remove PlotKit entirely. Yay!
[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 = {
168 "strokeWidth": 0.5,
169 "drawXAxis": true,
170 "drawYAxis": true,
171 "axisLineColor": Color.blackColor(),
172 "axisLineWidth": 0.5,
173 "axisTickSize": 3,
174 "axisLabelColor": Color.blackColor(),
175 "axisLabelFont": "Arial",
176 "axisLabelFontSize": 9,
177 "axisLabelWidth": 50,
178 "drawYGrid": true,
179 "drawXGrid": true,
180 "gridLineColor": MochiKit.Color.Color.grayColor()
181 };
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182 MochiKit.Base.update(this.options, options);
183
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184 this.layout = layout;
185 this.element = MochiKit.DOM.getElement(element);
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
218 MochiKit.DOM.updateNodeAttributes(this.container,
219 {"style":{ "position": "relative", "width": this.width + "px"}});
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) {
233 this.clearDelay = MochiKit.Async.wait(this.IEDelay);
234 this.clearDelay.addCallback(bind(this.clear, this));
235 return;
236 }
237 }
238
239 var context = this.element.getContext("2d");
240 context.clearRect(0, 0, this.width, this.height);
241
242 MochiKit.Iter.forEach(this.xlabels, MochiKit.DOM.removeElement);
243 MochiKit.Iter.forEach(this.ylabels, MochiKit.DOM.removeElement);
244 this.xlabels = new Array();
245 this.ylabels = new Array();
246};
247
248
249DygraphCanvasRenderer.isSupported = function(canvasName) {
250 var canvas = null;
251 try {
252 if (MochiKit.Base.isUndefinedOrNull(canvasName))
253 canvas = MochiKit.DOM.CANVAS({});
254 else
255 canvas = MochiKit.DOM.getElement(canvasName);
256 var context = canvas.getContext("2d");
257 }
258 catch (e) {
259 var ie = navigator.appVersion.match(/MSIE (\d\.\d)/);
260 var opera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1);
261 if ((!ie) || (ie[1] < 6) || (opera))
262 return false;
263 return true;
264 }
265 return true;
6a1aa64f 266};
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267
268/**
269 * Draw an X/Y grid on top of the existing plot
270 */
285a6bda 271DygraphCanvasRenderer.prototype.render = function() {
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272 // Draw the new X/Y grid
273 var ctx = this.element.getContext("2d");
274 if (this.options.drawYGrid) {
275 var ticks = this.layout.yticks;
276 ctx.save();
277 ctx.strokeStyle = this.options.gridLineColor.toRGBString();
278 ctx.lineWidth = this.options.axisLineWidth;
279 for (var i = 0; i < ticks.length; i++) {
280 var x = this.area.x;
281 var y = this.area.y + ticks[i][0] * this.area.h;
282 ctx.beginPath();
283 ctx.moveTo(x, y);
284 ctx.lineTo(x + this.area.w, y);
285 ctx.closePath();
286 ctx.stroke();
287 }
288 }
289
290 if (this.options.drawXGrid) {
291 var ticks = this.layout.xticks;
292 ctx.save();
293 ctx.strokeStyle = this.options.gridLineColor.toRGBString();
294 ctx.lineWidth = this.options.axisLineWidth;
295 for (var i=0; i<ticks.length; i++) {
296 var x = this.area.x + ticks[i][0] * this.area.w;
297 var y = this.area.y + this.area.h;
298 ctx.beginPath();
299 ctx.moveTo(x, y);
300 ctx.lineTo(x, this.area.y);
301 ctx.closePath();
302 ctx.stroke();
303 }
304 }
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305
306 // Do the ordinary rendering, as before
307 // TODO(danvk) Call super.render()
308 this._renderLineChart();
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309 this._renderAxis();
310};
311
312
313DygraphCanvasRenderer.prototype._renderAxis = function() {
314 if (!this.options.drawXAxis && !this.options.drawYAxis)
315 return;
316
317 var context = this.element.getContext("2d");
318
319 var labelStyle = {"style":
320 {"position": "absolute",
321 "fontSize": this.options.axisLabelFontSize + "px",
322 "zIndex": 10,
323 "color": this.options.axisLabelColor.toRGBString(),
