Merge pull request #303 from danvk/fix-hidpi
[dygraphs.git] / dygraph-canvas.js
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1/**
2 * @license
3 * Copyright 2006 Dan Vanderkam (danvdk@gmail.com)
4 * MIT-licensed (http://opensource.org/licenses/MIT)
5 */
6
7/**
8 * @fileoverview Based on PlotKit.CanvasRenderer, but modified to meet the
9 * needs of dygraphs.
10 *
11 * In particular, support for:
12 * - grid overlays
13 * - error bars
14 * - dygraphs attribute system
15 */
16
17/**
18 * The DygraphCanvasRenderer class does the actual rendering of the chart onto
19 * a canvas. It's based on PlotKit.CanvasRenderer.
20 * @param {Object} element The canvas to attach to
21 * @param {Object} elementContext The 2d context of the canvas (injected so it
22 * can be mocked for testing.)
23 * @param {Layout} layout The DygraphLayout object for this graph.
24 * @constructor
25 */
26
27/*jshint globalstrict: true */
28/*global Dygraph:false */
29"use strict";
30
31
32/**
33 * @constructor
34 *
35 * This gets called when there are "new points" to chart. This is generally the
36 * case when the underlying data being charted has changed. It is _not_ called
37 * in the common case that the user has zoomed or is panning the view.
38 *
39 * The chart canvas has already been created by the Dygraph object. The
40 * renderer simply gets a drawing context.
41 *
42 * @param {Dygraph} dygraph The chart to which this renderer belongs.
43 * @param {HTMLCanvasElement} element The <canvas> DOM element on which to draw.
44 * @param {CanvasRenderingContext2D} elementContext The drawing context.
45 * @param {DygraphLayout} layout The chart's DygraphLayout object.
46 *
47 * TODO(danvk): remove the elementContext property.
48 */
49var DygraphCanvasRenderer = function(dygraph, element, elementContext, layout) {
50 this.dygraph_ = dygraph;
51
52 this.layout = layout;
53 this.element = element;
54 this.elementContext = elementContext;
55
56 this.height = this.element.height;
57 this.width = this.element.width;
58
59 // --- check whether everything is ok before we return
60 // NOTE(konigsberg): isIE is never defined in this object. Bug of some sort.
61 if (!this.isIE && !(Dygraph.isCanvasSupported(this.element)))
62 throw "Canvas is not supported.";
63
64 // internal state
65 this.area = layout.getPlotArea();
66
67 // Set up a clipping area for the canvas (and the interaction canvas).
68 // This ensures that we don't overdraw.
69 if (this.dygraph_.isUsingExcanvas_) {
70 this._createIEClipArea();
71 } else {
72 // on Android 3 and 4, setting a clipping area on a canvas prevents it from
73 // displaying anything.
74 if (!Dygraph.isAndroid()) {
75 var ctx = this.dygraph_.canvas_ctx_;
76 ctx.beginPath();
77 ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h);
78 ctx.clip();
79
80 ctx = this.dygraph_.hidden_ctx_;
81 ctx.beginPath();
82 ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h);
83 ctx.clip();
84 }
85 }
86};
87
88/**
89 * Clears out all chart content and DOM elements.
90 * This is called immediately before render() on every frame, including
91 * during zooms and pans.
92 * @private
93 */
94DygraphCanvasRenderer.prototype.clear = function() {
95 var context;
96 if (this.isIE) {
97 // VML takes a while to start up, so we just poll every this.IEDelay
98 try {
99 if (this.clearDelay) {
100 this.clearDelay.cancel();
101 this.clearDelay = null;
102 }
103 context = this.elementContext;
104 }
105 catch (e) {
106 // TODO(danvk): this is broken, since MochiKit.Async is gone.
107 // this.clearDelay = MochiKit.Async.wait(this.IEDelay);
108 // this.clearDelay.addCallback(bind(this.clear, this));
109 return;
110 }
111 }
112
113 context = this.elementContext;
114 context.clearRect(0, 0, this.width, this.height);
115};
116
117/**
118 * This method is responsible for drawing everything on the chart, including
119 * lines, error bars, fills and axes.
