Re: scroll view

From:

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 17 Aug 2006 13:09:52 -0400

Message-ID:

<uBLXt$hwGHA.4460@TK2MSFTNGP04.phx.gbl>

mec wrote:

problem with bitmap.

I am displaying a continuous image on a scroll view. It slides downward.
when the image's hight reaches the GetBitmapSize().cy, it stops and donot
update the screen.
What i want is, when the image's hight reaches the GetBitmapSize().cy, I
want to delete some portion of the image from bottom. So the image will be
displayed continuously.
How to delete some portion of the image from the bottom and update the
current drawing line number?

any help would be great..
thanks in advance.
mec

If you have continuous updating, where new lines get added and scroll
off the oldest lines, the approach I have used is to store the bitmap
data in a circular buffer. (CreateDIBSection will let you store the
bitmap data in your own memory.) Then the screen update usually
requires two BitBlt's. You blit from the newest line back to the start
of the buffer, then blit from the end of the buffer back to the oldest
data line.

--
Scott McPhillips [VC++ MVP]