1378c131a89e19328990222497b14061618b7241
[dygraphs.git] / dygraph.js
1 // Copyright 2006 Dan Vanderkam (danvdk@gmail.com)
2 // All Rights Reserved.
3
4 /**
5 * @fileoverview Creates an interactive, zoomable graph based on a CSV file or
6 * string. Dygraph can handle multiple series with or without error bars. The
7 * date/value ranges will be automatically set. Dygraph uses the
8 * <canvas> tag, so it only works in FF1.5+.
9 * @author danvdk@gmail.com (Dan Vanderkam)
10
11 Usage:
12 <div id="graphdiv" style="width:800px; height:500px;"></div>
13 <script type="text/javascript">
14 new Dygraph(document.getElementById("graphdiv"),
15 "datafile.csv", // CSV file with headers
16 { }); // options
17 </script>
18
19 The CSV file is of the form
20
21 Date,SeriesA,SeriesB,SeriesC
22 YYYYMMDD,A1,B1,C1
23 YYYYMMDD,A2,B2,C2
24
25 If the 'errorBars' option is set in the constructor, the input should be of
26 the form
27
28 Date,SeriesA,SeriesB,...
29 YYYYMMDD,A1,sigmaA1,B1,sigmaB1,...
30 YYYYMMDD,A2,sigmaA2,B2,sigmaB2,...
31
32 If the 'fractions' option is set, the input should be of the form:
33
34 Date,SeriesA,SeriesB,...
35 YYYYMMDD,A1/B1,A2/B2,...
36 YYYYMMDD,A1/B1,A2/B2,...
37
38 And error bars will be calculated automatically using a binomial distribution.
39
40 For further documentation and examples, see http://www.danvk.org/dygraphs
41
42 */
43
44 /**
45 * An interactive, zoomable graph
46 * @param {String | Function} file A file containing CSV data or a function that
47 * returns this data. The expected format for each line is
48 * YYYYMMDD,val1,val2,... or, if attrs.errorBars is set,
49 * YYYYMMDD,val1,stddev1,val2,stddev2,...
50 * @param {Object} attrs Various other attributes, e.g. errorBars determines
51 * whether the input data contains error ranges.
52 */
53 Dygraph = function(div, data, opts) {
54 if (arguments.length > 0) {
55 if (arguments.length == 4) {
56 // Old versions of dygraphs took in the series labels as a constructor
57 // parameter. This doesn't make sense anymore, but it's easy to continue
58 // to support this usage.
59 this.warn("Using deprecated four-argument dygraph constructor");
60 this.__old_init__(div, data, arguments[2], arguments[3]);
61 } else {
62 this.__init__(div, data, opts);
63 }
64 }
65 };
66
67 Dygraph.NAME = "Dygraph";
68 Dygraph.VERSION = "1.2";
69 Dygraph.__repr__ = function() {
70 return "[" + this.NAME + " " + this.VERSION + "]";
71 };
72 Dygraph.toString = function() {
73 return this.__repr__();
74 };
75
76 // Various default values
77 Dygraph.DEFAULT_ROLL_PERIOD = 1;
78 Dygraph.DEFAULT_WIDTH = 480;
79 Dygraph.DEFAULT_HEIGHT = 320;
80 Dygraph.AXIS_LINE_WIDTH = 0.3;
81
82 // Default attribute values.
83 Dygraph.DEFAULT_ATTRS = {
84 highlightCircleSize: 3,
85 pixelsPerXLabel: 60,
86 pixelsPerYLabel: 30,
87
88 labelsDivWidth: 250,
89 labelsDivStyles: {
90 // TODO(danvk): move defaults from createStatusMessage_ here.
91 },
92 labelsSeparateLines: false,
93 labelsKMB: false,
94 labelsKMG2: false,
95
96 strokeWidth: 1.0,
97
98 axisTickSize: 3,
99 axisLabelFontSize: 14,
100 xAxisLabelWidth: 50,
101 yAxisLabelWidth: 50,
102 rightGap: 5,
103
104 showRoller: false,
105 xValueFormatter: Dygraph.dateString_,
106 xValueParser: Dygraph.dateParser,
107 xTicker: Dygraph.dateTicker,
108
109 delimiter: ',',
110
111 logScale: false,
112 sigma: 2.0,
113 errorBars: false,
114 fractions: false,
115 wilsonInterval: true, // only relevant if fractions is true
116 customBars: false,
117 fillGraph: false
118 };
119
120 // Various logging levels.
121 Dygraph.DEBUG = 1;
122 Dygraph.INFO = 2;
123 Dygraph.WARNING = 3;
124 Dygraph.ERROR = 3;
125
126 Dygraph.prototype.__old_init__ = function(div, file, labels, attrs) {
127 // Labels is no longer a constructor parameter, since it's typically set
128 // directly from the data source. It also conains a name for the x-axis,
129 // which the previous constructor form did not.
130 if (labels != null) {
131 var new_labels = ["Date"];
132 for (var i = 0; i < labels.length; i++) new_labels.push(labels[i]);
133 Dygraph.update(attrs, { 'labels': new_labels });
134 }
135 this.__init__(div, file, attrs);
136 };
137
138 /**
139 * Initializes the Dygraph. This creates a new DIV and constructs the PlotKit
140 * and interaction &lt;canvas&gt; inside of it. See the constructor for details
141 * on the parameters.
142 * @param {String | Function} file Source data
143 * @param {Array.<String>} labels Names of the data series
144 * @param {Object} attrs Miscellaneous other options
145 * @private
146 */
147 Dygraph.prototype.__init__ = function(div, file, attrs) {
148 // Support two-argument constructor
149 if (attrs == null) { attrs = {}; }
150
151 // Copy the important bits into the object
152 // TODO(danvk): most of these should just stay in the attrs_ dictionary.
153 this.maindiv_ = div;
154 this.file_ = file;
155 this.rollPeriod_ = attrs.rollPeriod || Dygraph.DEFAULT_ROLL_PERIOD;
156 this.previousVerticalX_ = -1;
157 this.fractions_ = attrs.fractions || false;
158 this.dateWindow_ = attrs.dateWindow || null;
159 this.valueRange_ = attrs.valueRange || null;
160 this.wilsonInterval_ = attrs.wilsonInterval || true;
161
162 // Clear the div. This ensure that, if multiple dygraphs are passed the same
163 // div, then only one will be drawn.
164 div.innerHTML = "";
165
166 // If the div isn't already sized then inherit from our attrs or
167 // give it a default size.
168 if (div.style.width == '') {
169 div.style.width = attrs.width || Dygraph.DEFAULT_WIDTH + "px";
170 }
171 if (div.style.height == '') {
172 div.style.height = attrs.height || Dygraph.DEFAULT_HEIGHT + "px";
173 }
174 this.width_ = parseInt(div.style.width, 10);
175 this.height_ = parseInt(div.style.height, 10);
176 // The div might have been specified as percent of the current window size,
177 // convert that to an appropriate number of pixels.
178 if (div.style.width.indexOf("%") == div.style.width.length - 1) {
179 // Minus ten pixels keeps scrollbars from showing up for a 100% width div.
180 this.width_ = (this.width_ * self.innerWidth / 100) - 10;
181 }
182 if (div.style.height.indexOf("%") == div.style.height.length - 1) {
183 this.height_ = (this.height_ * self.innerHeight / 100) - 10;
184 }
185
186 // Dygraphs has many options, some of which interact with one another.
187 // To keep track of everything, we maintain two sets of options:
188 //
189 // this.user_attrs_ only options explicitly set by the user.
190 // this.attrs_ defaults, options derived from user_attrs_, data.
191 //
192 // Options are then accessed this.attr_('attr'), which first looks at
193 // user_attrs_ and then computed attrs_. This way Dygraphs can set intelligent
194 // defaults without overriding behavior that the user specifically asks for.
195 this.user_attrs_ = {};
196 Dygraph.update(this.user_attrs_, attrs);
197
198 this.attrs_ = {};
199 Dygraph.update(this.attrs_, Dygraph.DEFAULT_ATTRS);
200
201 // Make a note of whether labels will be pulled from the CSV file.
202 this.labelsFromCSV_ = (this.attr_("labels") == null);
203
204 // Create the containing DIV and other interactive elements
205 this.createInterface_();
206
207 this.start_();
208 };
209
210 Dygraph.prototype.attr_ = function(name) {
211 if (typeof(this.user_attrs_[name]) != 'undefined') {
212 return this.user_attrs_[name];
213 } else if (typeof(this.attrs_[name]) != 'undefined') {
214 return this.attrs_[name];
215 } else {
216 return null;
217 }
218 };
219
220 // TODO(danvk): any way I can get the line numbers to be this.warn call?
221 Dygraph.prototype.log = function(severity, message) {
222 if (typeof(console) != 'undefined') {
223 switch (severity) {
224 case Dygraph.DEBUG:
225 console.debug('dygraphs: ' + message);
226 break;
227 case Dygraph.INFO:
228 console.info('dygraphs: ' + message);
229 break;
230 case Dygraph.WARNING:
231 console.warn('dygraphs: ' + message);
232 break;
233 case Dygraph.ERROR:
234 console.error('dygraphs: ' + message);
235 break;
236 }
237 }
238 }
239 Dygraph.prototype.info = function(message) {
240 this.log(Dygraph.INFO, message);
241 }
242 Dygraph.prototype.warn = function(message) {
243 this.log(Dygraph.WARNING, message);
244 }
245 Dygraph.prototype.error = function(message) {
246 this.log(Dygraph.ERROR, message);
247 }
248
249 /**
250 * Returns the current rolling period, as set by the user or an option.
