toggle visibility in stock demo
[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.
fc80a396 20 Dygraph.update(this.options, options ? options : {});
efe0829a 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;
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40 if (this.options.dateWindow) {
41 this.minxval = this.options.dateWindow[0];
42 this.maxxval = this.options.dateWindow[1];
43 } else {
44 for (var name in this.datasets) {
45 if (!this.datasets.hasOwnProperty(name)) continue;
46 var series = this.datasets[name];
47 var x1 = series[0][0];
48 if (!this.minxval || x1 < this.minxval) this.minxval = x1;
85b99f0b 49
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50 var x2 = series[series.length - 1][0];
51 if (!this.maxxval || x2 > this.maxxval) this.maxxval = x2;
52 }
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53 }
54 this.xrange = this.maxxval - this.minxval;
55 this.xscale = (this.xrange != 0 ? 1/this.xrange : 1.0);
56
57 this.minyval = this.options.yAxis[0];
58 this.maxyval = this.options.yAxis[1];
59 this.yrange = this.maxyval - this.minyval;
60 this.yscale = (this.yrange != 0 ? 1/this.yrange : 1.0);
61};
62
63DygraphLayout.prototype._evaluateLineCharts = function() {
64 // add all the rects
65 this.points = new Array();
66 for (var setName in this.datasets) {
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67 if (!this.datasets.hasOwnProperty(setName)) continue;
68
69 var dataset = this.datasets[setName];
70 for (var j = 0; j < dataset.length; j++) {
71 var item = dataset[j];
72 var point = {
73 x: ((parseFloat(item[0]) - this.minxval) * this.xscale),
74 y: 1.0 - ((parseFloat(item[1]) - this.minyval) * this.yscale),
75 xval: parseFloat(item[0]),
76 yval: parseFloat(item[1]),
77 name: setName
78 };
79
80 // limit the x, y values so they do not overdraw
81 if (point.y <= 0.0) {
82 point.y = 0.0;
83 }
84 if (point.y >= 1.0) {
85 point.y = 1.0;
86 }
87 if ((point.x >= 0.0) && (point.x <= 1.0)) {
88 this.points.push(point);
89 }
90 }
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91 }
92};
93
94DygraphLayout.prototype._evaluateLineTicks = function() {
95 this.xticks = new Array();
96 for (var i = 0; i < this.options.xTicks.length; i++) {
97 var tick = this.options.xTicks[i];
98 var label = tick.label;
99 var pos = this.xscale * (tick.v - this.minxval);
100 if ((pos >= 0.0) && (pos <= 1.0)) {
101 this.xticks.push([pos, label]);
102 }
103 }
104
105 this.yticks = new Array();
106 for (var i = 0; i < this.options.yTicks.length; i++) {
107 var tick = this.options.yTicks[i];
108 var label = tick.label;
109 var pos = 1.0 - (this.yscale * (tick.v - this.minyval));
110 if ((pos >= 0.0) && (pos <= 1.0)) {
111 this.yticks.push([pos, label]);
112 }
113 }
114};
115
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116
117/**
118 * Behaves the same way as PlotKit.Layout, but also copies the errors
119 * @private
120 */
285a6bda 121DygraphLayout.prototype.evaluateWithError = function() {
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122 this.evaluate();
123 if (!this.options.errorBars) return;
124
125 // Copy over the error terms
126 var i = 0; // index in this.points
127 for (var setName in this.datasets) {
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128 if (!this.datasets.hasOwnProperty(setName)) continue;
129 var j = 0;
130 var dataset = this.datasets[setName];
131 for (var j = 0; j < dataset.length; j++, i++) {
132 var item = dataset[j];
133 var xv = parseFloat(item[0]);
134 var yv = parseFloat(item[1]);
135
136 if (xv == this.points[i].xval &&
137 yv == this.points[i].yval) {
138 this.points[i].errorMinus = parseFloat(item[2]);
139 this.points[i].errorPlus = parseFloat(item[3]);
140 }
141 }
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142 }
143};
144
145/**
146 * Convenience function to remove all the data sets from a graph
147 */
285a6bda 148DygraphLayout.prototype.removeAllDatasets = function() {
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149 delete this.datasets;
150 this.datasets = new Array();
151};
152
153/**
154 * Change the values of various layout options
155 * @param {Object} new_options an associative array of new properties
156 */
285a6bda 157DygraphLayout.prototype.updateOptions = function(new_options) {
fc80a396 158 Dygraph.update(this.options, new_options ? new_options : {});
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159};
160
161// Subclass PlotKit.CanvasRenderer to add:
162// 1. X/Y grid overlay
163// 2. Ability to draw error bars (if required)
164
165/**
166 * Sets some PlotKit.CanvasRenderer options
167 * @param {Object} element The canvas to attach to
285a6bda 168 * @param {Layout} layout The DygraphLayout object for this graph.
