X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph-canvas.js;h=8cb004052e1c4d3cb9b83e65e87ee3d423c6c120;hb=ee53deb9db465f5eea54e102ca755decef005496;hp=5e6766dcf63dd89e5df65129d150fa5c1d60de42;hpb=107f9d8e86feef0bd886393edd40944c587ac2e7;p=dygraphs.git diff --git a/dygraph-canvas.js b/dygraph-canvas.js index 5e6766d..8cb0040 100644 --- a/dygraph-canvas.js +++ b/dygraph-canvas.js @@ -28,6 +28,24 @@ /*global Dygraph:false,RGBColor:false */ "use strict"; + +/** + * @constructor + * + * This gets called when there are "new points" to chart. This is generally the + * case when the underlying data being charted has changed. It is _not_ called + * in the common case that the user has zoomed or is panning the view. + * + * The chart canvas has already been created by the Dygraph object. The + * renderer simply gets a drawing context. + * + * @param {Dyraph} dygraph The chart to which this renderer belongs. + * @param {Canvas} element The <canvas> DOM element on which to draw. + * @param {CanvasRenderingContext2D} elementContext The drawing context. + * @param {DygraphLayout} layout The chart's DygraphLayout object. + * + * TODO(danvk): remove the elementContext property. + */ var DygraphCanvasRenderer = function(dygraph, element, elementContext, layout) { this.dygraph_ = dygraph; @@ -47,7 +65,6 @@ var DygraphCanvasRenderer = function(dygraph, element, elementContext, layout) { this.xlabels = []; this.ylabels = []; this.annotations = []; - this.chartLabels = {}; this.area = layout.getPlotArea(); this.container.style.position = "relative"; @@ -78,6 +95,12 @@ DygraphCanvasRenderer.prototype.attr_ = function(x) { return this.dygraph_.attr_(x); }; +/** + * Clears out all chart content and DOM elements. + * This is called immediately before render() on every frame, including + * during zooms and pans. + * @private + */ DygraphCanvasRenderer.prototype.clear = function() { var context; if (this.isIE) { @@ -111,18 +134,15 @@ DygraphCanvasRenderer.prototype.clear = function() { removeArray(this.ylabels); removeArray(this.annotations); - for (var k in this.chartLabels) { - if (!this.chartLabels.hasOwnProperty(k)) continue; - var el = this.chartLabels[k]; - if (el.parentNode) el.parentNode.removeChild(el); - } this.xlabels = []; this.ylabels = []; this.annotations = []; - this.chartLabels = {}; }; - +/** + * Checks whether the browser supports the <canvas> tag. + * @private + */ DygraphCanvasRenderer.isSupported = function(canvasName) { var canvas = null; try { @@ -152,7 +172,11 @@ DygraphCanvasRenderer.prototype.setColors = function(colors) { }; /** - * Draw an X/Y grid on top of the existing plot + * This method is responsible for drawing everything on the chart, including + * lines, error bars, fills and axes. + * It is called immediately after clear() on every frame, including during pans + * and zooms. + * @private */ DygraphCanvasRenderer.prototype.render = function() { // Draw the new X/Y grid. Lines appear crisper when pixels are rounded to @@ -185,6 +209,7 @@ DygraphCanvasRenderer.prototype.render = function() { ctx.closePath(); ctx.stroke(); } + ctx.restore(); } if (this.attr_('drawXGrid')) { @@ -201,13 +226,13 @@ DygraphCanvasRenderer.prototype.render = function() { ctx.closePath(); ctx.stroke(); } + ctx.restore(); } // Do the ordinary rendering, as before this._renderLineChart(); this._renderAxis(); - this._renderChartLabels(); - this._renderAnnotations(); + // this._renderAnnotations(); }; DygraphCanvasRenderer.prototype._createIEClipArea = function() { @@ -311,7 +336,7 @@ DygraphCanvasRenderer.prototype._renderAxis = function() { inner_div.className = 'dygraph-axis-label' + ' dygraph-axis-label-' + axis + (prec_axis ? ' dygraph-axis-label-' + prec_axis : ''); - inner_div.appendChild(document.createTextNode(txt)); + inner_div.innerHTML=txt; div.appendChild(inner_div); return div; }; @@ -380,9 +405,17 @@ DygraphCanvasRenderer.prototype._renderAxis = function() { } // draw a vertical line on the left to separate the chart from the labels. + var axisX; + if (this.attr_('drawAxesAtZero')) { + var r = this.dygraph_.toPercentXCoord(0); + if (r > 1 || r < 0) r = 0; + axisX = halfUp(this.area.x + r * this.area.w); + } else { + axisX = halfUp(this.area.x); + } context.beginPath(); - context.moveTo(halfUp(this.area.x), halfDown(this.area.y)); - context.lineTo(halfUp(this.area.x), halfDown(this.area.y + this.area.h)); + context.moveTo(axisX, halfDown(this.area.y)); + context.lineTo(axisX, halfDown(this.area.y + this.area.h)); context.closePath(); context.stroke(); @@ -433,8 +466,16 @@ DygraphCanvasRenderer.prototype._renderAxis = function() { } context.beginPath(); - context.moveTo(halfUp(this.area.x), halfDown(this.area.y + this.area.h)); - context.lineTo(halfUp(this.area.x + this.area.w), halfDown(this.area.y + this.area.h)); + var axisY; + if (this.attr_('drawAxesAtZero')) { + var r = this.dygraph_.toPercentYCoord(0, 0); + if (r > 1 || r < 0) r = 1; + axisY = halfDown(this.area.y + r * this.area.h); + } else { + axisY = halfDown(this.area.y + this.area.h); + } + context.moveTo(halfUp(this.area.x), axisY); + context.lineTo(halfUp(this.area.x + this.area.w), axisY); context.closePath(); context.stroke(); } @@ -443,123 +484,6 @@ DygraphCanvasRenderer.prototype._renderAxis = function() { }; -DygraphCanvasRenderer.prototype._renderChartLabels = function() { - var div, class_div; - - // Generate divs for the chart title, xlabel and ylabel. - // Space for these divs has already been taken away from the charting area in - // the DygraphCanvasRenderer constructor. - if (this.attr_('title')) { - div = document.createElement("div"); - div.style.position = 'absolute'; - div.style.top = '0px'; - div.style.left = this.area.x + 'px'; - div.style.width = this.area.w + 'px'; - div.style.height = this.attr_('titleHeight') + 'px'; - div.style.textAlign = 'center'; - div.style.fontSize = (this.attr_('titleHeight') - 8) + 'px'; - div.style.fontWeight = 'bold'; - class_div = document.createElement("div"); - class_div.className = 'dygraph-label dygraph-title'; - class_div.innerHTML = this.attr_('title'); - div.appendChild(class_div); - this.container.appendChild(div); - this.chartLabels.title = div; - } - - if (this.attr_('xlabel')) { - div = document.createElement("div"); - div.style.position = 'absolute'; - div.style.bottom = 0; // TODO(danvk): this is lazy. Calculate style.top. - div.style.left = this.area.x + 'px'; - div.style.width = this.area.w + 'px'; - div.style.height = this.attr_('xLabelHeight') + 'px'; - div.style.textAlign = 'center'; - div.style.fontSize = (this.attr_('xLabelHeight') - 2) + 'px'; - - class_div = document.createElement("div"); - class_div.className = 'dygraph-label dygraph-xlabel'; - class_div.innerHTML = this.attr_('xlabel'); - div.appendChild(class_div); - this.container.appendChild(div); - this.chartLabels.xlabel = div; - } - - var that = this; - function createRotatedDiv(axis, classes, html) { - var box = { - left: 0, - top: that.area.y, - width: that.attr_('yLabelWidth'), - height: that.area.h - }; - // TODO(danvk): is this outer div actually necessary? - div = document.createElement("div"); - div.style.position = 'absolute'; - if (axis == 1) { - div.style.left = box.left; - } else { - div.style.right = box.left; - } - div.style.top = box.top + 'px'; - div.style.width = box.width + 'px'; - div.style.height = box.height + 'px'; - div.style.fontSize = (that.attr_('yLabelWidth') - 2) + 'px'; - - var inner_div = document.createElement("div"); - inner_div.style.position = 'absolute'; - inner_div.style.width = box.height + 'px'; - inner_div.style.height = box.width + 'px'; - inner_div.style.top = (box.height / 2 - box.width / 2) + 'px'; - inner_div.style.left = (box.width / 2 - box.height / 2) + 'px'; - inner_div.style.textAlign = 'center'; - - // CSS rotation is an HTML5 feature which is not standardized. Hence every - // browser has its own name for the CSS style. - var val = 'rotate(' + (axis == 1 ? '-' : '') + '90deg)'; - inner_div.style.transform = val; // HTML5 - inner_div.style.WebkitTransform = val; // Safari/Chrome - inner_div.style.MozTransform = val; // Firefox - inner_div.style.OTransform = val; // Opera - inner_div.style.msTransform = val; // IE9 - - if (typeof(document.documentMode) !