Over the weekend, TheMuuj mentioned in a comment:

As far as I know, there are new classes in Whidbey for drawing text with GDI (as a result of GDI+'s questionable screen rendering in some cases). Are these based on DrawText?

This is not exactly the reason. There are two basic problems that come into play with GDI+:

  • There are some performance issues caused by the somewhat stateless nature of GDI+, where device contexts would be set and then the original restored after each call.
  • The shaping engines for international text have been updated many times for Windows/Uniscribe and for Avalon, but have not been updated for GDI+, which causes international rendering support for new languages to not have the same level of quality.

The object is the System.Windows.Forms.TextRenderer class, which has two methods that can be used to render text using GDI/Uniscribe rather than GDI+:

  • DrawText - Draws the specified text at the specified location using the specified device context, font, and color.
  • MeasureText - Measures the specified text when drawn with the specified font.

This class and these methods (which have several different overrides) allow WinForms to support new languages as the OS support is added. For example, the ELK support in Windows XP SP2 added font and rendering support to the operating system for Bengali and Malayalam, but versions 1.0 and 1.1 of the .NET Framework would not render these scripts properly, even when the right font was being used. However, version 2.0 (Whidbey) will be able to properly support these scripts whenever the OS can support them....

I have not personally experienced the performance issues but have beentold by people who have that the support can also very useful. I am more of a "language support" guy myself, though. :-)

 

This post brought to you by "আ" (U+0986, BENGALI LETTER AA)
(A letter that was happy to see proper rendering support of Bengali and Assamese conuncts in managed code using XP SP2 and Whidbey!)