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169 * @param {Object} options Options to pass on to CanvasRenderer
170 */
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171DygraphCanvasRenderer = function(dygraph, element, layout, options) {
172 // TODO(danvk): remove options, just use dygraph.attr_.
9317362d 173 this.dygraph_ = dygraph;
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174
175 // default options
176 this.options = {
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177 "strokeWidth": 0.5,
178 "drawXAxis": true,
179 "drawYAxis": true,
180 "axisLineColor": "black",
181 "axisLineWidth": 0.5,
182 "axisTickSize": 3,
183 "axisLabelColor": "black",
184 "axisLabelFont": "Arial",
185 "axisLabelFontSize": 9,
186 "axisLabelWidth": 50,
187 "drawYGrid": true,
188 "drawXGrid": true,
189 "gridLineColor": "rgb(128,128,128)"
fbe31dc8 190 };
fc80a396 191 Dygraph.update(this.options, options);
6a1aa64f 192
fbe31dc8 193 this.layout = layout;
b0c3b730 194 this.element = element;
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195 this.container = this.element.parentNode;
196
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197 this.height = this.element.height;
198 this.width = this.element.width;
199
200 // --- check whether everything is ok before we return
201 if (!this.isIE && !(DygraphCanvasRenderer.isSupported(this.element)))
202 throw "Canvas is not supported.";
203
204 // internal state
205 this.xlabels = new Array();
206 this.ylabels = new Array();
207
208 this.area = {
209 x: this.options.yAxisLabelWidth + 2 * this.options.axisTickSize,
210 y: 0
211 };
212 this.area.w = this.width - this.area.x - this.options.rightGap;
213 this.area.h = this.height - this.options.axisLabelFontSize -
214 2 * this.options.axisTickSize;
215
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216 this.container.style.position = "relative";
217 this.container.style.width = this.width + "px";
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218};
219
220DygraphCanvasRenderer.prototype.clear = function() {
221 if (this.isIE) {
222 // VML takes a while to start up, so we just poll every this.IEDelay
223 try {
224 if (this.clearDelay) {
225 this.clearDelay.cancel();
226 this.clearDelay = null;
227 }
228 var context = this.element.getContext("2d");
229 }
230 catch (e) {
76171648 231 // TODO(danvk): this is broken, since MochiKit.Async is gone.
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232 this.clearDelay = MochiKit.Async.wait(this.IEDelay);
233 this.clearDelay.addCallback(bind(this.clear, this));
234 return;
235 }
236 }
237
238 var context = this.element.getContext("2d");
239 context.clearRect(0, 0, this.width, this.height);
240
2160ed4a 241 for (var i = 0; i < this.xlabels.length; i++) {
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242 var el = this.xlabels[i];
243 el.parentNode.removeChild(el);
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244 }
245 for (var i = 0; i < this.ylabels.length; i++) {
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246 var el = this.ylabels[i];
247 el.parentNode.removeChild(el);
2160ed4a 248 }
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249 this.xlabels = new Array();
250 this.ylabels = new Array();
251};
252
253
254DygraphCanvasRenderer.isSupported = function(canvasName) {
255 var canvas = null;
256 try {
21d3323f 257 if (typeof(canvasName) == 'undefined' || canvasName == null)
b0c3b730 258 canvas = document.createElement("canvas");
fbe31dc8 259 else
b0c3b730 260 canvas = canvasName;
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261 var context = canvas.getContext("2d");
262 }
263 catch (e) {
264 var ie = navigator.appVersion.match(/MSIE (\d\.\d)/);
265 var opera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1);
266 if ((!ie) || (ie[1] < 6) || (opera))
267 return false;
268 return true;
269 }
270 return true;
6a1aa64f 271};
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272
273/**
274 * Draw an X/Y grid on top of the existing plot
275 */
285a6bda 276DygraphCanvasRenderer.prototype.render = function() {
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277 // Draw the new X/Y grid
278 var ctx = this.element.getContext("2d");
