#454 – UseLayoutRounding vs. SnapsToDevicePixels

The UIElement class has a SnapsToDevicePixels property that controls pixel snapping.  When set to true for a top-level element, all child elements will be set to line up with pixel boundaries at render time, to avoid anti-aliasing.

In .NET 4.0, the FrameworkElement class got a UseLayoutRounding property that also prevents anti-aliasing by snapping things to device pixels.

When you use the  UseLayoutRounding property, objects are lined up with pixel boundaries during the Measure and Arrange passes of the layout process.  When you use the SnapsToDevicePixels property, pixel snapping occurs when rendering elements.

You should use UseLayoutRounding when possible, or use SnapsToDevicePixels on child elements when it’s not possible to use UseLayoutRounding.