251 * @return {Number} The number of days in the rolling window
252 */
253 Dygraph.prototype.rollPeriod = function() {
254 return this.rollPeriod_;
255 };
256
257 Dygraph.addEvent = function(el, evt, fn) {
258 var normed_fn = function(e) {
259 if (!e) var e = window.event;
260 fn(e);
261 };
262 if (window.addEventListener) { // Mozilla, Netscape, Firefox
263 el.addEventListener(evt, normed_fn, false);
264 } else { // IE
265 el.attachEvent('on' + evt, normed_fn);
266 }
267 };
268
269 /**
270 * Generates interface elements for the Dygraph: a containing div, a div to
271 * display the current point, and a textbox to adjust the rolling average
272 * period. Also creates the Renderer/Layout elements.
273 * @private
274 */
275 Dygraph.prototype.createInterface_ = function() {
276 // Create the all-enclosing graph div
277 var enclosing = this.maindiv_;
278
279 this.graphDiv = document.createElement("div");
280 this.graphDiv.style.width = this.width_ + "px";
281 this.graphDiv.style.height = this.height_ + "px";
282 enclosing.appendChild(this.graphDiv);
283
284 // Create the canvas for interactive parts of the chart.
285 // this.canvas_ = document.createElement("canvas");
286 this.canvas_ = Dygraph.createCanvas();
287 this.canvas_.style.position = "absolute";
288 this.canvas_.width = this.width_;
289 this.canvas_.height = this.height_;
290 this.canvas_.style.width = this.width_ + "px"; // for IE
291 this.canvas_.style.height = this.height_ + "px"; // for IE
292 this.graphDiv.appendChild(this.canvas_);
293
294 // ... and for static parts of the chart.
295 this.hidden_ = this.createPlotKitCanvas_(this.canvas_);
296
297 var dygraph = this;
298 Dygraph.addEvent(this.hidden_, 'mousemove', function(e) {
299 dygraph.mouseMove_(e);
300 });
301 Dygraph.addEvent(this.hidden_, 'mouseout', function(e) {
302 dygraph.mouseOut_(e);
303 });
304
305 // Create the grapher
306 // TODO(danvk): why does the Layout need its own set of options?
307 this.layoutOptions_ = { 'xOriginIsZero': false };
308 Dygraph.update(this.layoutOptions_, this.attrs_);
309 Dygraph.update(this.layoutOptions_, this.user_attrs_);
310 Dygraph.update(this.layoutOptions_, {
311 'errorBars': (this.attr_("errorBars") || this.attr_("customBars")) });
312
313 this.layout_ = new DygraphLayout(this, this.layoutOptions_);
314
315 // TODO(danvk): why does the Renderer need its own set of options?
316 this.renderOptions_ = { colorScheme: this.colors_,
317 strokeColor: null,
318 axisLineWidth: Dygraph.AXIS_LINE_WIDTH };
319 Dygraph.update(this.renderOptions_, this.attrs_);
320 Dygraph.update(this.renderOptions_, this.user_attrs_);
321 this.plotter_ = new DygraphCanvasRenderer(this,
322 this.hidden_, this.layout_,
323 this.renderOptions_);
324
325 this.createStatusMessage_();
326 this.createRollInterface_();
327 this.createDragInterface_();
328 }
329
330 /**
331 * Creates the canvas containing the PlotKit graph. Only plotkit ever draws on
332 * this particular canvas. All Dygraph work is done on this.canvas_.
333 * @param {Object} canvas The Dygraph canvas over which to overlay the plot
334 * @return {Object} The newly-created canvas
335 * @private
336 */
337 Dygraph.prototype.createPlotKitCanvas_ = function(canvas) {
338 // var h = document.createElement("canvas");
339 var h = Dygraph.createCanvas();
340 h.style.position = "absolute";
341 h.style.top = canvas.style.top;
342 h.style.left = canvas.style.left;
343 h.width = this.width_;
344 h.height = this.height_;
345 h.style.width = this.width_ + "px"; // for IE
346 h.style.height = this.height_ + "px"; // for IE
347 this.graphDiv.appendChild(h);
348 return h;
349 };
350
351 // Taken from MochiKit.Color
352 Dygraph.hsvToRGB = function (hue, saturation, value) {
353 var red;
354 var green;
355 var blue;
356 if (saturation === 0) {
357 red = value;
358 green = value;
359 blue = value;
360 } else {
361 var i = Math.floor(hue * 6);
362 var f = (hue * 6) - i;
363 var p = value * (1 - saturation);
364 var q = value * (1 - (saturation * f));
365 var t = value * (1 - (saturation * (1 - f)));
366 switch (i) {
367 case 1: red = q; green = value; blue = p; break;
368 case 2: red = p; green = value; blue = t; break;
369 case 3: red = p; green = q; blue = value; break;
370 case 4: red = t; green = p; blue = value; break;
371 case 5: red = value; green = p; blue = q; break;
372 case 6: // fall through
373 case 0: red = value; green = t; blue = p; break;
374 }
375 }
376 red = Math.floor(255 * red + 0.5);
377 green = Math.floor(255 * green + 0.5);
378 blue = Math.floor(255 * blue + 0.5);
379 return 'rgb(' + red + ',' + green + ',' + blue + ')';
380 };
381
382
383 /**
384 * Generate a set of distinct colors for the data series. This is done with a
385 * color wheel. Saturation/Value are customizable, and the hue is
386 * equally-spaced around the color wheel. If a custom set of colors is
387 * specified, that is used instead.
388 * @private
389 */
390 Dygraph.prototype.setColors_ = function() {
391 // TODO(danvk): compute this directly into this.attrs_['colorScheme'] and do
392 // away with this.renderOptions_.
393 var num = this.attr_("labels").length - 1;
394 this.colors_ = [];
395 var colors = this.attr_('colors');
396 if (!colors) {
397 var sat = this.attr_('colorSaturation') || 1.0;
398 var val = this.attr_('colorValue') || 0.5;
399 for (var i = 1; i <= num; i++) {
400 var hue = (1.0*i/(1+num));
401 this.colors_.push( Dygraph.hsvToRGB(hue, sat, val) );
402 }
403 } else {
404 for (var i = 0; i < num; i++) {
405 var colorStr = colors[i % colors.length];
406 this.colors_.push(colorStr);
407 }
408 }
409
410 // TODO(danvk): update this w/r/t/ the new options system.
411 this.renderOptions_.colorScheme = this.colors_;
412 Dygraph.update(this.plotter_.options, this.renderOptions_);
413 Dygraph.update(this.layoutOptions_, this.user_attrs_);
414 Dygraph.update(this.layoutOptions_, this.attrs_);
415 }
416
417 // The following functions are from quirksmode.org
418 // http://www.quirksmode.org/js/findpos.html
419 Dygraph.findPosX = function(obj) {
420 var curleft = 0;
421 if (obj.offsetParent) {
422 while (obj.offsetParent) {
423 curleft += obj.offsetLeft;
424 obj = obj.offsetParent;
425 }
426 }
427 else if (obj.x)
428 curleft += obj.x;
429 return curleft;
430 };
431
432 Dygraph.findPosY = function(obj) {
433 var curtop = 0;
434 if (obj.offsetParent) {
435 while (obj.offsetParent) {
436 curtop += obj.offsetTop;
437 obj = obj.offsetParent;
438 }
439 }
440 else if (obj.y)
441 curtop += obj.y;
442 return curtop;
443 };
444
445 /**
446 * Create the div that contains information on the selected point(s)
447 * This goes in the top right of the canvas, unless an external div has already
448 * been specified.
449 * @private
450 */
451 Dygraph.prototype.createStatusMessage_ = function(){
452 if (!this.attr_("labelsDiv")) {
453 var divWidth = this.attr_('labelsDivWidth');
454 var messagestyle = {
455 "position": "absolute",
456 "fontSize": "14px",
457 "zIndex": 10,
458 "width": divWidth + "px",
459 "top": "0px",
460 "left": (this.width_ - divWidth - 2) + "px",
461 "background": "white",
462 "textAlign": "left",
463 "overflow": "hidden"};
464 Dygraph.update(messagestyle, this.attr_('labelsDivStyles'));
465 var div = document.createElement("div");
466 for (var name in messagestyle) {
467 if (messagestyle.hasOwnProperty(name)) {
468 div.style[name] = messagestyle[name];
469 }
470 }
471 this.graphDiv.appendChild(div);
472 this.attrs_.labelsDiv = div;
473 }
474 };
475
476 /**
477 * Create the text box to adjust the averaging period
478 * @return {Object} The newly-created text box
479 * @private
480 */
481 Dygraph.prototype.createRollInterface_ = function() {
482 var display = this.attr_('showRoller') ? "block" : "none";
483 var textAttr = { "position": "absolute",
484 "zIndex": 10,
485 "top": (this.plotter_.area.h - 25) + "px",
486 "left": (this.plotter_.area.x + 1) + "px",
487 "display": display
488 };
489 var roller = document.createElement("input");
490 roller.type = "text";
491 roller.size = "2";
492 roller.value = this.rollPeriod_;
493 for (var name in textAttr) {
494 if (textAttr.hasOwnProperty(name)) {
495 roller.style[name] = textAttr[name];
496 }
497 }
498
499 var pa = this.graphDiv;
500 pa.appendChild(roller);
501 var dygraph = this;
502 roller.onchange = function() { dygraph.adjustRoll(roller.value); };
503 return roller;
504 };
505
506 // These functions are taken from MochiKit.Signal
507 Dygraph.pageX = function(e) {
508 if (e.pageX) {
509 return (!e.pageX || e.pageX < 0) ? 0 : e.pageX;
510 } else {
511 var de = document;
512 var b = document.body;
513 return e.clientX +
514 (de.scrollLeft || b.scrollLeft) -
515 (de.clientLeft || 0);
516 }
517 };
518
519 Dygraph.pageY = function(e) {
520 if (e.pageY) {
521 return (!e.pageY || e.pageY < 0) ? 0 : e.pageY;
522 } else {
523 var de = document;
524 var b = document.body;
525 return e.clientY +
526 (de.scrollTop || b.scrollTop) -
527 (de.clientTop || 0);
528 }
529 };
530
531 /**
532 * Set up all the mouse handlers needed to capture dragging behavior for zoom
533 * events.
