Display problems with Cleartype enabled

[Michael Keppler]

Hi, on all systems with WindowsXP, where ClearType is activated for smoother font renderings (in control panel, display settings, effects), we have display problems in lists where the list items are much wider than the list. This can be reproduced by opening a configuration maps browser, scrolling to the end of the list and then scrolling the left list (with the configuration map names) somewhat to the left and to the right.

If you reproduce the behaviour, you can see that the display artifacts become stronger with each graphical update (caused by moving the scrollbar left and right). Therefore I have the suspicion that the display area is not set to a clear background which causes the ClearType rendering to take the already existing black pixels (from the last graphical update) into its calculation which causes a saturation effect on all pixels that are changed by the ClearType font rendering.

The effect does only occur for items, where the tooltip is wider than the list itself. That's why two list items in the attached screen shot are displayed correctly. The effect occurs in the IDE and also in our shipped applications.

If needed, I can also provide you with a video showing how to reproduce that effect.

[marten]

Hello Michael,

I tried it here at home (XP Pro and VA 7.5.2) and I can not see this behaviour.

Another question: why is the background of your window (screenshot) not white ???

[marten]

I follow up in this thread - because this might be related with each other.

I use V8.0 Beta 1 and the "Tahoma" font is - with this version - the default font for code. I noticed - more or less - rendering problems with this font in the code browser.

This seems to be related with the syntax coloring available with VAAssist. When I turn off the coloring syntax mode, the problems are not there any more. The character "[" is very often - with the default size - only readable as "|". I increase the Tahoma font size to 10 to reduce the problems.

Another way to get rid of these problems is to turn off "ClearType" smoothing rendering within Windows XP

Turning on "bold" on that used font also reduces the problems - but they are still there.