279 if (this.options.drawYGrid) {
280 var ticks = this.layout.yticks;
281 ctx.save();
f2f24402 282 ctx.strokeStyle = this.options.gridLineColor;
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283 ctx.lineWidth = this.options.axisLineWidth;
284 for (var i = 0; i < ticks.length; i++) {
285 var x = this.area.x;
286 var y = this.area.y + ticks[i][0] * this.area.h;
287 ctx.beginPath();
288 ctx.moveTo(x, y);
289 ctx.lineTo(x + this.area.w, y);
290 ctx.closePath();
291 ctx.stroke();
292 }
293 }
294
295 if (this.options.drawXGrid) {
296 var ticks = this.layout.xticks;
297 ctx.save();
f2f24402 298 ctx.strokeStyle = this.options.gridLineColor;
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299 ctx.lineWidth = this.options.axisLineWidth;
300 for (var i=0; i<ticks.length; i++) {
301 var x = this.area.x + ticks[i][0] * this.area.w;
302 var y = this.area.y + this.area.h;
303 ctx.beginPath();
304 ctx.moveTo(x, y);
305 ctx.lineTo(x, this.area.y);
306 ctx.closePath();
307 ctx.stroke();
308 }
309 }
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310
311 // Do the ordinary rendering, as before
2ce09b19 312 this._renderLineChart();
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313 this._renderAxis();
314};
315
316
317DygraphCanvasRenderer.prototype._renderAxis = function() {
318 if (!this.options.drawXAxis && !this.options.drawYAxis)
319 return;
320
321 var context = this.element.getContext("2d");
322
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323 var labelStyle = {
324 "position": "absolute",
325 "fontSize": this.options.axisLabelFontSize + "px",
326 "zIndex": 10,
f474c2a3 327 "color": this.options.axisLabelColor,
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328 "width": this.options.axisLabelWidth + "px",
329 "overflow": "hidden"
330 };
331 var makeDiv = function(txt) {
332 var div = document.createElement("div");
333 for (var name in labelStyle) {
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334 if (labelStyle.hasOwnProperty(name)) {
335 div.style[name] = labelStyle[name];
336 }
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
fbe31dc8 347 if (this.options.drawYAxis) {
8b7a0cc3 348 if (this.layout.yticks && this.layout.yticks.length > 0) {
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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;
5954ef32 449 var fillGraph = this.layout.options.fillGraph;
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450
451 var setNames = [];
ca43052c 452 for (var name in this.layout.datasets) {
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453 if (this.layout.datasets.hasOwnProperty(name)) {
454 setNames.push(name);
455 }
ca43052c 456 }
21d3323f 457 var setCount = setNames.length;
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458
459 //Update Points
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460 for (var i = 0; i < this.layout.points.length; i++) {
461 var point = this.layout.points[i];
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462 point.canvasx = this.area.w * point.x + this.area.x;
463 point.canvasy = this.area.h * point.y + this.area.y;
464 }
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465
466 // create paths
9317362d 467 var isOK = function(x) { return x && !isNaN(x); };
6a1aa64f 468
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469 var ctx = context;
470 if (errorBars) {
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471 if (fillGraph) {
472 this.dygraph_.warn("Can't use fillGraph option with error bars");
473 }
474
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475 for (var i = 0; i < setCount; i++) {
476 var setName = setNames[i];
477 var color = colorScheme[i % colorCount];
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478
479 // setup graphics context
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480 ctx.save();
481 ctx.strokeStyle = color;
482 ctx.lineWidth = this.options.strokeWidth;
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483 var prevX = -1;
484 var prevYs = [-1, -1];
485 var count = 0;
486 var yscale = this.layout.yscale;
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487 // should be same color as the lines but only 15% opaque.
