document some more options
[dygraphs.git] / dygraph-canvas.js
1 // Copyright 2006 Dan Vanderkam (danvdk@gmail.com)
2 // All Rights Reserved.
3
4 /**
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
10 */
11
12 /**
13 * Creates a new DygraphLayout object.
14 * @param {Object} options Options for PlotKit.Layout
15 * @return {Object} The DygraphLayout object
16 */
17 DygraphLayout = function(dygraph, options) {
18 this.dygraph_ = dygraph;
19 this.options = {}; // TODO(danvk): remove, use attr_ instead.
20 Dygraph.update(this.options, options ? options : {});
21 this.datasets = new Array();
22 };
23
24 DygraphLayout.prototype.attr_ = function(name) {
25 return this.dygraph_.attr_(name);
26 };
27
28 DygraphLayout.prototype.addDataset = function(setname, set_xy) {
29 this.datasets[setname] = set_xy;
30 };
31
32 DygraphLayout.prototype.evaluate = function() {
33 this._evaluateLimits();
34 this._evaluateLineCharts();
35 this._evaluateLineTicks();
36 };
37
38 DygraphLayout.prototype._evaluateLimits = function() {
39 this.minxval = this.maxxval = null;
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;
49
50 var x2 = series[series.length - 1][0];
51 if (!this.maxxval || x2 > this.maxxval) this.maxxval = x2;
52 }
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
63 DygraphLayout.prototype._evaluateLineCharts = function() {
64 // add all the rects
65 this.points = new Array();
66 for (var setName in this.datasets) {
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 // TODO(danvk): here
74 x: ((parseFloat(item[0]) - this.minxval) * this.xscale),
75 y: 1.0 - ((parseFloat(item[1]) - this.minyval) * this.yscale),
76 xval: parseFloat(item[0]),
77 yval: parseFloat(item[1]),
78 name: setName
79 };
80
81 // limit the x, y values so they do not overdraw
82 if (point.y <= 0.0) {
83 point.y = 0.0;
84 }
85 if (point.y >= 1.0) {
86 point.y = 1.0;
87 }
88 this.points.push(point);
89 }
90 }
91 };
92
93 DygraphLayout.prototype._evaluateLineTicks = function() {
94 this.xticks = new Array();
95 for (var i = 0; i < this.options.xTicks.length; i++) {
96 var tick = this.options.xTicks[i];
97 var label = tick.label;
98 var pos = this.xscale * (tick.v - this.minxval);
99 if ((pos >= 0.0) && (pos <= 1.0)) {
100 this.xticks.push([pos, label]);
101 }
102 }
103
104 this.yticks = new Array();
105 for (var i = 0; i < this.options.yTicks.length; i++) {
106 var tick = this.options.yTicks[i];
107 var label = tick.label;
108 var pos = 1.0 - (this.yscale * (tick.v - this.minyval));
109 if ((pos >= 0.0) && (pos <= 1.0)) {
110 this.yticks.push([pos, label]);
111 }
112 }
113 };
114
115
116 /**
117 * Behaves the same way as PlotKit.Layout, but also copies the errors
118 * @private
119 */
120 DygraphLayout.prototype.evaluateWithError = function() {
121 this.evaluate();
122 if (!this.options.errorBars) return;
123
124 // Copy over the error terms
125 var i = 0; // index in this.points
126 for (var setName in this.datasets) {
127 if (!this.datasets.hasOwnProperty(setName)) continue;
128 var j = 0;
129 var dataset = this.datasets[setName];
130 for (var j = 0; j < dataset.length; j++, i++) {
131 var item = dataset[j];
132 var xv = parseFloat(item[0]);
133 var yv = parseFloat(item[1]);
134
135 if (xv == this.points[i].xval &&
136 yv == this.points[i].yval) {
137 this.points[i].errorMinus = parseFloat(item[2]);
138 this.points[i].errorPlus = parseFloat(item[3]);
139 }
140 }
141 }
142 };
143
144 /**
145 * Convenience function to remove all the data sets from a graph
146 */
147 DygraphLayout.prototype.removeAllDatasets = function() {
148 delete this.datasets;
149 this.datasets = new Array();
150 };
151
152 /**
153 * Change the values of various layout options
154 * @param {Object} new_options an associative array of new properties
155 */
156 DygraphLayout.prototype.updateOptions = function(new_options) {
157 Dygraph.update(this.options, new_options ? new_options : {});
158 };
159
160 // Subclass PlotKit.CanvasRenderer to add:
161 // 1. X/Y grid overlay
162 // 2. Ability to draw error bars (if required)
163
164 /**
165 * Sets some PlotKit.CanvasRenderer options
166 * @param {Object} element The canvas to attach to
167 * @param {Layout} layout The DygraphLayout object for this graph.