120 * It is called immediately after clear() on every frame, including during pans
121 * and zooms.
122 * @private
123 */
124DygraphCanvasRenderer.prototype.render = function() {
125 // attaches point.canvas{x,y}
126 this._updatePoints();
127
128 // actually draws the chart.
129 this._renderLineChart();
130};
131
132DygraphCanvasRenderer.prototype._createIEClipArea = function() {
133 var className = 'dygraph-clip-div';
134 var graphDiv = this.dygraph_.graphDiv;
135
136 // Remove old clip divs.
137 for (var i = graphDiv.childNodes.length-1; i >= 0; i--) {
138 if (graphDiv.childNodes[i].className == className) {
139 graphDiv.removeChild(graphDiv.childNodes[i]);
140 }
141 }
142
143 // Determine background color to give clip divs.
144 var backgroundColor = document.bgColor;
145 var element = this.dygraph_.graphDiv;
146 while (element != document) {
147 var bgcolor = element.currentStyle.backgroundColor;
148 if (bgcolor && bgcolor != 'transparent') {
149 backgroundColor = bgcolor;
150 break;
151 }
152 element = element.parentNode;
153 }
154
155 function createClipDiv(area) {
156 if (area.w === 0 || area.h === 0) {
157 return;
158 }
159 var elem = document.createElement('div');
160 elem.className = className;
161 elem.style.backgroundColor = backgroundColor;
162 elem.style.position = 'absolute';
163 elem.style.left = area.x + 'px';
164 elem.style.top = area.y + 'px';
165 elem.style.width = area.w + 'px';
166 elem.style.height = area.h + 'px';
167 graphDiv.appendChild(elem);
168 }
169
170 var plotArea = this.area;
171 // Left side
172 createClipDiv({
173 x:0, y:0,
174 w:plotArea.x,
175 h:this.height
176 });
177
178 // Top
179 createClipDiv({
180 x: plotArea.x, y: 0,
181 w: this.width - plotArea.x,
182 h: plotArea.y
183 });
184
185 // Right side
186 createClipDiv({
187 x: plotArea.x + plotArea.w, y: 0,
188 w: this.width-plotArea.x - plotArea.w,
189 h: this.height
190 });
191
192 // Bottom
193 createClipDiv({
194 x: plotArea.x,
195 y: plotArea.y + plotArea.h,
196 w: this.width - plotArea.x,
197 h: this.height - plotArea.h - plotArea.y
198 });
199};
200
201
202/**
203 * Returns a predicate to be used with an iterator, which will
204 * iterate over points appropriately, depending on whether
205 * connectSeparatedPoints is true. When it's false, the predicate will
206 * skip over points with missing yVals.
207 */
208DygraphCanvasRenderer._getIteratorPredicate = function(connectSeparatedPoints) {
209 return connectSeparatedPoints ?
210 DygraphCanvasRenderer._predicateThatSkipsEmptyPoints :
211 null;
212};
213
214DygraphCanvasRenderer._predicateThatSkipsEmptyPoints =
215 function(array, idx) {
216 return array[idx].yval !== null;
217};
218
219/**
220 * Draws a line with the styles passed in and calls all the drawPointCallbacks.
221 * @param {Object} e The dictionary passed to the plotter function.
222 * @private
223 */
224DygraphCanvasRenderer._drawStyledLine = function(e,
225 color, strokeWidth, strokePattern, drawPoints,
226 drawPointCallback, pointSize) {
227 var g = e.dygraph;
228 // TODO(konigsberg): Compute attributes outside this method call.
