/**
* Creates a new DygraphLayout object.
- * @param {Object} options Options for PlotKit.Layout
* @return {Object} The DygraphLayout object
*/
-DygraphLayout = function(dygraph, options) {
+DygraphLayout = function(dygraph) {
this.dygraph_ = dygraph;
- this.options = {}; // TODO(danvk): remove, use attr_ instead.
- Dygraph.update(this.options, options ? options : {});
this.datasets = new Array();
this.annotations = new Array();
+ this.yAxes_ = null;
+
+ // TODO(danvk): it's odd that xTicks_ and yTicks_ are inputs, but xticks and
+ // yticks are outputs. Clean this up.
+ this.xTicks_ = null;
+ this.yTicks_ = null;
};
DygraphLayout.prototype.attr_ = function(name) {
}
};
+DygraphLayout.prototype.setXTicks = function(xTicks) {
+ this.xTicks_ = xTicks;
+};
+
+// TODO(danvk): add this to the Dygraph object's API or move it into Layout.
+DygraphLayout.prototype.setYAxes = function (yAxes) {
+ this.yAxes_ = yAxes;
+};
+
+DygraphLayout.prototype.setDateWindow = function(dateWindow) {
+ this.dateWindow_ = dateWindow;
+};
+
DygraphLayout.prototype.evaluate = function() {
this._evaluateLimits();
this._evaluateLineCharts();
DygraphLayout.prototype._evaluateLimits = function() {
this.minxval = this.maxxval = null;
- if (this.options.dateWindow) {
- this.minxval = this.options.dateWindow[0];
- this.maxxval = this.options.dateWindow[1];
+ if (this.dateWindow_) {
+ this.minxval = this.dateWindow_[0];
+ this.maxxval = this.dateWindow_[1];
} else {
for (var name in this.datasets) {
if (!this.datasets.hasOwnProperty(name)) continue;
this.xrange = this.maxxval - this.minxval;
this.xscale = (this.xrange != 0 ? 1/this.xrange : 1.0);
- for (var i = 0; i < this.options.yAxes.length; i++) {
- var axis = this.options.yAxes[i];
+ for (var i = 0; i < this.yAxes_.length; i++) {
+ var axis = this.yAxes_[i];
axis.minyval = axis.computedValueRange[0];
axis.maxyval = axis.computedValueRange[1];
axis.yrange = axis.maxyval - axis.minyval;
if (!this.datasets.hasOwnProperty(setName)) continue;
var dataset = this.datasets[setName];
- var axis = this.options.yAxes[this.options.seriesToAxisMap[setName]];
+ var axis = this.dygraph_.axisPropertiesForSeries(setName);
for (var j = 0; j < dataset.length; j++) {
var item = dataset[j];
DygraphLayout.prototype._evaluateLineTicks = function() {
this.xticks = new Array();
- for (var i = 0; i < this.options.xTicks.length; i++) {
- var tick = this.options.xTicks[i];
+ for (var i = 0; i < this.xTicks_.length; i++) {
+ var tick = this.xTicks_[i];
var label = tick.label;
var pos = this.xscale * (tick.v - this.minxval);
if ((pos >= 0.0) && (pos <= 1.0)) {
}
this.yticks = new Array();
- for (var i = 0; i < this.options.yAxes.length; i++ ) {
- var axis = this.options.yAxes[i];
+ for (var i = 0; i < this.yAxes_.length; i++ ) {
+ var axis = this.yAxes_[i];
for (var j = 0; j < axis.ticks.length; j++) {
var tick = axis.ticks[j];
var label = tick.label;
*/
DygraphLayout.prototype.evaluateWithError = function() {
this.evaluate();
- if (!this.options.errorBars) return;
+ if (!(this.attr_('errorBars') || this.attr_('customBars'))) return;
// Copy over the error terms
var i = 0; // index in this.points
};
/**
- * Change the values of various layout options
- * @param {Object} new_options an associative array of new properties
- */
-DygraphLayout.prototype.updateOptions = function(new_options) {
- Dygraph.update(this.options, new_options ? new_options : {});
-};
-
-/**
* Return a copy of the point at the indicated index, with its yval unstacked.
