X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph-utils.js;h=4f90c65e2480a9a992b823e6dab35fc680c4679b;hb=9f79cb9489fd18858e4f5b661cb4b03be988b3b3;hp=f4bb2ffccdabce5207cc62d63402e1fa39fbdcf0;hpb=8887663f6cb6a96cecc1c88d46720438cbab9db0;p=dygraphs.git

diff --git a/dygraph-utils.js b/dygraph-utils.js
index f4bb2ff..4f90c65 100644
--- a/dygraph-utils.js
+++ b/dygraph-utils.js
@@ -735,13 +735,13 @@ Dygraph.getContextPixelRatio = function(context) {
                             context.mozBackingStorePixelRatio ||
                             context.msBackingStorePixelRatio ||
                             context.oBackingStorePixelRatio ||
-                            context.backingStorePixelRatio;
-    if (devicePixelRatio !== undefined &&
-        backingStorePixelRatio !== undefined) {
+                            context.backingStorePixelRatio || 1;
+    if (devicePixelRatio !== undefined) {
       return devicePixelRatio / backingStoreRatio;
     } else {
-      // If either value is undefined, the ratio is meaningless so we want to
-      // return 1.
+      // At least devicePixelRatio must be defined for this ratio to make sense.
+      // We default backingStoreRatio to 1: this does not exist on some browsers
+      // (i.e. desktop Chrome).
       return 1;
     }
   } catch (e) {