== 'undefined' && - document.documentMode < 9) { - // We're dealing w/ an old version of IE, so we have to rotate the text - // using a BasicImage transform. This uses a different origin of rotation - // than HTML5 rotation (top left of div vs. its center). - inner_div.style.filter = - 'progid:DXImageTransform.Microsoft.BasicImage(rotation=' + - (axis == 1 ? '3' : '1') + ')'; - inner_div.style.left = '0px'; - inner_div.style.top = '0px'; - } - - class_div = document.createElement("div"); - class_div.className = classes; - class_div.innerHTML = html; - - inner_div.appendChild(class_div); - div.appendChild(inner_div); - return div; - } - - var div; - if (this.attr_('ylabel')) { - div = createRotatedDiv(1, 'dygraph-label dygraph-ylabel', - this.attr_('ylabel')); - this.container.appendChild(div); - this.chartLabels.ylabel = div; - } - if (this.attr_('y2label') && this.dygraph_.numAxes() == 2) { - div = createRotatedDiv(2, 'dygraph-label dygraph-y2label', - this.attr_('y2label')); - this.container.appendChild(div); - this.chartLabels.y2label = div; - } -}; - - DygraphCanvasRenderer.prototype._renderAnnotations = function() { var annotationStyle = { "position": "absolute", @@ -583,7 +507,8 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() { var points = this.layout.annotated_points; for (var i = 0; i < points.length; i++) { var p = points[i]; - if (p.canvasx < this.area.x || p.canvasx > this.area.x + this.area.w) { + if (p.canvasx < this.area.x || p.canvasx > this.area.x + this.area.w || + p.canvasy < this.area.y || p.canvasy > this.area.y + this.area.h) { continue; } @@ -630,13 +555,13 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() { div.style.borderColor = this.colors[p.name]; a.div = div; - Dygraph.addEvent(div, 'click', + this.dygraph_.addEvent(div, 'click', bindEvt('clickHandler', 'annotationClickHandler', p, this)); - Dygraph.addEvent(div, 'mouseover', + this.dygraph_.addEvent(div, 'mouseover', bindEvt('mouseOverHandler', 'annotationMouseOverHandler', p, this)); - Dygraph.addEvent(div, 'mouseout', + this.dygraph_.addEvent(div, 'mouseout', bindEvt('mouseOutHandler', 'annotationMouseOutHandler', p, this)); - Dygraph.addEvent(div, 'dblclick', + this.dygraph_.addEvent(div, 'dblclick', bindEvt('dblClickHandler', 'annotationDblClickHandler', p, this)); this.container.appendChild(div); @@ -657,6 +582,197 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() { } }; +/** + * Returns a predicate to be used with an iterator, which will + * iterate over points appropriately, depending on whether + * connectSeparatedPoints is true. When it's false, the predicate will + * skip over points with missing yVals. + */ +DygraphCanvasRenderer._getIteratorPredicate = function(connectSeparatedPoints) { + return connectSeparatedPoints ? DygraphCanvasRenderer._predicateThatSkipsEmptyPoints : null; +} + +DygraphCanvasRenderer._predicateThatSkipsEmptyPoints = + function(array, idx) { return array[idx].yval !== null; } + +DygraphCanvasRenderer.prototype._drawStyledLine = function( + ctx, i, setName, color, strokeWidth, strokePattern, drawPoints, + drawPointCallback, pointSize) { + // TODO(konigsberg): Compute attributes outside this method call. + var stepPlot = this.attr_("stepPlot"); + var firstIndexInSet = this.layout.setPointsOffsets[i]; + var setLength = this.layout.setPointsLengths[i]; + var points = this.layout.points; + if (!Dygraph.isArrayLike(strokePattern)) { + strokePattern = null; + } + var drawGapPoints = this.dygraph_.attr_('drawGapEdgePoints', setName); + + ctx.save(); + + var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, + DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); + + var pointsOnLine; + var strategy; + if (!strokePattern || strokePattern.length <= 1) { + strategy = trivialStrategy(ctx, color, strokeWidth); + } else { + strategy = nonTrivialStrategy(this, ctx, color, strokeWidth, strokePattern); + } + pointsOnLine = this._drawSeries(ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, stepPlot, strategy); + this._drawPointsOnLine(ctx, pointsOnLine, drawPointCallback, setName, color, pointSize); + + ctx.restore(); +}; + +var nonTrivialStrategy = function(renderer, ctx, color, strokeWidth, strokePattern) { + return new function() { + this.init = function() { }; + this.finish = function() { }; + this.startSegment = function() { + ctx.beginPath(); + ctx.strokeStyle = color; + ctx.lineWidth = strokeWidth; + }; + this.endSegment = function() { + ctx.stroke(); // should this include closePath? + }; + this.drawLine = function(x1, y1, x2, y2) { + renderer._dashedLine(ctx, x1, y1, x2, y2, strokePattern); + }; + this.skipPixel = function(prevX, prevY, curX, curY) { + // TODO(konigsberg): optimize with http://jsperf.com/math-round-vs-hack/6 ? + return (Math.round(prevX) == Math.round(curX) && + Math.round(prevY) == Math.round(curY)); + }; + }; +}; + +var trivialStrategy = function(ctx, color, strokeWidth) { + return new function() { + this.init = function() { + ctx.beginPath(); + ctx.strokeStyle = color; + ctx.lineWidth = strokeWidth; + }; + this.finish = function() { + ctx.stroke(); // should this include closePath? + }; + this.startSegment = function() { }; + this.endSegment = function() { }; + this.drawLine = function(x1, y1, x2, y2) { + ctx.moveTo(x1, y1); + ctx.lineTo(x2, y2); + }; + // don't skip pixels. + this.skipPixel = function() { + return false; + }; + }; +}; + +DygraphCanvasRenderer.prototype._drawPointsOnLine = function(ctx, pointsOnLine, drawPointCallback, setName, color, pointSize) { + for (var idx = 0; idx < pointsOnLine.length; idx++) { + var cb = pointsOnLine[idx]; + ctx.save(); + drawPointCallback( + this.dygraph_, setName, ctx, cb[0], cb[1], color, pointSize); + ctx.restore(); + } +} + +DygraphCanvasRenderer.prototype._drawSeries = function( + ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, + stepPlot, strategy) { + + var prevCanvasX = null; + var prevCanvasY = null; + var nextCanvasY = null; + var isIsolated; // true if this point is isolated (no line segments) + var point; // the point being processed in the while loop + var pointsOnLine = []; // Array of [canvasx, canvasy] pairs. + var first = true; // the first cycle through the while loop + + strategy.init(); + + while(iter.hasNext()) { + point = iter.next(); + if (point.canvasy === null || point.canvasy != point.canvasy) { + if (stepPlot && prevCanvasX !== null) { + // Draw a horizontal line to the start of the missing data + strategy.startSegment(); + strategy.drawLine(prevX, prevY, point.canvasx, prevY); + strategy.endSegment(); + } + prevCanvasX = prevCanvasY = null; + } else { + nextCanvasY = iter.hasNext() ? iter.peek().canvasy : null; + // TODO: we calculate isNullOrNaN for this point, and the next, and then, when + // we iterate, test for isNullOrNaN again. Why bother? + var isNextCanvasYNullOrNaN = nextCanvasY === null || nextCanvasY != nextCanvasY; + isIsolated = (!prevCanvasX && isNextCanvasYNullOrNaN); + if (drawGapPoints) { + // Also consider a point to be "isolated" if it's adjacent to a + // null point, excluding the graph edges. + if ((!first && !prevCanvasX) || + (iter.hasNext() && isNextCanvasYNullOrNaN)) { + isIsolated = true; + } + } + if (prevCanvasX !== null) { + if (strategy.skipPixel(prevCanvasX, prevCanvasY, point.canvasx, point.canvasy)) { + continue; + } + if (strokeWidth) { + strategy.startSegment(); + if (stepPlot) { + strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, prevCanvasY); + prevCanvasX = point.canvasx; + } + strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, point.canvasy); + strategy.endSegment(); + } + } + if (drawPoints || isIsolated) { + pointsOnLine.push([point.canvasx, point.canvasy]); + } + prevCanvasX = point.canvasx; + prevCanvasY = point.canvasy; + } + first = false; + } + strategy.finish(); + return pointsOnLine; +}; + +DygraphCanvasRenderer.prototype._drawLine = function(ctx, i) { + var