534 * @private
535 */
536 Dygraph.prototype.createDragInterface_ = function() {
537 var self = this;
538
539 // Tracks whether the mouse is down right now
540 var isZooming = false;
541 var isPanning = false;
542 var dragStartX = null;
543 var dragStartY = null;
544 var dragEndX = null;
545 var dragEndY = null;
546 var prevEndX = null;
547 var draggingDate = null;
548 var dateRange = null;
549
550 // Utility function to convert page-wide coordinates to canvas coords
551 var px = 0;
552 var py = 0;
553 var getX = function(e) { return Dygraph.pageX(e) - px };
554 var getY = function(e) { return Dygraph.pageX(e) - py };
555
556 // Draw zoom rectangles when the mouse is down and the user moves around
557 Dygraph.addEvent(this.hidden_, 'mousemove', function(event) {
558 if (isZooming) {
559 dragEndX = getX(event);
560 dragEndY = getY(event);
561
562 self.drawZoomRect_(dragStartX, dragEndX, prevEndX);
563 prevEndX = dragEndX;
564 } else if (isPanning) {
565 dragEndX = getX(event);
566 dragEndY = getY(event);
567
568 // Want to have it so that:
569 // 1. draggingDate appears at dragEndX
570 // 2. daterange = (dateWindow_[1] - dateWindow_[0]) is unaltered.
571
572 self.dateWindow_[0] = draggingDate - (dragEndX / self.width_) * dateRange;
573 self.dateWindow_[1] = self.dateWindow_[0] + dateRange;
574 self.drawGraph_(self.rawData_);
575 }
576 });
577
578 // Track the beginning of drag events
579 Dygraph.addEvent(this.hidden_, 'mousedown', function(event) {
580 px = Dygraph.findPosX(self.canvas_);
581 py = Dygraph.findPosY(self.canvas_);
582 dragStartX = getX(event);
583 dragStartY = getY(event);
584
585 if (event.altKey || event.shiftKey) {
586 if (!self.dateWindow_) return; // have to be zoomed in to pan.
587 isPanning = true;
588 dateRange = self.dateWindow_[1] - self.dateWindow_[0];
589 draggingDate = (dragStartX / self.width_) * dateRange +
590 self.dateWindow_[0];
591 } else {
592 isZooming = true;
593 }
594 });
595
596 // If the user releases the mouse button during a drag, but not over the
597 // canvas, then it doesn't count as a zooming action.
598 Dygraph.addEvent(document, 'mouseup', function(event) {
599 if (isZooming || isPanning) {
600 isZooming = false;
601 dragStartX = null;
602 dragStartY = null;
603 }
604
605 if (isPanning) {
606 isPanning = false;
607 draggingDate = null;
608 dateRange = null;
609 }
610 });
611
612 // Temporarily cancel the dragging event when the mouse leaves the graph
613 Dygraph.addEvent(this.hidden_, 'mouseout', function(event) {
614 if (isZooming) {
615 dragEndX = null;
616 dragEndY = null;
617 }
618 });
619
620 // If the mouse is released on the canvas during a drag event, then it's a
621 // zoom. Only do the zoom if it's over a large enough area (>= 10 pixels)
622 Dygraph.addEvent(this.hidden_, 'mouseup', function(event) {
623 if (isZooming) {
624 isZooming = false;
625 dragEndX = getX(event);
626 dragEndY = getY(event);
627 var regionWidth = Math.abs(dragEndX - dragStartX);
628 var regionHeight = Math.abs(dragEndY - dragStartY);
629
630 if (regionWidth < 2 && regionHeight < 2 &&
631 self.attr_('clickCallback') != null &&
632 self.lastx_ != undefined) {
633 // TODO(danvk): pass along more info about the points.
634 self.attr_('clickCallback')(event, self.lastx_, self.selPoints_);
635 }
636
637 if (regionWidth >= 10) {
638 self.doZoom_(Math.min(dragStartX, dragEndX),
639 Math.max(dragStartX, dragEndX));
640 } else {
641 self.canvas_.getContext("2d").clearRect(0, 0,
642 self.canvas_.width,
643 self.canvas_.height);
644 }
645
646 dragStartX = null;
647 dragStartY = null;
648 }
649
650 if (isPanning) {
651 isPanning = false;
652 draggingDate = null;
653 dateRange = null;
654 }
655 });
656
657 // Double-clicking zooms back out
658 Dygraph.addEvent(this.hidden_, 'dblclick', function(event) {
659 if (self.dateWindow_ == null) return;
660 self.dateWindow_ = null;
661 self.drawGraph_(self.rawData_);
662 var minDate = self.rawData_[0][0];
663 var maxDate = self.rawData_[self.rawData_.length - 1][0];
664 if (self.attr_("zoomCallback")) {
665 self.attr_("zoomCallback")(minDate, maxDate);
666 }
667 });
668 };
669
670 /**
671 * Draw a gray zoom rectangle over the desired area of the canvas. Also clears
672 * up any previous zoom rectangles that were drawn. This could be optimized to
673 * avoid extra redrawing, but it's tricky to avoid interactions with the status
674 * dots.
675 * @param {Number} startX The X position where the drag started, in canvas
676 * coordinates.
677 * @param {Number} endX The current X position of the drag, in canvas coords.
678 * @param {Number} prevEndX The value of endX on the previous call to this
679 * function. Used to avoid excess redrawing
680 * @private
681 */
682 Dygraph.prototype.drawZoomRect_ = function(startX, endX, prevEndX) {
683 var ctx = this.canvas_.getContext("2d");
684
685 // Clean up from the previous rect if necessary
686 if (prevEndX) {
687 ctx.clearRect(Math.min(startX, prevEndX), 0,
688 Math.abs(startX - prevEndX), this.height_);
689 }
690
691 // Draw a light-grey rectangle to show the new viewing area
692 if (endX && startX) {
693 ctx.fillStyle = "rgba(128,128,128,0.33)";
694 ctx.fillRect(Math.min(startX, endX), 0,
695 Math.abs(endX - startX), this.height_);
696 }
697 };
698
699 /**
700 * Zoom to something containing [lowX, highX]. These are pixel coordinates
701 * in the canvas. The exact zoom window may be slightly larger if there are no
702 * data points near lowX or highX. This function redraws the graph.
703 * @param {Number} lowX The leftmost pixel value that should be visible.
704 * @param {Number} highX The rightmost pixel value that should be visible.
705 * @private
706 */
707 Dygraph.prototype.doZoom_ = function(lowX, highX) {
708 // Find the earliest and latest dates contained in this canvasx range.
709 var points = this.layout_.points;
710 var minDate = null;
711 var maxDate = null;
712 // Find the nearest [minDate, maxDate] that contains [lowX, highX]
713 for (var i = 0; i < points.length; i++) {
714 var cx = points[i].canvasx;
715 var x = points[i].xval;
716 if (cx < lowX && (minDate == null || x > minDate)) minDate = x;
717 if (cx > highX && (maxDate == null || x < maxDate)) maxDate = x;
718 }
719 // Use the extremes if either is missing
720 if (minDate == null) minDate = points[0].xval;
721 if (maxDate == null) maxDate = points[points.length-1].xval;
722
723 this.dateWindow_ = [minDate, maxDate];
724 this.drawGraph_(this.rawData_);
725 if (this.attr_("zoomCallback")) {
726 this.attr_("zoomCallback")(minDate, maxDate);
727 }
728 };
729
730 /**
731 * When the mouse moves in the canvas, display information about a nearby data
732 * point and draw dots over those points in the data series. This function
733 * takes care of cleanup of previously-drawn dots.
734 * @param {Object} event The mousemove event from the browser.
735 * @private
736 */
737 Dygraph.prototype.mouseMove_ = function(event) {
738 var canvasx = Dygraph.pageX(event) - Dygraph.findPosX(this.hidden_);
739 var points = this.layout_.points;
740
741 var lastx = -1;
742 var lasty = -1;
743
744 // Loop through all the points and find the date nearest to our current
745 // location.
