Fix charts shinking in size on certain Zoom values in Chrome (#12097)

Author: bojidar-bg

src/helpers/helpers.dom.ts

@@ -211,11 +211,11 @@ export function retinaScale(
   forceStyle?: boolean
 ): boolean | void {
   const pixelRatio = forceRatio || 1;
-  const deviceHeight = Math.floor(chart.height * pixelRatio);
-  const deviceWidth = Math.floor(chart.width * pixelRatio);
+  const deviceHeight = round1(chart.height * pixelRatio);
+  const deviceWidth = round1(chart.width * pixelRatio);
 
-  (chart as PrivateChart).height = Math.floor(chart.height);
-  (chart as PrivateChart).width = Math.floor(chart.width);
+  (chart as PrivateChart).height = round1(chart.height);
+  (chart as PrivateChart).width = round1(chart.width);
 
   const canvas = chart.canvas;
 

test/specs/helpers.dom.tests.js

@@ -268,8 +268,8 @@ describe('DOM helpers tests', function() {
     helpers.retinaScale(chart, devicePixelRatio, true);
 
     var canvas = chart.canvas;
-    expect(canvas.width).toBe(Math.floor(chartWidth * devicePixelRatio));
-    expect(canvas.height).toBe(Math.floor(chartHeight * devicePixelRatio));
+    expect(canvas.width).toBe(Math.round(chartWidth * devicePixelRatio));
+    expect(canvas.height).toBe(Math.round(chartHeight * devicePixelRatio));
 
     expect(chart.width).toBe(chartWidth);
     expect(chart.height).toBe(chartHeight);