* @param int index of point in layout_.points
*/
return unstackedPoint;
}
-// Subclass PlotKit.CanvasRenderer to add:
-// 1. X/Y grid overlay
-// 2. Ability to draw error bars (if required)
-
/**
- * Sets some PlotKit.CanvasRenderer options
+ * The DygraphCanvasRenderer class does the actual rendering of the chart onto
+ * a canvas. It's based on PlotKit.CanvasRenderer.
* @param {Object} element The canvas to attach to
+ * @param {Object} elementContext The 2d context of the canvas (injected so it
+ * can be mocked for testing.)
* @param {Layout} layout The DygraphLayout object for this graph.
- * @param {Object} options Options to pass on to CanvasRenderer
*/
-DygraphCanvasRenderer = function(dygraph, element, layout, options) {
- // TODO(danvk): remove options, just use dygraph.attr_.
+DygraphCanvasRenderer = function(dygraph, element, elementContext, layout) {
this.dygraph_ = dygraph;
- // default options
- this.options = {
- "strokeWidth": 0.5,
- "drawXAxis": true,
- "drawYAxis": true,
- "axisLineColor": "black",
- "axisLineWidth": 0.5,
- "axisTickSize": 3,
- "axisLabelColor": "black",
- "axisLabelFont": "Arial",
- "axisLabelFontSize": 9,
- "axisLabelWidth": 50,
- "drawYGrid": true,
- "drawXGrid": true,
- "gridLineColor": "rgb(128,128,128)",
- "fillAlpha": 0.15,
- "underlayCallback": null
- };
- Dygraph.update(this.options, options);
-
this.layout = layout;
this.element = element;
+ this.elementContext = elementContext;
this.container = this.element.parentNode;
this.height = this.element.height;
this.annotations = new Array();
this.chartLabels = {};
- // TODO(danvk): consider all axes in this computation.
- this.area = {
+ this.area = this.computeArea_();
+ this.container.style.position = "relative";
+ this.container.style.width = this.width + "px";
+
+ // Set up a clipping area for the canvas (and the interaction canvas).
+ // This ensures that we don't overdraw.
+ var ctx = this.dygraph_.canvas_ctx_;
+ ctx.beginPath();
+ ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h);
+ ctx.clip();
+
+ ctx = this.dygraph_.hidden_ctx_;
+ ctx.beginPath();
+ ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h);
+ ctx.clip();
+};
+
+DygraphCanvasRenderer.prototype.attr_ = function(x) {
+ return this.dygraph_.attr_(x);
+};
+
+// Compute the box which the chart should be drawn in. This is the canvas's
+// box, less space needed for axis and chart labels.
+// TODO(danvk): this belongs in DygraphLayout.
+DygraphCanvasRenderer.prototype.computeArea_ = function() {
+ var area = {
// TODO(danvk): per-axis setting.
- x: this.options.yAxisLabelWidth + 2 * this.options.axisTickSize,
+ x: 0,
y: 0
};
- this.area.w = this.width - this.area.x - this.options.rightGap;
- this.area.h = this.height - this.options.axisLabelFontSize -
- 2 * this.options.axisTickSize;
+ if (this.attr_('drawYAxis')) {
+ area.x = this.attr_('yAxisLabelWidth') + 2 * this.attr_('axisTickSize');
+ }
+
+ area.w = this.width - area.x - this.attr_('rightGap');
+ area.h = this.height;
+ if (this.attr_('drawXAxis')) {
+ if (this.attr_('xAxisHeight')) {
+ area.h -= this.attr_('xAxisHeight');
+ } else {
+ area.h -= this.attr_('axisLabelFontSize') + 2 * this.attr_('axisTickSize');
+ }
+ }
// Shrink the drawing area to accomodate additional y-axes.
if (this.dygraph_.numAxes() == 2) {
// TODO(danvk): per-axis setting.