324 "width": this.options.axisLabelWidth + "px",
325 "overflow": "hidden"
326 }
327 };
328
329 // axis lines
330 context.save();
331 context.strokeStyle = this.options.axisLineColor.toRGBString();
332 context.lineWidth = this.options.axisLineWidth;
333
334
335 if (this.options.drawYAxis) {
336 if (this.layout.yticks) {
337 var drawTick = function(tick) {
338 if (typeof(tick) == "function") return;
339 var x = this.area.x;
340 var y = this.area.y + tick[0] * this.area.h;
341 context.beginPath();
342 context.moveTo(x, y);
343 context.lineTo(x - this.options.axisTickSize, y);
344 context.closePath();
345 context.stroke();
346
347 var label = DIV(labelStyle, tick[1]);
348 var top = (y - this.options.axisLabelFontSize / 2);
349 if (top < 0) top = 0;
350
351 if (top + this.options.axisLabelFontSize + 3 > this.height) {
352 label.style.bottom = "0px";
353 } else {
354 label.style.top = top + "px";
355 }
356 label.style.left = "0px";
357 label.style.textAlign = "right";
358 label.style.width = this.options.yAxisLabelWidth + "px";
359 MochiKit.DOM.appendChildNodes(this.container, label);
360 this.ylabels.push(label);
361 };
362
363 MochiKit.Iter.forEach(this.layout.yticks, bind(drawTick, this));
364
365 // The lowest tick on the y-axis often overlaps with the leftmost
366 // tick on the x-axis. Shift the bottom tick up a little bit to
367 // compensate if necessary.
368 var bottomTick = this.ylabels[0];
369 var fontSize = this.options.axisLabelFontSize;
370 var bottom = parseInt(bottomTick.style.top) + fontSize;
371 if (bottom > this.height - fontSize) {
372 bottomTick.style.top = (parseInt(bottomTick.style.top) -
373 fontSize / 2) + "px";
374 }
375 }
376
377 context.beginPath();
378 context.moveTo(this.area.x, this.area.y);
379 context.lineTo(this.area.x, this.area.y + this.area.h);
380 context.closePath();
381 context.stroke();
382 }
383
384 if (this.options.drawXAxis) {
385 if (this.layout.xticks) {
386 var drawTick = function(tick) {
387 if (typeof(dataset) == "function") return;
388
389 var x = this.area.x + tick[0] * this.area.w;
390 var y = this.area.y + this.area.h;
391 context.beginPath();
392 context.moveTo(x, y);
393 context.lineTo(x, y + this.options.axisTickSize);
394 context.closePath();
395 context.stroke();
396
397 var label = DIV(labelStyle, tick[1]);
398 label.style.textAlign = "center";
399 label.style.bottom = "0px";
400
401 var left = (x - this.options.axisLabelWidth/2);
402 if (left + this.options.axisLabelWidth > this.width) {
403 left = this.width - this.options.xAxisLabelWidth;
404 label.style.textAlign = "right";
405 }
406 if (left < 0) {
407 left = 0;
408 label.style.textAlign = "left";
409 }
410
411 label.style.left = left + "px";
412 label.style.width = this.options.xAxisLabelWidth + "px";
413 MochiKit.DOM.appendChildNodes(this.container, label);
414 this.xlabels.push(label);
415 };
416
417 MochiKit.Iter.forEach(this.layout.xticks, bind(drawTick, this));
418 }
419
420 context.beginPath();
421 context.moveTo(this.area.x, this.area.y + this.area.h);
422 context.lineTo(this.area.x + this.area.w, this.area.y + this.area.h);
423 context.closePath();
424 context.stroke();
425 }
426
427 context.restore();
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428};
429
fbe31dc8 430
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431/**
432 * Overrides the CanvasRenderer method to draw error bars
433 */
285a6bda 434DygraphCanvasRenderer.prototype._renderLineChart = function() {
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435 var context = this.element.getContext("2d");
436 var colorCount = this.options.colorScheme.length;
437 var colorScheme = this.options.colorScheme;
438 var setNames = MochiKit.Base.keys(this.layout.datasets);
439 var errorBars = this.layout.options.errorBars;
440 var setCount = setNames.length;
441 var bind = MochiKit.Base.bind;
442 var partial = MochiKit.Base.partial;