488 var rgb = new RGBColor(color);
489 var err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',0.15)';
490 ctx.fillStyle = err_color;
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491 ctx.beginPath();
492 for (var j = 0; j < this.layout.points.length; j++) {
493 var point = this.layout.points[j];
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494 count++;
495 if (point.name == setName) {
5954ef32 496 if (!isOK(point.y)) {
5011e7a1 497 prevX = -1;
ae85914a 498 continue;
5011e7a1 499 }
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500 var newYs = [ point.y - point.errorPlus * yscale,
501 point.y + point.errorMinus * yscale ];
502 newYs[0] = this.area.h * newYs[0] + this.area.y;
503 newYs[1] = this.area.h * newYs[1] + this.area.y;
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504 if (prevX >= 0) {
505 ctx.moveTo(prevX, prevYs[0]);
506 ctx.lineTo(point.canvasx, newYs[0]);
507 ctx.lineTo(point.canvasx, newYs[1]);
508 ctx.lineTo(prevX, prevYs[1]);
509 ctx.closePath();
510 }
511 prevYs[0] = newYs[0];
512 prevYs[1] = newYs[1];
513 prevX = point.canvasx;
514 }
515 }
516 ctx.fill();
517 }
518 } else if (fillGraph) {
519 for (var i = 0; i < setCount; i++) {
520 var setName = setNames[i];
521 var setNameLast;
522 if (i>0) setNameLast = setNames[i-1];
523 var color = colorScheme[i % colorCount];
524
525 // setup graphics context
526 ctx.save();
527 ctx.strokeStyle = color;
528 ctx.lineWidth = this.options.strokeWidth;
529 var prevX = -1;
530 var prevYs = [-1, -1];
531 var count = 0;
532 var yscale = this.layout.yscale;
533 // should be same color as the lines but only 15% opaque.
534 var rgb = new RGBColor(color);
535 var err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',0.15)';
536 ctx.fillStyle = err_color;
537 ctx.beginPath();
538 for (var j = 0; j < this.layout.points.length; j++) {
539 var point = this.layout.points[j];
540 count++;
541 if (point.name == setName) {
542 if (!isOK(point.y)) {
543 prevX = -1;
544 continue;
545 }
546 var pX = 1.0 + this.layout.minyval * this.layout.yscale;
547 if (pX < 0.0) pX = 0.0;
548 else if (pX > 1.0) pX = 1.0;
549 var newYs = [ point.y, pX ];
550 newYs[0] = this.area.h * newYs[0] + this.area.y;
551 newYs[1] = this.area.h * newYs[1] + this.area.y;
6a1aa64f 552 if (prevX >= 0) {
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553 ctx.moveTo(prevX, prevYs[0]);
554 ctx.lineTo(point.canvasx, newYs[0]);
555 ctx.lineTo(point.canvasx, newYs[1]);
556 ctx.lineTo(prevX, prevYs[1]);
557 ctx.closePath();
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558 }
559 prevYs[0] = newYs[0];
560 prevYs[1] = newYs[1];
561 prevX = point.canvasx;
562 }
05c9d0c4 563 }
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564 ctx.fill();
565 }
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566 }
567
568 for (var i = 0; i < setCount; i++) {
569 var setName = setNames[i];
570 var color = colorScheme[i%colorCount];
571
572 // setup graphics context
573 context.save();
574 var point = this.layout.points[0];
575 var pointSize = this.dygraph_.attr_("pointSize");
576 var prevX = null, prevY = null;
577 var drawPoints = this.dygraph_.attr_("drawPoints");
578 var points = this.layout.points;
579 for (var j = 0; j < points.length; j++) {
580 var point = points[j];
581 if (point.name == setName) {
582 if (!isOK(point.canvasy)) {
583 // this will make us move to the next point, not draw a line to it.
584 prevX = prevY = null;
585 } else {
586 // A point is "isolated" if it is non-null but both the previous
587 // and next points are null.
588 var isIsolated = (!prevX && (j == points.length - 1 ||
589 !isOK(points[j+1].canvasy)));
590
591 if (!prevX) {
592 prevX = point.canvasx;
593 prevY = point.canvasy;
594 } else {
595 ctx.beginPath();
596 ctx.strokeStyle = color;
597 ctx.lineWidth = this.options.strokeWidth;
598 ctx.moveTo(prevX, prevY);
599 prevX = point.canvasx;
600 prevY = point.canvasy;
601 ctx.lineTo(prevX, prevY);
602 ctx.stroke();
603 }
604
605 if (drawPoints || isIsolated) {
606 ctx.beginPath();
607 ctx.fillStyle = color;
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608 ctx.arc(point.canvasx, point.canvasy, pointSize,
609 0, 2 * Math.PI, false);
80aaae18
DV
610 ctx.fill();
611 }
612 }
613 }
614 }
615 }
6a1aa64f 616
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617 context.restore();
618};