X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph-canvas.js;h=29341e1b83bd5b0b883ad4d3d2ca30a078816275;hb=2c95097e35231ad5b40c6ce1903c77a07b3f3158;hp=c12622f8eb2aca62adff706245174eaf02ddf07d;hpb=2f5e7e1a7f5fd071b08ce92167fcab8863234075;p=dygraphs.git

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index c12622f..29341e1 100644
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -309,17 +309,21 @@ DygraphCanvasRenderer = function(dygraph, element, layout, options) {
 
   // Set up a clipping area for the canvas (and the interaction canvas).
   // This ensures that we don't overdraw.
-  var ctx = this.element.getContext("2d");
+  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();
 
-  var ctx = this.dygraph_.hidden_.getContext("2d");
+  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);
+};
+
 DygraphCanvasRenderer.prototype.clear = function() {
   if (this.isIE) {
     // VML takes a while to start up, so we just poll every this.IEDelay
@@ -343,15 +347,15 @@ DygraphCanvasRenderer.prototype.clear = function() {
 
   for (var i = 0; i < this.xlabels.length; i++) {
     var el = this.xlabels[i];
-    el.parentNode.removeChild(el);
+    if (el.parentNode) el.parentNode.removeChild(el);
   }
   for (var i = 0; i < this.ylabels.length; i++) {
     var el = this.ylabels[i];
-    el.parentNode.removeChild(el);
+    if (el.parentNode) el.parentNode.removeChild(el);
   }
   for (var i = 0; i < this.annotations.length; i++) {
     var el = this.annotations[i];
-    el.parentNode.removeChild(el);
+    if (el.parentNode) el.parentNode.removeChild(el);
   }
   this.xlabels = new Array();
   this.ylabels = new Array();
@@ -382,8 +386,11 @@ DygraphCanvasRenderer.isSupported = function(canvasName) {
  * Draw an X/Y grid on top of the existing plot
  */
 DygraphCanvasRenderer.prototype.render = function() {
-  // Draw the new X/Y grid
+  // 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");
+  function halfUp(x){return Math.round(x)+0.5};
+  function halfDown(y){return Math.round(y)-0.5};
 
   if (this.options.underlayCallback) {
     this.options.underlayCallback(ctx, this.area, this.layout, this.dygraph_);
@@ -397,8 +404,8 @@ DygraphCanvasRenderer.prototype.render = function() {
     for (var i = 0; i < ticks.length; i++) {
       // TODO(danvk): allow secondary axes to draw a grid, too.
       if (ticks[i][0] != 0) continue;
-      var x = this.area.x;
-      var y = this.area.y + ticks[i][1] * this.area.h;
+      var x = halfUp(this.area.x);
+      var y = halfDown(this.area.y + ticks[i][1] * this.area.h);
       ctx.beginPath();
       ctx.moveTo(x, y);
       ctx.lineTo(x + this.area.w, y);
@@ -413,8 +420,8 @@ DygraphCanvasRenderer.prototype.render = function() {
     ctx.strokeStyle = this.options.gridLineColor;
     ctx.lineWidth = this.options.axisLineWidth;
     for (var i=0; i<ticks.length; i++) {
-      var x = this.area.x + ticks[i][0] * this.area.w;
-      var y = this.area.y + this.area.h;
+      var x = halfUp(this.area.x + ticks[i][0] * this.area.w);
+      var y = halfDown(this.area.y + this.area.h);
       ctx.beginPath();
       ctx.moveTo(x, y);
       ctx.lineTo(x, this.area.y);
@@ -434,6 +441,10 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
   if (!this.options.drawXAxis && !this.options.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 labelStyle = {
@@ -473,8 +484,8 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
         }
         var y = this.area.y + tick[1] * this.area.h;
         context.beginPath();
-        context.moveTo(x, y);
-        context.lineTo(x - sgn * this.options.axisTickSize, y);
+        context.moveTo(halfUp(x), halfDown(y));
+        context.lineTo(halfUp(x - sgn * this.options.axisTickSize), halfDown(y));
         context.closePath();
         context.stroke();
 
@@ -512,16 +523,18 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
       }
     }
 
+    // draw a vertical line on the left to separate the chart from the labels.
     context.beginPath();
-    context.moveTo(this.area.x, this.area.y);
-    context.lineTo(this.area.x, this.area.y + this.area.h);
+    context.moveTo(halfUp(this.area.x), halfDown(this.area.y));
+    context.lineTo(halfUp(this.area.x), halfDown(this.area.y + this.area.h));
     context.closePath();
     context.stroke();
 
+    // if there's a secondary y-axis, draw a vertical line for that, too.
     if (this.dygraph_.numAxes() == 2) {
       context.beginPath();
-      context.moveTo(this.area.x + this.area.w, this.area.y);
-      context.lineTo(this.area.x + this.area.w, this.area.y + this.area.h);
+      context.moveTo(halfDown(this.area.x + this.area.w), halfDown(this.area.y));
+      context.lineTo(halfDown(this.area.x + this.area.w), halfDown(this.area.y + this.area.h));
       context.closePath();
       context.stroke();
     }
@@ -536,8 +549,8 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
         var x = this.area.x + tick[0] * this.area.w;
         var y = this.area.y + this.area.h;
         context.beginPath();
-        context.moveTo(x, y);
-        context.lineTo(x, y + this.options.axisTickSize);
+        context.moveTo(halfUp(x), halfDown(y));
+        context.lineTo(halfUp(x), halfDown(y + this.options.axisTickSize));
         context.closePath();
         context.stroke();
 
@@ -563,8 +576,8 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
     }
 
     context.beginPath();
-    context.moveTo(this.area.x, this.area.y + this.area.h);
-    context.lineTo(this.area.x + this.area.w, this.area.y + this.area.h);
+    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));
     context.closePath();
     context.stroke();
   }
@@ -675,12 +688,13 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() {
  * Overrides the CanvasRenderer method to draw error bars
  */
 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 fillGraph = this.layout.options.fillGraph;
+  var fillGraph = this.attr_("fillGraph");
   var stackedGraph = this.layout.options.stackedGraph;
   var stepPlot = this.layout.options.stepPlot;