Re: [Pysdl-devel] running SDL Scrolling program on exiting Video

[Charles D. <cd...@sp...>]

SDL is perhaps not the appropriate tool for this; interfering with
another program's window (or doing pathed window borders to simulate
this effect) is outside of its scope.

Perhaps you should consider PyOSD; see its web page at
http://repose.cx/pyosd/

Now, if PyOSD does not have all the capabilities you're interested in,
here comes the discouraging bit:

Note that (last time I was involved in TV work, about 6-8 years ago)
most software doing what you suggest produces output with a specific
background color which is then overlayed onto a different source via
specialized hardware, or is written to utilize hardware which can take
advantage of an alpha channel. While I'm by no means saying that what
you suggest to do is impossible, if you want capabilities such as
alpha-channel mixing, it may be a bit harder than you otherwise expect;
X and company were certainly not written with such capabilities in mind.

(One rather extreme approach that comes to mind is modifying an Xvfb
server to overlay a alpha-channel-enabled video stream over its output;
I'm certain, however, that this is far more complex than need be).