welter@ils.nwu.edu (Pete Welter) (01/23/91)
I am trying to display a large colored bitmap using BitBlt. When the bitmap is drawn, it appears rather slowly in a series of (about 4 or 5) horizontal swipes. I have noticed the same behavior when zooming out on this same image using MS-Paint; seemingly the use of StretchBlt rather than BitBlt is causing this. When the image is at normal size is MS-Paint, the drawing seems pretty fast. My question is: Is there any reason why BitBlt would redraw in these horizontal strips? Thanks! Pete Welter Institute for the Learning Sciences Northwestern University welter@ils.nwu.edu
jls@hsv3.UUCP (James Seidman) (01/26/91)
In article <703@anaxagoras.ils.nwu.edu> welter@ils.nwu.edu (Pete Welter) writes: >I am trying to display a large colored bitmap using BitBlt. >When the bitmap is drawn, it appears rather slowly in a series >of (about 4 or 5) horizontal swipes... >My question is: Is there any reason why BitBlt would redraw in >these horizontal strips? The BitBlt functionality is implemented by the video display driver, not the GDI. Are you using the standard VGA driver? If not, you might try switching to it and seeing if the problem goes away. (I've never seen the symptoms you're describing.) -- Jim Seidman (Drax), the accidental engineer. "It doesn't have to work... they'll be paralyzed just from laughing at me." - Dr. Who, _Shada_ UUCP: ames!vsi1!hsv3!jls INTERNET: hsv3.UUCP!jls@apple.com