- this.area.w -= (this.options.yAxisLabelWidth + 2 * this.options.axisTickSize);
+ area.w -= (this.attr_('yAxisLabelWidth') + 2 * this.attr_('axisTickSize'));
} else if (this.dygraph_.numAxes() > 2) {
this.dygraph_.error("Only two y-axes are supported at this time. (Trying " +
"to use " + this.dygraph_.numAxes() + ")");
// Add space for chart labels: title, xlabel and ylabel.
if (this.attr_('title')) {
- // TODO(danvk): make this a parameter
- this.area.h -= this.attr_('titleHeight');
- this.area.y += this.attr_('titleHeight');
+ area.h -= this.attr_('titleHeight');
+ area.y += this.attr_('titleHeight');
}
if (this.attr_('xlabel')) {
- // TODO(danvk): make this a parameter
- this.area.h -= this.attr_('xLabelHeight');
+ area.h -= this.attr_('xLabelHeight');
}
if (this.attr_('ylabel')) {
- var yLabelWidth = 16;
- this.area.x += this.attr_('yLabelWidth');
- this.area.w -= this.attr_('yLabelWidth');
+ // It would make sense to shift the chart here to make room for the y-axis
+ // label, but the default yAxisLabelWidth is large enough that this results
+ // in overly-padded charts. The y-axis label should fit fine. If it
+ // doesn't, the yAxisLabelWidth option can be increased.
}
- this.container.style.position = "relative";
- this.container.style.width = this.width + "px";
-
- // Set up a clipping area for the canvas (and the interaction canvas).
- // This ensures that we don't overdraw.
- var ctx = this.dygraph_.canvas_.getContext("2d");
- ctx.beginPath();
- ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h);
- ctx.clip();
-
- ctx = this.dygraph_.hidden_.getContext("2d");
- ctx.beginPath();
- ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h);
- ctx.clip();
-};
-
-DygraphCanvasRenderer.prototype.attr_ = function(x) {
- return this.dygraph_.attr_(x);
+ return area;
};
DygraphCanvasRenderer.prototype.clear = function() {
this.clearDelay.cancel();
this.clearDelay = null;
}
- var context = this.element.getContext("2d");
+ var context = this.elementContext;
}
catch (e) {
// TODO(danvk): this is broken, since MochiKit.Async is gone.
}
}
- var context = this.element.getContext("2d");
+ var context = this.elementContext;
context.clearRect(0, 0, this.width, this.height);
for (var i = 0; i < this.xlabels.length; i++) {
};
/**
+ * @param { [String] } colors Array of color strings. Should have one entry for
+ * each series to be rendered.
+ */
+DygraphCanvasRenderer.prototype.setColors = function(colors) {
+ this.colorScheme_ = colors;
+};
+
+/**
* Draw an X/Y grid on top of the existing plot
*/
DygraphCanvasRenderer.prototype.render = function() {
// Draw the new X/Y grid. Lines appear crisper when pixels are rounded to
// half-integers. This prevents them from drawing in two rows/cols.
- var ctx = this.element.getContext("2d");
+ var ctx = this.elementContext;
function halfUp(x){return Math.round(x)+0.5};
function halfDown(y){return Math.round(y)-0.5};
- if (this.options.underlayCallback) {
+ if (this.attr_('underlayCallback')) {
// NOTE: we pass the dygraph object to this callback twice to avoid breaking
// users who expect a deprecated form of this callback.
- this.options.underlayCallback(ctx, this.area, this.dygraph_, this.dygraph_);
+ this.attr_('underlayCallback')(ctx, this.area, this.dygraph_, this.dygraph_);
}
- if (this.options.drawYGrid) {
+ if (this.attr_('drawYGrid')) {
var ticks = this.layout.yticks;
ctx.save();
- ctx.strokeStyle = this.options.gridLineColor;
- ctx.lineWidth = this.options.axisLineWidth;
+ ctx.strokeStyle = this.attr_('gridLineColor');
+ ctx.lineWidth = this.attr_('gridLineWidth');
for (var i = 0; i < ticks.length; i++) {
// TODO(danvk): allow secondary axes to draw a grid, too.