746 var minDist = 1e+100;
747 var idx = -1;
748 for (var i = 0; i < points.length; i++) {
749 var dist = Math.abs(points[i].canvasx - canvasx);
750 if (dist > minDist) break;
751 minDist = dist;
752 idx = i;
753 }
754 if (idx >= 0) lastx = points[idx].xval;
755 // Check that you can really highlight the last day's data
756 if (canvasx > points[points.length-1].canvasx)
757 lastx = points[points.length-1].xval;
758
759 // Extract the points we've selected
760 this.selPoints_ = [];
761 for (var i = 0; i < points.length; i++) {
762 if (points[i].xval == lastx) {
763 this.selPoints_.push(points[i]);
764 }
765 }
766
767 if (this.attr_("highlightCallback")) {
768 this.attr_("highlightCallback")(event, lastx, this.selPoints_);
769 }
770
771 // Clear the previously drawn vertical, if there is one
772 var circleSize = this.attr_('highlightCircleSize');
773 var ctx = this.canvas_.getContext("2d");
774 if (this.previousVerticalX_ >= 0) {
775 var px = this.previousVerticalX_;
776 ctx.clearRect(px - circleSize - 1, 0, 2 * circleSize + 2, this.height_);
777 }
778
779 var isOK = function(x) { return x && !isNaN(x); };
780
781 if (this.selPoints_.length > 0) {
782 var canvasx = this.selPoints_[0].canvasx;
783
784 // Set the status message to indicate the selected point(s)
785 var replace = this.attr_('xValueFormatter')(lastx, this) + ":";
786 var clen = this.colors_.length;
787 for (var i = 0; i < this.selPoints_.length; i++) {
788 if (!isOK(this.selPoints_[i].canvasy)) continue;
789 if (this.attr_("labelsSeparateLines")) {
790 replace += "<br/>";
791 }
792 var point = this.selPoints_[i];
793 var c = new RGBColor(this.colors_[i%clen]);
794 replace += " <b><font color='" + c.toHex() + "'>"
795 + point.name + "</font></b>:"
796 + this.round_(point.yval, 2);
797 }
798 this.attr_("labelsDiv").innerHTML = replace;
799
800 // Save last x position for callbacks.
801 this.lastx_ = lastx;
802
803 // Draw colored circles over the center of each selected point
804 ctx.save()
805 for (var i = 0; i < this.selPoints_.length; i++) {
806 if (!isOK(this.selPoints_[i%clen].canvasy)) continue;
807 ctx.beginPath();
808 ctx.fillStyle = this.colors_[i%clen];
809 ctx.arc(canvasx, this.selPoints_[i%clen].canvasy, circleSize,
810 0, 2 * Math.PI, false);
811 ctx.fill();
812 }
813 ctx.restore();
814
815 this.previousVerticalX_ = canvasx;
816 }
817 };
818
819 /**
820 * The mouse has left the canvas. Clear out whatever artifacts remain
821 * @param {Object} event the mouseout event from the browser.
822 * @private
823 */
824 Dygraph.prototype.mouseOut_ = function(event) {
825 // Get rid of the overlay data
826 var ctx = this.canvas_.getContext("2d");
827 ctx.clearRect(0, 0, this.width_, this.height_);
828 this.attr_("labelsDiv").innerHTML = "";
829 };
830
831 Dygraph.zeropad = function(x) {
832 if (x < 10) return "0" + x; else return "" + x;
833 }
834
835 /**
836 * Return a string version of the hours, minutes and seconds portion of a date.
837 * @param {Number} date The JavaScript date (ms since epoch)
838 * @return {String} A time of the form "HH:MM:SS"
839 * @private
840 */
841 Dygraph.prototype.hmsString_ = function(date) {
842 var zeropad = Dygraph.zeropad;
843 var d = new Date(date);
844 if (d.getSeconds()) {
845 return zeropad(d.getHours()) + ":" +
846 zeropad(d.getMinutes()) + ":" +
847 zeropad(d.getSeconds());
848 } else if (d.getMinutes()) {
849 return zeropad(d.getHours()) + ":" + zeropad(d.getMinutes());
850 } else {
851 return zeropad(d.getHours());
852 }
853 }
854
855 /**
856 * Convert a JS date (millis since epoch) to YYYY/MM/DD
857 * @param {Number} date The JavaScript date (ms since epoch)
858 * @return {String} A date of the form "YYYY/MM/DD"
859 * @private
860 * TODO(danvk): why is this part of the prototype?
861 */
862 Dygraph.dateString_ = function(date, self) {
863 var zeropad = Dygraph.zeropad;
864 var d = new Date(date);
865
866 // Get the year:
867 var year = "" + d.getFullYear();
868 // Get a 0 padded month string
869 var month = zeropad(d.getMonth() + 1); //months are 0-offset, sigh
870 // Get a 0 padded day string
871 var day = zeropad(d.getDate());
872
873 var ret = "";
874 var frac = d.getHours() * 3600 + d.getMinutes() * 60 + d.getSeconds();
875 if (frac) ret = " " + self.hmsString_(date);
876
877 return year + "/" + month + "/" + day + ret;
878 };
879
880 /**
881 * Round a number to the specified number of digits past the decimal point.
882 * @param {Number} num The number to round
883 * @param {Number} places The number of decimals to which to round
884 * @return {Number} The rounded number
885 * @private
886 */
887 Dygraph.prototype.round_ = function(num, places) {
888 var shift = Math.pow(10, places);
889 return Math.round(num * shift)/shift;
890 };
891
892 /**
893 * Fires when there's data available to be graphed.
894 * @param {String} data Raw CSV data to be plotted
895 * @private
896 */
897 Dygraph.prototype.loadedEvent_ = function(data) {
898 this.rawData_ = this.parseCSV_(data);
899 this.drawGraph_(this.rawData_);
900 };
901
902 Dygraph.prototype.months = ["Jan", "Feb", "Mar", "Apr", "May", "Jun",
903 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
904 Dygraph.prototype.quarters = ["Jan", "Apr", "Jul", "Oct"];
905
906 /**
907 * Add ticks on the x-axis representing years, months, quarters, weeks, or days
908 * @private
909 */
910 Dygraph.prototype.addXTicks_ = function() {
911 // Determine the correct ticks scale on the x-axis: quarterly, monthly, ...
912 var startDate, endDate;
913 if (this.dateWindow_) {
914 startDate = this.dateWindow_[0];
915 endDate = this.dateWindow_[1];
916 } else {
917 startDate = this.rawData_[0][0];
918 endDate = this.rawData_[this.rawData_.length - 1][0];
919 }
920
921 var xTicks = this.attr_('xTicker')(startDate, endDate, this);
922 this.layout_.updateOptions({xTicks: xTicks});
923 };
924
925 // Time granularity enumeration
926 Dygraph.SECONDLY = 0;
927 Dygraph.TWO_SECONDLY = 1;
928 Dygraph.FIVE_SECONDLY = 2;
929 Dygraph.TEN_SECONDLY = 3;
930 Dygraph.THIRTY_SECONDLY = 4;
931 Dygraph.MINUTELY = 5;
932 Dygraph.TWO_MINUTELY = 6;
933 Dygraph.FIVE_MINUTELY = 7;
934 Dygraph.TEN_MINUTELY = 8;
935 Dygraph.THIRTY_MINUTELY = 9;
936 Dygraph.HOURLY = 10;
937 Dygraph.TWO_HOURLY = 11;
938 Dygraph.SIX_HOURLY = 12;
939 Dygraph.DAILY = 13;
940 Dygraph.WEEKLY = 14;
941 Dygraph.MONTHLY = 15;
942 Dygraph.QUARTERLY = 16;
943 Dygraph.BIANNUAL = 17;
944 Dygraph.ANNUAL = 18;
945 Dygraph.DECADAL = 19;
946 Dygraph.NUM_GRANULARITIES = 20;
947
948 Dygraph.SHORT_SPACINGS = [];
949 Dygraph.SHORT_SPACINGS[Dygraph.SECONDLY] = 1000 * 1;
950 Dygraph.SHORT_SPACINGS[Dygraph.TWO_SECONDLY] = 1000 * 2;
951 Dygraph.SHORT_SPACINGS[Dygraph.FIVE_SECONDLY] = 1000 * 5;
952 Dygraph.SHORT_SPACINGS[Dygraph.TEN_SECONDLY] = 1000 * 10;
953 Dygraph.SHORT_SPACINGS[Dygraph.THIRTY_SECONDLY] = 1000 * 30;
954 Dygraph.SHORT_SPACINGS[Dygraph.MINUTELY] = 1000 * 60;
955 Dygraph.SHORT_SPACINGS[Dygraph.TWO_MINUTELY] = 1000 * 60 * 2;
956 Dygraph.SHORT_SPACINGS[Dygraph.FIVE_MINUTELY] = 1000 * 60 * 5;
957 Dygraph.SHORT_SPACINGS[Dygraph.TEN_MINUTELY] = 1000 * 60 * 10;
958 Dygraph.SHORT_SPACINGS[Dygraph.THIRTY_MINUTELY] = 1000 * 60 * 30;
959 Dygraph.SHORT_SPACINGS[Dygraph.HOURLY] = 1000 * 3600;
960 Dygraph.SHORT_SPACINGS[Dygraph.TWO_HOURLY] = 1000 * 3600 * 2;
961 Dygraph.SHORT_SPACINGS[Dygraph.SIX_HOURLY] = 1000 * 3600 * 6;
962 Dygraph.SHORT_SPACINGS[Dygraph.DAILY] = 1000 * 86400;
963 Dygraph.SHORT_SPACINGS[Dygraph.WEEKLY] = 1000 * 604800;
964
965 // NumXTicks()
966 //
967 // If we used this time granularity, how many ticks would there be?
968 // This is only an approximation, but it's generally good enough.
969 //
970 Dygraph.prototype.NumXTicks = function(start_time, end_time, granularity) {
971 if (granularity < Dygraph.MONTHLY) {
972 // Generate one tick mark for every fixed interval of time.
973 var spacing = Dygraph.SHORT_SPACINGS[granularity];
974 return Math.floor(0.5 + 1.0 * (end_time - start_time) / spacing);
975 } else {
976 var year_mod = 1; // e.g. to only print one point every 10 years.
