Re: Solving the repaint problem?

From:

"Jonathan Wood" <jwood@softcircuits.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sun, 19 Aug 2007 14:31:06 -0600

Message-ID:

<eBchr$p4HHA.3940@TK2MSFTNGP05.phx.gbl>

I would recommend first eliminating any painting done in OnEraseBkgnd.
Second, I would carefully consider how you paint your window. For example,
clearing the background of a rectangle and then drawing text in TRANSPARENT
mode is probably faster than simply drawing the text in OPAQUE mode, but the
first approach will cause more flicker.

Only after those issues have been thoroughly addressed would I looking into
drawing first to a bitmap, which uses more resources and can be slower
overall.

--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com

"Peter Olcott" <NoSpam@SeeScreen.com> wrote in message
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"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp> wrote in message
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"Peter Olcott" <NoSpam@SeeScreen.com> wrote in message
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I know that the basic process of eliminating the flash when the screen
updates is to paint everything to an offscreen memory bitmap, and then to
BitBlt() this memory bitmap to the screen in the OnPaint event. Is the
only other reason why I may still have a screen flash is that I did not
yet over-ride the OnEraseBkgnd(CDC* pDC) function?

Yes, overriding OnEraseBkgnd is fundamental to eliminating the flash. The
flash is caused by painting twice: once in OnEraseBkgnd, again in
OnPaint. The eye can see both steps.

This is the only other possible requirement besides painting everything to
an offscreen memory bitmap?