;
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263 var context = canvas.getContext("2d");
264 }
265 catch (e) {
266 var ie = navigator.appVersion.match(/MSIE (\d\.\d)/);
267 var opera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1);
268 if ((!ie) || (ie[1] < 6) || (opera))
269 return false;
270 return true;
271 }
272 return true;
6a1aa64f 273};
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274
275/**
276 * Draw an X/Y grid on top of the existing plot
277 */
285a6bda 278DygraphCanvasRenderer.prototype.render = function() {
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279 // Draw the new X/Y grid
280 var ctx = this.element.getContext("2d");
281 if (this.options.drawYGrid) {
282 var ticks = this.layout.yticks;
283 ctx.save();
f2f24402 284 ctx.strokeStyle = this.options.gridLineColor;
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285 ctx.lineWidth = this.options.axisLineWidth;
286 for (var i = 0; i < ticks.length; i++) {
287 var x = this.area.x;
288 var y = this.area.y + ticks[i][0] * this.area.h;
289 ctx.beginPath();
290 ctx.moveTo(x, y);
291 ctx.lineTo(x + this.area.w, y);
292 ctx.closePath();
293 ctx.stroke();
294 }
295 }
296
297 if (this.options.drawXGrid) {
298 var ticks = this.layout.xticks;
299 ctx.save();
f2f24402 300 ctx.strokeStyle = this.options.gridLineColor;
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301 ctx.lineWidth = this.options.axisLineWidth;
302 for (var i=0; i<ticks.length; i++) {
303 var x = this.area.x + ticks[i][0] * this.area.w;
304 var y = this.area.y + this.area.h;
305 ctx.beginPath();
306 ctx.moveTo(x, y);
307 ctx.lineTo(x, this.area.y);
308 ctx.closePath();
309 ctx.stroke();
310 }
311 }
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312
313 // Do the ordinary rendering, as before
2ce09b19 314 this._renderLineChart();
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315 this._renderAxis();
316};
317
318
319DygraphCanvasRenderer.prototype._renderAxis = function() {
320 if (!this.options.drawXAxis && !this.options.drawYAxis)
321 return;
322
323 var context = this.element.getContext("2d");
324
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325 var labelStyle = {
326 "position": "absolute",
327 "fontSize": this.options.axisLabelFontSize + "px",
328 "zIndex": 10,
f474c2a3 329 "color": this.options.axisLabelColor,
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330 "width": this.options.axisLabelWidth + "px",
331 "overflow": "hidden"
332 };
333 var makeDiv = function(txt) {
334 var div = document.createElement("div");
335 for (var name in labelStyle) {
336 div.style[name] = labelStyle[name];
fbe31dc8 337 }
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338 div.appendChild(document.createTextNode(txt));
339 return div;
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340 };
341
342 // axis lines
343 context.save();
f474c2a3 344 context.strokeStyle = this.options.axisLineColor;
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345 context.lineWidth = this.options.axisLineWidth;
346
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347 if (this.options.drawYAxis) {
348 if (this.layout.yticks) {
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349 for (var i = 0; i < this.layout.yticks.length; i++) {
350 var tick = this.layout.yticks[i];
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351 if (typeof(tick) == "function") return;
352 var x = this.area.x;
353 var y = this.area.y + tick[0] * this.area.h;
354 context.beginPath();
355 context.moveTo(x, y);
356 context.lineTo(x - this.options.axisTickSize, y);
357 context.closePath();
358 context.stroke();
359
34fedff8 360 var label = makeDiv(tick[1]);
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361 var top = (y - this.options.axisLabelFontSize / 2);
362 if (top < 0) top = 0;
363
364 if (top + this.options.axisLabelFontSize + 3 > this.height) {
365 label.style.bottom = "0px";
366 } else {
367 label.style.top = top + "px";
368 }
369 label.style.left = "0px";
370 label.style.textAlign = "right";
371 label.style.width = this.options.yAxisLabelWidth + "px";
b0c3b730 372 this.container.appendChild(label);
fbe31dc8 373 this.ylabels.push(label);
2160ed4a 374 }
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375
376 // The lowest tick on the y-axis often overlaps with the leftmost
377 // tick on the x-axis. Shift the bottom tick up a little bit to
378 // compensate if necessary.
