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Title: Drawing in an existing window?
Post by: knockjoke on February 10, 2011, 07:56:11 PM

Hi,

I know this is possible with GDI but that is flickering like hell. Is there a way to draw some text in an existing directx9 window without this flickering issue?
Ive stumbled across DirectDraw but it seems so damn complex.. What would you guys suggest me? Can anyone hook me with a small example?
Thanks in advance.

Title: Re: Drawing in an existing window?
Post by: dedndave on February 10, 2011, 10:46:39 PM

use the forum search tool
look for "CreateCompatibleDC", "BitBlt", "DIB"
you might also try "flicker"

Title: Re: Drawing in an existing window?
Post by: jj2007 on February 11, 2011, 12:33:24 AM

   mov hDC, rv(GetDC, hCanvas) ; canvas can be the main window, or a static child, or an edit window, or ...
   mov memDC, rv(CreateCompatibleDC, eax)   ; prepare for a bitmap
   mov hBmp, rv(CreateCompatibleBitmap, hDC, esi, ebx)   ; hDC, not memDC!
   invoke SelectObject, memDC, eax

CASE WM_PAINT
... do drawing to memDC ...

   lea edi, ps   ; ptr PAINTSTRUCT
   invoke BeginPaint, hCanvas, edi
   invoke BitBlt, eax, 0, 0, rc.right, rc.bottom, memDC, 0, 0, SRCCOPY
   invoke EndPaint, hCanvas, edi

And read Microsoft's view on CS_OWNDC (http://www.microsoft.com/msj/0298/c0298.aspx) vs Raymond Chen's view (http://blogs.msdn.com/b/oldnewthing/archive/2006/06/01/612970.aspx)

Title: Re: Drawing in an existing window?
Post by: zemtex on February 11, 2011, 08:45:23 AM

There are three things to keep in mind to avvoid flicker.

1: You should avvoid the system of erasing the background of the window, if it does that it will update the window pixels data two times per one time window update, this will produce flicker.
2: You should use double buffering with a compatible dc and bitmap.
3: If your controls flicker you can set WS_CLIPCHILDREN in the style of your window

Beside this you can also look into the the extended window style WS_EX_COMPOSITED, it speaks about double buffering, I havent checked it out though, just recall I've seen it.

Title: Re: Drawing in an existing window?
Post by: jj2007 on February 11, 2011, 09:35:20 AM

Quote from: zemtex on February 11, 2011, 08:45:23 AM
WS_EX_COMPOSITED

Can someone explain WS_EX_COMPOSITED (http://social.msdn.microsoft.com/Forums/en-US/vcgeneral/thread/ca0e6cc1-8e03-4dfc-832d-0a7a6ae38d56)
controls implemented as non managed child window's are deprecated. Support to draw them flicker free has been effectively removed

Microsoft at work :lol

Title: Re: Drawing in an existing window?
Post by: dedndave on February 11, 2011, 10:13:18 AM

Quote3: If your controls flicker you can set WS_CLIPCHILDREN in the style of your window

thanks for the tip zemtex
hadn't thought of it, but it makes perfect sense

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General Forums => The Workshop => Topic started by: knockjoke on February 10, 2011, 07:56:11 PM