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From: ervin@pinbot.enet.dec.com (Joseph James Ervin)
Newsgroups: comp.sys.handhelds
Subject: HP48SX Screen Dissolver (DISS)
Message-ID: <20652@shlump.nac.dec.com>
Date: 1 Mar 91 15:11:17 GMT
Sender: newsdaemon@shlump.nac.dec.com
Reply-To: ervin@pinbot.enet.dec.com (Joseph James Ervin)
Organization: Digital Equipment Corporation
Lines: 59

Hello all,

I have finally finished the first version of "DISS",  my screen dissolver 
program.

What is a "screen dissolver" you ask?

The program takes two arguments:

2: real number (zero or one)
1: GROB (131x64)

The program will do different things with the GROB depending on whether a 1 or
a 0 is in level 2.  If level 2 contains a 0, then the program will do a
bit-wise dissolve of the GROB on level 1 into PICT.  The idea here is that you
would use DISS in a program  after previously displaying some graphic
image via 
PVIEW.  When you execute DISS, the new graphic on level 1 will replace
the
graphic currently on the display 1 pixel at a time, in a random fashion.

If a 1 is on level 2 when DISS is executed, then instead of doing a bit-wise
dissolve, it will do what I call "tiling".  In this mode of operation, the
program will move random _nibbles_ from the level 1 GROB into PICT, rather than
doing one bit at a time.  The effect is slightly different, and it runs around
5 times as fast as the bit-wise dissolve (5 seconds for a bit-wise dissolve,
and 1 second for tiling).  I think both modes look pretty cool (of course). :-)

Well, below is the code in ASC format.  It is written in a combination of
system RPL and machine language (like Bill Wickes ASC routines themselves), and
there are no known bugs.  When you ASC-> the code, you'll have a directory
object in level 1.  Just store this using any name you like.  Then you'll
probably want to go down into the directory you just created and copy the DISS
program up into the home directory, so you can use it from any directory.  

I will be watching the conference dilligently for feedback, and ideas for
improvement. (I'd love to see this used in TETRIS, for example).

Enjoy!

>>>Joe Ervin

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