Pre-compute coordinates for each line of text.

The values don't change, so there's no reason to repeat those
calculations on every redraw.  The resulting code is not just faster,
but also smaller and simpler, and we no longer need to store halign in
the text info object.

jquery.flot.canvas.js

@@ -98,11 +98,6 @@ browser, but needs to redraw with canvas text when exporting as an image.
 										continue;
 									}
 
-									var x = info.x,
-										y = info.y,
-										lines = info.lines,
-										halign = info.halign;
-
 									// Since every element at this level of the cache have the
 									// same font and fill styles, we can just change them once
 									// using the values from the first element.
@@ -113,34 +108,10 @@ browser, but needs to redraw with canvas text when exporting as an image.
 										updateStyles = false;
 									}
 
+									var lines = info.lines;
 									for (var i = 0; i < lines.length; ++i) {
-
-										var line = lines[i],
-											linex = x;
-
-										// Apply horizontal alignment per-line
-
-										if (halign == "center") {
-											linex -= line.width / 2;
-										} else if (halign == "right") {
-											linex -= line.width;
-										}
-
-										// FIXME: LEGACY BROWSER FIX
-										// AFFECTS: Opera < 12.00
-
-										// Round the coordinates, since Opera otherwise
-										// switches to uglier (probably non-hinted) rendering.
-										// Also offset the y coordinate, since Opera is off
-										// pretty consistently compared to the other browsers.
-
-										if (!!(window.opera && window.opera.version().split(".")[0] < 12)) {
-											linex = Math.floor(linex);
-											y = Math.ceil(y - 2);
-										}
-
-										context.fillText(line.text, Math.round(linex), Math.round(y));
-										y += line.height;
+										var line = lines[i];
+										context.fillText(line.text, line.x, line.y);
 									}
 								}
 							}
@@ -247,8 +218,6 @@ browser, but needs to redraw with canvas text when exporting as an image.
 				// zero so we can count them up line-by-line.
 
 				info = styleCache[text] = {
-					x: null,
-					y: null,
 					width: 0,
 					height: 0,
 					active: false,
@@ -317,19 +286,41 @@ browser, but needs to redraw with canvas text when exporting as an image.
 
 			info.active = true;
 
-			// Save horizontal alignment for later; we'll apply it per-line
-
-			info.x = x;
-			info.halign = halign;
-
 			// Tweak the initial y-position to match vertical alignment
 
 			if (valign == "middle") {
-				info.y = y - info.height / 2;
+				y = Math.round(y - info.height / 2);
 			} else if (valign == "bottom") {
-				info.y = y - info.height;
+				y = Math.round(y - info.height);
 			} else {
-				info.y = y;
+				y = Math.round(y);
+			}
+
+			// FIXME: LEGACY BROWSER FIX
+			// AFFECTS: Opera < 12.00
+
+			// Offset the y coordinate, since Opera is off pretty
+			// consistently compared to the other browsers.
+
+			if (!!(window.opera && window.opera.version().split(".")[0] < 12)) {
+				y -= 2;
+			}
+
+			// Fill in the x & y positions of each line, adjusting them
+			// individually for horizontal alignment.
+
+			var lines = info.lines;
+			for (var i = 0; i < lines.length; ++i) {
+				var line = lines[i];
+				line.y = y;
+				y += line.height;
+				if (halign == "center") {
+					line.x = Math.round(x - line.width / 2);
+				} else if (halign == "right") {
+					line.x = Math.round(x - line.width);
+				} else {
+					line.x = Math.round(x);
+				}
 			}
 		};
 	}