- // fillRect(x, y, width, height)
- // Bottom section: y = (-Infinity, 2.25)
- canvas.fillStyle = 'pink';
- canvas.fillRect(area.x, splitHeight, area.w, area.h - splitHeight);
+ // splitX and splitY are the coordinates on the canvas for (2006-11-19, 2.25).
+ var splitX = coords[0];
+ var splitY = coords[1];
+
+ // The drawing area doesn't start at (0, 0), it starts at (area.x, area.y).
+ // That's why we subtract them from splitX and splitY. This gives us the
+ // actual distance from the upper-left hand corder of the graph itself.
+ var leftSideWidth = splitX - area.x;
+ var rightSideWidth = area.w - leftSideWidth;
+ var topHeight = splitY - area.y;
+ var bottomHeight = area.h - topHeight;