};
/**
+ * Returns the context's pixel ratio, which is the ratio between the device
+ * pixel ratio and the backing store ratio. Typically this is 1 for conventional
+ * displays, and > 1 for HiDPI displays (such as the Retina MBP).
+ * See http://www.html5rocks.com/en/tutorials/canvas/hidpi/ for more details.
+ *
+ * @param {!CanvasRenderingContext2D} context The canvas's 2d context.
+ * @return {number} The ratio of the device pixel ratio and the backing store
+ * ratio for the specified context.
+ */
+Dygraph.getContextPixelRatio = function(context) {
+ try {
+ var devicePixelRatio = window.devicePixelRatio || 1,
+ backingStoreRatio = context.webkitBackingStorePixelRatio ||
+ context.mozBackingStorePixelRatio ||
+ context.msBackingStorePixelRatio ||
+ context.oBackingStorePixelRatio ||
+ context.backingStorePixelRatio || 1;
+ return devicePixelRatio / backingStoreRatio;
+ } catch (e) {
+ return 1;
+ }
+};
+
+/**
* Checks whether the user is on an Android browser.
* Android does not fully support the <canvas> tag, e.g. w/r/t/ clipping.
* @return {boolean}