add test.html

index.js

@@ -8,12 +8,14 @@
  */
 
 module.exports = function(canvas){
-  var ratio = window.devicePixelRatio || 1;
-  canvas.style.width = canvas.width;
-  canvas.style.height = canvas.height;
-  canvas.width *= ratio;
-  canvas.height *= ratio;
   var ctx = canvas.getContext('2d');
-  ctx.scale(ratio, ratio);
+  var ratio = window.devicePixelRatio || 1;
+  if (1 != ratio) {
+    canvas.style.width = canvas.width;
+    canvas.style.height = canvas.height;
+    canvas.width *= ratio;
+    canvas.height *= ratio;
+    ctx.scale(ratio, ratio);
+  }
   return canvas;
 };

test.html

@@ -0,0 +1,8 @@
+<canvas width=200 height=200></canvas>
+<script>
+  var canvas = document.querySelector('canvas');
+  var ctx = canvas.getContext('2d');
+  ctx.strokeRect(0, 0, 200, 200);
+  ctx.font = '28px Helvetica';
+  ctx.fillText('[o_O]', 60, 100);
+</script>