977 var num_months = 12;
978 if (granularity == Dygraph.QUARTERLY) num_months = 3;
979 if (granularity == Dygraph.BIANNUAL) num_months = 2;
980 if (granularity == Dygraph.ANNUAL) num_months = 1;
981 if (granularity == Dygraph.DECADAL) { num_months = 1; year_mod = 10; }
982
983 var msInYear = 365.2524 * 24 * 3600 * 1000;
984 var num_years = 1.0 * (end_time - start_time) / msInYear;
985 return Math.floor(0.5 + 1.0 * num_years * num_months / year_mod);
986 }
987 };
988
989 // GetXAxis()
990 //
991 // Construct an x-axis of nicely-formatted times on meaningful boundaries
992 // (e.g. 'Jan 09' rather than 'Jan 22, 2009').
993 //
994 // Returns an array containing {v: millis, label: label} dictionaries.
995 //
996 Dygraph.prototype.GetXAxis = function(start_time, end_time, granularity) {
997 var ticks = [];
998 if (granularity < Dygraph.MONTHLY) {
999 // Generate one tick mark for every fixed interval of time.
1000 var spacing = Dygraph.SHORT_SPACINGS[granularity];
1001 var format = '%d%b'; // e.g. "1Jan"
1002
1003 // Find a time less than start_time which occurs on a "nice" time boundary
1004 // for this granularity.
1005 var g = spacing / 1000;
1006 var d = new Date(start_time);
1007 if (g <= 60) { // seconds
1008 var x = d.getSeconds(); d.setSeconds(x - x % g);
1009 } else {
1010 d.setSeconds(0);
1011 g /= 60;
1012 if (g <= 60) { // minutes
1013 var x = d.getMinutes(); d.setMinutes(x - x % g);
1014 } else {
1015 d.setMinutes(0);
1016 g /= 60;
1017
1018 if (g <= 24) { // days
1019 var x = d.getHours(); d.setHours(x - x % g);
1020 } else {
1021 d.setHours(0);
1022 g /= 24;
1023
1024 if (g == 7) { // one week
1025 d.setDate(d.getDate() - d.getDay());
1026 }
1027 }
1028 }
1029 }
1030 start_time = d.getTime();
1031
1032 for (var t = start_time; t <= end_time; t += spacing) {
1033 var d = new Date(t);
1034 var frac = d.getHours() * 3600 + d.getMinutes() * 60 + d.getSeconds();
1035 if (frac == 0 || granularity >= Dygraph.DAILY) {
1036 // the extra hour covers DST problems.
1037 ticks.push({ v:t, label: new Date(t + 3600*1000).strftime(format) });
1038 } else {
1039 ticks.push({ v:t, label: this.hmsString_(t) });
1040 }
1041 }
1042 } else {
1043 // Display a tick mark on the first of a set of months of each year.
1044 // Years get a tick mark iff y % year_mod == 0. This is useful for
1045 // displaying a tick mark once every 10 years, say, on long time scales.
1046 var months;
1047 var year_mod = 1; // e.g. to only print one point every 10 years.
1048
1049 if (granularity == Dygraph.MONTHLY) {
1050 months = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
1051 } else if (granularity == Dygraph.QUARTERLY) {
1052 months = [ 0, 3, 6, 9 ];
1053 } else if (granularity == Dygraph.BIANNUAL) {
1054 months = [ 0, 6 ];
1055 } else if (granularity == Dygraph.ANNUAL) {
1056 months = [ 0 ];
1057 } else if (granularity == Dygraph.DECADAL) {
1058 months = [ 0 ];
1059 year_mod = 10;
1060 }
1061
1062 var start_year = new Date(start_time).getFullYear();
1063 var end_year = new Date(end_time).getFullYear();
1064 var zeropad = Dygraph.zeropad;
1065 for (var i = start_year; i <= end_year; i++) {
1066 if (i % year_mod != 0) continue;
1067 for (var j = 0; j < months.length; j++) {
1068 var date_str = i + "/" + zeropad(1 + months[j]) + "/01";
1069 var t = Date.parse(date_str);
1070 if (t < start_time || t > end_time) continue;
1071 ticks.push({ v:t, label: new Date(t).strftime('%b %y') });
1072 }
1073 }
1074 }
1075
1076 return ticks;
1077 };
1078
1079
1080 /**
1081 * Add ticks to the x-axis based on a date range.
1082 * @param {Number} startDate Start of the date window (millis since epoch)
1083 * @param {Number} endDate End of the date window (millis since epoch)
1084 * @return {Array.<Object>} Array of {label, value} tuples.
1085 * @public
1086 */
1087 Dygraph.dateTicker = function(startDate, endDate, self) {
1088 var chosen = -1;
1089 for (var i = 0; i < Dygraph.NUM_GRANULARITIES; i++) {
1090 var num_ticks = self.NumXTicks(startDate, endDate, i);
1091 if (self.width_ / num_ticks >= self.attr_('pixelsPerXLabel')) {
1092 chosen = i;
1093 break;
1094 }
1095 }
1096
1097 if (chosen >= 0) {
1098 return self.GetXAxis(startDate, endDate, chosen);
1099 } else {
1100 // TODO(danvk): signal error.
1101 }
1102 };
1103
1104 /**
1105 * Add ticks when the x axis has numbers on it (instead of dates)
1106 * @param {Number} startDate Start of the date window (millis since epoch)
1107 * @param {Number} endDate End of the date window (millis since epoch)
1108 * @return {Array.<Object>} Array of {label, value} tuples.
1109 * @public
1110 */
1111 Dygraph.numericTicks = function(minV, maxV, self) {
1112 // Basic idea:
1113 // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
1114 // Calculate the resulting tick spacing (i.e. this.height_ / nTicks).
1115 // The first spacing greater than pixelsPerYLabel is what we use.
1116 // TODO(danvk): version that works on a log scale.
1117 if (self.attr_("labelsKMG2")) {
1118 var mults = [1, 2, 4, 8];
1119 } else {
1120 var mults = [1, 2, 5];
1121 }
1122 var scale, low_val, high_val, nTicks;
1123 // TODO(danvk): make it possible to set this for x- and y-axes independently.
1124 var pixelsPerTick = self.attr_('pixelsPerYLabel');
1125 for (var i = -10; i < 50; i++) {
1126 if (self.attr_("labelsKMG2")) {
1127 var base_scale = Math.pow(16, i);
1128 } else {
1129 var base_scale = Math.pow(10, i);
1130 }
1131 for (var j = 0; j < mults.length; j++) {
1132 scale = base_scale * mults[j];
1133 low_val = Math.floor(minV / scale) * scale;
1134 high_val = Math.ceil(maxV / scale) * scale;
1135 nTicks = (high_val - low_val) / scale;
1136 var spacing = self.height_ / nTicks;
1137 // wish I could break out of both loops at once...
1138 if (spacing > pixelsPerTick) break;
1139 }
1140 if (spacing > pixelsPerTick) break;
1141 }
1142
1143 // Construct labels for the ticks
1144 var ticks = [];
1145 var k;
1146 var k_labels = [];
1147 if (self.attr_("labelsKMB")) {
1148 k = 1000;
1149 k_labels = [ "K", "M", "B", "T" ];
1150 }
1151 if (self.attr_("labelsKMG2")) {
1152 if (k) self.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
1153 k = 1024;
1154 k_labels = [ "k", "M", "G", "T" ];
1155 }
1156
1157 for (var i = 0; i < nTicks; i++) {
1158 var tickV = low_val + i * scale;
1159 var absTickV = Math.abs(tickV);
1160 var label = self.round_(tickV, 2);
1161 if (k_labels.length) {
1162 // Round up to an appropriate unit.
1163 var n = k*k*k*k;
1164 for (var j = 3; j >= 0; j--, n /= k) {
1165 if (absTickV >= n) {
1166 label = self.round_(tickV / n, 1) + k_labels[j];
1167 break;
1168 }
1169 }
1170 }
1171 ticks.push( {label: label, v: tickV} );
1172 }
1173 return ticks;
1174 };
1175
1176 /**
1177 * Adds appropriate ticks on the y-axis
1178 * @param {Number} minY The minimum Y value in the data set
1179 * @param {Number} maxY The maximum Y value in the data set
1180 * @private
1181 */
1182 Dygraph.prototype.addYTicks_ = function(minY, maxY) {
1183 // Set the number of ticks so that the labels are human-friendly.
1184 // TODO(danvk): make this an attribute as well.
1185 var ticks = Dygraph.numericTicks(minY, maxY, this);
1186 this.layout_.updateOptions( { yAxis: [minY, maxY],
1187 yTicks: ticks } );
1188 };
1189
1190 // Computes the range of the data series (including confidence intervals).
1191 // series is either [ [x1, y1], [x2, y2], ... ] or
1192 // [ [x1, [y1, dev_low, dev_high]], [x2, [y2, dev_low, dev_high]], ...
1193 // Returns [low, high]
1194 Dygraph.prototype.extremeValues_ = function(series) {
1195 var minY = null, maxY = null;
1196
1197 var bars = this.attr_("errorBars") || this.attr_("customBars");
1198 if (bars) {
1199 // With custom bars, maxY is the max of the high values.
