X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph-canvas.js;h=bdca5908ca91b661fe005ab688acc8a0f2f22394;hb=31f8e58ba608d0b046411ac82f54c968c70e4f37;hp=3f1b17bb0766639146fe1870cd934cd1462b38b6;hpb=ccb0001c3c8aadd02358995c8d7b71fbb37c0bc3;p=dygraphs.git

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index 3f1b17b..bdca590 100644
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -678,30 +678,17 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() {
 };
 
 /**
- * Returns a function which returns the next index with a renderable point.
- * When connectSeparatedPoints is false, it just returns the next index.
- * But when it's true, the returned function will skip past points with null
- * yvals.
- *
- * @private
+ * 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.makeNextPointStep_ = function(
-    connectSeparatedPoints, points, start, end) {
-  if (connectSeparatedPoints) {
-    return function(j) {
-      while (++j + start < end) {
-        if (!(points[start + j].yval === null)) break;
-      }
-      return j;
-    }
-  } else {
-    return function(j) { return j + 1 };
-  }
-};
+DygraphCanvasRenderer._getIteratorPredicate = function(connectSeparatedPoints) {
+  return connectSeparatedPoints ? DygraphCanvasRenderer._predicateThatSkipsEmptyPoints : null;
+}
 
-DygraphCanvasRenderer.isNullOrNaN_ = function(x) {
-  return (x === null || isNaN(x));
-};
+DygraphCanvasRenderer._predicateThatSkipsEmptyPoints =
+  function(array, idx) { return array[idx].yval !== null; }
 
 DygraphCanvasRenderer.prototype._drawStyledLine = function(
     ctx, i, setName, color, strokeWidth, strokePattern, drawPoints,
@@ -717,83 +704,70 @@ DygraphCanvasRenderer.prototype._drawStyledLine = function(
   var drawGapPoints = this.dygraph_.attr_('drawGapEdgePoints', setName);
 
   ctx.save();
-  if (strokeWidth && !stepPlot && (!strokePattern || strokePattern.length <= 1)) {
-    this._drawTrivialLine(ctx, points, setLength, firstIndexInSet, setName, color, strokeWidth, drawPointCallback, pointSize, drawPoints, drawGapPoints);
+
+  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 {
-    this._drawNonTrivialLine(ctx, points, setLength, firstIndexInSet, setName, color, strokeWidth, strokePattern, drawPointCallback, pointSize, drawPoints, drawGapPoints, stepPlot);
+    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();
 };
 
-DygraphCanvasRenderer.prototype._drawNonTrivialLine = function(
-    ctx, points, setLength, firstIndexInSet, setName, color, strokeWidth, strokePattern, drawPointCallback, pointSize, drawPoints, drawGapPoints, stepPlot) {
-  var prevX = null;
-  var prevY = null;
-  var nextY = null;
-  var point, nextPoint;
-  var pointsOnLine = []; // Array of [canvasx, canvasy] pairs.
-  var next = DygraphCanvasRenderer.makeNextPointStep_(
-      this.attr_('connectSeparatedPoints'), points, firstIndexInSet,
-      firstIndexInSet + setLength);
-  for (var j = 0; j < setLength; j = next(j)) {
-    point = points[firstIndexInSet + j];
-    nextY = (next(j) < setLength) ?
-        points[firstIndexInSet + next(j)].canvasy : null;
-    if (DygraphCanvasRenderer.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');
-        this._dashedLine(ctx, prevX, prevY, point.canvasx, prevY, strokePattern);
-        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 && DygraphCanvasRenderer.isNullOrNaN_(nextY));
-      if (drawGapPoints) {
-        // Also consider a point to be is "isolated" if it's adjacent to a
-        // null point, excluding the graph edges.
-        if ((j > 0 && !prevX) ||
-            (next(j) < setLength && DygraphCanvasRenderer.isNullOrNaN_(nextY))) {
-          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)) {
-          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;
-          if (stepPlot) {
-            this._dashedLine(ctx, prevX, prevY, point.canvasx, prevY, strokePattern);
-            prevX = point.canvasx;
-          }
-          this._dashedLine(ctx, prevX, prevY, point.canvasx, point.canvasy, strokePattern);
-          prevX = point.canvasx;
-          prevY = point.canvasy;
-          ctx.stroke();
-        }
-      }
+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));
+    };
+  };
+};
 
