Re[2]: [paragui-users] messages

[taurus]

Hello Teunis,

Friday, November 08, 2002, 18:43:45, you wrote:

TP> On Fri, 8 Nov 2002, taurus wrote:

>> PS. I`ve posted 2 questions about zooming and transparent fading, but
>> didn`t receive any answer... I have problems to cross-fade 2 pictures,
>> maybe anybody has any thoughts - I will appreciate any help!

TP> cross-fade?  there's lots of ways.  Note that rendering SDL_Surface*
TP> on a widget is fairly easy....  ummm.

Hm, I`ve faced one strange problem when blitting with alpha...
In cycle I fade from black to normal 1st picture, then I start to fade
from transparent to opaque the 2nd one...
What I`ve got is: after 1st is ready, the widget is cleaned (filled
with black) :( and when the 2nd starts, it goes from transparent on
black instead of overlapping with the 1st!
What I`m doing wrong?

My algorithm:

create temp srf
cycle
{
      set alpha for pic1
      blit pic1 to srf

      blit srf to screen
}

cycle
{
      set alpha for pic2
      blit pic2 to srf

      blit srf to screen
}


Mess in alpha settings??

TP> Also zooming's possible using the scaling blit functions provided.

Yep, I know that, but if I need to zoom only a rect from the surface
(like magnify effect)? I`ve solved it by creating a small temp surface
and zoomblitting in on the dest surface. In sum, there are 4
creating/destroying temp surface sequences (blit, zoomblit, blit,
blit), and it makes one frame for 100 ms on P4/1.5GHz for 800x600x30...
The only way to optimize it - zoom rect of a surface directly to a
surface, as I understand there is no function even in SDL_gfx.
So, I`m going to implement it.




Kind regards,
       taurus                          

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