改进的 CHoverButton 支持focus，四种状态，修复BUG

头文件。

Code
#if !defined(AFX_HOVERBUTTON_H__1155737E_628E_11D2_81B5_0020AFC24C58__INCLUDED_)
#define AFX_HOVERBUTTON_H__1155737E_628E_11D2_81B5_0020AFC24C58__INCLUDED_

#if _MSC_VER >= 1000
#pragma once
#endif // _MSC_VER >= 1000
// HoverButton.h : header file
//

/////////////////////////////////////////////////////////////////////////////
// CHoverButton window
enum BUTTON_STATE{ BUTTON_OFF, BUTTON_ON, BUTTON_OVER, BUTTON_GREYED};

class CHoverButton : public CBitmapButton
{
// Construction
public:
    // Constructor: default is to use buttons defined in our resources
    CHoverButton();
// Attributes
public:
    // The only way of accessing data from outside this class is to call these 2 functions
    BUTTON_STATE GetButtonState(void) {    return(m_ButtonState);};
    BUTTON_STATE SetButtonState(BUTTON_STATE nState);

private:
    BOOL            m_bMouseTracking;
    BUTTON_STATE    m_ButtonState;
    CBitmap            m_bmpButtonDown;
    CBitmap            m_bmpButtonFocussed;
    CBitmap            m_bmpButtonUp;
    CBitmap            m_bmpButtonDisabled;
    HWND            m_hWndOld;

// Operations
public:

// Overrides
    // ClassWizard generated virtual function overrides
    //{{AFX_VIRTUAL(CHoverButton)
    public:
    virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);
    //}}AFX_VIRTUAL
private:
    // Called by OnMouseMove() when entering/leaving the button
    void OnMouseLeave(void);
    void OnMouseEnter(void);

// Implementation
public:
    virtual ~CHoverButton();
    BOOL LoadBitmaps(UINT nBitmapUp, UINT nBitmapDown, UINT nBitmapFocus, UINT nBitmapDisabled);
    BOOL LoadBitmaps(LPCSTR lpszBitmapUp, LPCSTR lpszBitmapDown, LPCSTR lpszBitmapFocus, LPCSTR lpszBitmapDisabled);
    void SizeToContent();
    // Generated message map functions
protected:
    //{{AFX_MSG(CHoverButton)
    afx_msg void OnMouseMove(UINT nFlags, CPoint point);
    afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
    afx_msg void OnLButtonDown(UINT, CPoint);
    //}}AFX_MSG
    DECLARE_MESSAGE_MAP()
};

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

//{{AFX_INSERT_LOCATION}}
// Microsoft Developer Studio will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_HOVERBUTTON_H__1155737E_628E_11D2_81B5_0020AFC24C58__INCLUDED_)

源码文件。

Code
// HoverButton.cpp : implementation file
//

#include "stdafx.h"
//#include "hovbutt.h"
#include "HoverButton.h"

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

/////////////////////////////////////////////////////////////////////////////
// CHoverButton

BEGIN_MESSAGE_MAP(CHoverButton, CBitmapButton)
    //{{AFX_MSG_MAP(CHoverButton)
    ON_WM_MOUSEMOVE()
    ON_WM_LBUTTONUP()
    ON_WM_LBUTTONDOWN()
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CHoverButton construction / destruction

CHoverButton::CHoverButton()
{
    // To start with, the button is switched off and we are NOT tracking the mouse
    m_ButtonState        = BUTTON_OFF;
    m_bMouseTracking    = FALSE;
}

CHoverButton::~CHoverButton()
{
}

/////////////////////////////////////////////////////////////////////////////
// CHoverButton message handlers

void CHoverButton::OnMouseMove(UINT nFlags, CPoint point) 
{
    CBitmapButton::OnMouseMove(nFlags, point);