setNames = this.layout.setNames; + var setName = setNames[i]; + + var strokeWidth = this.dygraph_.attr_("strokeWidth", setName); + var borderWidth = this.dygraph_.attr_("strokeBorderWidth", setName); + var drawPointCallback = this.dygraph_.attr_("drawPointCallback", setName) || + Dygraph.Circles.DEFAULT; + + if (borderWidth && strokeWidth) { + this._drawStyledLine(ctx, i, setName, + this.dygraph_.attr_("strokeBorderColor", setName), + strokeWidth + 2 * borderWidth, + this.dygraph_.attr_("strokePattern", setName), + this.dygraph_.attr_("drawPoints", setName), + drawPointCallback, + this.dygraph_.attr_("pointSize", setName)); + } + + this._drawStyledLine(ctx, i, setName, + this.colors[setName], + strokeWidth, + this.dygraph_.attr_("strokePattern", setName), + this.dygraph_.attr_("drawPoints", setName), + drawPointCallback, + this.dygraph_.attr_("pointSize", setName)); +}; /** * Actually draw the lines chart, including error bars. @@ -664,12 +780,8 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() { * @private */ DygraphCanvasRenderer.prototype._renderLineChart = function() { - var isNullOrNaN = function(x) { - return (x === null || isNaN(x)); - }; - // TODO(danvk): use this.attr_ for many of these. - var context = this.elementContext; + var ctx = this.elementContext; var fillAlpha = this.attr_('fillAlpha'); var errorBars = this.attr_("errorBars") || this.attr_("customBars"); var fillGraph = this.attr_("fillGraph"); @@ -677,24 +789,23 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { var stepPlot = this.attr_("stepPlot"); var points = this.layout.points; var pointsLength = points.length; - var point, i, j, prevX, prevY, prevYs, color, setName, newYs, err_color, rgb, yscale, axis; + var point, i, prevX, prevY, prevYs, color, setName, newYs, err_color, rgb, yscale, axis; - var setNames = []; - for (var name in this.layout.datasets) { - if (this.layout.datasets.hasOwnProperty(name)) { - setNames.push(name); - } - } + var setNames = this.layout.setNames; var setCount = setNames.length; // TODO(danvk): Move this mapping into Dygraph and get it out of here. - this.colors = {}; - for (i = 0; i < setCount; i++) { - this.colors[setNames[i]] = this.colorScheme_[i % this.colorScheme_.length]; - } + this.colors = this.dygraph_.colorsMap_; + // for (i = 0; i < setCount; i++) { + // this.colors[setNames[i]] = this.colorScheme_[i % this.colorScheme_.length]; + // } // Update Points // TODO(danvk): here + // + // TODO(bhs): this loop is a hot-spot for high-point-count charts. These + // transformations can be pushed into the canvas via linear transformation + // matrices. for (i = pointsLength; i--;) { point = points[i]; point.canvasx = this.area.w * point.x + this.area.x; @@ -702,8 +813,8 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { } // create paths - var ctx = context; if (errorBars) { + ctx.save(); if (fillGraph) { this.dygraph_.warn("Can't use fillGraph option with error bars"); } @@ -713,8 +824,13 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { axis = this.dygraph_.axisPropertiesForSeries(setName); color = this.colors[setName]; + var firstIndexInSet = this.layout.setPointsOffsets[i]; + var setLength = this.layout.setPointsLengths[i]; + + var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, + DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); + // setup graphics context - ctx.save(); prevX = NaN; prevY = NaN; prevYs = [-1, -1]; @@ -725,9 +841,9 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { fillAlpha + ')'; ctx.fillStyle = err_color; ctx.beginPath(); - for (j = 0; j < pointsLength; j++) { - point = points[j]; - if (point.name == setName) { + while (iter.hasNext()) { + point = iter.next(); + if (point.name == setName) { // TODO(klausw): this is always true if (!Dygraph.isOK(point.y)) { prevX = NaN; continue; @@ -763,8 +879,11 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { } ctx.fill(); } + ctx.restore(); } else if (fillGraph) { - var baseline = []; // for stacked graphs: baseline for filling + ctx.save(); + var