Here’s a tricky one

So it's only a coincidence... Still don't know what it could be... :(
Interestingly all the computers that produces black background have ZoneAlarm installed. Could this be the problem?
 
Look what I found (so I'm not alone with this problem):
Code: 
// Not clear why this is need to clear whole background to white;
// otherwise -- only sometimes -- part of bitmap is black instead.
RESULT.Canvas.Brush.Color := clWhite;
RESULT.Canvas.FillRect( RESULT.Canvas.ClipRect );
This would be the solution, but I can't use it without the source... :(
So I'm still hoping there's a windows setting that could solve the problem...
 
Interestingly all the computers that produces black background have ZoneAlarm installed. Could this be the problem?
Click to expand...
Now ur shooting in the dark! :P (no worries... been there done that.... still there :P)

I'll have a look around.. gimme some time ... been busy.
 
I FIGURED OUT AT LAST!

At the display settings I changed the color depth from 32 bpp to 16 bpp and the program works fine now!
But what the heck could be the difference between these two video settings?
 
What about 24bit ... oh and btw not to ruin your parade.... mine is on 32bit color and works fine (also works on 16 and 24)
 
I only have 16 or 32 at color depth options (my card is an ATI All-in-wonder), so I can't check what happens at 24 bit...
Could be a video-driver bug that produces that bitmap black-out?
 
Maybe an ATI/nvidia dealy? I wouldnt think so cuz i dont have any problems on my ATi based systems. What driver revisions have you tested on?
 
It's surely not an ATI/Nvidia thing, because on another computer there's an Nvidia and the background is also black.
I'll test that computer's video settings too in a couple of days...
 
Tested the NVidia too. And it works the same way: 32 bpp -> black, 16 or 24 bpp -> white.
On my computer I had 3 versions of ATI drivers so far, and every time it was a bitmap blackout. But I had the same video card and display settings on Win98 too, and it was ok...

So:
1. Only happens in XP
2. This problem does not affect all systems
3. Not depends on video card manufacturer
4. It's not a driver bug
5. Only happens in 32 bpp
6. Not depends on any other settings (transparencies, etc.)

What could it be then?
 
BTW, what’s the 32 bpp thing?
24 bpp means that there is 1 byte for each colour (R, G, B), thus 256 shades on every channel. This gives a total of 16.777.216 possible colours.
An RGB image saved in 32 bpp colour depth has in fact a 24 bpp RGB colour space combined with 1 byte alpha channel (for transparency). So it has also 16.777.216 possible colours.
But what’s the difference between the 24 bpp and the 32 bpp display setting? What’s the use of that extra byte?
 
Only happens in 32 bpp
Click to expand...
Mine was 32bit and didnt have a problem.

As for 32bit, there IS a reason for it:
TGA - The real name for this format is just plain "TGA" or "Truevision File Format", but a lot of people call it "Targa", after the Truevision video card that first used it. There's a lot of this name confusion in image file formats. It supports 1 to 32 bit images and professional features like an alpha (mask) channel, gamma settings and a built-in thumbnail image.
Click to expand...
32 bit textures are typically only tga (Targa) files. A 32 bit texture includes 'built in' transparency via an 8 bit alpha mask, which is laid over a 24 bit true color bitmap. This gives you up to 255 different variations in transparency, which is quite a few.
Click to expand...

Mostly image/texture creation and gamedev will have actual use of 32bit color
 
Look what I found:
Some versions of XP and 2003 do not create 32bpp icons properly in the drivebar.
Click to expand...
(This text was listed at some program's bugs.)
Is it possible that we have different versions of XP?
 
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