229 var stepPlot = g.getBooleanOption("stepPlot", e.setName);
230
231 if (!Dygraph.isArrayLike(strokePattern)) {
232 strokePattern = null;
233 }
234
235 var drawGapPoints = g.getBooleanOption('drawGapEdgePoints', e.setName);
236
237 var points = e.points;
238 var setName = e.setName;
239 var iter = Dygraph.createIterator(points, 0, points.length,
240 DygraphCanvasRenderer._getIteratorPredicate(
241 g.getBooleanOption("connectSeparatedPoints", setName)));
242
243 var stroking = strokePattern && (strokePattern.length >= 2);
244
245 var ctx = e.drawingContext;
246 ctx.save();
247 if (stroking) {
248 ctx.installPattern(strokePattern);
249 }
250
251 var pointsOnLine = DygraphCanvasRenderer._drawSeries(
252 e, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, stepPlot, color);
253 DygraphCanvasRenderer._drawPointsOnLine(
254 e, pointsOnLine, drawPointCallback, color, pointSize);
255
256 if (stroking) {
257 ctx.uninstallPattern();
258 }
259
260 ctx.restore();
261};
262
263/**
264 * This does the actual drawing of lines on the canvas, for just one series.
265 * Returns a list of [canvasx, canvasy] pairs for points for which a
266 * drawPointCallback should be fired. These include isolated points, or all
267 * points if drawPoints=true.
268 * @param {Object} e The dictionary passed to the plotter function.
269 * @private
270 */
271DygraphCanvasRenderer._drawSeries = function(e,
272 iter, strokeWidth, pointSize, drawPoints, drawGapPoints, stepPlot, color) {
273
274 var prevCanvasX = null;
275 var prevCanvasY = null;
276 var nextCanvasY = null;
277 var isIsolated; // true if this point is isolated (no line segments)
278 var point; // the point being processed in the while loop
279 var pointsOnLine = []; // Array of [canvasx, canvasy] pairs.
280 var first = true; // the first cycle through the while loop
281
282 var ctx = e.drawingContext;
283 ctx.beginPath();
284 ctx.strokeStyle = color;
285 ctx.lineWidth = strokeWidth;
286
287 // NOTE: we break the iterator's encapsulation here for about a 25% speedup.
288 var arr = iter.array_;
289 var limit = iter.end_;
290 var predicate = iter.predicate_;
291
292 for (var i = iter.start_; i < limit; i++) {
293 point = arr[i];
294 if (predicate) {
295 while (i < limit && !predicate(arr, i)) {
296 i++;
297 }
298 if (i == limit) break;
299 point = arr[i];
300 }
301
302 // FIXME: The 'canvasy != canvasy' test here catches NaN values but the test
303 // doesn't catch Infinity values. Could change this to
304 // !isFinite(point.canvasy), but I assume it avoids isNaN for performance?
305 if (point.canvasy === null || point.canvasy != point.canvasy) {
306 if (stepPlot && prevCanvasX !== null) {
307 // Draw a horizontal line to the start of the missing data
308 ctx.moveTo(prevCanvasX, prevCanvasY);
309 ctx.lineTo(point.canvasx, prevCanvasY);
310 }
311 prevCanvasX = prevCanvasY = null;
312 } else {
313 isIsolated = false;
314 if (drawGapPoints || !prevCanvasX) {
315 iter.nextIdx_ = i;
316 iter.next();
317 nextCanvasY = iter.hasNext ? iter.peek.canvasy : null;
318
319 var isNextCanvasYNullOrNaN = nextCanvasY === null ||
320 nextCanvasY != nextCanvasY;
321 isIsolated = (!prevCanvasX && isNextCanvasYNullOrNaN);
322 if (drawGapPoints) {
323 // Also consider a point to be "isolated" if it's adjacent to a
324 // null point, excluding the graph edges.