baseline = {}; // for stacked graphs: baseline for filling + var currBaseline; // process sets in reverse order (needed for stacked graphs) for (i = setCount - 1; i >= 0; i--) { @@ -775,9 +894,13 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { if (axisY < 0.0) axisY = 0.0; else if (axisY > 1.0) axisY = 1.0; axisY = this.area.h * axisY + this.area.y; + var firstIndexInSet = this.layout.setPointsOffsets[i]; + var setLength = this.layout.setPointsLengths[i]; + + var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, + DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); // setup graphics context - ctx.save(); prevX = NaN; prevYs = [-1, -1]; yscale = axis.yscale; @@ -787,29 +910,58 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { fillAlpha + ')'; ctx.fillStyle = err_color; ctx.beginPath(); - for (j = 0; j < pointsLength; j++) { - point = points[j]; - if (point.name == setName) { + while(iter.hasNext()) { + point = iter.next(); + if (point.name == setName) { // TODO(klausw): this is always true if (!Dygraph.isOK(point.y)) { prevX = NaN; continue; } if (stackedGraph) { - var lastY = baseline[point.canvasx]; - if (lastY === undefined) lastY = axisY; - baseline[point.canvasx] = point.canvasy; + currBaseline = baseline[point.canvasx]; + var lastY; + if (currBaseline === undefined) { + lastY = axisY; + } else { + if(stepPlot) { + lastY = currBaseline[0]; + } else { + lastY = currBaseline; + } + } newYs = [ point.canvasy, lastY ]; + + if(stepPlot) { + // Step plots must keep track of the top and bottom of + // the baseline at each point. + if(prevYs[0] === -1) { + baseline[point.canvasx] = [ point.canvasy, axisY ]; + } else { + baseline[point.canvasx] = [ point.canvasy, prevYs[0] ]; + } + } else { + baseline[point.canvasx] = point.canvasy; + } + } else { newYs = [ point.canvasy, axisY ]; } if (!isNaN(prevX)) { ctx.moveTo(prevX, prevYs[0]); + if (stepPlot) { ctx.lineTo(point.canvasx, prevYs[0]); + if(currBaseline) { + // Draw to the bottom of the baseline + ctx.lineTo(point.canvasx, currBaseline[1]); + } else { + ctx.lineTo(point.canvasx, newYs[1]); + } } else { ctx.lineTo(point.canvasx, newYs[0]); + ctx.lineTo(point.canvasx, newYs[1]); } - ctx.lineTo(point.canvasx, newYs[1]); + ctx.lineTo(prevX, prevYs[1]); ctx.closePath(); } @@ -819,82 +971,102 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() { } ctx.fill(); } + ctx.restore(); } // Drawing the lines. - var firstIndexInSet = 0; - var afterLastIndexInSet = 0; - var setLength = 0; for (i = 0; i < setCount; i += 1) { - setLength = this.layout.setPointsLengths[i]; - afterLastIndexInSet += setLength; - setName = setNames[i]; - color = this.colors[setName]; - var strokeWidth = this.dygraph_.attr_("strokeWidth", setName); - - // setup graphics context - context.save(); - var pointSize = this.dygraph_.attr_("pointSize", setName); - prevX = null; - prevY = null; - var drawPoints = this.dygraph_.attr_("drawPoints", setName); - for (j = firstIndexInSet; j < afterLastIndexInSet; j++) { - point = points[j]; - if (isNullOrNaN(point.canvasy)) { - if (stepPlot && prevX !== null) { - // Draw a horizontal line to the start of the missing data - ctx.beginPath(); - ctx.strokeStyle = color; - ctx.lineWidth = this.attr_('strokeWidth'); - ctx.moveTo(prevX, prevY); - ctx.lineTo(point.canvasx, prevY); - ctx.stroke(); - } - // this will make us move to the next point, not draw a line to it. - prevX = prevY = null; - } else { - // A point is "isolated" if it is non-null but both the previous - // and next points are null. - var isIsolated = (!prevX && (j == points.length - 1 || - isNullOrNaN(points[j+1].canvasy))); - if (prevX === null) { - prevX = point.canvasx; - prevY = point.canvasy; - } else { - // Skip over points that will be drawn in the same pixel. - if (Math.round(prevX) == Math.round(point.canvasx) && - Math.round(prevY) == Math.round(point.canvasy)) { - continue; - } - // TODO(antrob): skip over points that lie on a line that is already - // going to be drawn. There is no need to have more than 2 - // consecutive