Xref: news2.mv.net comp.os.msdos.djgpp:5247
From: Ben Ashley <Ben AT flag DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Allegro's Grabber
Date: Thu, 20 Jun 96 22:49:17 GMT
Organization: Flag Bearers
Lines: 43
Message-ID: <835310957snz@flag.demon.co.uk>
References: <Pine DOT SGI DOT 3 DOT 91 DOT 960618173249 DOT 174C-100000 AT tower DOT york DOT ac DOT uk> <835267355snz AT flag DOT demon DOT co DOT uk> <31C97079 DOT 5CD3 AT tower DOT york DOT ac DOT uk>
Reply-To: Ben AT flag DOT demon DOT co DOT uk
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

In article <31C97079 DOT 5CD3 AT tower DOT york DOT ac DOT uk>
           jrm101 AT tower DOT york DOT ac DOT uk "Jonathan Markland" writes:

> [stuff snipped]
> 
> Observing the butchered version of the code reveals something a bit
> suspicious. I guess that Shawn offered the solution in a moment of haste.
> I know, it happens to me too! ;)
> 
> Try this instead:
> 
> > >    while (!mouse_b) {
> > >       x = mouse_x;                      <----- I've changed this
> > >       if (x + bmp->w > graphic->w)
> > >          x = (graphic->w - bmp->w) & 0xFFF0;  <--- [See below]
> > >       if (x < 0)
> > >          x = 0;
> > >       y = mouse_y;                      <----- I've changed this too
> 
> Also, I think the line that I have indicated may also need the "& 0xFFF0"
>  removing?

Well, it was in fact just changing the last '0' to F.  That worked. 

> 
> This would explain why the grabbing box never moves, as the variables X and Y
>  are
> never updated (they probably get fixed at zero)!

I can't believe I missed that.  'x' never gets set!!  Hehehe... sounds like the
sort of bug that comes up in my programs...  Y'know, really silly things :)

-- 
Cheers,

Ben                                     -=Look for "Moo-Juice" on the IRC=-

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