if (ticks[i][0] != 0) continue;
}
}
- if (this.options.drawXGrid) {
+ if (this.attr_('drawXGrid')) {
var ticks = this.layout.xticks;
ctx.save();
- ctx.strokeStyle = this.options.gridLineColor;
- ctx.lineWidth = this.options.axisLineWidth;
+ ctx.strokeStyle = this.attr_('gridLineColor');
+ ctx.lineWidth = this.attr_('gridLineWidth');
for (var i=0; i<ticks.length; i++) {
var x = halfUp(this.area.x + ticks[i][0] * this.area.w);
var y = halfDown(this.area.y + this.area.h);
DygraphCanvasRenderer.prototype._renderAxis = function() {
- if (!this.options.drawXAxis && !this.options.drawYAxis)
- return;
+ if (!this.attr_('drawXAxis') && !this.attr_('drawYAxis')) return;
// Round pixels to half-integer boundaries for crisper drawing.
function halfUp(x){return Math.round(x)+0.5};
function halfDown(y){return Math.round(y)-0.5};
- var context = this.element.getContext("2d");
+ var context = this.elementContext;
var labelStyle = {
- "position": "absolute",
- "fontSize": this.options.axisLabelFontSize + "px",
- "zIndex": 10,
- "color": this.options.axisLabelColor,
- "width": this.options.axisLabelWidth + "px",
- "overflow": "hidden"
+ position: "absolute",
+ fontSize: this.attr_('axisLabelFontSize') + "px",
+ zIndex: 10,
+ color: this.attr_('axisLabelColor'),
+ width: this.attr_('axisLabelWidth') + "px",
+ overflow: "hidden"
};
- var makeDiv = function(txt) {
+ var makeDiv = function(txt, axis) {
var div = document.createElement("div");
for (var name in labelStyle) {
if (labelStyle.hasOwnProperty(name)) {
div.style[name] = labelStyle[name];
}
}
- div.appendChild(document.createTextNode(txt));
+ var inner_div = document.createElement("div");
+ // TODO(danvk): separate class for secondary y-axis
+ inner_div.className = 'dygraph-axis-label dygraph-axis-label-' + axis;
+ inner_div.appendChild(document.createTextNode(txt));
+ div.appendChild(inner_div);
return div;
};
// axis lines
context.save();
- context.strokeStyle = this.options.axisLineColor;
- context.lineWidth = this.options.axisLineWidth;
+ context.strokeStyle = this.attr_('axisLineColor');
+ context.lineWidth = this.attr_('axisLineWidth');
- if (this.options.drawYAxis) {
+ if (this.attr_('drawYAxis')) {
if (this.layout.yticks && this.layout.yticks.length > 0) {
for (var i = 0; i < this.layout.yticks.length; i++) {
var tick = this.layout.yticks[i];
var y = this.area.y + tick[1] * this.area.h;
context.beginPath();
context.moveTo(halfUp(x), halfDown(y));
- context.lineTo(halfUp(x - sgn * this.options.axisTickSize), halfDown(y));
+ context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y));
context.closePath();
context.stroke();
- var label = makeDiv(tick[2]);
- var top = (y - this.options.axisLabelFontSize / 2);
+ var label = makeDiv(tick[2], 'y');
+ var top = (y - this.attr_('axisLabelFontSize') / 2);
if (top < 0) top = 0;
- if (top + this.options.axisLabelFontSize + 3 > this.height) {
+ if (top + this.attr_('axisLabelFontSize') + 3 > this.height) {
label.style.bottom = "0px";
} else {
label.style.top = top + "px";
}
if (tick[0] == 0) {
- label.style.left = (this.area.x - this.options.yAxisLabelWidth - this.options.axisTickSize) + "px";
+ label.style.left = (this.area.x - this.attr_('yAxisLabelWidth') - this.attr_('axisTickSize')) + "px";
label.style.textAlign = "right";
} else if (tick[0] == 1) {
label.style.left = (this.area.x + this.area.w +
- this.options.axisTickSize) + "px";
+ this.attr_('axisTickSize')) + "px";
label.style.textAlign = "left";
}
- label.style.width = this.options.yAxisLabelWidth + "px";
+ label.style.width = this.attr_('yAxisLabelWidth') + "px";
this.container.appendChild(label);
this.ylabels.push(label);
}
// tick on the x-axis. Shift the bottom tick up a little bit to
// compensate if necessary.