443
444 //Update Points
445 var updatePoint = function(point) {
446 point.canvasx = this.area.w * point.x + this.area.x;
447 point.canvasy = this.area.h * point.y + this.area.y;
448 }
449 MochiKit.Iter.forEach(this.layout.points, updatePoint, this);
450
451 // create paths
9317362d 452 var isOK = function(x) { return x && !isNaN(x); };
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453 var makePath = function(ctx) {
454 for (var i = 0; i < setCount; i++) {
455 var setName = setNames[i];
456 var color = colorScheme[i%colorCount];
457 var strokeX = this.options.strokeColorTransform;
458
459 // setup graphics context
460 context.save();
461 context.strokeStyle = color.toRGBString();
462 context.lineWidth = this.options.strokeWidth;
6a1aa64f 463 var point = this.layout.points[0];
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464 var pointSize = this.dygraph_.attr_("pointSize");
465 var prevX = null, prevY = null;
466 var drawPoints = this.dygraph_.attr_("drawPoints");
467 var points = this.layout.points;
468 for (var j = 0; j < points.length; j++) {
469 var point = points[j];
6a1aa64f 470 if (point.name == setName) {
9317362d 471 if (!isOK(point.canvasy)) {
9a730910 472 // this will make us move to the next point, not draw a line to it.
9317362d 473 prevX = prevY = null;
9a730910 474 } else {
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475 // A point is "isolated" if it is non-null but both the previous
476 // and next points are null.
477 var isIsolated = (!prevX && (j == points.length - 1 ||
478 !isOK(points[j+1].canvasy)));
479
480 if (!prevX) {
481 prevX = point.canvasx;
482 prevY = point.canvasy;
9a730910 483 } else {
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484 ctx.beginPath();
485 ctx.moveTo(prevX, prevY);
486 prevX = point.canvasx;
487 prevY = point.canvasy;
488 ctx.lineTo(prevX, prevY);
489 ctx.stroke();
490 }
491
492 if (drawPoints || isIsolated) {
493 ctx.beginPath();
494 ctx.fillStyle = color.toRGBString();
495 ctx.arc(point.canvasx, point.canvasy, pointSize, 0, 360, false);
496 ctx.fill();
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497 }
498 }
6a1aa64f 499 }
9317362d 500 }
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501 }
502 };
503
504 var makeErrorBars = function(ctx) {
505 for (var i = 0; i < setCount; i++) {
506 var setName = setNames[i];
507 var color = colorScheme[i % colorCount];
508 var strokeX = this.options.strokeColorTransform;
509
510 // setup graphics context
511 context.save();
512 context.strokeStyle = color.toRGBString();
513 context.lineWidth = this.options.strokeWidth;
514 var prevX = -1;
515 var prevYs = [-1, -1];
516 var count = 0;
517 var yscale = this.layout.yscale;
518 var errorTrapezoid = function(ctx_,point) {
519 count++;
520 if (point.name == setName) {
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521 if (!point.y || isNaN(point.y)) {
522 prevX = -1;
523 return;
524 }
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525 var newYs = [ point.y - point.errorPlus * yscale,
526 point.y + point.errorMinus * yscale ];
527 newYs[0] = this.area.h * newYs[0] + this.area.y;
528 newYs[1] = this.area.h * newYs[1] + this.area.y;
529 if (prevX >= 0) {
530 ctx_.moveTo(prevX, prevYs[0]);
531 ctx_.lineTo(point.canvasx, newYs[0]);
532 ctx_.lineTo(point.canvasx, newYs[1]);
533 ctx_.lineTo(prevX, prevYs[1]);
534 ctx_.closePath();
535 }
536 prevYs[0] = newYs[0];
537 prevYs[1] = newYs[1];
538 prevX = point.canvasx;
539 }
540 };
541 // should be same color as the lines
542 var err_color = color.colorWithAlpha(0.15);
543 ctx.fillStyle = err_color.toRGBString();
544 ctx.beginPath();
545 MochiKit.Iter.forEach(this.layout.points, partial(errorTrapezoid, ctx), this);
546 ctx.fill();
547 }
548 };
549
550 if (errorBars)
551 bind(makeErrorBars, this)(context);
552 bind(makePath, this)(context);
553 context.restore();
554};