I am using DrawDIB to draw a Bitmap. If the size of the Bitmap increases. The scrolls become very slow. If the size oif the map is small then horizontal and vertical scrolling works fine. How can i load a large bitmap without effecting the scrolls.
Try experimenting with these;
How are you drawing the image to the screen? BitBlt() or StretchBlt()
Using a screen buffer (double buffer) system?
Trying to scroll and draw to the screen at the same time, small increment at a time?
Or calculating the WHOLE scroll distance then doing the drawing?
Handling WM_ERASEBKGND msg's?
Using InvalidateRect() with the bErase set to TRUE?
Using GetUpdateRect() before your call to BeginPaint() to reduce the area draw?