[GD-Windows] GetDeviceGammaRamp() is lieing to me

[Jon W. <hp...@mi...>]

In my program, I call GetDeviceGammaRamp() to read the user's 
active gamma settings. Then, if there's not "sufficient" gamma 
adjustment, I set my own gamma ramp with SetDeviceGammaRamp(). 
When the program exits, I restore the ramp I read back from 
GetDeviceGammaRamp() on start-up.

Unfortunately, it appears that the device is lieing to me. I 
get the data as such:

  WORD userRamp[ 768 ];
  HDC dc = CreateDC( "DISPLAY", 0, 0, 0 );
  GetDeviceGammaRamp( dc, userRamp );

What ends up happening is that I always get back some "default" 
gamma ramp with a little bit of compensation; I apply my own 
ramp, and then on shutdown I set the ramp "back" to some very 
low gamma setting.

If I go into my display control panel settings and crank the 
gamma way up (both "game gamma" and "desktop gamma"), then 
starting my program will still retrieve the same "default" gamma 
ramp, apply its ramp (which is dimmer), and on shutdown, set the 
screen to a very dim setting.

This is on a Radeon 9700, though I've heard similar problems 
from users with nVIDIA hardware as well.

What's going on?

                    / h+


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