diff --git a/www/js/ui.js b/www/js/ui.js
index 12ba7de..29fee72 100644
--- a/www/js/ui.js
+++ b/www/js/ui.js
@@ -454,8 +454,8 @@ const UI = {
     },
 
     draw_play_icons(canvas, moves) {
-        canvas.width = canvas.clientWidth;
-        canvas.height = canvas.clientHeight;
+        canvas.width = canvas.clientWidth * (window.devicePixelRatio || 1);
+        canvas.height = canvas.clientHeight * (window.devicePixelRatio || 1);
         let ctx = canvas.getContext("2d");
 
         let size = canvas.height / 2;