Transparent group box

If you make a dialog with a bitmap as background, you'll probably handle WM_CTLCOLOR and CTLCOLOR_STATIC to set a transparent background for text items.

This works fine except with groupboxes: if the text is transparent the group rectangle goes right through your text, which looks BAD.

To make it look better, use this class CTGroupBox. It draws every side of the box rectangle using LineTo's and takes care of the text position and extent.

Usage is simple: just give your group boxes unique IDs (instead of IDC_STATIC) and then subclass them in OnInitDialog:

// in your .cpp file
void CMyBitmappedDialog::OnInitDialog()
{
	CBitmapDialog::OnInitDialog();  // I'm using Joerg Koenigs CBitmapDialog class
        
	m_TGrpBox1.SubclassDlgItem(IDC_GRPBOX1, this);
	m_TGrpBox2.SubclassDlgItem(IDC_GRPBOX2, this);
	...

	return TRUE;
}

// in your .h file
#include "TGroupBox.h"

class CMyBitmappedDialog : public CBitmapDialog
{
private:
	CTGroupBox m_TGrpBox1;
	CTGroupBox m_TGrpBox2;
	...
}

Thats all!

Remark: Group boxes are technically buttons(!) with style BS_GROUPBOX but they don't seem to receive WM_DRAWITEM messages even if BS_OWNERDRAW is set. So I do the drawing in an WM_PAINT handler but thats not too hard here because they can't be "pressed" or get the focus rect.

Comments, suggestions, bug reports etc. are welcome! Put them here as comment or send them directly to me.

Enjoy!