325 if ((!first && !prevCanvasX) ||
326 (iter.hasNext && isNextCanvasYNullOrNaN)) {
327 isIsolated = true;
328 }
329 }
330 }
331
332 if (prevCanvasX !== null) {
333 if (strokeWidth) {
334 if (stepPlot) {
335 ctx.moveTo(prevCanvasX, prevCanvasY);
336 ctx.lineTo(point.canvasx, prevCanvasY);
337 }
338
339 ctx.lineTo(point.canvasx, point.canvasy);
340 }
341 } else {
342 ctx.moveTo(point.canvasx, point.canvasy);
343 }
344 if (drawPoints || isIsolated) {
345 pointsOnLine.push([point.canvasx, point.canvasy, point.idx]);
346 }
347 prevCanvasX = point.canvasx;
348 prevCanvasY = point.canvasy;
349 }
350 first = false;
351 }
352 ctx.stroke();
353 return pointsOnLine;
354};
355
356/**
357 * This fires the drawPointCallback functions, which draw dots on the points by
358 * default. This gets used when the "drawPoints" option is set, or when there
359 * are isolated points.
360 * @param {Object} e The dictionary passed to the plotter function.
361 * @private
362 */
363DygraphCanvasRenderer._drawPointsOnLine = function(
364 e, pointsOnLine, drawPointCallback, color, pointSize) {
365 var ctx = e.drawingContext;
366 for (var idx = 0; idx < pointsOnLine.length; idx++) {
367 var cb = pointsOnLine[idx];
368 ctx.save();
369 drawPointCallback(
370 e.dygraph, e.setName, ctx, cb[0], cb[1], color, pointSize, cb[2]);
371 ctx.restore();
372 }
373};
374
375/**
376 * Attaches canvas coordinates to the points array.
377 * @private
378 */
379DygraphCanvasRenderer.prototype._updatePoints = function() {
380 // Update Points
381 // TODO(danvk): here
382 //
383 // TODO(bhs): this loop is a hot-spot for high-point-count charts. These
384 // transformations can be pushed into the canvas via linear transformation
385 // matrices.
386 // NOTE(danvk): this is trickier than it sounds at first. The transformation
387 // needs to be done before the .moveTo() and .lineTo() calls, but must be
388 // undone before the .stroke() call to ensure that the stroke width is
389 // unaffected. An alternative is to reduce the stroke width in the
390 // transformed coordinate space, but you can't specify different values for
391 // each dimension (as you can with .scale()). The speedup here is ~12%.
392 var sets = this.layout.points;
393 for (var i = sets.length; i--;) {
394 var points = sets[i];
395 for (var j = points.length; j--;) {
396 var point = points[j];
397 point.canvasx = this.area.w * point.x + this.area.x;
398 point.canvasy = this.area.h * point.y + this.area.y;
399 }
400 }
401};
402
403/**
404 * Add canvas Actually draw the lines chart, including error bars.
405 *
406 * This function can only be called if DygraphLayout's points array has been
407 * updated with canvas{x,y} attributes, i.e. by
408 * DygraphCanvasRenderer._updatePoints.
409 *
410 * @param {string=} opt_seriesName when specified, only that series will
411 * be drawn. (This is used for expedited redrawing with highlightSeriesOpts)
412 * @param {CanvasRenderingContext2D} opt_ctx when specified, the drawing
413 * context. However, lines are typically drawn on the object's
414 * elementContext.
415 * @private
416 */
417DygraphCanvasRenderer.prototype._renderLineChart = function(opt_seriesName, opt_ctx) {
418 var ctx = opt_ctx || this.elementContext;
419 var i;
420
421 var sets = this.layout.points;
422 var setNames = this.layout.setNames;
423 var setName;
424
425 this.colors = this.dygraph_.colorsMap_;
426
427 // Determine which series have specialized plotters.
428 var plotter_attr = this.dygraph_.getOption("plotter");
429 var plotters = plotter_attr;
430 if (!Dygraph.isArrayLike(plotters)) {
431 plotters = [plotters];
432 }
433
434 var setPlotters = {}; // series name -> plotter fn.
435 for (i = 0; i < setNames.length; i++) {
436 setName = setNames[i];
437 var setPlotter = this.dygraph_.getOption("plotter", setName);
438 if (setPlotter == plotter_attr) continue; // not specialized.
439
440 setPlotters[setName] = setPlotter;
441 }
442
443 for (i = 0; i < plotters.length; i++) {
444 var plotter = plotters[i];
445 var is_last = (i == plotters.length - 1);
446
447 for (var j = 0; j < sets.length; j++) {
448 setName = setNames[j];
449 if (opt_seriesName && setName != opt_seriesName) continue;
450
451 var points = sets[j];
452
453 // Only throw in the specialized plotters on the last iteration.
