From bd60fa2dfd25bae95520e7968a72eecac218f7ba Mon Sep 17 00:00:00 2001
From: Simon Brunel <simonbrunel@users.noreply.github.com>
Date: Sat, 18 Mar 2017 11:54:56 +0100
Subject: [PATCH] Correctly handle decimal display size (#4009)

Fix the `readUsedSize` regular expression to correctly parse (truncate) pixel decimal values.
---
 src/platforms/platform.dom.js    |  2 +-
 test/specs/platform.dom.tests.js | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/platforms/platform.dom.js b/src/platforms/platform.dom.js
index 761337b061c..317d4bfed73 100644
--- a/src/platforms/platform.dom.js
+++ b/src/platforms/platform.dom.js
@@ -33,7 +33,7 @@ module.exports = function(Chart) {
 	 */
 	function readUsedSize(element, property) {
 		var value = helpers.getStyle(element, property);
-		var matches = value && value.match(/(\d+)px/);
+		var matches = value && value.match(/^(\d+)(\.\d+)?px$/);
 		return matches? Number(matches[1]) : undefined;
 	}
 
diff --git a/test/specs/platform.dom.tests.js b/test/specs/platform.dom.tests.js
index 06562c9191f..898de9c4842 100644
--- a/test/specs/platform.dom.tests.js
+++ b/test/specs/platform.dom.tests.js
@@ -226,6 +226,24 @@ describe('Platform.dom', function() {
 				rw: 165, rh: 85,
 			});
 		});
+
+		// https://github.com/chartjs/Chart.js/issues/3860
+		it('should support decimal display width and/or height', function() {
+			var chart = acquireChart({
+				options: {
+					responsive: false
+				}
+			}, {
+				canvas: {
+					style: 'width: 345.42px; height: 125.42px;'
+				}
+			});
+
+			expect(chart).toBeChartOfSize({
+				dw: 345, dh: 125,
+				rw: 345, rh: 125,
+			});
+		});
 	});
 
 	describe('config.options.responsive: true (maintainAspectRatio: true)', function() {