🚀 go-pugleaf

weinkam@fraser.sfu.ca (James Lawrence Weinkam) writes:

 > I am writing a graphics program that takes a long time to generate
 > the image.  I was wondering what the best way of doing redraws is.
 > The only way I can think of that would provide good performance is
 > to create a memory context of the window as well as a screen
 > context and draw to both.  In this way, when I get the WM_PAINT
 > message I just BitBlt from the memory context to the screen
 > context.
 > Is there a way of achiving the same without having to open two HPS,
 > and drawing to both?  (like an option when opening the window to
 > tell the OS to maintain both the screen and memory context)

Why not simply draw only in the memory context, and then always use
bitblt to update the display?  With a typical dumb frame buffer
display card, this can speed up drawing considerably.  (With a good
accelerator board, it may be faster to draw only on the display and
then save the display to memory.)  It doesn't make sense to draw in
both contexts.

Best regards,
John