454 var p = plotter;
455 if (setName in setPlotters) {
456 if (is_last) {
457 p = setPlotters[setName];
458 } else {
459 // Don't use the standard plotters in this case.
460 continue;
461 }
462 }
463
464 var color = this.colors[setName];
465 var strokeWidth = this.dygraph_.getOption("strokeWidth", setName);
466
467 ctx.save();
468 ctx.strokeStyle = color;
469 ctx.lineWidth = strokeWidth;
470 p({
471 points: points,
472 setName: setName,
473 drawingContext: ctx,
474 color: color,
475 strokeWidth: strokeWidth,
476 dygraph: this.dygraph_,
477 axis: this.dygraph_.axisPropertiesForSeries(setName),
478 plotArea: this.area,
479 seriesIndex: j,
480 seriesCount: sets.length,
481 singleSeriesName: opt_seriesName,
482 allSeriesPoints: sets
483 });
484 ctx.restore();
485 }
486 }
487};
488
489/**
490 * Standard plotters. These may be used by clients via Dygraph.Plotters.
491 * See comments there for more details.
492 */
493DygraphCanvasRenderer._Plotters = {
494 linePlotter: function(e) {
495 DygraphCanvasRenderer._linePlotter(e);
496 },
497
498 fillPlotter: function(e) {
499 DygraphCanvasRenderer._fillPlotter(e);
500 },
501
502 errorPlotter: function(e) {
503 DygraphCanvasRenderer._errorPlotter(e);
504 }
505};
506
507/**
508 * Plotter which draws the central lines for a series.
509 * @private
510 */
511DygraphCanvasRenderer._linePlotter = function(e) {
512 var g = e.dygraph;
513 var setName = e.setName;
514 var strokeWidth = e.strokeWidth;
515
516 // TODO(danvk): Check if there's any performance impact of just calling
517 // getOption() inside of _drawStyledLine. Passing in so many parameters makes
518 // this code a bit nasty.
519 var borderWidth = g.getNumericOption("strokeBorderWidth", setName);
520 var drawPointCallback = g.getOption("drawPointCallback", setName) ||
521 Dygraph.Circles.DEFAULT;
522 var strokePattern = g.getOption("strokePattern", setName);
523 var drawPoints = g.getBooleanOption("drawPoints", setName);
524 var pointSize = g.getNumericOption("pointSize", setName);
525
526 if (borderWidth && strokeWidth) {
527 DygraphCanvasRenderer._drawStyledLine(e,
528 g.getOption("strokeBorderColor", setName),
529 strokeWidth + 2 * borderWidth,
530 strokePattern,
531 drawPoints,
532 drawPointCallback,
533 pointSize
534 );
535 }
536
537 DygraphCanvasRenderer._drawStyledLine(e,
538 e.color,
539 strokeWidth,
540 strokePattern,
541 drawPoints,
542 drawPointCallback,
543 pointSize
544 );
545};
546
547/**
548 * Draws the shaded error bars/confidence intervals for each series.
549 * This happens before the center lines are drawn, since the center lines
550 * need to be drawn on top of the error bars for all series.
551 * @private
552 */
553DygraphCanvasRenderer._errorPlotter = function(e) {
554 var g = e.dygraph;
555 var setName = e.setName;
556 var errorBars = g.getBooleanOption("errorBars") ||
557 g.getBooleanOption("customBars");
558 if (!errorBars) return;
559
560 var fillGraph = g.getBooleanOption("fillGraph", setName);
561 if (fillGraph) {
562 Dygraph.warn("Can't use fillGraph option with error bars");
563 }
564
565 var ctx = e.drawingContext;
566 var color = e.color;
567 var fillAlpha = g.getNumericOption('fillAlpha', setName);
568 var stepPlot = g.getBooleanOption("stepPlot", setName);
569 var points = e.points;
570
571 var iter = Dygraph.createIterator(points, 0, points.length,
572 DygraphCanvasRenderer._getIteratorPredicate(
573 g.getBooleanOption("connectSeparatedPoints", setName)));
574
575 var newYs;
576
577 // setup graphics context
578 var prevX = NaN;
579 var prevY = NaN;
580 var prevYs = [-1, -1];
581 // should be same color as the lines but only 15% opaque.