    // 1. Mouse has moved and we are not tracking this button, or 
    // 2. mouse has moved and the cursor was not above this window
    // == Is equivalent to WM_MOUSEENTER (for which there is no message)
    if((!m_bMouseTracking || GetCapture()!=this) && (m_ButtonState == BUTTON_OFF))
    {
        OnMouseEnter();
    }
    else 
    {
        if(m_ButtonState == BUTTON_OVER)
        {
            CRect rc;
            GetClientRect(&rc);
            if(!rc.PtInRect(point))    // The mouse cursor is no longer above this button
                OnMouseLeave();
        }
    }
}

void CHoverButton::SizeToContent()
{
    ASSERT(m_bmpButtonUp.m_hObject != NULL);
    CSize bitmapSize;
    BITMAP bmInfo;
    VERIFY(m_bmpButtonUp.GetObject(sizeof(bmInfo), &bmInfo) == sizeof(bmInfo));
    VERIFY(SetWindowPos(NULL, -1, -1, bmInfo.bmWidth, bmInfo.bmHeight,
        SWP_NOMOVE|SWP_NOZORDER|SWP_NOREDRAW|SWP_NOACTIVATE));
}

void CHoverButton::OnMouseEnter(void)
{
    // We are now tracking the mouse, OVER this button
    m_bMouseTracking = TRUE;
    m_ButtonState = BUTTON_OVER;

    // Ensure that mouse input is sent to the button
    SetCapture();
    Invalidate();
    UpdateWindow();
}

void CHoverButton::OnMouseLeave(void)
{
    // We are not tracking the mouse, this button is OFF.
    m_ButtonState = BUTTON_OFF;
    m_bMouseTracking = FALSE;

    // Release mouse capture from the button and restore normal mouse input
    Invalidate();
    UpdateWindow();
    ReleaseCapture();
}

void CHoverButton::OnLButtonDown(UINT nFlags, CPoint point) 
{
            // Highlight button
    SetButtonState(BUTTON_OFF);
    m_ButtonState = BUTTON_ON;
    CBitmapButton::OnLButtonDown(nFlags, point);
        
}

void CHoverButton::OnLButtonUp(UINT nFlags, CPoint point) 
{
    SetButtonState(BUTTON_ON);            // Highlight button
    m_ButtonState = BUTTON_OFF;
    CBitmapButton::OnLButtonUp(nFlags, point);
}

// Purpose:        Set the new state of the button 
// Return:        Returns the old state of the button
// Parameters:    nState = Either ON or OFF. The default is OFF. This is NOT tri-state button!
BUTTON_STATE CHoverButton::SetButtonState(BUTTON_STATE nState) 
{
    BUTTON_STATE nOldState = (BUTTON_STATE)GetCheck();
    
    m_ButtonState = nState;
    switch(m_ButtonState)
    {
    case BUTTON_ON:
        EnableWindow(TRUE);
        SetState(BUTTON_ON);
        break;
    case BUTTON_GREYED:
        EnableWindow(FALSE);
        break;
    case BUTTON_OVER:
        EnableWindow(TRUE);
        SetState(BUTTON_OVER);
        break;
    default:
        EnableWindow(TRUE);
        SetState(BUTTON_OFF);
        m_ButtonState = BUTTON_OFF;
        break;
    }
    return(nOldState);
}

// Draws the buttons in their relevant state, and text labels
void CHoverButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
    CDC            memDC;
    CBitmap*    pOld=NULL;
    CBitmap*    pBitmap=NULL;
    CDC*        pDC;
    CRect        rc;
    int            iSaveDC;

    pDC= CDC::FromHandle(lpDrawItemStruct->hDC);
    memDC.CreateCompatibleDC(pDC);
    VERIFY(pDC);
    iSaveDC=pDC->SaveDC();
    rc.CopyRect(&lpDrawItemStruct->rcItem);
    pDC->SetBkMode(TRANSPARENT);
    pDC->SetTextColor(GetSysColor(COLOR_WINDOWFRAME));// Black text color

    switch(m_ButtonState)
    {
    case BUTTON_ON:
        pBitmap=&m_bmpButtonDown;
        break;
    case BUTTON_OVER:
        pBitmap=&m_bmpButtonFocussed;
        break;
    case BUTTON_GREYED:
        pBitmap=&m_bmpButtonDisabled;
        break;
    default:
        pBitmap=&m_bmpButtonUp;
        break;
    }

