QT 4.7.2 : Hardware Accelaration causes font corruption and images not displayed

[AGRAWAL]

Hello,

I have been developing a QT Application using Visual Studio IDE and QT 4.7.1 and 4.7.2. The application uses DrawText (Arial font) and also displays GIF and JPG images using QPainter::drawPixmap. The font and images were good on my laptop and some other laptops. But then we had to use this on multiple machines including desktops. On most of the desktops, images were not displayed and text was garbled. We then found that changing Hardware Acceleration setting from Full to None; and Unchecking "Enable write combining" in the display properties fixes the problem. This means hardware acceleration worsens the graphics in this scenario.
Does anyone have more information on this, what is causing this. Can this display be made independent of Hardware Acceleration settings.

We have to distribute this software to external clients and we should not require to ask them to change hardware acceleration settings.

Thanks in advance.
Anil

[ChrisW67]

Since the deployed software didn't change, and the surrounding environment did, the trigger/cause is in the surrounding environment. Isolation of the problem requires more than just the Qt version number. "Hardware Acceleration" is a setting of the video driver, and write-combining is a low level motherboard behaviour setting, and nothing that is within Qt's control.

How about you share a little information about what was common between the machines it did not work on.

What is the video hardware? Is that common between malfunctioning devices?
What is the video driver version? Is it the latest available? Is that common between malfunctioning devices?
What is the operating system? Is that common between malfunctioning devices?
Does the problem persist if you start your application with the software raster renderer? (Should be the default on Windows but worth a try)

myexe -graphicssystem raster

myexe -graphicssystem raster

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Have you searched Qt bug reports for the video hardware type?

[AGRAWAL]

Response:

What is the video hardware? Is that common between malfunctioning devices?
Mostly common but not all. All desktops had the problem but one laptop also has the problem. Desktops have Plug and Play Monitor. Display adapter "Intel(R) 946GZ Express Chipset Family".

What is the video driver version? Is it the latest available? Is that common between malfunctioning devices?
Video driver version is not the latest but is common between malfunctioning devices.

What is the operating system? Is that common between malfunctioning devices?
OS is XP SP2. Is common among all devices including the ones where it works.

Does the problem persist if you start your application with the software raster renderer? (Should be the default on Windows but worth a try)
I will try this.

Thanks for your advise, based on that I will try updating the driver etc. I am also hoping for something within QT that should fix this problem.

Anil