X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph-canvas.js;h=2874990041c65bf93d36ccc9343dd4c002768402;hb=a12f271c5fc6420d764bae5a5c12ca0785f7fd4c;hp=72716ba195ac5ce23c45cd9216959afac712ed08;hpb=34de8b760a9e1cf72f3a8fdfa66163a7fad4c403;p=dygraphs.git

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index 72716ba..2874990 100644
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -4,9 +4,27 @@
 /**
  * @fileoverview Based on PlotKit, but modified to meet the needs of dygraphs.
  * In particular, support for:
- * - grid overlays 
+ * - grid overlays
  * - error bars
  * - dygraphs attribute system
+ *
+ * High level overview of classes:
+ *
+ * - DygraphLayout
+ *     This contains all the data to be charted.
+ *     It uses data coordinates, but also records the chart range (in data
+ *     coordinates) and hence is able to calculate percentage positions ('In
+ *     this view, Point A lies 25% down the x-axis.')
+ *     Two things that it does not do are:
+ *     1. Record pixel coordinates for anything.
+ *     2. (oddly) determine anything about the layout of chart elements.
+ *     The naming is a vestige of Dygraph's original PlotKit roots.
+ *
+ * - DygraphCanvasRenderer
+ *     This class determines the charting area (in pixel coordinates), maps the
+ *     percentage coordinates in the DygraphLayout to pixels and draws them.
+ *     It's also responsible for creating chart DOM elements, i.e. annotations,
+ *     tick mark labels, the title and the x/y-axis labels.
  */
 
 /**
@@ -19,7 +37,7 @@ DygraphLayout = function(dygraph, options) {
   this.options = {};  // TODO(danvk): remove, use attr_ instead.
   Dygraph.update(this.options, options ? options : {});
   this.datasets = new Array();
-  this.annotations = new Array()
+  this.annotations = new Array();
 };
 
 DygraphLayout.prototype.attr_ = function(name) {
@@ -32,9 +50,9 @@ DygraphLayout.prototype.addDataset = function(setname, set_xy) {
 
 DygraphLayout.prototype.setAnnotations = function(ann) {
   // The Dygraph object's annotations aren't parsed. We parse them here and
-  // save a copy.
+  // save a copy. If there is no parser, then the user must be using raw format.
   this.annotations = [];
-  var parse = this.attr_('xValueParser');
+  var parse = this.attr_('xValueParser') || function(x) { return x; };
   for (var i = 0; i < ann.length; i++) {
     var a = {};
     if (!ann[i].xval && !ann[i].x) {
@@ -88,6 +106,16 @@ DygraphLayout.prototype._evaluateLimits = function() {
     axis.maxyval = axis.computedValueRange[1];
     axis.yrange = axis.maxyval - axis.minyval;
     axis.yscale = (axis.yrange != 0 ? 1.0 / axis.yrange : 1.0);
+
+    if (axis.g.attr_("logscale")) {
+      axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
+      axis.ylogscale = (axis.ylogrange != 0 ? 1.0 / axis.ylogrange : 1.0);
+      if (!isFinite(axis.ylogrange) || isNaN(axis.ylogrange)) {
+        axis.g.error('axis ' + i + ' of graph at ' + axis.g +
+            ' can\'t be displayed in log scale for range [' +
+            axis.minyval + ' - ' + axis.maxyval + ']');
+      }
+    }
   }
 };
 
@@ -102,22 +130,22 @@ DygraphLayout.prototype._evaluateLineCharts = function() {
 
     for (var j = 0; j < dataset.length; j++) {
       var item = dataset[j];
+
+      var yval;
+      if (axis.logscale) {
+        yval = 1.0 - ((Dygraph.log10(parseFloat(item[1])) - Dygraph.log10(axis.minyval)) * axis.ylogscale); // really should just be yscale.
+      } else {
+        yval = 1.0 - ((parseFloat(item[1]) - axis.minyval) * axis.yscale);
+      }
       var point = {
         // TODO(danvk): here
         x: ((parseFloat(item[0]) - this.minxval) * this.xscale),
-        y: 1.0 - ((parseFloat(item[1]) - axis.minyval) * axis.yscale),
+        y: yval,
         xval: parseFloat(item[0]),
         yval: parseFloat(item[1]),
         name: setName
       };
 