582 var rgb = Dygraph.toRGB_(color);
583 var err_color =
584 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + fillAlpha + ')';
585 ctx.fillStyle = err_color;
586 ctx.beginPath();
587
588 var isNullUndefinedOrNaN = function(x) {
589 return (x === null ||
590 x === undefined ||
591 isNaN(x));
592 };
593
594 while (iter.hasNext) {
595 var point = iter.next();
596 if ((!stepPlot && isNullUndefinedOrNaN(point.y)) ||
597 (stepPlot && !isNaN(prevY) && isNullUndefinedOrNaN(prevY))) {
598 prevX = NaN;
599 continue;
600 }
601
602 if (stepPlot) {
603 newYs = [ point.y_bottom, point.y_top ];
604 prevY = point.y;
605 } else {
606 newYs = [ point.y_bottom, point.y_top ];
607 }
608 newYs[0] = e.plotArea.h * newYs[0] + e.plotArea.y;
609 newYs[1] = e.plotArea.h * newYs[1] + e.plotArea.y;
610 if (!isNaN(prevX)) {
611 if (stepPlot) {
612 ctx.moveTo(prevX, prevYs[0]);
613 ctx.lineTo(point.canvasx, prevYs[0]);
614 ctx.lineTo(point.canvasx, prevYs[1]);
615 } else {
616 ctx.moveTo(prevX, prevYs[0]);
617 ctx.lineTo(point.canvasx, newYs[0]);
618 ctx.lineTo(point.canvasx, newYs[1]);
619 }
620 ctx.lineTo(prevX, prevYs[1]);
621 ctx.closePath();
622 }
623 prevYs = newYs;
624 prevX = point.canvasx;
625 }
626 ctx.fill();
627};
628
629/**
630 * Draws the shaded regions when "fillGraph" is set. Not to be confused with
631 * error bars.
632 *
633 * For stacked charts, it's more convenient to handle all the series
634 * simultaneously. So this plotter plots all the points on the first series
635 * it's asked to draw, then ignores all the other series.
636 *
637 * @private
638 */
639DygraphCanvasRenderer._fillPlotter = function(e) {
640 // Skip if we're drawing a single series for interactive highlight overlay.
641 if (e.singleSeriesName) return;
642
643 // We'll handle all the series at once, not one-by-one.
644 if (e.seriesIndex !== 0) return;
645
646 var g = e.dygraph;
647 var setNames = g.getLabels().slice(1); // remove x-axis
648
649 // getLabels() includes names for invisible series, which are not included in
650 // allSeriesPoints. We remove those to make the two match.
651 // TODO(danvk): provide a simpler way to get this information.
652 for (var i = setNames.length; i >= 0; i--) {
653 if (!g.visibility()[i]) setNames.splice(i, 1);
654 }
655
656 var anySeriesFilled = (function() {
657 for (var i = 0; i < setNames.length; i++) {
658 if (g.getBooleanOption("fillGraph", setNames[i])) return true;
659 }
660 return false;
661 })();
662
663 if (!anySeriesFilled) return;
664
665 var ctx = e.drawingContext;
666 var area = e.plotArea;
667 var sets = e.allSeriesPoints;
668 var setCount = sets.length;
669
670 var fillAlpha = g.getNumericOption('fillAlpha');
671 var stackedGraph = g.getBooleanOption("stackedGraph");
672 var colors = g.getColors();
673
674 // For stacked graphs, track the baseline for filling.
