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From: acmfiu@serss0.fiu.edu (ACMFIU)
Newsgroups: comp.sys.apple2
Subject: off-screen grafports ... solved but more problems.
Message-ID: <2585@kluge.fiu.edu>
Date: 23 Feb 91 05:10:55 GMT
Sender: news@kluge.fiu.edu
Organization: Florida International University, Miami
Lines: 54

I have finally figured out how to create and draw to off-screen grafports.
However, i'm still having problems. Now, my problem is with copying the
contents of my windows pixelimage to the off-screen grafport and back.
here's a sample of what my code looks like:

void
foo (void)
{
	GrafPort *g1, g2;
	LocInfo g2_locinfo = { mode640, NULL, 160, 0, 0, 200, 640 };

	g1 = GetPort ();
	g2_locinfo.ptrToPixImage = *NewHandle (0x8000, userid, attrPage +
						attrLocked, NULL);
	OpenPort (&g2);
	SetPortLoc (&g2_locinfo);
	SetPort (&g2);
	PPToPort (&g1->portInfo, &g1->portInfo.boundsRect, 0, 0, modeCopy);

	/* i then draw to the off-screen grafport */

	SetPort (g1);
	PPToPort (&g2.portInfo, &g2.portInfo.boundsRect, 0, 0, modeCopy);
	ClosePort (&g2);
	DisposeHandle (FindHandle (g2_locinfo.ptrToPixImage));
}

now, my window which is set to the current grafport before this routine is
called is created via NewWindow with bounds being { 20, 0, 200, 640 }. Now,
the problem here is that after the update to the off-screen grafport is
done and i draw back onto my on-screen window, the off-screen grafport's
contents don't get drawn fully into the window. by that i mean i see the
menu bar on the screen which also gets drawn into the window. i think this
is a problem with PPToPort but i can't figure out what the problem is. if
i set the coordinates of the window to { 0, 0, 200, 640 } then everything
works. also, if my window is defined as before and the off-screen grafport's
locinfo boundsRect is defined as { 20, 0, 200, 640 }, this doesn't work as
if both off-screen/on-screen boundsRect were defined to be { 0, 0, 200, 640 }.

also, the update to the screen is SLOW. i can't stand it. you can *see* the
update to the window. i thought it was suppose to be *BANG*, screen update.
however, this doesn't work at all. i'm getting real tired of these toolsets.
right now i just want to write my own graphic routines and forget about
everything else, because i want and need speed for this program. however,
because this is my first venture into the toolsets (and QD is the only toolset
i hate so far), i am probably doing something wrong. how can i squeeze more
speed out of QD.

please help, i need it.

albert

ps. i would like to thank Julian Pugh (he wrote GSNumerics) for his help
    on the off-screen grafport.


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