Visual C++ and MFC Programming 2nd Edition

Visual C++ and MFC Fundamentals Chapter 15: Fundamental Controls

?? If you create three bitmaps, the first would display when the button is not being

accessed and another control has focus. The second picture would display when

the user is clicking the button and as long as the mouse is down on the button.

The third would be used when the button has focus but it is not being used

?? If you create four bitmaps, the first would display when the button is not being

accessed and another control has focus. The second picture would display when

the user is clicking the button and as long as the mouse is down on the button.

The third would be used when the button has focus but it is not being used or

pressed. The fourth would be used when the button is disabled

With these options, to use a bitmap button to its fullest, you should strive to provide four

bitmaps. After creating the bitmaps, you can load them into the button. This is done using

the LoadBitmaps() method. It comes in two versions as follows:

BOOL LoadBitmaps(LPCTSTR lpszBitmapResource,

LPCTSTR lpszBitmapResourceSel = NULL,

LPCTSTR lpszBitmapResourceFocus = NULL,

LPCTSTR lpszBitmapResourceDisabled = NULL );

BOOL LoadBitmaps(UINT nIDBitmapResource,

UINT nIDBitmapResourceSel = 0,

UINT nIDBitmapResourceFocus = 0,

UINT nIDBitmapResourceDisabled = 0 );

Each version takes four arguments. The first version uses the bitmaps as string resources

while the second version uses resource identifiers.

As stated above, you can use one to four bitmaps. The first argument must specify the

first or default bitmap and is required. The second argument is the name or identifier of

the bitmap that would be used when the button is selected. The third is used when the

button has focus. The last bitmap is used when the button is disabled. Here is an example:

BOOL CDialog6Dlg::OnInitDialog()

{

CDialog::OnInitDialog();

...

// TODO: Add extra initialization here

CBitmapButton *btnMap = new CBitmapButton;

btnMap->Create(NULL, WS_CHILD|WS_VISIBLE|BS_OWNERDRAW,

CRect(10,10,100,100), this, IDC_BTN_NEW);

btnMap->LoadBitmaps(IDB_BMP_BTN1, IDB_BMP_BTN2, IDB_BMP_BTN3,

IDB_BMP_BTN4);

return TRUE; // return TRUE unless you set the focus to a control

}

It is very likely that you may not be able to design the button on one hand and the

bitmaps on the other hand at exactly the same dimensions. To adjust these measures, the

CBitmapButton class is equipped with the SizeToContent() method. Its syntax is:

void SizeToContent();

When this method is called on the button, it resizes it to the size of the bitmaps. If one

bitmap is larger and/or taller than the others, and if you had loaded more than one, this

method would resize the button to the larger or largest and taller or tallest bitmap. For