Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!wuarchive!uunet!mcsun!ukc!stl!servax0!sersun1!whisd
From: whisd@sersun1.essex.ac.uk (Whiteside S D B)
Newsgroups: comp.windows.ms.programmer
Subject: Re: Bitmaps on Buttons
Keywords: bitmaps buttons
Message-ID: <5144@servax0.essex.ac.uk>
Date: 13 May 91 09:55:41 GMT
References: <1991May9.034417.17137@leland.Stanford.EDU>
Sender: news@servax0.essex.ac.uk
Reply-To: whisd@essex.ac.uk (Whiteside S D B)
Organization: University of Essex, Colchester, UK
Lines: 32


Many thanks to all who replied to my recent query regarding putting bitmaps on buttons. I've managed to do this thanks to their help!

One way to do this is:

i)	Create the button with the style WS_OWNERDRAW, which means you have to draw the item 
ii)	The window procedure associated with the button (or the dialog box function of the dialog with the control in) will receive 3 kinds of message which it will have to deal with:

Each message is of type WM_DRAWITEM. This message has the following components:

wParam	-	child control ID
lParam	-	long pointer to DRAWITEMSTRUCT

It's the DRAWITEMSTRUCT that tells you what to do.

When the control needs to be first drawn the itemAction field of the structure contains ODA_DRAWENTIRE.

When the control is pushed the itemAction is ODA_SELECT and the is also received when the button is released. I keep a BOOL variable to alternate two bitmaps: one for button up, one for button down.

When focus is given to the button itemAction is ODA_FOCUS

Also in the structure you get: the button window handle, a device context and a rectangle structure showing the size of the button.

I used LoadBitmap to get a handle to the bitmap and called Petzold's DrawBitmap() function to put it into the device context.

Remember to delete the bitmap once you've done this. (The bitmap is selected into a memory device context, thence into the actual device context by DrawBitmap, so it's okay to delete the bitmap).

I use C++ so for speed I load the bitmaps in the class constructor and delete them in the class destructor.

I hope this info (which isn't all in one place in the literature I've got) helps others make a very pretty interface!

Simon Whiteside