[comp.sys.mac.programmer] Picture scrolling?

wolf@mel.cipl.uiowa (07/12/90)

I was wondering if it is possible to use a PICT resource to do a CopyBits from
to a visible window.  I want to do a scrolling of an image with the use of the
keypad.  The image is 1536x1536 pixels and a bitmap resource would be 288K of
data which is a bit larger than I want, a PICT resource would be smaller if I
could do it.

I tried setting a non-visible windows picture to one I wanted and doing the
CopyBits, but of course the bits copied were non-existant because the window
was not visible and thus there were no bits within the visible region for the
picture to be displayed in.

Another option which would be okay would be to simply be able to scroll a PICT
resource in a window which is much smaller than the actual picture.  But if the
picture is of the size I have stated would the DrawPicture command be slow?  I
could use DrawPicture and simply offset the picture rectangle to draw into
within the window to give the impression of scrolling the window.  

I want to keep the scolling to appear as quick as possible.

Any ideas?

Michael
WOLF@MEL.CIPL.UIOWA.EDU

Thanks!