675 //
676 // The filled areas below graph lines are trapezoids with two
677 // vertical edges. The top edge is the line segment being drawn, and
678 // the baseline is the bottom edge. Each baseline corresponds to the
679 // top line segment from the previous stacked line. In the case of
680 // step plots, the trapezoids are rectangles.
681 var baseline = {};
682 var currBaseline;
683 var prevStepPlot; // for different line drawing modes (line/step) per series
684
685 // process sets in reverse order (needed for stacked graphs)
686 for (var setIdx = setCount - 1; setIdx >= 0; setIdx--) {
687 var setName = setNames[setIdx];
688 if (!g.getBooleanOption('fillGraph', setName)) continue;
689
690 var stepPlot = g.getBooleanOption('stepPlot', setName);
691 var color = colors[setIdx];
692 var axis = g.axisPropertiesForSeries(setName);
693 var axisY = 1.0 + axis.minyval * axis.yscale;
694 if (axisY < 0.0) axisY = 0.0;
695 else if (axisY > 1.0) axisY = 1.0;
696 axisY = area.h * axisY + area.y;
697
698 var points = sets[setIdx];
699 var iter = Dygraph.createIterator(points, 0, points.length,
700 DygraphCanvasRenderer._getIteratorPredicate(
701 g.getBooleanOption("connectSeparatedPoints", setName)));
702
703 // setup graphics context
704 var prevX = NaN;
705 var prevYs = [-1, -1];
706 var newYs;
707 // should be same color as the lines but only 15% opaque.
708 var rgb = Dygraph.toRGB_(color);
709 var err_color =
710 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + fillAlpha + ')';
711 ctx.fillStyle = err_color;
712 ctx.beginPath();
713 var last_x, is_first = true;
714 while (iter.hasNext) {
715 var point = iter.next();
716 if (!Dygraph.isOK(point.y) && !stepPlot) {
717 prevX = NaN;
718 if (point.y_stacked !== null && !isNaN(point.y_stacked)) {
719 baseline[point.canvasx] = area.h * point.y_stacked + area.y;
720 }
721 continue;
722 }
723 if (stackedGraph) {
724 if (!is_first && last_x == point.xval) {
725 continue;
726 } else {
727 is_first = false;
728 last_x = point.xval;
729 }
730
731 currBaseline = baseline[point.canvasx];
732 var lastY;
733 if (currBaseline === undefined) {
734 lastY = axisY;
735 } else {
736 if(prevStepPlot) {
737 lastY = currBaseline[0];
738 } else {
739 lastY = currBaseline;
740 }
741 }
742 newYs = [ point.canvasy, lastY ];
743
744 if(stepPlot) {
745 // Step plots must keep track of the top and bottom of
746 // the baseline at each point.
747 if(prevYs[0] === -1) {
748 baseline[point.canvasx] = [ point.canvasy, axisY ];
749 } else {
750 baseline[point.canvasx] = [ point.canvasy, prevYs[0] ];
751 }
752 } else {
753 baseline[point.canvasx] = point.canvasy;
754 }
755
756 } else {
757 if (isNaN(point.canvasy) && stepPlot) {
758 newYs = [ area.y + area.h, axisY ];
759 } else {
760 newYs = [ point.canvasy, axisY ];
761 }
762 }
763 if (!isNaN(prevX)) {
764 ctx.moveTo(prevX, prevYs[0]);
765
766 // Move to top fill point
767 if (stepPlot) {
768 ctx.lineTo(point.canvasx, prevYs[0]);
769 } else {
770 ctx.lineTo(point.canvasx, newYs[0]);
771 }
772 // Move to bottom fill point
773 if (prevStepPlot && currBaseline) {
774 // Draw to the bottom of the baseline
775 ctx.lineTo(point.canvasx, currBaseline[1]);
776 } else {
777 ctx.lineTo(point.canvasx, newYs[1]);
778 }
779
780 ctx.lineTo(prevX, prevYs[1]);
781 ctx.closePath();
782 }
783 prevYs = newYs;
784 prevX = point.canvasx;
785 }
786 prevStepPlot = stepPlot;
787 ctx.fill();
788 }
789};