168 * @param {Object} options Options to pass on to CanvasRenderer
169 */
170 DygraphCanvasRenderer = function(dygraph, element, layout, options) {
171 // TODO(danvk): remove options, just use dygraph.attr_.
172 this.dygraph_ = dygraph;
173
174 // default options
175 this.options = {
176 "strokeWidth": 0.5,
177 "drawXAxis": true,
178 "drawYAxis": true,
179 "axisLineColor": "black",
180 "axisLineWidth": 0.5,
181 "axisTickSize": 3,
182 "axisLabelColor": "black",
183 "axisLabelFont": "Arial",
184 "axisLabelFontSize": 9,
185 "axisLabelWidth": 50,
186 "drawYGrid": true,
187 "drawXGrid": true,
188 "gridLineColor": "rgb(128,128,128)",
189 "fillAlpha": 0.15,
190 "underlayCallback": null
191 };
192 Dygraph.update(this.options, options);
193
194 this.layout = layout;
195 this.element = element;
196 this.container = this.element.parentNode;
197
198 this.height = this.element.height;
199 this.width = this.element.width;
200
201 // --- check whether everything is ok before we return
202 if (!this.isIE && !(DygraphCanvasRenderer.isSupported(this.element)))
203 throw "Canvas is not supported.";
204
205 // internal state
206 this.xlabels = new Array();
207 this.ylabels = new Array();
208
209 this.area = {
210 x: this.options.yAxisLabelWidth + 2 * this.options.axisTickSize,
211 y: 0
212 };
213 this.area.w = this.width - this.area.x - this.options.rightGap;
214 this.area.h = this.height - this.options.axisLabelFontSize -
215 2 * this.options.axisTickSize;
216
217 this.container.style.position = "relative";
218 this.container.style.width = this.width + "px";
219 };
220
221 DygraphCanvasRenderer.prototype.clear = function() {
222 if (this.isIE) {
223 // VML takes a while to start up, so we just poll every this.IEDelay
224 try {
225 if (this.clearDelay) {
226 this.clearDelay.cancel();
227 this.clearDelay = null;
228 }
229 var context = this.element.getContext("2d");
230 }
231 catch (e) {
232 // TODO(danvk): this is broken, since MochiKit.Async is gone.
