nanogui: Blitting
Subject:
Re: [nanogui] blitting
From:
"Greg Haerr" ####@####.####
Date:
8 Aug 2002 15:22:17 -0000
Message-Id: <06de01c23eec$d2c62480$3aba46a6@xmission.com>
> I've an application which will have two windows in the exact same
co-ordinates. Obviously only one will ever be on screen at any one
time, but there will be a need to update one, while the other is on
screen. I assume I need to implement the blitting screen drivers
for this. The updates needed for off screen drawing will be simple
functions like GrRect, GrFillRect and GrText.
You can't draw to a window that's offscreen. Use NewPixmap
for that. One way to solve this problem is to implement
the EXPOSURE event for each window, and only draw
the window in the EXPOSURE event processing. Then you
don't have to worry about any of the above.
> it a matter of implementing functions like those in fblin8.c. When
it comes to bring the hidden window onto the screen I assume some
kind of memory to screen function should be called?? Does there
have to be a draw pixel, draw horz line, draw vert line and get pixel
for storing off screen and drawing it back to the screen again??
To copy a pixmap to the screen, you would use the GrCopyArea
function from the pixmap to the window. This will end up using
the screen driver blit entry point, like those in fblin*.c. It doesn't
have anything to do with drawpixel, horzline, etc.
Are you running a special screen driver?
Regards,
Greg
