From 05d33e03ab85bb0d4d08c9a5fca2e557142a70dd Mon Sep 17 00:00:00 2001
From: Alex Yatskov <alex@foosoft.net>
Date: Sat, 30 Aug 2014 11:44:35 +0900
Subject: [PATCH] Display baseline on graph

---
 client/grapher.js | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/client/grapher.js b/client/grapher.js
index 24fa5af..c4220b3 100644
--- a/client/grapher.js
+++ b/client/grapher.js
@@ -68,6 +68,13 @@ function Column(canvas, name, params, scale, range, bounds) {
                 originX:  'center',
                 originY:  'center',
             });
+
+            if (goog.math.Range.containsPoint(this.range, 0.0)) {
+                var position = this.getPosFromValue(0.0);
+                this.updateLine('baseline', [this.columnBounds.left, position, this.hintBounds.left, position], {
+                    stroke: this.strokeColor
+                });
+            }
         }
 
         this.updateRect('fillRect', {
@@ -113,6 +120,18 @@ function Column(canvas, name, params, scale, range, bounds) {
         }
     }
 
+    this.updateLine = function(name, points, args) {
+        if (name in this) {
+            this[name].set(args);
+        }
+        else {
+            var line = new fabric.Line(points, args);
+            this.canvas.add(line);
+            this.shapes.push(line);
+            this[name] = line;
+        }
+    }
+
     this.updateColor = function(color) {
         var fillColorRgb   = goog.color.hexToRgb(goog.color.parse(color).hex);
         var handleColorRgb = goog.color.darken(fillColorRgb, this.handleDarken);
@@ -270,6 +289,11 @@ function Column(canvas, name, params, scale, range, bounds) {
         return this.range.start + this.range.getLength() * percent;
     }
 
+    this.getPosFromValue = function(value) {
+        var percent = 1.0 - (value - this.range.start) / this.range.getLength();
+        return this.columnBounds.top + this.columnBounds.height * percent;
+    }
+
     this.isHovering = function(position) {
         return this.isGrabbing(position);
     }