/*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;
this.xlabels = [];
this.ylabels = [];
this.annotations = [];
- this.chartLabels = {};
this.area = layout.getPlotArea();
this.container.style.position = "relative";
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) {
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 {
};
/**
- * 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
ctx.closePath();
ctx.stroke();
}
+ ctx.restore();
}
if (this.attr_('drawXGrid')) {
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() {
}
// 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();
}
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();
}
};
-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",
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;
}
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);
}
};
+/**
+ * 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.
* @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");
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;
}
// create paths
- var ctx = context;
if (errorBars) {
+ ctx.save();
if (fillGraph) {
this.dygraph_.warn("Can't use fillGraph option with error bars");
}
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];
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;
}
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--) {
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;
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();
}
}
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();
};
projects / dygraphs.git / blobdiff