1200 for (var j = 0; j < series.length; j++) {
1201 var y = series[j][1][0];
1202 if (!y) continue;
1203 var low = y - series[j][1][1];
1204 var high = y + series[j][1][2];
1205 if (low > y) low = y; // this can happen with custom bars,
1206 if (high < y) high = y; // e.g. in tests/custom-bars.html
1207 if (maxY == null || high > maxY) {
1208 maxY = high;
1209 }
1210 if (minY == null || low < minY) {
1211 minY = low;
1212 }
1213 }
1214 } else {
1215 for (var j = 0; j < series.length; j++) {
1216 var y = series[j][1];
1217 if (y === null || isNaN(y)) continue;
1218 if (maxY == null || y > maxY) {
1219 maxY = y;
1220 }
1221 if (minY == null || y < minY) {
1222 minY = y;
1223 }
1224 }
1225 }
1226
1227 return [minY, maxY];
1228 };
1229
1230 /**
1231 * Update the graph with new data. Data is in the format
1232 * [ [date1, val1, val2, ...], [date2, val1, val2, ...] if errorBars=false
1233 * or, if errorBars=true,
1234 * [ [date1, [val1,stddev1], [val2,stddev2], ...], [date2, ...], ...]
1235 * @param {Array.<Object>} data The data (see above)
1236 * @private
1237 */
1238 Dygraph.prototype.drawGraph_ = function(data) {
1239 var minY = null, maxY = null;
1240 this.layout_.removeAllDatasets();
1241 this.setColors_();
1242 this.attrs_['pointSize'] = 0.5 * this.attr_('highlightCircleSize');
1243
1244 // Loop over all fields in the dataset
1245 for (var i = 1; i < data[0].length; i++) {
1246 if (!this.visibility()[i - 1]) continue;
1247
1248 var series = [];
1249 for (var j = 0; j < data.length; j++) {
1250 var date = data[j][0];
1251 series[j] = [date, data[j][i]];
1252 }
1253 series = this.rollingAverage(series, this.rollPeriod_);
1254
1255 // Prune down to the desired range, if necessary (for zooming)
1256 var bars = this.attr_("errorBars") || this.attr_("customBars");
1257 if (this.dateWindow_) {
1258 var low = this.dateWindow_[0];
1259 var high= this.dateWindow_[1];
1260 var pruned = [];
1261 for (var k = 0; k < series.length; k++) {
1262 if (series[k][0] >= low && series[k][0] <= high) {
1263 pruned.push(series[k]);
1264 }
1265 }
1266 series = pruned;
1267 }
1268
1269 var extremes = this.extremeValues_(series);
1270 var thisMinY = extremes[0];
1271 var thisMaxY = extremes[1];
1272 if (!minY || thisMinY < minY) minY = thisMinY;
1273 if (!maxY || thisMaxY > maxY) maxY = thisMaxY;
1274
1275 if (bars) {
1276 var vals = [];
1277 for (var j=0; j<series.length; j++)
1278 vals[j] = [series[j][0],
1279 series[j][1][0], series[j][1][1], series[j][1][2]];
1280 this.layout_.addDataset(this.attr_("labels")[i], vals);
1281 } else {
1282 this.layout_.addDataset(this.attr_("labels")[i], series);
1283 }
1284 }
1285
1286 // Use some heuristics to come up with a good maxY value, unless it's been
1287 // set explicitly by the user.
1288 if (this.valueRange_ != null) {
1289 this.addYTicks_(this.valueRange_[0], this.valueRange_[1]);
1290 } else {
1291 // Add some padding and round up to an integer to be human-friendly.
1292 var span = maxY - minY;
1293 var maxAxisY = maxY + 0.1 * span;
1294 var minAxisY = minY - 0.1 * span;
1295
1296 // Try to include zero and make it minAxisY (or maxAxisY) if it makes sense.
1297 if (minAxisY < 0 && minY >= 0) minAxisY = 0;
1298 if (maxAxisY > 0 && maxY <= 0) maxAxisY = 0;
1299
1300 if (this.attr_("includeZero")) {
1301 if (maxY < 0) maxAxisY = 0;
1302 if (minY > 0) minAxisY = 0;
1303 }
1304
1305 this.addYTicks_(minAxisY, maxAxisY);
1306 }
1307
1308 this.addXTicks_();
1309
1310 // Tell PlotKit to use this new data and render itself
1311 this.layout_.updateOptions({dateWindow: this.dateWindow_});
1312 this.layout_.evaluateWithError();
1313 this.plotter_.clear();
1314 this.plotter_.render();
1315 this.canvas_.getContext('2d').clearRect(0, 0, this.canvas_.width,
1316 this.canvas_.height);
1317 };
1318
1319 /**
1320 * Calculates the rolling average of a data set.
1321 * If originalData is [label, val], rolls the average of those.
1322 * If originalData is [label, [, it's interpreted as [value, stddev]
1323 * and the roll is returned in the same form, with appropriately reduced
1324 * stddev for each value.
1325 * Note that this is where fractional input (i.e. '5/10') is converted into
1326 * decimal values.
1327 * @param {Array} originalData The data in the appropriate format (see above)
1328 * @param {Number} rollPeriod The number of days over which to average the data
1329 */
1330 Dygraph.prototype.rollingAverage = function(originalData, rollPeriod) {
1331 if (originalData.length < 2)
1332 return originalData;
1333 var rollPeriod = Math.min(rollPeriod, originalData.length - 1);
1334 var rollingData = [];
1335 var sigma = this.attr_("sigma");
1336
1337 if (this.fractions_) {
1338 var num = 0;
1339 var den = 0; // numerator/denominator
1340 var mult = 100.0;
1341 for (var i = 0; i < originalData.length; i++) {
1342 num += originalData[i][1][0];
1343 den += originalData[i][1][1];
1344 if (i - rollPeriod >= 0) {
1345 num -= originalData[i - rollPeriod][1][0];
1346 den -= originalData[i - rollPeriod][1][1];
1347 }
1348
1349 var date = originalData[i][0];
1350 var value = den ? num / den : 0.0;
1351 if (this.attr_("errorBars")) {
1352 if (this.wilsonInterval_) {
1353 // For more details on this confidence interval, see:
1354 // http://en.wikipedia.org/wiki/Binomial_confidence_interval
1355 if (den) {
1356 var p = value < 0 ? 0 : value, n = den;
1357 var pm = sigma * Math.sqrt(p*(1-p)/n + sigma*sigma/(4*n*n));
1358 var denom = 1 + sigma * sigma / den;
1359 var low = (p + sigma * sigma / (2 * den) - pm) / denom;
1360 var high = (p + sigma * sigma / (2 * den) + pm) / denom;
1361 rollingData[i] = [date,
1362 [p * mult, (p - low) * mult, (high - p) * mult]];
1363 } else {
1364 rollingData[i] = [date, [0, 0, 0]];
1365 }
1366 } else {
1367 var stddev = den ? sigma * Math.sqrt(value * (1 - value) / den) : 1.0;
1368 rollingData[i] = [date, [mult * value, mult * stddev, mult * stddev]];
1369 }
1370 } else {
1371 rollingData[i] = [date, mult * value];
1372 }
1373 }
1374 } else if (this.attr_("customBars")) {
1375 var low = 0;
1376 var mid = 0;
1377 var high = 0;
1378 var count = 0;
1379 for (var i = 0; i < originalData.length; i++) {
1380 var data = originalData[i][1];
1381 var y = data[1];
1382 rollingData[i] = [originalData[i][0], [y, y - data[0], data[2] - y]];
1383
1384 if (y != null && !isNaN(y)) {
1385 low += data[0];
1386 mid += y;
1387 high += data[2];
1388 count += 1;
1389 }
1390 if (i - rollPeriod >= 0) {
1391 var prev = originalData[i - rollPeriod];
1392 if (prev[1][1] != null && !isNaN(prev[1][1])) {
1393 low -= prev[1][0];
1394 mid -= prev[1][1];
1395 high -= prev[1][2];
1396 count -= 1;
1397 }
1398 }
1399 rollingData[i] = [originalData[i][0], [ 1.0 * mid / count,
1400 1.0 * (mid - low) / count,
1401 1.0 * (high - mid) / count ]];
1402 }
1403 } else {
1404 // Calculate the rolling average for the first rollPeriod - 1 points where
1405 // there is not enough data to roll over the full number of days
1406 var num_init_points = Math.min(rollPeriod - 1, originalData.length - 2);
1407 if (!this.attr_("errorBars")){
1408 if (rollPeriod == 1) {
1409 return originalData;
1410 }
1411
1412 for (var i = 0; i < originalData.length; i++) {
1413 var sum = 0;
1414 var num_ok = 0;
1415 for (var j = Math.max(0, i - rollPeriod + 1); j < i + 1; j++) {
1416 var y = originalData[j][1];
1417 if (y == null || isNaN(y)) continue;
1418 num_ok++;
1419 sum += originalData[j][1];
1420 }
1421 if (num_ok) {
1422 rollingData[i] = [originalData[i][0], sum / num_ok];
1423 } else {
1424 rollingData[i] = [originalData[i][0], null];
1425 }
1426 }
1427
1428 } else {
1429 for (var i = 0; i < originalData.length; i++) {
1430 var sum = 0;
1431 var variance = 0;
1432 var num_ok = 0;
1433 for (var j = Math.max(0, i - rollPeriod + 1); j < i + 1; j++) {
1434 var y = originalData[j][1][0];
1435 if (y == null || isNaN(y)) continue;
1436 num_ok++;
1437 sum += originalData[j][1][0];
1438 variance += Math.pow(originalData[j][1][1], 2);
1439 }
1440 if (num_ok) {
1441 var stddev = Math.sqrt(variance) / num_ok;
1442 rollingData[i] = [originalData[i][0],
1443 [sum / num_ok, sigma * stddev, sigma * stddev]];
1444 } else {
1445 rollingData[i] = [originalData[i][0], [null, null, null]];
1446 }
1447 }
1448 }
1449 }
1450
1451 return rollingData;
1452 };
1453
1454 /**
1455 * Parses a date, returning the number of milliseconds since epoch. This can be
1456 * passed in as an xValueParser in the Dygraph constructor.
