psymaster@caths.co.uk wrote:
I have written a program that does a slideshow, but I want to make the
transition softer, and I want to do this by fading between the two
images.
Anybody can point me to more info about how this can be done in
pygame?
You can set the image alpha value to something like 20 and blit it
several times. This won't be entirely fast but it gives you a decent
fade speed. Eventually you should blit the 'opaque' version of the
image so you are really seeing the right thing. This will be pretty
slow, so be careful. Perhaps give the transition a time limit, so if
the transparent blits are slow it will only do 1 or 2 in between
steps.
I'd recommend using some simple "wipe" effects where you just draw
sections of the image from the top down. This will run fast and easy.
No performance problems on the slowest of platforms.
Or, if you don't mind making your software depend on OpenGL.. it's
definitely the best way to do transitions between images. Apple uses
this technique quite often, in Keynote or any other time that there's a
full-screen fade. As of OS X 10.2, even their WindowServer tries to do
most things with OpenGL (if the video card supports non-power-2
textures, and some other things).