var bottomTick = this.ylabels[0];
- var fontSize = this.options.axisLabelFontSize;
+ var fontSize = this.attr_('axisLabelFontSize');
var bottom = parseInt(bottomTick.style.top) + fontSize;
if (bottom > this.height - fontSize) {
bottomTick.style.top = (parseInt(bottomTick.style.top) -
}
}
- if (this.options.drawXAxis) {
+ if (this.attr_('drawXAxis')) {
if (this.layout.xticks) {
for (var i = 0; i < this.layout.xticks.length; i++) {
var tick = this.layout.xticks[i];
var y = this.area.y + this.area.h;
context.beginPath();
context.moveTo(halfUp(x), halfDown(y));
- context.lineTo(halfUp(x), halfDown(y + this.options.axisTickSize));
+ context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize')));
context.closePath();
context.stroke();
- var label = makeDiv(tick[1]);
+ var label = makeDiv(tick[1], 'x');
label.style.textAlign = "center";
- label.style.top = (y + this.options.axisTickSize) + 'px';
+ label.style.top = (y + this.attr_('axisTickSize')) + 'px';
- var left = (x - this.options.axisLabelWidth/2);
- if (left + this.options.axisLabelWidth > this.width) {
- left = this.width - this.options.xAxisLabelWidth;
+ var left = (x - this.attr_('axisLabelWidth')/2);
+ if (left + this.attr_('axisLabelWidth') > this.width) {
+ left = this.width - this.attr_('xAxisLabelWidth');
label.style.textAlign = "right";
}
if (left < 0) {
}
label.style.left = left + "px";
- label.style.width = this.options.xAxisLabelWidth + "px";
+ label.style.width = this.attr_('xAxisLabelWidth') + "px";
this.container.appendChild(label);
this.xlabels.push(label);
}
div.style.width = this.area.w + 'px';
div.style.height = this.attr_('titleHeight') + 'px';
div.style.textAlign = 'center';
- div.style.fontSize = (this.attr_('titleHeight') - 2) + 'px';
+ div.style.fontSize = (this.attr_('titleHeight') - 8) + 'px';
div.style.fontWeight = 'bold';
- // div.style.border = '1px solid black';
- div.innerHTML = this.attr_('title');
+ var 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;
}
div.style.height = this.attr_('xLabelHeight') + 'px';
div.style.textAlign = 'center';
div.style.fontSize = (this.attr_('xLabelHeight') - 2) + 'px';
- // div.style.border = '1px solid black';
- div.innerHTML = this.attr_('xlabel');
+
+ var 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;
}
width: this.attr_('yLabelWidth'),
height: this.area.h
};
+ // TODO(danvk): is this outer div actually necessary?
var div = document.createElement("div");
div.style.position = 'absolute';
div.style.left = box.left;
div.style.width = box.width + 'px';
div.style.height = box.height + 'px';
div.style.fontSize = (this.attr_('yLabelWidth') - 2) + 'px';
- // div.style.border = '1px solid black';
var inner_div = document.createElement("div");
inner_div.style.position = 'absolute';
- // inner_div.style.border = '1px solid red';
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.
