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FooButton

Ravi Bhavnani

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7 Oct 2006

A lightweight general-purpose owner drawn bitmap button.

Introduction

This article describes FooButton, a lightweight owner-drawn button class that's served me well for several years. Although there are plenty of other excellent button classes at CodeProject, I thought I'd add this trusty friend to the pile in the hope that someone may find it equally useful.

Features

FooButton lets you use a vanilla CButton as a:

standard pushbutton
pushbutton button with a drop-down indicator
multi pushbutton (like IE's "Back" and "Next" buttons)
checkbutton
hyperlink
static text control that's responsive to mouse clicks
check box
radio button

Support is also provided for:

bitmaps (currently only 16-color)
left-justified, centered and multi-line captions
colored captions
gradient shaded button backgrounds
popup menus
hot tracking
optional focus rectangle and "default button" indicator
grouped checkbuttons

How to use FooButton

First, associate a standard button control (eg: IDC_FOO_BUTTON) in your dialog with an instance of the object.

  /////////////

  // MyDialog.h

  #include "FooButton.h"

  ...
  FooButton m_fooButton;

  ///////////////

  // MyDialog.cpp

  void CMyDialog::DoDataExchange(CDataExchange* pDX)
  {
    CDialog::DoDataExchange(pDX);
    //{{AFX_DATA_MAP(CMyDialog)

    DDX_Control(pDX, IDC_FOO_BUTTON, m_fooButton);
    //}}AFX_DATA_MAP

  }

Then, initialize the instance in your dialog's OnInitDialog() method to suit your needs. In this example, the button is set to display a bitmap and a drop-down indicator.
// Initialize FooButton m_fooButton.setBitmapId (IDB_FOO_BUTTON); m_fooButton.setType (FooButton::Type::pushButtonDropDown);

API

Method	Purpose
`getType(), setType()`	Gets and sets the button's type
`getTextStyle(), setTextStyle()`	Gets and sets the button's text style
`getTextColor(), setTextColor()`	Gets and sets the button's text color
`getFocusStyle(), setFocusStyle()`	Gets and sets the button's focus style
`getGradient(), setGradient()`	Gets and sets the button's gradient property
`getBitmapId(), setBitmapId()`	Gets and sets the button's (optional) bitmap id

`displayPopupMenu()`	Displays a popup menu below the button
`isChecked(), check()`	Gets and sets a `checkButton`'s checked state
`isMultiClicked(), clearMultiClick()`	Gets and resets a `multiPushButton`'s multi-clicked state
`addToGroup(), removeFromGroup()`	Adds/removes a `checkButton` to/from a button group
`reset()`	Frees storage used by all button groups

Using FooButton as a check button

You can freely change any property of the button at run time. This code snippet turns the button into a checkbutton and checks it. Use check() and isChecked() to set and retrieve the button's checked state.

  // Make it a checkbutton and check it

  m_fooButton.setType (FooButton::Type::checkButton);
  m_fooButton.check (true);
  ASSERT (m_fooButton.isChecked());    // testing

Gradient shading

Pushbuttons and checkbuttons can be set to display a gradient shaded background by calling setGradient(). This method has no effect if the button isn't a pushbutton or checkbutton.

  // Use a gradient shaded background

  m_fooButton.setGradient (true);

Button groups

You can make a bunch of checkButtons behave as mutually exclusive radio buttons by adding them to a button group. A button group is just a named collection of buttons. FooButton automatically handles group creation, membership and cleanup.

  // Make "size" checkbuttons mutually exclusive

  m_btnSmall.addToGroup (_T("foo"));
  m_btnMedium.addToGroup (_T("foo"));
  m_btnLarge.addToGroup (_T("foo"));
  m_btnXLarge.addToGroup (_T("foo"));

Displaying a popup menu

To display a popup menu in response to a button click, call displayPopupMenu(). You can call this method for any type of FooButton.

  void CMyDialog::OnFooButton()
  {
    CMenu menu;
    menu.LoadMenu (IDR_POPUP_MENU);
    CMenu* pPopupMenu = menu.GetSubMenu (0);
    int nResult = m_fooButton.displayPopupMenu (pPopupMenu);
    if (0 != nResult)
       PostMessage (WM_COMMAND, nResult);
  }