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 for (var i = 0; i < this.xlabels.length; i++) {
243 var el = this.xlabels[i];
244 el.parentNode.removeChild(el);
245 }
246 for (var i = 0; i < this.ylabels.length; i++) {
247 var el = this.ylabels[i];
248 el.parentNode.removeChild(el);
249 }
250 this.xlabels = new Array();
251 this.ylabels = new Array();
252 };
253
254
255 DygraphCanvasRenderer.isSupported = function(canvasName) {
256 var canvas = null;
257 try {
258 if (typeof(canvasName) == 'undefined' || canvasName == null)
259 canvas = document.createElement("canvas");
260 else
261 canvas = canvasName;
262 var context = canvas.getContext("2d");
263 }
264 catch (e) {
265 var ie = navigator.appVersion.match(/MSIE (\d\.\d)/);
266 var opera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1);
267 if ((!ie) || (ie[1] < 6) || (opera))
268 return false;
269 return true;
270 }
271 return true;
272 };
273
274 /**
275 * Draw an X/Y grid on top of the existing plot
276 */
277 DygraphCanvasRenderer.prototype.render = function() {
278 // Draw the new X/Y grid
279 var ctx = this.element.getContext("2d");
280
281 if (this.options.underlayCallback) {
282 this.options.underlayCallback(ctx, this.area, this.layout);
283 }
284
285 if (this.options.drawYGrid) {
286 var ticks = this.layout.yticks;
287 ctx.save();
288 ctx.strokeStyle = this.options.gridLineColor;
289 ctx.lineWidth = this.options.axisLineWidth;
290 for (var i = 0; i < ticks.length; i++) {
291 var x = this.area.x;
292 var y = this.area.y + ticks[i][0] * this.area.h;
293 ctx.beginPath();
294 ctx.moveTo(x, y);
295 ctx.lineTo(x + this.area.w, y);
296 ctx.closePath();
297 ctx.stroke();
298 }
299 }
300
301 if (this.options.drawXGrid) {
302 var ticks = this.layout.xticks;
303 ctx.save();
304 ctx.strokeStyle = this.options.gridLineColor;
305 ctx.lineWidth = this.options.axisLineWidth;
306 for (var i=0; i<ticks.length; i++) {
307 var x = this.area.x + ticks[i][0] * this.area.w;
308 var y = this.area.y + this.area.h;
309 ctx.beginPath();
310 ctx.moveTo(x, y);
311 ctx.lineTo(x, this.area.y);
312 ctx.closePath();
313 ctx.stroke();
314 }
315 }
316
317 // Do the ordinary rendering, as before
318 this._renderLineChart();
319 this._renderAxis();
320 };
321
322
323 DygraphCanvasRenderer.prototype._renderAxis = function() {
324 if (!this.options.drawXAxis && !this.options.drawYAxis)
325 return;
326
327 var context = this.element.getContext("2d");
328
329 var labelStyle = {
330 "position": "absolute",
331 "fontSize": this.options.axisLabelFontSize + "px",
332 "zIndex": 10,
333 "color": this.options.axisLabelColor,
334 "width": this.options.axisLabelWidth + "px",
335 "overflow": "hidden"
336 };
337 var makeDiv = function(txt) {
338 var div = document.createElement("div");
339 for (var name in labelStyle) {
340 if (labelStyle.hasOwnProperty(name)) {
341 div.style[name] = labelStyle[name];
342 }
343 }
344 div.appendChild(document.createTextNode(txt));
345 return div;
346 };
347
348 // axis lines
349 context.save();
350 context.strokeStyle = this.options.axisLineColor;
351 context.lineWidth = this.options.axisLineWidth;
352
353 if (this.options.drawYAxis) {
354 if (this.layout.yticks && this.layout.yticks.length > 0) {
355 for (var i = 0; i < this.layout.yticks.length; i++) {
356 var tick = this.layout.yticks[i];
357 if (typeof(tick) == "function") return;
358 var x = this.area.x;
359 var y = this.area.y + tick[0] * this.area.h;
360 context.beginPath();
361 context.moveTo(x, y);
362 context.lineTo(x - this.options.axisTickSize, y);
363 context.closePath();
364 context.stroke();
365
366 var label = makeDiv(tick[1]);
367 var top = (y - this.options.axisLabelFontSize / 2);
368 if (top < 0) top = 0;
369
370 if (top + this.options.axisLabelFontSize + 3 > this.height) {
371 label.style.bottom = "0px";
372 } else {
373 label.style.top = top + "px";
374 }
375 label.style.left = "0px";
376 label.style.textAlign = "right";
377 label.style.width = this.options.yAxisLabelWidth + "px";
378 this.container.appendChild(label);
379 this.ylabels.push(label);
380 }
381
382 // The lowest tick on the y-axis often overlaps with the leftmost
383 // tick on the x-axis. Shift the bottom tick up a little bit to
384 // compensate if necessary.
