refresh problem using app over terminal server

[bartdeman]

Hello,

I am having problems related to the refreshing of the canvas. It seems that sometimes part of the canvas is not correctly refreshed. I see this behaviour when running on the server and accessing it through remote desktop. But the weird thing is that everything is ok when i run the app locally on my pc.

To illustrate:
this is how the canvas looks as it should be:


and this is after clicking an element (a new element with the adornments is added then). You see the grey area behind the new element.


I troubleshooted already for possible causes like the background of the added element, the opacity,... but did not find anything. Also i tried out different settings for the remote desktop connection (color depth, user experience settings).

Any idea what might cause this?
As a workaround, is there a way to 'force' a complete redraw of the visible area of the canvas?

[jfmopt]

Frank already answered about that problem in this post:

viewtopic.php?f=1&t=514

According to Frank the issue is with the remote desktop's display driver, although I haven't yet seen this problem with another software.

[Frank Hileman]

Hello,

Can you please send us a copy of the app that does this or some simple reproducible test? The area drawn in a different is the area drawn by VG.net to update the screen. Why is it a different color? It is surely a bug in the driver, but we would like to investigate and possibly to find a work-around. Please let us know as well what operating system is the client and server.

You can cause the Canvas to refresh by calling Canvas.Invalidate (it is a Control method). If that does nothing, we would like to investigate to ensure the problem is not in the backing bitmap. However there is no reason the backing bitmap would behave differently in a remote display, since it is not on the screen.

Regards,

[Frank Hileman]

Hello,

Also if someone could determine if the VG.net sample "Animation.exe" also has the problem, we might be able to narrow it down. That is, is it always a problem, or only in certain circumstances.

Regards,

[Frank Hileman]

Just realized the first post was in June 20 2009. Not sure why I missed that but I doubt the original poster is monitoring the thread. At any rate, anyone who has this problem, we would like more information if you can get it, or a test.

Thanks,

[jfmopt]

Sorry, I also didn't notice that the post was so old. It wasn't answered so I thought it was new.

His problem looks exactly as in the one in my post, although the image is no longer available.

I can confirm that it happens consistently under at least these conditions:
Windows XP Remote Desktop in 16bit color mode.
When there are very few pictures in the canvas (I have a big white empty picture that is the model workspace and one small picture that represents a task).
Moving the small picture will expand the darker area.
When I add more pictures to the canvas the problem seems to disappear. Although I think that the darker color seems to replace the full white when this happens.

This issue it's no longer in my priority so I don't think I will be able to make an example soon, I'm sorry.

[Frank Hileman]

I tried again, but still could not reproduce it.
Thanks,