MFC Extension library : Enhanced print preview plug-in

// MappedBitmapButton.cpp : implementation file
//
// Draws color-correct buttons
//
// Copyright (c) 1999 Robin J. Leatherbarrow, Erithacus Software Limited
// 
// Use and distribute freely, except: don't remove my name from the
// source or documentation, mark your changes, don't alter
// or remove this notice.
// No warrantee of any kind, express or implied, is included with this
// software; use at your own risk, responsibility for damages (if any) to
// anyone resulting from the use of this software rests entirely with the
// user.
//
// Send bug reports, bug fixes, enhancements, requests, flames, etc.,
// and I'll try to keep a version up to date.  I can be reached at:
//    robin@erithacus.com
//
// Usage -- a replacement for the MFC CBitmapButton
// 1. include an owner-draw button in your dialog
// 2. declare a CMappedBitmapButton member in the CDialog code
// 3. hook in the CMappedBitmapButton using a call to AutoLoad
//
// the bitmap resource specified in AutoLoad must be divisable into
// 4 equally sized images that represent (left to right) the
// up, down, focused and disabled states of the button

#include "stdafx.h"
#include "MappedBitmapButton.h"

IMPLEMENT_DYNAMIC( CMappedBitmapButton, CButton )

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CMappedBitmapButton

CMappedBitmapButton::CMappedBitmapButton()
{
	m_idResource = (UINT)-1;
}

CMappedBitmapButton::~CMappedBitmapButton()
{
}


BEGIN_MESSAGE_MAP(CMappedBitmapButton, CButton)
	//{{AFX_MSG_MAP(CMappedBitmapButton)
	ON_WM_SYSCOLORCHANGE()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()


BOOL CMappedBitmapButton::LoadBitmap( UINT idBitmapResource )
{
	m_image.DeleteImageList();

	m_idResource = idBitmapResource;

	CBitmap bitImage;
	if (!bitImage.LoadMappedBitmap( idBitmapResource )) {
		ASSERT( FALSE ); // failed to load the bitmap. Does this resource ID exist?
		return FALSE;
		}

	BITMAP bm;
	if (0==bitImage.GetBitmap( &bm ))
		return FALSE;

	// we don't use a mask for the bitmaps in this case
	UINT flags = 0;
	if (bm.bmBitsPixel <= 4)
		flags |= ILC_COLOR4;
	else if (bm.bmBitsPixel <= 8)
		flags |= ILC_COLOR8;
	else if (bm.bmBitsPixel <= 16)
		flags |= ILC_COLOR16;
	else
		flags |= ILC_COLOR24;

	// image should contain EXACTLY four subimages
	ASSERT( bm.bmWidth % 4 == 0 );

	if (!m_image.Create( bm.bmWidth/4, bm.bmHeight, flags, 4, 0 ))
		return FALSE;

	// the mask bitmap will be ignored here, so use the	bitImage for both
	if (-1 == m_image.Add( &bitImage, &bitImage ))
		return FALSE;

	return TRUE;
}


// SizeToContent will resize the button to the size of the bitmap
void CMappedBitmapButton::SizeToContent()
{
	ASSERT(m_image.GetImageCount() == 4);

	IMAGEINFO info;
	VERIFY( m_image.GetImageInfo( 0, &info ) );
	VERIFY(SetWindowPos(NULL, -1, -1, info.rcImage.right, info.rcImage.bottom,
		SWP_NOMOVE|SWP_NOZORDER|SWP_NOREDRAW|SWP_NOACTIVATE));
}

// Autoload will load the bitmap resources
BOOL CMappedBitmapButton::AutoLoad(UINT nID, CWnd* pParent, UINT idBitmapResource)
{
	// first attach the CMappedBitmapButton to the dialog control
	if (!SubclassDlgItem(nID, pParent))
		return FALSE;

	if (!LoadBitmap(idBitmapResource))
		return FALSE;

	// size to content
	SizeToContent();
	return TRUE;
}


/////////////////////////////////////////////////////////////////////////////
// CMappedBitmapButton message handlers

void CMappedBitmapButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
	ASSERT(lpDrawItemStruct != NULL);
	ASSERT(m_image.GetImageCount() == 4);

	// images are:
	// 0 = up
	// 1 = down
	// 2 = focused
	// 3 = disabled
	int image = 0;
	UINT state = lpDrawItemStruct->itemState;
	if (state & ODS_SELECTED)
		image = 1;
	else if (state & ODS_FOCUS)
		image = 2;   // third image for focused
	else if (state & ODS_DISABLED)
		image = 3;   // last image for disabled

	// draw the whole button
	CRect rect;
	rect.CopyRect(&lpDrawItemStruct->rcItem);

	CDC* pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
	VERIFY( m_image.Draw( pDC, image, rect.TopLeft(), ILD_NORMAL ) );
}

void CMappedBitmapButton::OnSysColorChange() 
{
	CButton::OnSysColorChange();
	
	if (m_image.GetImageCount() == 4) {
		LoadBitmap( m_idResource );
		}

	Invalidate();
}