1457 * TODO(danvk): enumerate formats that this understands.
1458 * @param {String} A date in YYYYMMDD format.
1459 * @return {Number} Milliseconds since epoch.
1460 * @public
1461 */
1462 Dygraph.dateParser = function(dateStr, self) {
1463 var dateStrSlashed;
1464 var d;
1465 if (dateStr.length == 10 && dateStr.search("-") != -1) { // e.g. '2009-07-12'
1466 dateStrSlashed = dateStr.replace("-", "/", "g");
1467 while (dateStrSlashed.search("-") != -1) {
1468 dateStrSlashed = dateStrSlashed.replace("-", "/");
1469 }
1470 d = Date.parse(dateStrSlashed);
1471 } else if (dateStr.length == 8) { // e.g. '20090712'
1472 // TODO(danvk): remove support for this format. It's confusing.
1473 dateStrSlashed = dateStr.substr(0,4) + "/" + dateStr.substr(4,2)
1474 + "/" + dateStr.substr(6,2);
1475 d = Date.parse(dateStrSlashed);
1476 } else {
1477 // Any format that Date.parse will accept, e.g. "2009/07/12" or
1478 // "2009/07/12 12:34:56"
1479 d = Date.parse(dateStr);
1480 }
1481
1482 if (!d || isNaN(d)) {
1483 self.error("Couldn't parse " + dateStr + " as a date");
1484 }
1485 return d;
1486 };
1487
1488 /**
1489 * Detects the type of the str (date or numeric) and sets the various
1490 * formatting attributes in this.attrs_ based on this type.
1491 * @param {String} str An x value.
1492 * @private
1493 */
1494 Dygraph.prototype.detectTypeFromString_ = function(str) {
1495 var isDate = false;
1496 if (str.indexOf('-') >= 0 ||
1497 str.indexOf('/') >= 0 ||
1498 isNaN(parseFloat(str))) {
1499 isDate = true;
1500 } else if (str.length == 8 && str > '19700101' && str < '20371231') {
1501 // TODO(danvk): remove support for this format.
1502 isDate = true;
1503 }
1504
1505 if (isDate) {
1506 this.attrs_.xValueFormatter = Dygraph.dateString_;
1507 this.attrs_.xValueParser = Dygraph.dateParser;
1508 this.attrs_.xTicker = Dygraph.dateTicker;
1509 } else {
1510 this.attrs_.xValueFormatter = function(x) { return x; };
1511 this.attrs_.xValueParser = function(x) { return parseFloat(x); };
1512 this.attrs_.xTicker = Dygraph.numericTicks;
1513 }
1514 };
1515
1516 /**
1517 * Parses a string in a special csv format. We expect a csv file where each
1518 * line is a date point, and the first field in each line is the date string.
1519 * We also expect that all remaining fields represent series.
1520 * if the errorBars attribute is set, then interpret the fields as:
1521 * date, series1, stddev1, series2, stddev2, ...
1522 * @param {Array.<Object>} data See above.
1523 * @private
1524 *
1525 * @return Array.<Object> An array with one entry for each row. These entries
1526 * are an array of cells in that row. The first entry is the parsed x-value for
1527 * the row. The second, third, etc. are the y-values. These can take on one of
1528 * three forms, depending on the CSV and constructor parameters:
1529 * 1. numeric value
1530 * 2. [ value, stddev ]
1531 * 3. [ low value, center value, high value ]
1532 */
1533 Dygraph.prototype.parseCSV_ = function(data) {
1534 var ret = [];
1535 var lines = data.split("\n");
1536
1537 // Use the default delimiter or fall back to a tab if that makes sense.
1538 var delim = this.attr_('delimiter');
1539 if (lines[0].indexOf(delim) == -1 && lines[0].indexOf('\t') >= 0) {
1540 delim = '\t';
1541 }
1542
1543 var start = 0;
1544 if (this.labelsFromCSV_) {
1545 start = 1;
1546 this.attrs_.labels = lines[0].split(delim);
1547 }
1548
1549 var xParser;
1550 var defaultParserSet = false; // attempt to auto-detect x value type
1551 var expectedCols = this.attr_("labels").length;
1552 for (var i = start; i < lines.length; i++) {
1553 var line = lines[i];
1554 if (line.length == 0) continue; // skip blank lines
1555 if (line[0] == '#') continue; // skip comment lines
1556 var inFields = line.split(delim);
1557 if (inFields.length < 2) continue;
1558
1559 var fields = [];
1560 if (!defaultParserSet) {
1561 this.detectTypeFromString_(inFields[0]);
1562 xParser = this.attr_("xValueParser");
1563 defaultParserSet = true;
1564 }
1565 fields[0] = xParser(inFields[0], this);
1566
1567 // If fractions are expected, parse the numbers as "A/B"
1568 if (this.fractions_) {
1569 for (var j = 1; j < inFields.length; j++) {
1570 // TODO(danvk): figure out an appropriate way to flag parse errors.
1571 var vals = inFields[j].split("/");
1572 fields[j] = [parseFloat(vals[0]), parseFloat(vals[1])];
1573 }
1574 } else if (this.attr_("errorBars")) {
1575 // If there are error bars, values are (value, stddev) pairs
1576 for (var j = 1; j < inFields.length; j += 2)
1577 fields[(j + 1) / 2] = [parseFloat(inFields[j]),
1578 parseFloat(inFields[j + 1])];
1579 } else if (this.attr_("customBars")) {
1580 // Bars are a low;center;high tuple
1581 for (var j = 1; j < inFields.length; j++) {
1582 var vals = inFields[j].split(";");
1583 fields[j] = [ parseFloat(vals[0]),
1584 parseFloat(vals[1]),
1585 parseFloat(vals[2]) ];
1586 }
1587 } else {
1588 // Values are just numbers
1589 for (var j = 1; j < inFields.length; j++) {
1590 fields[j] = parseFloat(inFields[j]);
1591 }
1592 }
1593 ret.push(fields);
1594
1595 if (fields.length != expectedCols) {
1596 this.error("Number of columns in line " + i + " (" + fields.length +
1597 ") does not agree with number of labels (" + expectedCols +
1598 ") " + line);
1599 }
1600 }
1601 return ret;
1602 };
1603
1604 /**
1605 * The user has provided their data as a pre-packaged JS array. If the x values
1606 * are numeric, this is the same as dygraphs' internal format. If the x values
1607 * are dates, we need to convert them from Date objects to ms since epoch.
1608 * @param {Array.<Object>} data
1609 * @return {Array.<Object>} data with numeric x values.
1610 */
1611 Dygraph.prototype.parseArray_ = function(data) {
1612 // Peek at the first x value to see if it's numeric.
1613 if (data.length == 0) {
1614 this.error("Can't plot empty data set");
1615 return null;
1616 }
1617 if (data[0].length == 0) {
1618 this.error("Data set cannot contain an empty row");
1619 return null;
1620 }
1621
1622 if (this.attr_("labels") == null) {
1623 this.warn("Using default labels. Set labels explicitly via 'labels' " +
1624 "in the options parameter");
1625 this.attrs_.labels = [ "X" ];
1626 for (var i = 1; i < data[0].length; i++) {
1627 this.attrs_.labels.push("Y" + i);
1628 }
1629 }
1630
1631 if (Dygraph.isDateLike(data[0][0])) {
1632 // Some intelligent defaults for a date x-axis.
1633 this.attrs_.xValueFormatter = Dygraph.dateString_;
1634 this.attrs_.xTicker = Dygraph.dateTicker;
1635
1636 // Assume they're all dates.
1637 var parsedData = Dygraph.clone(data);
1638 for (var i = 0; i < data.length; i++) {
1639 if (parsedData[i].length == 0) {
1640 this.error("Row " << (1 + i) << " of data is empty");
1641 return null;
1642 }
1643 if (parsedData[i][0] == null
1644 || typeof(parsedData[i][0].getTime) != 'function') {
1645 this.error("x value in row " << (1 + i) << " is not a Date");
1646 return null;
1647 }
1648 parsedData[i][0] = parsedData[i][0].getTime();
1649 }
1650 return parsedData;
1651 } else {
1652 // Some intelligent defaults for a numeric x-axis.
1653 this.attrs_.xValueFormatter = function(x) { return x; };
1654 this.attrs_.xTicker = Dygraph.numericTicks;
1655 return data;
1656 }
1657 };
1658
1659 /**
1660 * Parses a DataTable object from gviz.
1661 * The data is expected to have a first column that is either a date or a
1662 * number. All subsequent columns must be numbers. If there is a clear mismatch
1663 * between this.xValueParser_ and the type of the first column, it will be
1664 * fixed. Returned value is in the same format as return value of parseCSV_.
1665 * @param {Array.<Object>} data See above.
