Merge from vscode 718331d6f3ebd1b571530ab499edb266ddd493d5

src/vs/editor/browser/viewParts/minimap/minimapCharRenderer.ts

@@ -5,6 +5,7 @@
 
 import { RGBA8 } from 'vs/editor/common/core/rgba';
 import { Constants, getCharIndex } from './minimapCharSheet';
+import { toUint8 } from 'vs/base/common/uint';
 
 export class MinimapCharRenderer {
 	_minimapCharRendererBrand: void;
@@ -20,7 +21,7 @@ export class MinimapCharRenderer {
 	private static soften(input: Uint8ClampedArray, ratio: number): Uint8ClampedArray {
 		let result = new Uint8ClampedArray(input.length);
 		for (let i = 0, len = input.length; i < len; i++) {
-			result[i] = input[i] * ratio;
+			result[i] = toUint8(input[i] * ratio);
 		}
 		return result;
 	}