Make seriesToPoints_ and stackPoints_ private. They are being rendered as part of...

[dygraphs.git] / dygraph-canvas.js

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index ce7fcbf..cba4f44 100644 (file)
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -440,9 +440,10 @@ DygraphCanvasRenderer.prototype._updatePoints = function() {
  * DygraphCanvasRenderer._updatePoints.
  *
  * @param {string=} opt_seriesName when specified, only that series will
- * be drawn. (This is used for expedited redrawing with highlightSeriesOpts)
- * @param {CanvasRenderingContext2D} opt_ctx when specified, the drawing context.
- * However, lines are typically drawn on the object's elementContext.
+ *     be drawn. (This is used for expedited redrawing with highlightSeriesOpts)
+ * @param {CanvasRenderingContext2D} opt_ctx when specified, the drawing
+ *     context.  However, lines are typically drawn on the object's
+ *     elementContext.
  * @private
  */
 DygraphCanvasRenderer.prototype._renderLineChart = function(opt_seriesName, opt_ctx) {
@@ -701,7 +702,14 @@ DygraphCanvasRenderer._fillPlotter = function(e) {
   var stackedGraph = g.getOption("stackedGraph");
   var colors = g.getColors();
 
-  var baseline = {};  // for stacked graphs: baseline for filling
+  // For stacked graphs, track the baseline for filling.
+  //
+  // The filled areas below graph lines are trapezoids with two
+  // vertical edges. The top edge is the line segment being drawn, and
+  // the baseline is the bottom edge. Each baseline corresponds to the
+  // top line segment from the previous stacked line. In the case of
+  // step plots, the trapezoids are rectangles.
+  var baseline = {};
   var currBaseline;
   var prevStepPlot;  // for different line drawing modes (line/step) per series
 
@@ -738,6 +746,9 @@ DygraphCanvasRenderer._fillPlotter = function(e) {
       var point = iter.next();
       if (!Dygraph.isOK(point.y)) {
         prevX = NaN;
+        if (point.y_stacked !== null && !isNaN(point.y_stacked)) {
+          baseline[point.canvasx] = area.h * point.y_stacked + area.y;
+        }
         continue;
       }
       if (stackedGraph) {