Replace measureText with helpers.measureText

Author: nagix

src/core/core.scale.js

@@ -83,17 +83,6 @@ function getPixelForGridLine(scale, index, offsetGridLines) {
 	return lineValue;
 }
 
-function measureText(ctx, data, gc, string) {
-	var key = ctx.font + ';' + string;
-	var textWidth = data[key];
-
-	if (!textWidth) {
-		textWidth = data[key] = ctx.measureText(string).width;
-		gc.push(key);
-	}
-	return textWidth;
-}
-
 /**
  * Returns {width, height, offset} objects for the first, last, widest, highest tick
  * labels where offset indicates the anchor point offset from the top in pixels.
@@ -103,43 +92,50 @@ function computeLabelSizes(ctx, tickFonts, ticks, cache) {
 	var widths = [];
 	var heights = [];
 	var offsets = [];
-	var data = cache.data = cache.data || {};
-	var gc = cache.garbageCollect = cache.garbageCollect || [];
-	var gcLen, i, j, jlen, tick, label, tickFont, width, height, nestedLabel, widest, highest;
+	var i, j, jlen, label, tickFont, fontString, data, gc, lineHeight, width, height, nestedLabel, widest, highest;
+
+	helpers.each(tickFonts, function(font) {
+		cache[font.string] = cache[font.string] || {data: {}, garbageCollect: []};
+	});
 
 	for (i = 0; i < length; ++i) {
-		tick = ticks[i];
-		label = tick.label;
-		tickFont = tick.major ? tickFonts.major : tickFonts.minor;
+		label = ticks[i].label;
+		tickFont = ticks[i].major ? tickFonts.major : tickFonts.minor;
+		ctx.font = fontString = tickFont.string;
+		data = cache[fontString].data;
+		gc = cache[fontString].garbageCollect;
+		lineHeight = tickFont.lineHeight;
 		width = height = 0;
-		ctx.font = tickFont.string;
 		// Undefined labels and arrays should not be measured
 		if (!helpers.isNullOrUndef(label) && !helpers.isArray(label)) {
-			width = measureText(ctx, data, gc, label);
-			height = tickFont.lineHeight;
+			width = helpers.measureText(ctx, data, gc, width, label);
+			height = lineHeight;
 		} else if (helpers.isArray(label)) {
 			// if it is an array lets measure each element
 			for (j = 0, jlen = label.length; j < jlen; ++j) {
 				nestedLabel = label[j];
 				// Undefined labels and arrays should not be measured
 				if (!helpers.isNullOrUndef(nestedLabel) && !helpers.isArray(nestedLabel)) {
-					width = Math.max(width, measureText(ctx, data, gc, nestedLabel));
-					height += tickFont.lineHeight;
+					width = helpers.measureText(ctx, data, gc, width, nestedLabel);
+					height += lineHeight;
 				}
 			}
 		}
 		widths.push(width);
 		heights.push(height);
-		offsets.push(tickFont.lineHeight / 2);
+		offsets.push(lineHeight / 2);
 	}
 
-	gcLen = gc.length / 2;
-	if (gcLen > length) {
-		for (i = 0; i < gcLen; ++i) {
-			delete data[gc[i]];
+	helpers.each(cache, function(fontCache) {
+		var garbageCollect = fontCache.garbageCollect;
+		var gcLen = garbageCollect.length / 2;
+		if (gcLen > length) {
+			for (i = 0; i < gcLen; ++i) {
+				delete fontCache.data[garbageCollect[i]];
+			}
+			garbageCollect.splice(0, gcLen);
 		}
-		gc.splice(0, gcLen);
-	}
+	});
 
 	widest = widths.indexOf(Math.max.apply(null, widths));
 	highest = heights.indexOf(Math.max.apply(null, heights));