Editing ClearType (section)

===ClearType in WPF===
All text in [[Windows Presentation Foundation]] is anti-aliased and rendered using ClearType. There are separate ClearType registry settings for GDI and WPF applications, but by default the WPF entries are absent, and the GDI values are used in their absence. WPF registry entries can be tuned using the instructions<ref>[http://blogs.msdn.com/text/archive/2006/10/18/tips-for-improving-your-wpf-text-rendering-experience.aspx Tips for improving your WPF text rendering experience]</ref> from the MSDN WPF Text Blog.

ClearType in WPF supports sub-pixel positioning, natural advance widths, Y-direction [[anti-aliasing]] and [[hardware acceleration]]. WPF supports aggressive caching of pre-rendered ClearType text in video memory.<ref>[http://msdn2.microsoft.com/en-us/library/ms749295.aspx MSDN Library : .NET Development : WPF : ClearType Overview]</ref> The extent to which this is supported is dependent on the [[video card]]. [[DirectX]] 10 cards will be able to cache the font glyphs in video memory, then perform the composition (assembling of character glyphs in the correct order, with the correct spacing), [[alpha blending]] (application of [[anti-aliasing]]), and RGB blending (ClearType's sub-pixel color calculations), entirely in hardware. This means that only the original glyphs need to be stored in video memory once per font (Microsoft estimates that this would require 2&nbsp;MB of video memory per font), and other operations such as the display of anti-aliased text on top of other graphics{{snd}} including video{{snd}} can also be done with no computation effort on the part of the CPU. DirectX 9 cards will only be able to cache the alpha-blended glyphs in memory, thus requiring the CPU to handle glyph composition and alpha-blending before passing this to the video card.  Caching these partially rendered glyphs requires significantly more memory (Microsoft estimates 5&nbsp;MB per process). Cards that don't support DirectX 9 have no hardware-accelerated text rendering capabilities.