Re: Avoiding Updates After Displaying Menus
You could change your paint routine to only redraw the parts that need to be
redrawn.
http://msdn2.microsoft.com/en-us/library/ms534890.aspx
You could also keep a bitmap of the current screen and just restore that in
your paint routine if you've determined that there is nothing that changed
in the graphic. You could grab the bitmap right after, or while, updating
the screen in the normal course of making a change.
Tom
"nomad" <nomad@discussions.microsoft.com> escribi?? en el mensaje de noticias
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I have an MDI app whose MDI child windows are graphics windows that display
images. These images can be fairly complex, and redrawing them may take
time.
More to the point, there are occasionally ephemeral message 'boxes' that I
display within these images that aren't drawn as part of the main imaging
code, and go away when the image is next refreshed.
Okay, so, I click on a menu item in the menu bar and the menu comes down
and
I select something. I now get a WM_PAINT event in my window, causing a
redraw. This has two unfortunate effects: one is to slow things down while
I
wait for an update, and the other is to erase my little message boxes.
I know in Mac OS (even back in the Bad Old Days of OS 9) there is a way to
tell the menu to make a copy of the bitmap behind the menu window, and to
restore it when the menu goes away. In this way, the underlying window
does
not require an update; the bits are simply restored automatically.
Is there a similar feature in MFC or Win32? If so, I haven't been able to
find it so far. Thanks.
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