Use placeholder dimensions instead og canvas dimensions in calculations which...

Use placeholder dimensions instead og canvas dimensions in calculations which fixes draw bug after introducing Retina support in Flot core

jquery.flot.pie.js

@@ -63,6 +63,8 @@ More detail and specific examples can be found in the included HTML file.
 	function init(plot) // this is the "body" of the plugin
 	{
 		var canvas = null;
+		var canvasWidth = 0;
+		var canvasHeight = 0;
 		var target = null;
 		var maxRadius = null;
 		var centerLeft = null;
@@ -180,6 +182,9 @@ More detail and specific examples can be found in the included HTML file.
 				target = $(canvas).parent();
 				options = plot.getOptions();
 
+                                canvasWidth = plot.getPlaceholder().width();
+                                canvasHeight = plot.getPlaceholder().height();
+
 				plot.setData(combine(plot.getData()));
 			}
 		}
@@ -189,9 +194,9 @@ More detail and specific examples can be found in the included HTML file.
 			legendWidth = target.children().filter('.legend').children().width();
 		
 			// calculate maximum radius and center point
-			maxRadius =  Math.min(canvas.width,(canvas.height/options.series.pie.tilt))/2;
-			centerTop = (canvas.height/2)+options.series.pie.offset.top;
-			centerLeft = (canvas.width/2);
+			maxRadius =  Math.min(canvasWidth,(canvasHeight/options.series.pie.tilt))/2;
+			centerTop = (canvasHeight/2)+options.series.pie.offset.top;
+			centerLeft = (canvasWidth/2);
 			
 			if (options.series.pie.offset.left=='auto')
 				if (options.legend.position.match('w'))
@@ -203,8 +208,8 @@ More detail and specific examples can be found in the included HTML file.
 					
 			if (centerLeft<maxRadius)
 				centerLeft = maxRadius;
-			else if (centerLeft>canvas.width-maxRadius)
-				centerLeft = canvas.width-maxRadius;
+			else if (centerLeft>canvasWidth-maxRadius)
+				centerLeft = canvasWidth-maxRadius;
 		}
 		
 		function fixData(data)
@@ -304,7 +309,7 @@ More detail and specific examples can be found in the included HTML file.
 			
 			function clear()
 			{
-				ctx.clearRect(0,0,canvas.width,canvas.height);
+				ctx.clearRect(0,0,canvasWidth,canvasHeight);
 				target.children().filter('.pieLabel, .pieLabelBackground').remove();
 			}
 			
@@ -321,7 +326,7 @@ More detail and specific examples can be found in the included HTML file.
 				else
 					var radius = maxRadius * options.series.pie.radius;
 					
-				if (radius>=(canvas.width/2)-shadowLeft || radius*options.series.pie.tilt>=(canvas.height/2)-shadowTop || radius<=edge)
+				if (radius>=(canvasWidth/2)-shadowLeft || radius*options.series.pie.tilt>=(canvasHeight/2)-shadowTop || radius<=edge)
 					return;	// shadow would be outside canvas, so don't draw it
 			
 				ctx.save();
@@ -466,7 +471,7 @@ More detail and specific examples can be found in the included HTML file.
 						label.css('left', labelLeft);
 						
 						// check to make sure that the label is not outside the canvas
-						if (0-labelTop>0 || 0-labelLeft>0 || canvas.height-(labelTop+label.height())<0 || canvas.width-(labelLeft+label.width())<0)
+						if (0-labelTop>0 || 0-labelLeft>0 || canvasHeight-(labelTop+label.height())<0 || canvasWidth-(labelLeft+label.width())<0)
 							redraw = true;
 						
 						if (options.series.pie.label.background.opacity != 0) {