MFC: How to draw a semi-transparent shape?

[Starlite]

I am using Microsoft visual c++ 6, and I want to draw a shape (say a
rectangle) on a view. The code that I have used is below, but this draws a
solid -filled rectangle, what I want is a displayed shape with a
semi-transparent color i.e. we should still be able to see whatever is
beneath the shape. Can anyone help me? Thanks.

void OnPaint()
{
CPaintDC dc(this);
CPen pPen(PS_SOLID, 1, RGB(0,0,0));
CBrush bBr(RGB(0,0,150 ));
CRect rec;

//rectangle to be drawn
rec.top = 0;
rec.left = 0;
rec.right = 100;
rec.bottom = 100;

dc.SelectObject (pPen);
dc.SelectObject (bBr);

dc.Rectangle(re c);
}

[Victor Bazarov]

"Starlite" <ge*********@ly cos.co.uk> wrote...

I am using Microsoft visual c++ 6, and I want [...]

Please post your MFC question to microsoft.publi c.vc.mfc

[Dan W.]

On Mon, 29 Dec 2003 14:32:34 +0400, "Starlite"
<ge*********@ly cos.co.uk> wrote:

I am using Microsoft visual c++ 6, and I want to draw a shape (say a
rectangle) on a view. The code that I have used is below, but this draws a
solid -filled rectangle, what I want is a displayed shape with a
semi-transparent color i.e. we should still be able to see whatever is
beneath the shape. Can anyone help me? Thanks.

void OnPaint()
{
CPaintDC dc(this);
CPen pPen(PS_SOLID, 1, RGB(0,0,0));
CBrush bBr(RGB(0,0,150 ));
CRect rec;

//rectangle to be drawn
rec.top = 0;
rec.left = 0;
rec.right = 100;
rec.bottom = 100;

dc.SelectObject (pPen);
dc.SelectObject (bBr);

dc.Rectangle(re c);
}

I've seen an MFC-specific newsgroup, you might care to search for
'mfc' throught the newsgroups list. I have a feeling that you need to
use Direct X if you want real-time alpha blending. Or OpenGL; I don't
think the GDI has built-in capabilities for that; but you might want
to check with MFC gurus.