-      // limit the x, y values so they do not overdraw
-      if (point.y <= 0.0) {
-        point.y = 0.0;
-      }
-      if (point.y >= 1.0) {
-        point.y = 1.0;
-      }
       this.points.push(point);
     }
   }
@@ -140,7 +168,7 @@ DygraphLayout.prototype._evaluateLineTicks = function() {
     for (var j = 0; j < axis.ticks.length; j++) {
       var tick = axis.ticks[j];
       var label = tick.label;
-      var pos = 1.0 - (axis.yscale * (tick.v - axis.minyval));
+      var pos = this.dygraph_.toPercentYCoord(tick.v, i);
       if ((pos >= 0.0) && (pos <= 1.0)) {
         this.yticks.push([i, pos, label]);
       }
@@ -249,10 +277,13 @@ DygraphLayout.prototype.unstackPointAtIndex = function(idx) {
 /**
  * Sets some PlotKit.CanvasRenderer options
  * @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) {
+DygraphCanvasRenderer = function(dygraph, element, elementContext, layout,
+    options) {
   // TODO(danvk): remove options, just use dygraph.attr_.
   this.dygraph_ = dygraph;
 
@@ -278,6 +309,7 @@ DygraphCanvasRenderer = function(dygraph, element, layout, options) {
 
   this.layout = layout;
   this.element = element;
+  this.elementContext = elementContext;
   this.container = this.element.parentNode;
 
   this.height = this.element.height;
@@ -291,6 +323,7 @@ DygraphCanvasRenderer = function(dygraph, element, layout, options) {
   this.xlabels = new Array();
   this.ylabels = new Array();
   this.annotations = new Array();
+  this.chartLabels = {};
 
   // TODO(danvk): consider all axes in this computation.
   this.area = {
@@ -311,22 +344,41 @@ DygraphCanvasRenderer = function(dygraph, element, layout, options) {
                         "to use " + this.dygraph_.numAxes() + ")");
   }
 
+  // Add space for chart labels: title, xlabel and ylabel.
+  if (this.attr_('title')) {
+    this.area.h -= this.attr_('titleHeight');
+    this.area.y += this.attr_('titleHeight');
+  }
+  if (this.attr_('xlabel')) {
+    this.area.h -= this.attr_('xLabelHeight');
+  }
+  if (this.attr_('ylabel')) {
+    // 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.element.getContext("2d");
+  var ctx = this.dygraph_.canvas_ctx_;
   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_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);
+};
+
 DygraphCanvasRenderer.prototype.clear = function() {
   if (this.isIE) {
     // VML takes a while to start up, so we just poll every this.IEDelay
@@ -335,7 +387,7 @@ 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.
@@ -345,24 +397,30 @@ DygraphCanvasRenderer.prototype.clear = function() {
     }
   }
 
-  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++) {
     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);
+  }
+  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 = new Array();
   this.ylabels = new Array();
   this.annotations = new Array();
+  this.chartLabels = {};
 };
 
 
@@ -389,11 +447,16 @@ 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
-  var ctx = this.element.getContext("2d");
+  // 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.elementContext;
+  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_);
+    // 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_);
   }
 
   if (this.options.drawYGrid) {
@@ -402,9 +465,10 @@ DygraphCanvasRenderer.prototype.render = function() {
     ctx.strokeStyle = this.options.gridLineColor;
     ctx.lineWidth = this.options.axisLineWidth;
     for (var i = 0; i < ticks.length; i++) {
-      if (ticks[i][0] != 0) continue;  // TODO(danvk): per-axis property
-      var x = this.area.x;
-      var y = this.area.y + ticks[i][1] * this.area.h;
+      // TODO(danvk): allow secondary axes to draw a grid, too.
+      if (ticks[i][0] != 0) continue;
+      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);
@@ -419,10 +483,10 @@ 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][1] * 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);  // x == NaN
+      ctx.moveTo(x, y);
       ctx.lineTo(x, this.area.y);
       ctx.closePath();
       ctx.stroke();
@@ -432,6 +496,7 @@ DygraphCanvasRenderer.prototype.render = function() {
   // Do the ordinary rendering, as before
   this._renderLineChart();
   this._renderAxis();
+  this._renderChartLabels(); 
   this._renderAnnotations();
 };
 
@@ -440,7 +505,11 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
   if (!this.options.drawXAxis && !this.options.drawYAxis)
     return;
 
