From abef7a2e4d230577dc476ab034d1da70d93172b2 Mon Sep 17 00:00:00 2001
From: Evert Timberg <evert.timberg+github@gmail.com>
Date: Fri, 7 Oct 2016 20:39:24 -0400
Subject: [PATCH] Properly merge colors for the label colors in the tooltip. I
 added a private helper to simplify the code in the tooltip

---
 src/core/core.tooltip.js | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/src/core/core.tooltip.js b/src/core/core.tooltip.js
index 54f9f49f5f7..8a0afe3dce0 100755
--- a/src/core/core.tooltip.js
+++ b/src/core/core.tooltip.js
@@ -4,6 +4,14 @@ module.exports = function(Chart) {
 
 	var helpers = Chart.helpers;
 
+	/**
+ 	 * Helper method to merge the opacity into a color
+ 	 */
+	function mergeOpacity(colorString, opacity) {
+		var color = helpers.color(colorString);
+		return color.alpha(opacity * color.alpha()).rgbaString();
+	}
+
 	Chart.defaults.global.tooltips = {
 		enabled: true,
 		custom: null,
@@ -556,8 +564,7 @@ module.exports = function(Chart) {
 				}
 			}
 
-			var bgColor = helpers.color(vm.backgroundColor);
-			ctx.fillStyle = bgColor.alpha(opacity * bgColor.alpha()).rgbString();
+			ctx.fillStyle = mergeOpacity(vm.backgroundColor, opacity);
 			ctx.beginPath();
 			ctx.moveTo(x1, y1);
 			ctx.lineTo(x2, y2);
@@ -575,8 +582,7 @@ module.exports = function(Chart) {
 				var titleFontSize = vm.titleFontSize,
 					titleSpacing = vm.titleSpacing;
 
-				var titleFontColor = helpers.color(vm.titleFontColor);
-				ctx.fillStyle = titleFontColor.alpha(opacity * titleFontColor.alpha()).rgbString();
+				ctx.fillStyle = mergeOpacity(vm.titleFontColor, opacity);
 				ctx.font = helpers.fontString(titleFontSize, vm._titleFontStyle, vm._titleFontFamily);
 
 				var i, len;
@@ -598,8 +604,7 @@ module.exports = function(Chart) {
 			ctx.textAlign = vm._bodyAlign;
 			ctx.textBaseline = 'top';
 
-			var bodyFontColor = helpers.color(vm.bodyFontColor);
-			var textColor = bodyFontColor.alpha(opacity * bodyFontColor.alpha()).rgbString();
+			var textColor = mergeOpacity(vm.bodyFontColor, opacity);
 			ctx.fillStyle = textColor;
 			ctx.font = helpers.fontString(bodyFontSize, vm._bodyFontStyle, vm._bodyFontFamily);
 
@@ -624,15 +629,15 @@ module.exports = function(Chart) {
 					// Draw Legend-like boxes if needed
 					if (drawColorBoxes) {
 						// Fill a white rect so that colours merge nicely if the opacity is < 1
-						ctx.fillStyle = helpers.color(vm.legendColorBackground).alpha(opacity).rgbaString();
+						ctx.fillStyle = mergeOpacity(vm.legendColorBackground, opacity);
 						ctx.fillRect(pt.x, pt.y, bodyFontSize, bodyFontSize);
 
 						// Border
-						ctx.strokeStyle = helpers.color(vm.labelColors[i].borderColor).alpha(opacity).rgbaString();
+						ctx.strokeStyle = mergeOpacity(vm.labelColors[i].borderColor, opacity);
 						ctx.strokeRect(pt.x, pt.y, bodyFontSize, bodyFontSize);
 
 						// Inner square
-						ctx.fillStyle = helpers.color(vm.labelColors[i].backgroundColor).alpha(opacity).rgbaString();
+						ctx.fillStyle = mergeOpacity(vm.labelColors[i].backgroundColor, opacity);
 						ctx.fillRect(pt.x + 1, pt.y + 1, bodyFontSize - 2, bodyFontSize - 2);
 
 						ctx.fillStyle = textColor;
@@ -660,8 +665,7 @@ module.exports = function(Chart) {
 				ctx.textAlign = vm._footerAlign;
 				ctx.textBaseline = 'top';
 
-				var footerFontColor = helpers.color(vm.footerFontColor);
-				ctx.fillStyle = footerFontColor.alpha(opacity * footerFontColor.alpha()).rgbString();
+				ctx.fillStyle = mergeOpacity(vm.footerFontColor, opacity);
 				ctx.font = helpers.fontString(vm.footerFontSize, vm._footerFontStyle, vm._footerFontFamily);
 
 				helpers.each(footer, function(line) {
@@ -671,8 +675,7 @@ module.exports = function(Chart) {
 			}
 		},
 		drawBackground: function(pt, vm, ctx, tooltipSize, opacity) {
-			var bgColor = helpers.color(vm.backgroundColor);
-			ctx.fillStyle = bgColor.alpha(opacity * bgColor.alpha()).rgbString();
+			ctx.fillStyle = mergeOpacity(vm.backgroundColor, opacity);
 			helpers.drawRoundedRectangle(ctx, pt.x, pt.y, tooltipSize.width, tooltipSize.height, vm.cornerRadius);
 			ctx.fill();
 		},