385 var bottomTick = this.ylabels[0];
386 var fontSize = this.options.axisLabelFontSize;
387 var bottom = parseInt(bottomTick.style.top) + fontSize;
388 if (bottom > this.height - fontSize) {
389 bottomTick.style.top = (parseInt(bottomTick.style.top) -
390 fontSize / 2) + "px";
391 }
392 }
393
394 context.beginPath();
395 context.moveTo(this.area.x, this.area.y);
396 context.lineTo(this.area.x, this.area.y + this.area.h);
397 context.closePath();
398 context.stroke();
399 }
400
401 if (this.options.drawXAxis) {
402 if (this.layout.xticks) {
403 for (var i = 0; i < this.layout.xticks.length; i++) {
404 var tick = this.layout.xticks[i];
405 if (typeof(dataset) == "function") return;
406
407 var x = this.area.x + tick[0] * this.area.w;
408 var y = this.area.y + this.area.h;
409 context.beginPath();
410 context.moveTo(x, y);
411 context.lineTo(x, y + this.options.axisTickSize);
412 context.closePath();
413 context.stroke();
414
415 var label = makeDiv(tick[1]);
416 label.style.textAlign = "center";
417 label.style.bottom = "0px";
418
419 var left = (x - this.options.axisLabelWidth/2);
420 if (left + this.options.axisLabelWidth > this.width) {
421 left = this.width - this.options.xAxisLabelWidth;
422 label.style.textAlign = "right";
423 }
424 if (left < 0) {
425 left = 0;
426 label.style.textAlign = "left";
427 }
428
429 label.style.left = left + "px";
430 label.style.width = this.options.xAxisLabelWidth + "px";
431 this.container.appendChild(label);
432 this.xlabels.push(label);
433 }
434 }
435
436 context.beginPath();
437 context.moveTo(this.area.x, this.area.y + this.area.h);
438 context.lineTo(this.area.x + this.area.w, this.area.y + this.area.h);
439 context.closePath();
440 context.stroke();
441 }
442
443 context.restore();
444 };
445
446
447 /**
448 * Overrides the CanvasRenderer method to draw error bars
449 */
450 DygraphCanvasRenderer.prototype._renderLineChart = function() {
451 var context = this.element.getContext("2d");
452 var colorCount = this.options.colorScheme.length;
453 var colorScheme = this.options.colorScheme;
454 var fillAlpha = this.options.fillAlpha;
455 var errorBars = this.layout.options.errorBars;
456 var fillGraph = this.layout.options.fillGraph;
457
458 var setNames = [];
459 for (var name in this.layout.datasets) {
460 if (this.layout.datasets.hasOwnProperty(name)) {
461 setNames.push(name);
462 }
463 }
464 var setCount = setNames.length;
465
466 // Update Points
467 // TODO(danvk): here
468 for (var i = 0; i < this.layout.points.length; i++) {
469 var point = this.layout.points[i];
470 point.canvasx = this.area.w * point.x + this.area.x;
471 point.canvasy = this.area.h * point.y + this.area.y;
472 }
473
474 // create paths
475 var isOK = function(x) { return x && !isNaN(x); };
476
477 var ctx = context;
478 if (errorBars) {
479 if (fillGraph) {
480 this.dygraph_.warn("Can't use fillGraph option with error bars");
481 }
482
483 for (var i = 0; i < setCount; i++) {
484 var setName = setNames[i];
485 var color = colorScheme[i % colorCount];
486
487 // setup graphics context
488 ctx.save();
489 ctx.strokeStyle = color;
490 ctx.lineWidth = this.options.strokeWidth;
491 var prevX = NaN;
492 var prevYs = [-1, -1];
493 var count = 0;
494 var yscale = this.layout.yscale;
495 // should be same color as the lines but only 15% opaque.
496 var rgb = new RGBColor(color);
497 var err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' +
498 fillAlpha + ')';
499 ctx.fillStyle = err_color;
500 ctx.beginPath();
501 for (var j = 0; j < this.layout.points.length; j++) {
502 var point = this.layout.points[j];
503 count++;
504 if (point.name == setName) {
505 if (!isOK(point.y)) {
506 prevX = NaN;
507 continue;
508 }
509 // TODO(danvk): here
510 var newYs = [ point.y - point.errorPlus * yscale,
511 point.y + point.errorMinus * yscale ];
512 newYs[0] = this.area.h * newYs[0] + this.area.y;
513 newYs[1] = this.area.h * newYs[1] + this.area.y;
514 if (!isNaN(prevX)) {
515 ctx.moveTo(prevX, prevYs[0]);
516 ctx.lineTo(point.canvasx, newYs[0]);
517 ctx.lineTo(point.canvasx, newYs[1]);
518 ctx.lineTo(prevX, prevYs[1]);
519 ctx.closePath();
520 }
521 prevYs[0] = newYs[0];
522 prevYs[1] = newYs[1];
523 prevX = point.canvasx;
524 }
525 }
526 ctx.fill();
527 }
528 } else if (fillGraph) {
529 // TODO(danvk): merge this code with the logic above; they're very similar.
