C++ – How to make the group-box text background transparent

cmfcvisual-studio-2005

I want to make a transparent dialog. I capture the OnCtlColor message in a CDialog derived class…this is the code:

HBRUSH CMyDialog::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor) 
{
   HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);
   if(bSetBkTransparent_)
   {
      pDC->SetBkMode(TRANSPARENT);
      hbr = (HBRUSH)GetStockObject(NULL_BRUSH);        
   }


   return hbr;
}

It works fine for all the controls but the group-box (CStatic). All the labels (CStatic) are been painted with a transparent text background but the text of the group box it is not transparent.

I already googled for this but I didn't find a solutions. Does anybody know how to make a real transparent group-box?

By the way, I am working in Windows XP. And I don't want to fully draw the control to avoid having to change the code if the application is migrated to another OS.

Thanks,

Javier

Note: I finally changed the dialog so that I don't need to make it transparent. Anyway, I add this information because maybe someone is still trying to do it. The groupbox isn't a CStatic but a CButton (I know this is not new). I changed the Windows XP theme to Windows classic and then the groupbox backgraund was transparent. The bad new is that in this case the frame line gets visible beneath the text…so if someone is following this approach I think maybe he/she would better follow the Adzm's advice.

Best Answer

You have two options.

You can not use Common Controls v6 (the XP-Styled controls), which will make your app lose the fanciness of newer windows versions. However IIRC the groupbox will respect the CTLCOLOR issue. If you are not using that anyway, and it is still not respecting your color, then you only have one option...

Which is to draw it yourself. I know you said you don't want to, but sometimes you have to. Thankfully a group box is a very simple control to draw. This page has an example for drawing a classic-style group box: http://www.codeguru.com/cpp/controls/controls/groupbox/article.php/c2273/ You can also draw it very simply using the UxTheme libraries that come with XP+.

If the application will be migrated to another OS, you will have plenty to deal with migrating over an MFC application in general. If that is your goal, then you should really look into developing with a cross-platform UI toolkit.

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I use this to split string by a delimiter. The first puts the results in a pre-constructed vector, the second returns a new vector.

#include <string>
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template <typename Out>
void split(const std::string &s, char delim, Out result) {
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Let's get pedantic, because there are differences that can actually affect your code's behavior. Much of the following is taken from comments made to an "Old New Thing" article.

Sometimes the memory returned by the new operator will be initialized, and sometimes it won't depending on whether the type you're newing up is a POD (plain old data), or if it's a class that contains POD members and is using a compiler-generated default constructor.

In C++1998 there are 2 types of initialization: zero and default
In C++2003 a 3rd type of initialization, value initialization was added.

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In a C++98 compiler, the following should occur:

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new B - default construct (B::m is uninitialized)
new B() - default construct (B::m is uninitialized)
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In a C++03 conformant compiler, things should work like so:

new A - indeterminate value
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And there's a difference in behavior between C++98 and C++03 for the case new B().

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Best Answer

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