Hello :)
Is there a way to double-buffer the common controls? Currently when they resize they flicker. A lot.....
EDIT: If it helps, it is a bunch of button controls and a few edit controls, all sitting on top of a tab control. The Tab control redraws itself, then the buttons redraw themselves. When the buttons redraw, they flicker.
EDIT2: Here's an example of the problem I'm having: http://billy-oneal.com/Lobfuscator.exe
indeed,
someone posted an answer for this on one of my posts a while ago. Check it out: Here
and be sure to upvote him for being awesome.
The code is C#, hopefully there is a simple translation.
Without knowing exactly what you're doing, I assume you're using either MFC or Win32 C for this.
You probably want to do the resize on WM_SIZE message. I'm not sure where you're resizing the controls, but I think you're doing it while it's being resized, which is why it's causing the flicker.
Also, I'm thinking but I don't know, you could probably use the SetWindowPos function, and for the uFlags, have SWP_NOREDRAW. Though I'm not sure how great this would work for common controls.
You can create a memory device context, MemDC at the very start. Draw everything into the MemDC, then when the window recieves a WM_PAINT message or is invalidated, copy the MemDC to the real DC by bit blitting.
I remember reading up the technique by Herbert Schildt in his book a few years back (Windows 98 Programming from the Ground Up). In that way, all the redrawing is faster as you blit the memory dc to the real dc. But the one big gotcha, was how big the memory dc you want to use! But he showed how to do it. There is a code download for all of the chapters in that book published by Osborne McGraw Hill.
Hope this helps, Best regards, Tom.
Larry Osterman recently blogged about this subject; you might find some interesting details there.
You're not using WS_EX_TRANSPARENT, are you? That will cause underlying windows to be painted before the controls, and when the bottom window erases you get flicker.
Look at using WS_EX_COMPOSITEDand WS_EX_TRANSPARENT styles. They provide doublebuffering, altough WM_PAINT will be called when the underlying bitmap is finished drawing, since it draws child controls from bottom to top, so you can paint only in your window procedure. I've used it in the past and work pretty well.
Set your top-level window (container) to extended style WS_EX_COMPOSITED and your child windows with WS_EX_TRANSPARENT. Also, remember to define:
#define WINVER 0x501
See CreateWindowEx for information on the composited style. This also makes possible to do perpixel transparency on child windows.
UPDATE
What about usign WM_PRINTCLIENT to transfer the client area to a bitmap on a DC and blit all the client area as a whole?
We use WTL::CDoubleBufferImpl mix-in for that purpose. We even draw stuff with GDI+ over. Zero flickering.
Usage is pretty simple: you just public-ly inherit from WTL::CDoubleBufferImpl<YourClass>, and chain it in the ATL message map.