🚀 go-pugleaf

In article <1991May19.152505.11357@sunee.waterloo.edu> gpsteffl@sunee.waterloo.edu (Glenn Steffler) writes:
Glenn>In article <1688@anaxagoras.ils.nwu.edu> neves@aristotle.ils.nwu.edu (David Neves) writes:
David>
David>We want to do some simple animation in Windows.  If anyone has some
David>pointers on this I would appreciate them.
[...]
David>One way we are considering is to prepare several bitmapped objects and
David>bitblt them (using BITBLT) to a complicated bitmapped background.  The
David>problem as I perceive it is how to specify the part of the bitmap you
David>want copied to the screen.  For example, lets say you have a donut
David>picture and want to send it to the screen.  The bitmap of the donut is
David>rectangular but the object is circular and it has an interior circle
David>that also must show the background.  Is there some secret transparent
David>color that one can use to construct the bitmap?  Or?
[...]
Glenn>
Glenn>Quick answer...NO.  Longer answer would ask you to phone those 
Glenn>nice people at Microsoft and inquire about the Multimedia Toolkit
Glenn>or Developement Kit for Windows.
Glenn>

Glenn "two days" Steffler,

Multimedia Windows DOES provide a transparent BLIT that does what
you want.  The background color in the source bitmap is not copied 
while everything else is...

Another way to avoid complete rectangular updates is to use the RLE
format of DIBs to do a delta-frame.  This method is available under
regular Windows.  The DIB format is not very well documented in the
regular Windows documentation, but the final Multimedia Development Kit 
(MDK) will document it pretty completely.

We have also improved the speed of graphic operations using DIBs  in
the Multimedia Extensions by implementing these operations directly 
in the video drivers instead of letting GDI simulate.

If anyone would like the Beta for the Multimedia Extensions, please
call 206 936-4082 and request an application packet.


Matt Saettler
Microsoft Multimedia Systems

Opinions expressed are my own.....