Multi-pushbuttons

A multi-pushbutton behaves as two buttons in one, similar to IE's "Back" and "Next" buttons. When the user clicks the button's drop-down region, FooButton sets its "multi-clicked" property to true. You can query this property by calling isMultiClicked(). Regardless of whether the user clicked in the button's main or drop-down region, a standard notification is sent to the parent. To clear the button's multi-click property, call clearMultiClick().

  void CMyDialog::OnFooButton() 
  {
    if (m_fooButton.isMultiClicked()) {
 
        // Display menu if drop-down region was clicked

        CMenu menu;
        menu.LoadMenu (IDR_POPUP_MENU);
        CMenu* pPopupMenu = menu.GetSubMenu (0);
        int nResult = m_fooButton.displayPopupMenu (pPopupMenu);
        if (0 != nResult)
           PostMessage (WM_COMMAND, nResult);
 
        // Remember to clear the button's multi-click property!

        m_fooButton.clearMultiClick();
 
    } else {
 
        // Otherwise do default action

        PostMessage (WM_COMMAND, IDC_DEFAULT_ACTION);
    }
  }

Check boxes and radio buttons

You can make a FooButton appear as a standard check box or radio button by using the FooButton:Type::checkBox and FooButton:Type::radio types. Of course, this is really only useful when you want to also display a bitmap or add menu support to the button.

  // Appear as check box and radio button

  m_fooButton1.setType (FooButton::Type::checkBox);
  m_fooButton2.setType (FooButton::Type::radio);

Hyperlink button

A hyperlink button is just a regular button that renders itself as a hyperlink. You can navigate to a URL or perform any other action in the button's handler.

  // Appear as hyperlink

  m_fooButton.setType (FooButton::Type::hyperink);

Text color

You can change the color of the button's text at any time by calling setTextColor(). The text of hyperlink buttons is always rendered in C_HyperlinkColor and that of disabled buttons is always rendered in the standard etched format.

  // Draw caption in red

  m_fooButton.setTextColor (RGB (192, 0, 0));

Focus rectangle

By default, a FooButton doesn't display a focus rectangle. Call setFocusStyle() with FooButton::Focus::normalFocus to enable the button to display a focus rectangle.

  // Allow focus rectangle to be displayed

  m_fooButton.setFocusStyle (FooButton::Focus::normalFocus);

Default button indicator

To enable a default FooButton to display its standard dark border, call setFocusStyle() with FooButton::Focus::defaultFocus.

  // Allow focus rectangle and default indicator to be displayed

  m_fooButton.setFocusStyle (FooButton::Focus::defaultFocus);

Rendering disabled bitmaps

Use the standard MFC EnableWindow() API to enable and disable the button. FooButton uses its original bitmap to render a disabled version.

  m_fooButton.EnableWindow (TRUE);   // enable button

  m_fooButton.EnableWindow (FALSE);  // disable button

Acknowledgement

Drawing a bitmap transparently by Zafir Anjum
Draw bitmap with grayed 3D effect by Jean-Edouard Lachand-Robert
Hyperlink control by Chris Maunder
A Gradient Static Control by Irek Zielinski
Thanks to those who've reported bugs, identified solutions and suggested features!

Revision history

7 Oct 2006

Bug Fix: m_hMsimg32 should be set to NULL in destructor. (Thanks, C. Young!)
Bug Fix: Memory leak in DisabledBlt(). (Thanks, Corrado Valli!)

6 Mar 2005

Bug Fix: Added definition of COLOR_HOTLIGHT to enable compilation on older systems.

5 Mar 2005

Enhancement: Added support for gradient shaded buttons.
Bug Fix: Reusing a group name across dialog invocations would cause a crash in FooButton::removeFromGroup().

19 Feb 2005

Enhancement: Added support for colored captions.
Enhancement: Removed requirement to call FooButton::reset() when your app terminates.
Enhancement: Now uses standard Win2000/XP hyperlink cursor.
Enhancement: Code now ASSERTs if you're not subclassing from a button control.
Bug Fix: All calls to Invalidate() now validate window handle, allowing a FooButton to be safely destroyed when clicked.

Fixed typo in default state rendering logic

17 Jul 2004

Added support for check boxes and radio buttons
Fixed typo in default state rendering logic

11 Jul 2004

Optimized fix for "unreferenced identifier" compiler warning
Exposed focus rectangle and default state modes
Added support for button groups

4 Jul 2004
Added multi-pushbutton and hyperlink styles.

3 Jul 2004
Submitted to CodeProject.

12 Sep 1998
Initial version.

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