Merge pull request #266 from hulkholden/fix_hidpi

[dygraphs.git] / auto_tests / tests / Util.js

diff --git a/auto_tests/tests/Util.js b/auto_tests/tests/Util.js
index 2793cb7..0e2c25d 100644 (file)
--- a/auto_tests/tests/Util.js
+++ b/auto_tests/tests/Util.js
@@ -91,7 +91,9 @@ Util.samplePixel = function(canvas, x, y) {
   // TODO(danvk): Any performance issues with this?
   var imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
 
-  var i = 4 * (x + imageData.width * y);
+  var scale = Dygraph.getContextPixelRatio(ctx);
+
+  var i = 4 * (x * scale + imageData.width * y * scale);
   var d = imageData.data;
   return [d[i], d[i+1], d[i+2], d[i+3]];
 };