530 for (var i = 0; i < setCount; i++) {
531 var setName = setNames[i];
532 var setNameLast;
533 if (i>0) setNameLast = setNames[i-1];
534 var color = colorScheme[i % colorCount];
535
536 // setup graphics context
537 ctx.save();
538 ctx.strokeStyle = color;
539 ctx.lineWidth = this.options.strokeWidth;
540 var prevX = NaN;
541 var prevYs = [-1, -1];
542 var count = 0;
543 var yscale = this.layout.yscale;
544 // should be same color as the lines but only 15% opaque.
545 var rgb = new RGBColor(color);
546 var err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' +
547 fillAlpha + ')';
548 ctx.fillStyle = err_color;
549 ctx.beginPath();
550 for (var j = 0; j < this.layout.points.length; j++) {
551 var point = this.layout.points[j];
552 count++;
553 if (point.name == setName) {
554 if (!isOK(point.y)) {
555 prevX = NaN;
556 continue;
557 }
558 var pX = 1.0 + this.layout.minyval * this.layout.yscale;
559 if (pX < 0.0) pX = 0.0;
560 else if (pX > 1.0) pX = 1.0;
561 var newYs = [ point.y, pX ];
562 newYs[0] = this.area.h * newYs[0] + this.area.y;
563 newYs[1] = this.area.h * newYs[1] + this.area.y;
564 if (!isNaN(prevX)) {
565 ctx.moveTo(prevX, prevYs[0]);
566 ctx.lineTo(point.canvasx, newYs[0]);
567 ctx.lineTo(point.canvasx, newYs[1]);
568 ctx.lineTo(prevX, prevYs[1]);
569 ctx.closePath();
570 }
571 prevYs[0] = newYs[0];
572 prevYs[1] = newYs[1];
573 prevX = point.canvasx;
574 }
575 }
576 ctx.fill();
577 }
578 }
579
580 for (var i = 0; i < setCount; i++) {
581 var setName = setNames[i];
582 var color = colorScheme[i%colorCount];
583
584 // setup graphics context
585 context.save();
586 var point = this.layout.points[0];
587 var pointSize = this.dygraph_.attr_("pointSize");
588 var prevX = null, prevY = null;
589 var drawPoints = this.dygraph_.attr_("drawPoints");
590 var points = this.layout.points;
591 for (var j = 0; j < points.length; j++) {
592 var point = points[j];
593 if (point.name == setName) {
594 if (!isOK(point.canvasy)) {
595 // this will make us move to the next point, not draw a line to it.
596 prevX = prevY = null;
597 } else {
598 // A point is "isolated" if it is non-null but both the previous
599 // and next points are null.
600 var isIsolated = (!prevX && (j == points.length - 1 ||
601 !isOK(points[j+1].canvasy)));
602
603 if (!prevX) {
604 prevX = point.canvasx;
605 prevY = point.canvasy;
606 } else {
607 ctx.beginPath();
608 ctx.strokeStyle = color;
609 ctx.lineWidth = this.options.strokeWidth;
610 ctx.moveTo(prevX, prevY);
611 prevX = point.canvasx;
612 prevY = point.canvasy;
613 ctx.lineTo(prevX, prevY);
614 ctx.stroke();
615 }
616
617 if (drawPoints || isIsolated) {
618 ctx.beginPath();
619 ctx.fillStyle = color;
620 ctx.arc(point.canvasx, point.canvasy, pointSize,
621 0, 2 * Math.PI, false);
622 ctx.fill();
623 }
624 }
625 }
626 }
627 }
628
629 context.restore();
630 };