points that are collinear. - if (strokeWidth) { - ctx.beginPath(); - ctx.strokeStyle = color; - ctx.lineWidth = strokeWidth; - ctx.moveTo(prevX, prevY); - if (stepPlot) { - ctx.lineTo(point.canvasx, prevY); - } - prevX = point.canvasx; - prevY = point.canvasy; - ctx.lineTo(prevX, prevY); - ctx.stroke(); - } - } + this._drawLine(ctx, i); + } +}; - if (drawPoints || isIsolated) { - ctx.beginPath(); - ctx.fillStyle = color; - ctx.arc(point.canvasx, point.canvasy, pointSize, - 0, 2 * Math.PI, false); - ctx.fill(); - } - } - } - firstIndexInSet = afterLastIndexInSet; +/** + * This does dashed lines onto a canvas for a given pattern. You must call + * ctx.stroke() after to actually draw it, much line ctx.lineTo(). It remembers + * the state of the line in regards to where we left off on drawing the pattern. + * You can draw a dashed line in several function calls and the pattern will be + * continous as long as you didn't call this function with a different pattern + * in between. + * @param ctx The canvas 2d context to draw on. + * @param x The start of the line's x coordinate. + * @param y The start of the line's y coordinate. + * @param x2 The end of the line's x coordinate. + * @param y2 The end of the line's y coordinate. + * @param pattern The dash pattern to draw, an array of integers where even + * index is drawn and odd index is not drawn (Ex. [10, 2, 5, 2], 10 is drawn 5 + * is drawn, 2 is the space between.). A null pattern, array of length one, or + * empty array will do just a solid line. + * @private + */ +DygraphCanvasRenderer.prototype._dashedLine = function(ctx, x, y, x2, y2, pattern) { + // Original version http://stackoverflow.com/questions/4576724/dotted-stroke-in-canvas + // Modified by Russell Valentine to keep line history and continue the pattern + // where it left off. + var dx, dy, len, rot, patternIndex, segment; + + // If we don't have a pattern or it is an empty array or of size one just + // do a solid line. + if (!pattern || pattern.length <= 1) { + ctx.moveTo(x, y); + ctx.lineTo(x2, y2); + return; } - context.restore(); + // If we have a different dash pattern than the last time this was called we + // reset our dash history and start the pattern from the begging + // regardless of state of the last pattern. + if (!Dygraph.compareArrays(pattern, this._dashedLineToHistoryPattern)) { + this._dashedLineToHistoryPattern = pattern; + this._dashedLineToHistory = [0, 0]; + } + ctx.save(); + + // Calculate transformation parameters + dx = (x2-x); + dy = (y2-y); + len = Math.sqrt(dx*dx + dy*dy); + rot = Math.atan2(dy, dx); + + // Set transformation + ctx.translate(x, y); + ctx.moveTo(0, 0); + ctx.rotate(rot); + + // Set last pattern index we used for this pattern. + patternIndex = this._dashedLineToHistory[0]; + x = 0; + while (len > x) { + // Get the length of the pattern segment we are dealing with. + segment = pattern[patternIndex]; + // If our last draw didn't complete the pattern segment all the way we + // will try to finish it. Otherwise we will try to do the whole segment. + if (this._dashedLineToHistory[1]) { + x += this._dashedLineToHistory[1]; + } else { + x += segment; + } + if (x > len) { + // We were unable to complete this pattern index all the way, keep + // where we are the history so our next draw continues where we left off + // in the pattern. + this._dashedLineToHistory = [patternIndex, x-len]; + x = len; + } else { + // We completed this patternIndex, we put in the history that we are on + // the beginning of the next segment. + this._dashedLineToHistory = [(patternIndex+1)%pattern.length, 0]; + } + + // We do a line on a even pattern index and just move on a odd pattern index. + // The move is the empty space in the dash. + if(patternIndex % 2 === 0) { + ctx.lineTo(x, 0); + } else { + ctx.moveTo(x, 0); + } + // If we are not done, next loop process the next pattern segment, or the + // first segment again if we are at the end of the pattern. + patternIndex = (patternIndex+1) % pattern.length; + } + ctx.restore(); };