CBitmapButton Class

 

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Creates pushbutton controls labeled with bitmapped images instead of text.

Syntax

class CBitmapButton : public CButton  

Members

Public Constructors

Name	Description
CBitmapButton::CBitmapButton	Constructs a CBitmapButton object.

Public Methods

Name	Description
CBitmapButton::AutoLoad	Associates a button in a dialog box with an object of the CBitmapButton class, loads the bitmap(s) by name, and sizes the button to fit the bitmap.
CBitmapButton::LoadBitmaps	Initializes the object by loading one or more named bitmap resources from the application's resource file and attaching the bitmaps to the object.
CBitmapButton::SizeToContent	Sizes the button to accommodate the bitmap.

Remarks

CBitmapButton objects contain up to four bitmaps, which contain images for the different states a button can assume: up (or normal), down (or selected), focused, and disabled. Only the first bitmap is required; the others are optional.

Bitmap-button images include the border around the image as well as the image itself. The border typically plays a part in showing the state of the button. For example, the bitmap for the focused state usually is like the one for the up state but with a dashed rectangle inset from the border or a thick solid line at the border. The bitmap for the disabled state usually resembles the one for the up state but has lower contrast (like a dimmed or grayed menu selection).

These bitmaps can be of any size, but all are treated as if they were the same size as the bitmap for the up state.

Various applications demand different combinations of bitmap images:

Up	Down	Focused	Disabled	Application
×				Bitmap
×	×			Button without WS_TABSTOP style
×	×	×	×	Dialog button with all states
×	×	×		Dialog button with WS_TABSTOP style

When creating a bitmap-button control, set the BS_OWNERDRAW style to specify that the button is owner-drawn. This causes Windows to send the WM_MEASUREITEM and WM_DRAWITEM messages for the button; the framework handles these messages and manages the appearance of the button for you.

To create a bitmap-button control in a window's client area

1. Create one to four bitmap images for the button.

2. Construct the CBitmapButton object.

3. Call the Create function to create the Windows button control and attach it to the CBitmapButton object.

4. Call the LoadBitmaps member function to load the bitmap resources after the bitmap button is constructed.

To include a bitmap-button control in a dialog box

1. Create one to four bitmap images for the button.

2. Create a dialog template with an owner-draw button positioned where you want the bitmap button. The size of the button in the template does not matter.

3. Set the button's caption to a value such as " MYIMAGE" and define a symbol for the button such as IDC_MYIMAGE.

4. In your application's resource script, give each of the images created for the button an ID constructed by appending one of the letters "U," "D," "F," or "X" (for up, down, focused, and disabled) to the string used for the button caption in step 3. For the button caption " MYIMAGE," for example, the IDs would be " MYIMAGEU," " MYIMAGED," " MYIMAGEF," and " MYIMAGEX." You must specify the ID of your bitmaps within double quotes. Otherwise the resource editor will assign an integer to the resource and MFC will fail when loading the image.

5. In your application's dialog class (derived from CDialog), add a CBitmapButton member object.

6. In the CDialog object's OnInitDialog routine, call the CBitmapButton object's AutoLoad function, using as parameters the button's control ID and the CDialog object's this pointer.

If you want to handle Windows notification messages, such as BN_CLICKED, sent by a bitmap-button control to its parent (usually a class derived from CDialog), add to the CDialog-derived object a message-map entry and message-handler member function for each message. The notifications sent by a CBitmapButton object are the same as those sent by a CButton object.

The class CToolBar takes a different approach to bitmap buttons.

For more information on CBitmapButton, see Controls.

Inheritance Hierarchy

CObject

CCmdTarget

CWnd

CButton

CBitmapButton

Requirements

Header: afxext.h

CBitmapButton::AutoLoad

Associates a button in a dialog box with an object of the CBitmapButton class, loads the bitmap(s) by name, and sizes the button to fit the bitmap.

BOOL AutoLoad(
    UINT nID,  
    CWnd* pParent);

Parameters

nID
The button's control ID.

pParent
Pointer to the object that owns the button.

Return Value

Nonzero if successful; otherwise 0.

Remarks

Use the AutoLoad function to initialize an owner-draw button in a dialog box as a bitmap button. Instructions for using this function are in the remarks for the CBitmapButton class.

Example

      CBitmapButton myButton;

      // Initialize the owner-drawn button with the id IDC_MYBUTTON as a bitmap 
      // button. This code is used in the OnInitDialog handler of my dialog.
      myButton.AutoLoad(IDC_MYBUTTON, this);

CBitmapButton::CBitmapButton

Creates a CBitmapButton object.

CBitmapButton();

Remarks

After creating the C++ CBitmapButton object, call CButton::Create to create the Windows button control and attach it to the CBitmapButton object.

Example

   // Declare a bitmap button object on the stack.
   CBitmapButton myButton;

   // Declare a bitmap button object on the heap.
   CBitmapButton* pmyButton = new CBitmapButton;

CBitmapButton::LoadBitmaps

Use this function when you want to load bitmap images identified by their resource names or ID numbers, or when you cannot use the AutoLoad function because, for example, you are creating a bitmap button that is not part of a dialog box.

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);

Parameters

lpszBitmapResource
Points to the null-terminated string that contains the name of the bitmap for a bitmap button's normal or "up" state. Required.

lpszBitmapResourceSel
Points to the null-terminated string that contains the name of the bitmap for a bitmap button's selected or "down" state. May be NULL.

lpszBitmapResourceFocus
Points to the null-terminated string that contains the name of the bitmap for a bitmap button's focused state. May be NULL.

lpszBitmapResourceDisabled
Points to the null-terminated string that contains the name of the bitmap for a bitmap button's disabled state. May be NULL.

nIDBitmapResource
Specifies the resource ID number of the bitmap resource for a bitmap button's normal or "up" state. Required.

nIDBitmapResourceSel
Specifies the resource ID number of the bitmap resource for a bitmap button's selected or "down" state. May be 0.

nIDBitmapResourceFocus
Specifies the resource ID number of the bitmap resource for a bitmap button's focused state. May be 0.

nIDBitmapResourceDisabled
Specifies the resource ID number of the bitmap resource for a bitmap button's disabled state. May be 0.

Return Value

Nonzero if successful; otherwise 0.

Example

   CBitmapButton* pmyButton = new CBitmapButton();

   // Create the bitmap button (must include the BS_OWNERDRAW style).
   pmyButton->Create(NULL, WS_CHILD|WS_VISIBLE|BS_OWNERDRAW, 
      CRect(10,10,100,100), pParentWnd, 1);

   // Load the bitmaps for this button.
   pmyButton->LoadBitmaps(IDB_UP, IDB_DOWN, IDB_FOCUS, IDB_DISABLE); 

CBitmapButton::SizeToContent

Call this function to resize a bitmap button to the size of the bitmap.

void SizeToContent();

Example

   CBitmapButton* pmyButton = new CBitmapButton();

   // Create the bitmap button (must include the BS_OWNERDRAW style).
   pmyButton->Create(NULL, WS_CHILD|WS_VISIBLE|BS_OWNERDRAW, 
      CRect(10,10,100,100), pParentWnd, 1);

   // Load the bitmaps for this button.
   pmyButton->LoadBitmaps(IDB_UP, IDB_DOWN, IDB_FOCUS, IDB_DISABLE); 

   // Resize the button to be the size of the bitmaps.
   pmyButton->SizeToContent();

See Also

MFC Sample CTRLTEST
CButton Class
Hierarchy Chart