}
};
-DygraphCanvasRenderer.makeNextPointStep_ = function(
- connect, points, start, end) {
- if (connect) {
- return function(j) {
- while (++j + start < end) {
- if (!(points[start + j].yval === null)) break;
- }
- return j;
- }
- } else {
- return function(j) { return j + 1 };
- }
-};
+/**
+ * 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) {
- var isNullOrNaN = function(x) {
- return (x === null || isNaN(x));
- };
-
+ // 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 afterLastIndexInSet = firstIndexInSet + setLength;
var points = this.layout.points;
- var prevX = null;
- var prevY = null;
- var nextY = null;
- var pointsOnLine = []; // Array of [canvasx, canvasy] pairs.
if (!Dygraph.isArrayLike(strokePattern)) {
strokePattern = null;
}
var drawGapPoints = this.dygraph_.attr_('drawGapEdgePoints', setName);
- var point, nextPoint;
- var next = DygraphCanvasRenderer.makeNextPointStep_(
- this.attr_('connectSeparatedPoints'), points, firstIndexInSet,
- afterLastIndexInSet);
ctx.save();
- for (var j = 0; j < setLength; j = next(j)) {
- point = points[firstIndexInSet + j];
- nextY = (next(j) < setLength) ?
- points[firstIndexInSet + next(j)].canvasy : null;
- if (isNullOrNaN(point.canvasy)) {
- if (stepPlot && prevX !== null) {
+
+ 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
- ctx.beginPath();
- ctx.strokeStyle = color;
- ctx.lineWidth = this.attr_('strokeWidth');
- this._dashedLine(ctx, prevX, prevY, point.canvasx, prevY, strokePattern);
- ctx.stroke();
+ strategy.startSegment();
+ strategy.drawLine(prevX, prevY, point.canvasx, prevY);
+ strategy.endSegment();
}
- // this will make us move to the next point, not draw a line to it.
- prevX = prevY = null;
+ prevCanvasX = prevCanvasY = null;
} else {
- // A point is "isolated" if it is non-null but both the previous
- // and next points are null.
- var isIsolated = (!prevX && isNullOrNaN(nextY));
+ 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 is "isolated" if it's adjacent to a
+ // Also consider a point to be "isolated" if it's adjacent to a
// null point, excluding the graph edges.
- if ((j > 0 && !prevX) ||
- (next(j) < setLength && isNullOrNaN(nextY))) {
+ if ((!first && !prevCanvasX) ||
+ (iter.hasNext && isNextCanvasYNullOrNaN)) {
isIsolated = true;
}
}
- 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)) {
+ if (prevCanvasX !== null) {
+ if (strategy.skipPixel(prevCanvasX, prevCanvasY, point.canvasx, 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;
+ strategy.startSegment();
if (stepPlot) {
- this._dashedLine(ctx, prevX, prevY, point.canvasx, prevY, strokePattern);
- prevX = point.canvasx;
+ strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, prevCanvasY);
+ prevCanvasX = point.canvasx;
}
- this._dashedLine(ctx, prevX, prevY, point.canvasx, point.canvasy, strokePattern);
- prevX = point.canvasx;
- prevY = point.canvasy;
- ctx.stroke();
+ 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;
}
- 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();
- }
- ctx.restore();
+ strategy.finish();
+ return pointsOnLine;
};
DygraphCanvasRenderer.prototype._drawLine = function(ctx, i) {
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),
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 = this.layout.setNames;
var setCount = setNames.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;
var firstIndexInSet = this.layout.setPointsOffsets[i];
var setLength = this.layout.setPointsLengths[i];
- var afterLastIndexInSet = firstIndexInSet + setLength;
- var next = DygraphCanvasRenderer.makeNextPointStep_(
- this.attr_('connectSeparatedPoints'), points,
- afterLastIndexInSet);
+ var iter = Dygraph.createIterator(points, firstIndexInSet, setLength,
+ DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints")));
// setup graphics context
prevX = NaN;
fillAlpha + ')';
ctx.fillStyle = err_color;
ctx.beginPath();
- for (j = firstIndexInSet; j < afterLastIndexInSet; j = next(j)) {
- point = points[j];
+ while (iter.hasNext) {
+ point = iter.next();
if (point.name == setName) { // TODO(klausw): this is always true
if (!Dygraph.isOK(point.y)) {
prevX = NaN;
axisY = this.area.h * axisY + this.area.y;
var firstIndexInSet = this.layout.setPointsOffsets[i];
var setLength = this.layout.setPointsLengths[i];
- var afterLastIndexInSet = firstIndexInSet + setLength;
- var next = DygraphCanvasRenderer.makeNextPointStep_(
- this.attr_('connectSeparatedPoints'), points,
- afterLastIndexInSet);
+ var iter = Dygraph.createIterator(points, firstIndexInSet, setLength,
+ DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints")));
// setup graphics context
prevX = NaN;
fillAlpha + ')';
ctx.fillStyle = err_color;
ctx.beginPath();
- for (j = firstIndexInSet; j < afterLastIndexInSet; j = next(j)) {
- point = points[j];
+ while(iter.hasNext) {
+ point = iter.next();
if (point.name == setName) { // TODO(klausw): this is always true
if (!Dygraph.isOK(point.y)) {
prevX = NaN;
}
}
newYs = [ point.canvasy, lastY ];
-
+
if(stepPlot) {
// Step plots must keep track of the top and bottom of
// the baseline at each point.
} 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) {
ctx.lineTo(point.canvasx, newYs[0]);
ctx.lineTo(point.canvasx, newYs[1]);
}
-
+
ctx.lineTo(prevX, prevYs[1]);
ctx.closePath();
}