1666 * @private
1667 */
1668 Dygraph.prototype.parseDataTable_ = function(data) {
1669 var cols = data.getNumberOfColumns();
1670 var rows = data.getNumberOfRows();
1671
1672 // Read column labels
1673 var labels = [];
1674 for (var i = 0; i < cols; i++) {
1675 labels.push(data.getColumnLabel(i));
1676 if (i != 0 && this.attr_("errorBars")) i += 1;
1677 }
1678 this.attrs_.labels = labels;
1679 cols = labels.length;
1680
1681 var indepType = data.getColumnType(0);
1682 if (indepType == 'date' || 'datetime') {
1683 this.attrs_.xValueFormatter = Dygraph.dateString_;
1684 this.attrs_.xValueParser = Dygraph.dateParser;
1685 this.attrs_.xTicker = Dygraph.dateTicker;
1686 } else if (indepType == 'number') {
1687 this.attrs_.xValueFormatter = function(x) { return x; };
1688 this.attrs_.xValueParser = function(x) { return parseFloat(x); };
1689 this.attrs_.xTicker = Dygraph.numericTicks;
1690 } else {
1691 this.error("only 'date', 'datetime' and 'number' types are supported for column 1 " +
1692 "of DataTable input (Got '" + indepType + "')");
1693 return null;
1694 }
1695
1696 var ret = [];
1697 for (var i = 0; i < rows; i++) {
1698 var row = [];
1699 if (typeof(data.getValue(i, 0)) === 'undefined' ||
1700 data.getValue(i, 0) === null) {
1701 this.warning("Ignoring row " + i +
1702 " of DataTable because of undefined or null first column.");
1703 continue;
1704 }
1705
1706 if (indepType == 'date' || indepType == 'datetime') {
1707 row.push(data.getValue(i, 0).getTime());
1708 } else {
1709 row.push(data.getValue(i, 0));
1710 }
1711 if (!this.attr_("errorBars")) {
1712 for (var j = 1; j < cols; j++) {
1713 row.push(data.getValue(i, j));
1714 }
1715 } else {
1716 for (var j = 0; j < cols - 1; j++) {
1717 row.push([ data.getValue(i, 1 + 2 * j), data.getValue(i, 2 + 2 * j) ]);
1718 }
1719 }
1720 ret.push(row);
1721 }
1722 return ret;
1723 }
1724
1725 // These functions are all based on MochiKit.
1726 Dygraph.update = function (self, o) {
1727 if (typeof(o) != 'undefined' && o !== null) {
1728 for (var k in o) {
1729 if (o.hasOwnProperty(k)) {
1730 self[k] = o[k];
1731 }
1732 }
1733 }
1734 return self;
1735 };
1736
1737 Dygraph.isArrayLike = function (o) {
1738 var typ = typeof(o);
1739 if (
1740 (typ != 'object' && !(typ == 'function' &&
1741 typeof(o.item) == 'function')) ||
1742 o === null ||
1743 typeof(o.length) != 'number' ||
1744 o.nodeType === 3
1745 ) {
1746 return false;
1747 }
1748 return true;
1749 };
1750
1751 Dygraph.isDateLike = function (o) {
1752 if (typeof(o) != "object" || o === null ||
1753 typeof(o.getTime) != 'function') {
1754 return false;
1755 }
1756 return true;
1757 };
1758
1759 Dygraph.clone = function(o) {
1760 // TODO(danvk): figure out how MochiKit's version works
1761 var r = [];
1762 for (var i = 0; i < o.length; i++) {
1763 if (Dygraph.isArrayLike(o[i])) {
1764 r.push(Dygraph.clone(o[i]));
1765 } else {
1766 r.push(o[i]);
1767 }
1768 }
1769 return r;
1770 };
1771
1772
1773 /**
1774 * Get the CSV data. If it's in a function, call that function. If it's in a
1775 * file, do an XMLHttpRequest to get it.
1776 * @private
1777 */
1778 Dygraph.prototype.start_ = function() {
1779 if (typeof this.file_ == 'function') {
1780 // CSV string. Pretend we got it via XHR.
1781 this.loadedEvent_(this.file_());
1782 } else if (Dygraph.isArrayLike(this.file_)) {
1783 this.rawData_ = this.parseArray_(this.file_);
1784 this.drawGraph_(this.rawData_);
1785 } else if (typeof this.file_ == 'object' &&
1786 typeof this.file_.getColumnRange == 'function') {
1787 // must be a DataTable from gviz.
1788 this.rawData_ = this.parseDataTable_(this.file_);
1789 this.drawGraph_(this.rawData_);
1790 } else if (typeof this.file_ == 'string') {
1791 // Heuristic: a newline means it's CSV data. Otherwise it's an URL.
1792 if (this.file_.indexOf('\n') >= 0) {
1793 this.loadedEvent_(this.file_);
1794 } else {
1795 var req = new XMLHttpRequest();
1796 var caller = this;
1797 req.onreadystatechange = function () {
1798 if (req.readyState == 4) {
1799 if (req.status == 200) {
1800 caller.loadedEvent_(req.responseText);
1801 }
1802 }
1803 };
1804
1805 req.open("GET", this.file_, true);
1806 req.send(null);
1807 }
1808 } else {
1809 this.error("Unknown data format: " + (typeof this.file_));
1810 }
1811 };
1812
1813 /**
1814 * Changes various properties of the graph. These can include:
1815 * <ul>
1816 * <li>file: changes the source data for the graph</li>
1817 * <li>errorBars: changes whether the data contains stddev</li>
1818 * </ul>
1819 * @param {Object} attrs The new properties and values
1820 */
1821 Dygraph.prototype.updateOptions = function(attrs) {
1822 // TODO(danvk): this is a mess. Rethink this function.
1823 if (attrs.rollPeriod) {
1824 this.rollPeriod_ = attrs.rollPeriod;
1825 }
1826 if (attrs.dateWindow) {
1827 this.dateWindow_ = attrs.dateWindow;
1828 }
1829 if (attrs.valueRange) {
1830 this.valueRange_ = attrs.valueRange;
1831 }
1832 Dygraph.update(this.user_attrs_, attrs);
1833
1834 this.labelsFromCSV_ = (this.attr_("labels") == null);
1835
1836 // TODO(danvk): this doesn't match the constructor logic
1837 this.layout_.updateOptions({ 'errorBars': this.attr_("errorBars") });
1838 if (attrs['file'] && attrs['file'] != this.file_) {
1839 this.file_ = attrs['file'];
1840 this.start_();
1841 } else {
1842 this.drawGraph_(this.rawData_);
1843 }
1844 };
1845
1846 /**
1847 * Resizes the dygraph. If no parameters are specified, resizes to fill the
1848 * containing div (which has presumably changed size since the dygraph was
1849 * instantiated. If the width/height are specified, the div will be resized.
1850 *
1851 * This is far more efficient than destroying and re-instantiating a
1852 * Dygraph, since it doesn't have to reparse the underlying data.
1853 *
1854 * @param {Number} width Width (in pixels)
1855 * @param {Number} height Height (in pixels)
1856 */
1857 Dygraph.prototype.resize = function(width, height) {
1858 if ((width === null) != (height === null)) {
1859 this.warn("Dygraph.resize() should be called with zero parameters or " +
1860 "two non-NULL parameters. Pretending it was zero.");
1861 width = height = null;
1862 }
1863
1864 // TODO(danvk): there should be a clear() method.
1865 this.maindiv_.innerHTML = "";
1866 this.attrs_.labelsDiv = null;
1867
1868 if (width) {
1869 this.maindiv_.style.width = width + "px";
1870 this.maindiv_.style.height = height + "px";
1871 this.width_ = width;
1872 this.height_ = height;
1873 } else {
1874 this.width_ = this.maindiv_.offsetWidth;
1875 this.height_ = this.maindiv_.offsetHeight;
1876 }
1877
1878 this.createInterface_();
1879 this.drawGraph_(this.rawData_);
1880 };
1881
1882 /**
1883 * Adjusts the number of days in the rolling average. Updates the graph to
1884 * reflect the new averaging period.
1885 * @param {Number} length Number of days over which to average the data.
1886 */
1887 Dygraph.prototype.adjustRoll = function(length) {
1888 this.rollPeriod_ = length;
1889 this.drawGraph_(this.rawData_);
1890 };
1891
1892 /**
1893 * Returns a boolean array of visibility statuses.
1894 */
1895 Dygraph.prototype.visibility = function() {
1896 // Do lazy-initialization, so that this happens after we know the number of
1897 // data series.
1898 if (!this.attr_("visibility")) {
1899 this.attrs_["visibility"] = [];
1900 }
1901 while (this.attr_("visibility").length < this.rawData_[0].length - 1) {
1902 this.attr_("visibility").push(true);
1903 }
1904 return this.attr_("visibility");
1905 };
1906
1907 /**
1908 * Changes the visiblity of a series.
1909 */
1910 Dygraph.prototype.setVisibility = function(num, value) {
1911 var x = this.visibility();
1912 if (num < 0 && num >= x.length) {
1913 this.warn("invalid series number in setVisibility: " + num);
1914 } else {
1915 x[num] = value;
1916 this.drawGraph_(this.rawData_);
1917 }
1918 };
1919
1920 /**
1921 * Create a new canvas element. This is more complex than a simple
1922 * document.createElement("canvas") because of IE and excanvas.
1923 */
1924 Dygraph.createCanvas = function() {
1925 var canvas = document.createElement("canvas");
1926
1927 isIE = (/MSIE/.test(navigator.userAgent) && !window.opera);
1928 if (isIE) {
1929 canvas = G_vmlCanvasManager.initElement(canvas);
1930 }
1931
1932 return canvas;
1933 };
1934
1935
1936 /**
1937 * A wrapper around Dygraph that implements the gviz API.
1938 * @param {Object} container The DOM object the visualization should live in.
1939 */
1940 Dygraph.GVizChart = function(container) {
1941 this.container = container;
1942 }
1943
1944 Dygraph.GVizChart.prototype.draw = function(data, options) {
1945 this.container.innerHTML = '';
1946 this.date_graph = new Dygraph(this.container, data, options);
1947 }
1948
1949 // Older pages may still use this name.
1950 DateGraph = Dygraph;