    CString        strTitle;
    GetWindowText(strTitle);

    if (pBitmap->m_hObject)
    {
        CRect    rcBitmap(rc);
        BITMAP    bmpInfo;            
        CSize    size;

        // Text
        size = pDC->GetTextExtent(strTitle);
        rcBitmap.OffsetRect(size.cx+5,0);

        // Draw bitmap
        if(!pBitmap->GetBitmap(&bmpInfo))
            return;
        pOld=memDC.SelectObject((CBitmap*) pBitmap);
        if (pOld==NULL) 
            return; //Destructors will clean up

        if(!pDC->BitBlt(0, 0, rc.Width(), rc.Height(), &memDC, 0, 0, SRCCOPY))
            return;
        memDC.SelectObject(pOld);    
        if(memDC==NULL)
            return;
    }
/*
    CRect    rcText(rc);
    UINT nFormat = DT_CENTER;

    if(m_ButtonState == BUTTON_GREYED)
    {
        rcText.OffsetRect(1,1);
        pDC->SetTextColor(GetSysColor(COLOR_BTNHIGHLIGHT));
        pDC->DrawText(strTitle,rcText,nFormat);
        rcText.OffsetRect(-1,-1);
        pDC->SetTextColor(GetSysColor(COLOR_BTNSHADOW));
        pDC->DrawText(strTitle,rcText,nFormat);
    } 
    else
        pDC->DrawText(strTitle,rcText,nFormat);
*/
    pDC->RestoreDC(iSaveDC);
}

BOOL CHoverButton::LoadBitmaps(UINT nBitmapUp, UINT nBitmapDown, 
                               UINT nBitmapFocus, UINT nBitmapDisabled)
{
    return LoadBitmaps(MAKEINTRESOURCE(nBitmapUp),
                        MAKEINTRESOURCE(nBitmapDown),
                        MAKEINTRESOURCE(nBitmapFocus),
                        MAKEINTRESOURCE(nBitmapDisabled));
}

BOOL CHoverButton::LoadBitmaps(LPCSTR lpszBitmapUp, LPCSTR lpszBitmapDown, 
                               LPCSTR lpszBitmapFocus, LPCSTR lpszBitmapDisabled)
{
    BOOL bAllLoaded=TRUE;

    //Delete old ones
    m_bmpButtonDown.DeleteObject();
    m_bmpButtonFocussed.DeleteObject();
    m_bmpButtonUp.DeleteObject();
    m_bmpButtonDisabled.DeleteObject();
    
    if (!m_bmpButtonUp.LoadBitmap(lpszBitmapUp))
    {
        TRACE0("Failed to load up bitmap of bitmap button\n");
        return FALSE;
    }

    if (lpszBitmapDown!=NULL)
    {
        if (!m_bmpButtonDown.LoadBitmap(lpszBitmapDown))
        {
            TRACE0("Failed to load down bitmap of bitmap button\n");
            return bAllLoaded=FALSE;
        }
    }
    
    if (lpszBitmapFocus!=NULL)
    {
        if (!m_bmpButtonFocussed.LoadBitmap(lpszBitmapFocus))
        {
            TRACE0("Failed to load focussed bitmap of bitmap button\n");
            return bAllLoaded=FALSE;
        }
    }
    
    if (lpszBitmapDisabled!=NULL)
    {
        if (!m_bmpButtonDisabled.LoadBitmap(lpszBitmapDisabled))
        {
            TRACE0("Failed to load disabled bitmap of bitmap button\n");
            return bAllLoaded=FALSE;
        }
    }
    return bAllLoaded;
}