I have been doing some tests with the WPF 4 cached composition in chronos as a way of try to improve performance when dragging windows and widgets on Render Tier 1 machines.
Using cached composition on windows and widgets improves the dragging performance dramatically, but, the text maybe rendered a bit blurry, while it remains perfectly readable (it’s the first time i use the cached composition support of WPF 4 so maybe i have done something wrong).
I have done the test on a Rendering Tier 1 machine with Windows XP at 1280×1024, using two fonts:
- Segoe WP (It’s the default font on Chronos v2.0)
- Segoe UI.
The Cache mode property in the WorkspaceWindowStyle and WidgetStyle styles has been set as:
<BitmapCache EnableClearType="True" RenderAtScale="1" SnapsToDevicePixels="True" />
And finally the TextFormatting mode has been set as Display for one of the tests.
<Setter Property="TextOptions.TextFormattingMode" Value="Display" />
The screenshots shows the Chronos Navigator widget
- Without using cached composition.
- Using Cached composition.
- Using Cached composition and the Display Text Formatting mode.
Here are the results when using Segoe WP.

And here when using Segoe UI.

Text rendering was better when using Segoe UI font, but that was expected.
Hope i will include cached composition support on widgets and windows in the Beta 2 of Chronos for Rendering Tier 1 machines.
Update: Test on Rendering Tier 2 machine, Windows 7 at 1920×1200, using the Magnifier Tool at 300%, using Segoe WP font