379 var bottomTick = this.ylabels[0];
380 var fontSize = this.options.axisLabelFontSize;
381 var bottom = parseInt(bottomTick.style.top) + fontSize;
382 if (bottom > this.height - fontSize) {
383 bottomTick.style.top = (parseInt(bottomTick.style.top) -
384 fontSize / 2) + "px";
385 }
386 }
387
388 context.beginPath();
389 context.moveTo(this.area.x, this.area.y);
390 context.lineTo(this.area.x, this.area.y + this.area.h);
391 context.closePath();
392 context.stroke();
393 }
394
395 if (this.options.drawXAxis) {
396 if (this.layout.xticks) {
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397 for (var i = 0; i < this.layout.xticks.length; i++) {
398 var tick = this.layout.xticks[i];
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399 if (typeof(dataset) == "function") return;
400
401 var x = this.area.x + tick[0] * this.area.w;
402 var y = this.area.y + this.area.h;
403 context.beginPath();
404 context.moveTo(x, y);
405 context.lineTo(x, y + this.options.axisTickSize);
406 context.closePath();
407 context.stroke();
408
34fedff8 409 var label = makeDiv(tick[1]);
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410 label.style.textAlign = "center";
411 label.style.bottom = "0px";
412
413 var left = (x - this.options.axisLabelWidth/2);
414 if (left + this.options.axisLabelWidth > this.width) {
415 left = this.width - this.options.xAxisLabelWidth;
416 label.style.textAlign = "right";
417 }
418 if (left < 0) {
419 left = 0;
420 label.style.textAlign = "left";
421 }
422
423 label.style.left = left + "px";
424 label.style.width = this.options.xAxisLabelWidth + "px";
b0c3b730 425 this.container.appendChild(label);
fbe31dc8 426 this.xlabels.push(label);
2160ed4a 427 }
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428 }
429
430 context.beginPath();
431 context.moveTo(this.area.x, this.area.y + this.area.h);
432 context.lineTo(this.area.x + this.area.w, this.area.y + this.area.h);
433 context.closePath();
434 context.stroke();
435 }
436
437 context.restore();
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438};
439
fbe31dc8 440
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441/**
442 * Overrides the CanvasRenderer method to draw error bars
443 */
285a6bda 444DygraphCanvasRenderer.prototype._renderLineChart = function() {
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445 var context = this.element.getContext("2d");
446 var colorCount = this.options.colorScheme.length;
447 var colorScheme = this.options.colorScheme;
6a1aa64f 448 var errorBars = this.layout.options.errorBars;
6a1aa64f 449 var bind = MochiKit.Base.bind;
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450
451 var setNames = [];
452 for (var name in this.layout.datasets) setNames.push(name);
453 var setCount = setNames.length;
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454
455 //Update Points
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456 for (var i = 0; i < this.layout.points.length; i++) {
457 var point = this.layout.points[i];
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458 point.canvasx = this.area.w * point.x + this.area.x;
459 point.canvasy = this.area.h * point.y + this.area.y;
460 }
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461
462 // create paths
9317362d 463 var isOK = function(x) { return x && !isNaN(x); };
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464 var makePath = function(ctx) {
465 for (var i = 0; i < setCount; i++) {
466 var setName = setNames[i];
467 var color = colorScheme[i%colorCount];
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468
469 // setup graphics context
470 context.save();
6a1aa64f 471 var point = this.layout.points[0];
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472 var pointSize = this.dygraph_.attr_("pointSize");
473 var prevX = null, prevY = null;
474 var drawPoints = this.dygraph_.attr_("drawPoints");
475 var points = this.layout.points;
476 for (var j = 0; j < points.length; j++) {
477 var point = points[j];
6a1aa64f 478 if (point.name == setName) {
9317362d 479 if (!isOK(point.canvasy)) {
9a730910 480 // this will make us move to the next point, not draw a line to it.
9317362d 481 prevX = prevY = null;
9a730910 482 } else {
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483 // A point is "isolated" if it is non-null but both the previous
484 // and next points are null.
485 var isIsolated = (!prevX && (j == points.length - 1 ||
486 !isOK(points[j+1].canvasy)));
487
488 if (!prevX) {
489 prevX = point.canvasx;
490 prevY = point.canvasy;
9a730910 491 } else {
9317362d 492 ctx.beginPath();
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493 ctx.strokeStyle = color;
494 ctx.lineWidth = this.options.strokeWidth;
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495 ctx.moveTo(prevX, prevY);
496 prevX = point.canvasx;
497 prevY = point.canvasy;
498 ctx.lineTo(prevX, prevY);
499 ctx.stroke();
500 }
501
502 if (drawPoints || isIsolated) {
503 ctx.beginPath();
f474c2a3 504 ctx.fillStyle = color;
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505 ctx.arc(point.canvasx, point.canvasy, pointSize, 0, 360, false);
506 ctx.fill();
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507 }
508 }
6a1aa64f 509 }
9317362d 510 }
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511 }
512 };
513
514 var makeErrorBars = function(ctx) {
515 for (var i = 0; i < setCount; i++) {
516 var setName = setNames[i];
517 var color = colorScheme[i % colorCount];
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518
519 // setup graphics context
520 context.save();
f474c2a3 521 context.strokeStyle = color;
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522 context.lineWidth = this.options.strokeWidth;
523 var prevX = -1;
524 var prevYs = [-1, -1];
525 var count = 0;
526 var yscale = this.layout.yscale;
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527 // should be same color as the lines but only 15% opaque.
528 var rgb = new RGBColor(color);
529 var err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',0.15)';
530 ctx.fillStyle = err_color;
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531 ctx.beginPath();
532 for (var j = 0; j < this.layout.points.length; j++) {
533 var point = this.layout.points[j];
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534 count++;
535 if (point.name == setName) {
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536 if (!point.y || isNaN(point.y)) {
537 prevX = -1;
538 return;
539 }
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540 var newYs = [ point.y - point.errorPlus * yscale,
541 point.y + point.errorMinus * yscale ];
542 newYs[0] = this.area.h * newYs[0] + this.area.y;
543 newYs[1] = this.area.h * newYs[1] + this.area.y;
544 if (prevX >= 0) {
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545 ctx.moveTo(prevX, prevYs[0]);
546 ctx.lineTo(point.canvasx, newYs[0]);
547 ctx.lineTo(point.canvasx, newYs[1]);
548 ctx.lineTo(prevX, prevYs[1]);
549 ctx.closePath();
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550 }
551 prevYs[0] = newYs[0];
552 prevYs[1] = newYs[1];
553 prevX = point.canvasx;
554 }
05c9d0c4 555 }
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556 ctx.fill();
557 }
558 };
559
560 if (errorBars)
561 bind(makeErrorBars, this)(context);
562 bind(makePath, this)(context);
563 context.restore();
564};