Reverse cache key order to ensure uniqueness.

Also switch from dashes to pipes, and remove the angle for now, since we
don't currently support rotated text.

jquery.flot.canvas.js

@@ -184,8 +184,9 @@ browser, but needs to redraw with canvas text when exporting as an image.
 
 			// The text + style + angle uniquely identify the text's dimensions
 			// and content; we'll use them to build the entry's text cache key.
+			// NOTE: We don't support rotated text yet, so the angle is unused.
 
-			cacheKey = text + "-" + textStyle + "-" + angle;
+			cacheKey = textStyle + "|" + text;
 
 			info = this._textCache[cacheKey];
 

jquery.flot.js

@@ -268,8 +268,9 @@ Licensed under the MIT license.
 
 		// The text + style + angle uniquely identify the text's dimensions and
 		// content; we'll use them to build this entry's text cache key.
+		// NOTE: We don't support rotated text yet, so the angle is unused.
 
-		cacheKey = text + "-" + textStyle + "-" + angle;
+		cacheKey = textStyle + "|" + text;
 
 		info = this._textCache[cacheKey];