Re: Update: Windows, GMastermind2

[Sheldon Gill]

carmstrong _AT_ fastmail dot com dot au wrote:
> Sheldon Gill wrote:
> > The problem isn't related to TIFF or any other file format. The problem isn't
> > really Windows, either. Its because of the way the backend is architected and
> > how it handles the image data. How to fix it is proving tricky.
>
> May I ask how it handles image data that is known to cause the problem?

A couple of things here.

The AlphaBlend() function has a number of limitations, one of which is source 
information must be in 32-bits per pixel single plane, ARGB LE format.

The backend is writing to device dependent bitmaps so what happens to the data 
is up to the driver. Many don't support an alpha channel so it gets quietly 
dropped.

Also, since it's device dependent and you have to have 32-bits running in 
16-bit or 24-bit mode ruins everything.

> What about its architecture that makes Windows problematic? It could be
> a matter of restructuring some gnustep-gui code (that isn't likely to
> be easy) or migrating it to a new API for compositing that suits better
> cross-platform needs. Is it something in the way colours are stored or
> how we handle device handles (HDC's)?

Actually, I've found a solution to the problem. Will update sometime in the 
next few days.


Regards,
Sheldon