-  var context = this.element.getContext("2d");
+  // 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.elementContext;
 
   var labelStyle = {
     "position": "absolute",
@@ -472,13 +541,15 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
         var tick = this.layout.yticks[i];
         if (typeof(tick) == "function") return;
         var x = this.area.x;
-        if (tick[0] == 1) {
-          x = this.area.x + this.area.w - labelStyle.width;
+        var sgn = 1;
+        if (tick[0] == 1) {  // right-side y-axis
+          x = this.area.x + this.area.w;
+          sgn = -1;
         }
         var y = this.area.y + tick[1] * this.area.h;
         context.beginPath();
-        context.moveTo(x, y);
-        context.lineTo(x - this.options.axisTickSize, y);
+        context.moveTo(halfUp(x), halfDown(y));
+        context.lineTo(halfUp(x - sgn * this.options.axisTickSize), halfDown(y));
         context.closePath();
         context.stroke();
 
@@ -492,7 +563,7 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
           label.style.top = top + "px";
         }
         if (tick[0] == 0) {
-          label.style.left = "0px";
+          label.style.left = (this.area.x - this.options.yAxisLabelWidth - this.options.axisTickSize) + "px";
           label.style.textAlign = "right";
         } else if (tick[0] == 1) {
           label.style.left = (this.area.x + this.area.w +
@@ -516,16 +587,18 @@ 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();
     }
@@ -540,14 +613,14 @@ 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();
 
         var label = makeDiv(tick[1]);
         label.style.textAlign = "center";
-        label.style.bottom = "0px";
+        label.style.top = (y + this.options.axisTickSize) + 'px';
 
         var left = (x - this.options.axisLabelWidth/2);
         if (left + this.options.axisLabelWidth > this.width) {
@@ -567,8 +640,8 @@ 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();
   }
@@ -577,6 +650,101 @@ DygraphCanvasRenderer.prototype._renderAxis = function() {
 };
 
 
+DygraphCanvasRenderer.prototype._renderChartLabels = function() {
+  // 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')) {
+    var 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';
+    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;
+  }
+
+  if (this.attr_('xlabel')) {
+    var 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';
+
+    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;
+  }
+
+  if (this.attr_('ylabel')) {
+    var box = {
+      left: 0,
+      top: this.area.y,
+      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.top = box.top + 'px';
+    div.style.width = box.width + 'px';
+    div.style.height = box.height + 'px';
+    div.style.fontSize = (this.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.
+    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.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",
@@ -659,7 +827,7 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() {
     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) {
@@ -679,12 +847,13 @@ DygraphCanvasRenderer.prototype._renderAnnotations = function() {
  * Overrides the CanvasRenderer method to draw error bars
  */
 DygraphCanvasRenderer.prototype._renderLineChart = function() {
-  var context = this.element.getContext("2d");
+  // TODO(danvk): use this.attr_ for many of these.
+  var context = this.elementContext;
   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;
 
@@ -710,8 +879,6 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
   }
 
   // create paths
-  var isOK = function(x) { return x && !isNaN(x); };
-
   var ctx = context;
   if (errorBars) {
     if (fillGraph) {
@@ -739,7 +906,7 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
       for (var j = 0; j < this.layout.points.length; j++) {
         var point = this.layout.points[j];
         if (point.name == setName) {
-          if (!isOK(point.y)) {
+          if (!Dygraph.isOK(point.y)) {
             prevX = NaN;
             continue;
           }
@@ -804,7 +971,7 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
       for (var j = 0; j < this.layout.points.length; j++) {
         var point = this.layout.points[j];
         if (point.name == setName) {
-          if (!isOK(point.y)) {
+          if (!Dygraph.isOK(point.y)) {
             prevX = NaN;
             continue;
           }
@@ -851,7 +1018,7 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
     for (var j = 0; j < points.length; j++) {
       var point = points[j];
       if (point.name == setName) {
-        if (!isOK(point.canvasy)) {
+        if (!Dygraph.isOK(point.canvasy)) {
           if (stepPlot && prevX != null) {
             // Draw a horizontal line to the start of the missing data
             ctx.beginPath();
@@ -867,7 +1034,7 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
           // 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 ||
-                                       !isOK(points[j+1].canvasy)));
+                                       !Dygraph.isOK(points[j+1].canvasy)));
 
           if (!prevX) {
             prevX = point.canvasx;