fix: Chart shrinking uncontrollably on browser zoom (chartjs#11089)

Author: gbaron

src/helpers/helpers.dom.ts

@@ -200,7 +200,7 @@ export function getMaximumSize(
   const maintainHeight = bbWidth !== undefined || bbHeight !== undefined;
 
   if (maintainHeight && aspectRatio && containerSize.height && height > containerSize.height) {
-    height = containerSize.height;
+    height = Math.round(containerSize.height);
     width = round1(Math.floor(height * aspectRatio));
   }
 

test/specs/helpers.dom.tests.js

@@ -545,4 +545,21 @@ describe('DOM helpers tests', function() {
 
     document.body.removeChild(container);
   });
+
+  it('should respect aspect ratio and container height and return height as integer', () => {
+    const container = document.createElement('div');
+    container.style.width = '500px';
+    container.style.height = '200px';
+
+    document.body.appendChild(container);
+
+    const target = document.createElement('div');
+    target.style.width = '500px';
+    target.style.height = '500px';
+    container.appendChild(target);
+
+    expect(helpers.getMaximumSize(target, 500, 199.975, 1)).toEqual(jasmine.objectContaining({width: 200, height: 200}));
+
+    document.body.removeChild(container);
+  });
 });