Re: [pygame] Problem: difference in surface alpha from pygame 1.7 and 1.8

[Lenard Lindstrom <len-l@xxxxxxxxx>]

James Paige wrote:
> On Mon, Dec 15, 2008 at 09:39:08AM +0100, Luca wrote:
>   
> > On Mon, Dec 15, 2008 at 12:36 AM, René Dudfield <renesd@xxxxxxxxx> wrote:
> >     
> > > hi,
> > >
> > > There were some bugs with 1.7.x with some surface arguments.
> > >       
> > Thanks for replying, but I found more natural the old 1.7 behaviour...
> > Now seems that the set_alpha is ignored... It's strange.
> >     
>
> I think in 1.7 you were getting a surface with no per-pixel alpha. 
> therefore you could use .set_alpha() to change the alpha for the whole 
> surface.
>
>   
There were some issues with what a surface defaults too before pygame 
was initialized and pygame.display.set_mode() called. For 1.8 and about 
the default is 32 bit with per-pixel alpha. I seem to remember that this 
change was necessary because what 1.7 did was buggy. And I don't 
remember per-pixel alpha surfaces using set_alpha() in 1.7.

> Now in 1.8 you are getting a surface with per-pixel alpha. That means 
> that .set_alpha() will not work.
>
> I know you can use .convert_alpha() to force a surface to have per-pixel 
> alpha, but I don't know if there is any way to force a surface NOT to 
> have per-pixel alpha.
>
>   
According to the documents .set_alpha(None) turns off per-pixel alpha. 
It removes the SRCALPHA flag anyways. This may be new to Pygame 1.9. I 
don't remember seeing it before.

--
Lenard Lindstrom
<len-l@xxxxxxxxx>