inner_div.style.transform = 'rotate(-90deg)'; // HTML5
inner_div.style.WebkitTransform = 'rotate(-90deg)'; // Safari/Chrome
inner_div.style.MozTransform = 'rotate(-90deg)'; // Firefox
inner_div.style.OTransform = 'rotate(-90deg)'; // Opera
- inner_div.style.filter =
- 'progid:DXImageTransform.Microsoft.BasicImage(rotation=3)';
- inner_div.innerHTML = this.attr_('ylabel');
+ inner_div.style.msTransform = 'rotate(-90deg)'; // 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=3)';
+ inner_div.style.left = '0px';
+ inner_div.style.top = '0px';
+ }
+
+ var class_div = document.createElement("div");
+ class_div.className = 'dygraph-label dygraph-ylabel';
+ class_div.innerHTML = this.attr_('ylabel');
+ inner_div.appendChild(class_div);
div.appendChild(inner_div);
this.container.appendChild(div);
this.chartLabels.ylabel = div;
DygraphCanvasRenderer.prototype._renderAnnotations = function() {
var annotationStyle = {
"position": "absolute",
- "fontSize": this.options.axisLabelFontSize + "px",
+ "fontSize": this.attr_('axisLabelFontSize') + "px",
"zIndex": 10,
"overflow": "hidden"
};
this.container.appendChild(div);
this.annotations.push(div);
- var ctx = this.element.getContext("2d");
+ var ctx = this.elementContext;
ctx.strokeStyle = this.colors[p.name];
ctx.beginPath();
if (!a.attachAtBottom) {
*/
DygraphCanvasRenderer.prototype._renderLineChart = function() {
// TODO(danvk): use this.attr_ for many of these.
- var context = this.element.getContext("2d");
- var colorCount = this.options.colorScheme.length;
- var colorScheme = this.options.colorScheme;
- var fillAlpha = this.options.fillAlpha;
- var errorBars = this.layout.options.errorBars;
+ var context = this.elementContext;
+ var fillAlpha = this.attr_('fillAlpha');
+ var errorBars = this.attr_("errorBars") || this.attr_("customBars");
var fillGraph = this.attr_("fillGraph");
- var stackedGraph = this.layout.options.stackedGraph;
- var stepPlot = this.layout.options.stepPlot;
+ var stackedGraph = this.attr_("stackedGraph");
+ var stepPlot = this.attr_("stepPlot");
var setNames = [];
for (var name in this.layout.datasets) {
}
var setCount = setNames.length;
+ // TODO(danvk): Move this mapping into Dygraph and get it out of here.
this.colors = {}
for (var i = 0; i < setCount; i++) {
- this.colors[setNames[i]] = colorScheme[i % colorCount];
+ this.colors[setNames[i]] = this.colorScheme_[i % this.colorScheme_.length];
}
// Update Points
for (var i = 0; i < setCount; i++) {
var setName = setNames[i];
- var axis = this.layout.options.yAxes[
- this.layout.options.seriesToAxisMap[setName]];
+ var axis = this.dygraph_.axisPropertiesForSeries(setName);
var color = this.colors[setName];
// setup graphics context
for (var i = setCount - 1; i >= 0; i--) {
var setName = setNames[i];
var color = this.colors[setName];
- var axis = this.layout.options.yAxes[
- this.layout.options.seriesToAxisMap[setName]];
+ var axis = this.dygraph_.axisPropertiesForSeries(setName);
var axisY = 1.0 + axis.minyval * axis.yscale;
if (axisY < 0.0) axisY = 0.0;
else if (axisY > 1.0) axisY = 1.0;
}
}
+ var isNullOrNaN = function(x) {
+ return (x === null || isNaN(x));
+ };
+
for (var i = 0; i < setCount; i++) {
var setName = setNames[i];
var color = this.colors[setName];
for (var j = 0; j < points.length; j++) {
var point = points[j];
if (point.name == setName) {
- if (!Dygraph.isOK(point.canvasy)) {
+ 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.options.strokeWidth;
+ ctx.lineWidth = this.attr_('strokeWidth');
ctx.moveTo(prevX, prevY);
ctx.lineTo(point.canvasx, prevY);
ctx.stroke();
// 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 ||
- !Dygraph.isOK(points[j+1].canvasy)));
+ isNullOrNaN(points[j+1].canvasy)));
- if (!prevX) {
+ if (prevX === null) {
prevX = point.canvasx;
prevY = point.canvasy;
} else {