transparent static control and display icon

[cj-wijtmans]

hi, i want to make my static control transparent, so it will draw transsparent background with text.
and i want to have a transparent static where i can display my icon.

i can set the WS_EX_TRANSPARENT but that does not make it transparent yet?

[Randor]

Did you try using SetBkMode?

http://msdn.microsoft.com/en-us/libr...62(VS.85).aspx

If you are using MFC you could do something like:

if(CTLCOLOR_STATIC == nCtlColor)
{
	pDC->SetBkMode(TRANSPARENT);
	return (HBRUSH)GetStockObject(NULL_BRUSH);
}

http://msdn.microsoft.com/en-us/library/0wwk06hc.aspx

Best Wishes,
-David Delaune

[egawtry]

Randor has a start, but there is more to it.

You need to set the back mode and color, then copy the bitmap to a monochrome. Using that monochrome bitmap as a mask, you then can paint a seemingly transparent background by just painting the rest of the bitmap.

There are hundreds of threads on this subject in this forum, just do a search.

-Erik

[cj-wijtmans]

i dont use MFC (this is the winapi forum not VC++ forum)

WS_EX_TRANSPARENT and SetBkMode seems to work fine.

now i just need to use DrawIcon... should i put it in WM_PAINT

[Randor]

i dont use MFC (this is the winapi forum not VC++ forum)

WS_EX_TRANSPARENT and SetBkMode seems to work fine.

now i just need to use DrawIcon... should i put it in WM_PAINT

My apologies, I am generally on codeproject.com and have only recently signed up here and have not become familiar with the codeguru forum peculiars and layout.

Yes, the WM_PAINT would be the correct location for calling DrawIcon. If you are concerned with flicker then perhaps you could experiment with disabling the WM_ERASEBKGND message by returning 1 or adding WS_CLIPCHILDREN to the parent window.

Best Wishes,
-David Delaune

[cj-wijtmans]

i already have the WS_CLIPCHILDREN flag set i wont have to handle the ERASEBKGND msg?

i tried drawing the icon there but it does not work it does not show up.

			PAINTSTRUCT ps = {0};
			HDC hdc = ::BeginPaint(Handle(), &ps);
			::DrawIcon(hdc, 0, 0, Arrow);
            ::EndPaint(Handle(), &ps);

[Randor]

i already have the WS_CLIPCHILDREN flag set i wont have to handle the ERASEBKGND msg?

WS_CLIPCHILDREN on the parent window will cause it to exclude the child when redrawing. Don't worry about the WM_ERASEBKGND message unless you have flicker issues that you want to resolve.

i tried drawing the icon there but it does not work it does not show up.

Have you invalidated the area associated with your static control? Try calling InvalidateRect on the client coordinates of the static.

http://msdn.microsoft.com/en-us/libr...03(VS.85).aspx
http://msdn.microsoft.com/en-us/libr...93(VS.85).aspx

Best Wishes,
-David Delaune

[cj-wijtmans]

thanks alot for your help

[VladimirF]

WS_CLIPCHILDREN on the parent window will cause it to exclude the child when redrawing.

Even if control has WS_EX_TRANSPARENT style?

[Randor]

Even if control has WS_EX_TRANSPARENT style?

Yes, even if the static control has the WS_EX_TRANSPARENT style. When the parent window is redrawn it will clip the child if the parent has the WS_CLIPCHILDREN flag.


By default, the windows affected by RedrawWindow depend on whether the specified window has the WS_CLIPCHILDREN style. Child windows that are not the WS_CLIPCHILDREN style are unaffected; non-WS_CLIPCHILDREN windows are recursively validated or invalidated until a WS_CLIPCHILDREN window is encountered.


http://msdn.microsoft.com/en-us/libr...00(VS.85).aspx

Best Wishes,
-David Delaune

[codecX]

If you want all of your static controls be transparent you can use the same method that mentioned in post 2 but for win32 API, especially for dialog box:

case WM_CTLCOLORSTATIC:
    SetBkMode ( (HDC)wParam, TRANSPARENT);
    return (BOOL)hbrush;

[VladimirF]

Yes, even if the static control has the WS_EX_TRANSPARENT style. When the parent window is redrawn it will clip the child if the parent has the WS_CLIPCHILDREN flag.

Then who draws the background under WS_EX_TRANSPARENT controls?

[cj-wijtmans]

i think WS_EX_TRANSPARENT will tell the parent window to draw the area behind the child first even if WS_CLIPCHILDREN is set

[VladimirF]

i think WS_EX_TRANSPARENT will tell the parent window to draw the area behind the child first even if WS_CLIPCHILDREN is set

That was my point

[Randor]

Then who draws the background under WS_EX_TRANSPARENT controls?

You are correct. I knew you were baiting me when you posted the response so I took the bait. The background is painted behind the child window and therefore non-clipped during the parent window painting. However during the recursive invalidation the child window is excluded/clipped.

Best Wishes,
-David Delaune