-      if (drawPoints || isIsolated) {
-        pointsOnLine.push([point.canvasx, point.canvasy]);
-      }
-    }
-  }
+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();
@@ -801,52 +775,71 @@ DygraphCanvasRenderer.prototype._drawNonTrivialLine = function(
         this.dygraph_, setName, ctx, cb[0], cb[1], color, pointSize);
     ctx.restore();
   }
-};
+}
 
-DygraphCanvasRenderer.prototype._drawTrivialLine = function(
-    ctx, points, setLength, firstIndexInSet, setName, color, strokeWidth, drawPointCallback, pointSize, drawPoints, drawGapPoints) {
-  var prevX = null;
-  var prevY = null;
-  var nextY = null;
+DygraphCanvasRenderer.prototype._drawSeries = function(
+    ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints,
+    stepPlot, strategy) {
+
+  var isNullOrNaN = function(x) {
+    return (x === null || isNaN(x));
+  };
+    
+  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.
-  ctx.beginPath();
-  ctx.strokeStyle = color;
-  ctx.lineWidth = strokeWidth;
-  for (var j = firstIndexInSet; j < firstIndexInSet + setLength; ++j) {
-    var point = points[j];
-    nextY = (j + 1 < firstIndexInSet + setLength) ? points[j + 1].canvasy : null;
-    if (DygraphCanvasRenderer.isNullOrNaN_(point.canvasy)) {
-      prevX = prevY = null;
+  var first = true; // the first cycle through the while loop
+
+  strategy.init();
+
+  while(iter.hasNext()) {
+    point = iter.next();
+    if (isNullOrNaN(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 {
-      var isIsolated = (!prevX && DygraphCanvasRenderer.isNullOrNaN_(nextY));
+      nextCanvasY = iter.hasNext() ? iter.peek().canvasy : null;
+      isIsolated = (!prevCanvasX && isNullOrNaN(nextCanvasY));
       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 > firstIndexInSet && !prevX) ||
-            ((j + 1 < firstIndexInSet + setLength) && DygraphCanvasRenderer.isNullOrNaN_(nextY))) {
+        if ((!first && !prevCanvasX) ||
+            (iter.hasNext() && isNullOrNaN(nextCanvasY))) {
           isIsolated = true;
         }
       }
-      if (prevX === null) {
-        prevX = point.canvasx;
-        prevY = point.canvasy;
-        ctx.moveTo(point.canvasx, point.canvasy);
-      } else {
-        ctx.lineTo(point.canvasx, point.canvasy);
+      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;
   }
-  ctx.stroke();
-  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();
-  }
+  strategy.finish();
+  return pointsOnLine;
 };
 
 DygraphCanvasRenderer.prototype._drawLine = function(ctx, i) {
@@ -858,7 +851,6 @@ DygraphCanvasRenderer.prototype._drawLine = function(ctx, i) {
   var drawPointCallback = this.dygraph_.attr_("drawPointCallback", setName) ||
       Dygraph.Circles.DEFAULT;
 
-  // TODO(konigsberg): Turn this into one call, and then consider inlining drawStyledLine.
   if (borderWidth && strokeWidth) {
     this._drawStyledLine(ctx, i, setName,
         this.dygraph_.attr_("strokeBorderColor", setName),
@@ -893,7 +885,7 @@ 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 = this.layout.setNames;
   var setCount = setNames.length;
@@ -930,11 +922,9 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
 
       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;
@@ -947,8 +937,8 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
                             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;
@@ -1002,11 +992,9 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
       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;
@@ -1018,8 +1006,8 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
                             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;