MFC + CxImage 实现自绘半透明按钮

#pragma once

// CBtn
#include "ximage/ximage.h"

class CBtn : public CButton
{
DECLARE_DYNAMIC(CBtn)
private:
CxImage * m_pImgNormal;
CxImage * m_pImgOver;
CxImage * m_pImgDown;
CxImage * m_pImgFocus;
CxImage * m_pImgDisable;

BOOL m_bTracking;
BOOL m_bMouseOver;
BOOL m_bLBtnDown;
public:
CBtn(UINT imgID_LbtnDown,UINT imgID_Over,UINT imgID_Normal,UINT imgID_Disabled=0,UINT imgID_Focus=0);
virtual ~CBtn();

protected:
DECLARE_MESSAGE_MAP()
public:
virtual void DrawItem(LPDRAWITEMSTRUCT /*lpDrawItemStruct*/);
afx_msg void OnDestroy();
afx_msg BOOL OnEraseBkgnd(CDC* pDC);
afx_msg void OnMouseMove(UINT nFlags, CPoint point);
afx_msg void OnMouseLeave();
afx_msg void OnMouseHover(UINT nFlags, CPoint point);
protected:
virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
public:
void PaintParent();
virtual BOOL Create(LPCTSTR lpszCaption, DWORD dwStyle, const RECT& rect, CWnd* pParentWnd, UINT nID);
afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
afx_msg void OnBnDoubleclicked();
afx_msg void OnKillFocus(CWnd* pNewWnd);
};

// Btn.cpp : 实现文件
//

#include "stdafx.h"
#include "Btn.h"

// CBtn

IMPLEMENT_DYNAMIC(CBtn, CButton)

CBtn::CBtn(UINT imgID_LbtnDown,UINT imgID_Over,UINT imgID_Normal,UINT imgID_Disabled,UINT imgID_Focus):
m_pImgNormal(NULL)
, m_pImgOver(NULL)
, m_pImgDown(NULL)
, m_pImgFocus(NULL)
, m_pImgDisable(NULL)
, m_bTracking(FALSE)
, m_bMouseOver(FALSE)
, m_bLBtnDown(FALSE)
{
if(imgID_Normal > 0)
{
if(!m_pImgNormal)
m_pImgNormal = new CxImage(CXIMAGE_FORMAT_PNG);
m_pImgNormal ->LoadResource(FindResource(NULL,MAKEINTRESOURCE(imgID_Normal),L"PNG"),CXIMAGE_FORMAT_PNG);
}
if(imgID_Focus > 0)
{
if(!m_pImgFocus)
m_pImgFocus = new CxImage(CXIMAGE_FORMAT_PNG);
m_pImgFocus ->LoadResource(FindResource(NULL,MAKEINTRESOURCE(imgID_Focus),L"PNG"),CXIMAGE_FORMAT_PNG);
}
if( imgID_LbtnDown>0 )
{
if(!m_pImgDown)
m_pImgDown = new CxImage(CXIMAGE_FORMAT_PNG);
m_pImgDown ->LoadResource(FindResource(NULL,MAKEINTRESOURCE(imgID_LbtnDown),L"PNG"),CXIMAGE_FORMAT_PNG);
}
if( imgID_Disabled > 0 )
{
if(!m_pImgDisable)
m_pImgDisable = new CxImage(CXIMAGE_FORMAT_PNG);
m_pImgDisable ->LoadResource(FindResource(NULL,MAKEINTRESOURCE(imgID_Disabled),L"PNG"),CXIMAGE_FORMAT_PNG);
}
if( imgID_Over > 0)
{
if(!m_pImgOver)
m_pImgOver = new CxImage(CXIMAGE_FORMAT_PNG);
m_pImgOver ->LoadResource(FindResource(NULL,MAKEINTRESOURCE(imgID_Over),L"PNG"),CXIMAGE_FORMAT_PNG);
}
}

CBtn::~CBtn()
{
}

BEGIN_MESSAGE_MAP(CBtn, CWnd)
ON_WM_DESTROY()
ON_WM_ERASEBKGND()
ON_WM_MOUSEMOVE()
ON_WM_MOUSELEAVE()
ON_WM_MOUSEHOVER()
ON_WM_LBUTTONDOWN()
ON_WM_LBUTTONUP()
ON_CONTROL_REFLECT(BN_DOUBLECLICKED, &CBtn::OnBnDoubleclicked)
ON_WM_KILLFOCUS()
END_MESSAGE_MAP()

// CBtn 消息处理程序
void CBtn::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
CDC ButtonDC;
CRect rc;

ButtonDC.Attach(lpDrawItemStruct->hDC); //得到用于绘制按钮的DC
rc=lpDrawItemStruct->rcItem; //获取按钮所占的矩形大小

UINT state = lpDrawItemStruct->itemState; //获取按钮目前所处的状态，根据不同的状态绘制不同的按钮

if(state&ODS_DISABLED && m_pImgDisable)
{
m_pImgDisable ->Draw(ButtonDC.GetSafeHdc(),rc);
}
else
{

if( m_bLBtnDown && m_pImgDown)
{
m_pImgDown ->Draw(ButtonDC.GetSafeHdc(),rc);
}
else if(m_bMouseOver && m_pImgOver)
{
m_pImgOver ->Draw(ButtonDC.GetSafeHdc(),rc);
}
else if(state&ODS_FOCUS && m_pImgFocus)
{
m_pImgFocus ->Draw(ButtonDC.GetSafeHdc(),rc);
}
else if(m_pImgNormal)
{
m_pImgNormal ->Draw(ButtonDC.GetSafeHdc(),rc);
}
}
}

void CBtn::OnDestroy()
{
CButton::OnDestroy();

// TODO: 在此处添加消息处理程序代码
if(m_pImgNormal)
{
m_pImgNormal ->Destroy();
delete m_pImgNormal;
m_pImgNormal = NULL;
}
if(m_pImgOver)
{
m_pImgOver ->Destroy();
delete m_pImgOver;
m_pImgOver = NULL;
}
if(m_pImgDown)
{
m_pImgDown ->Destroy();
delete m_pImgDown;
m_pImgDown = NULL;
}
if(m_pImgFocus)
{
m_pImgFocus ->Destroy();
delete m_pImgFocus;
m_pImgFocus = NULL;
}
if(m_pImgDisable)
{
m_pImgDisable ->Destroy();
delete m_pImgDisable;
m_pImgDisable = NULL;
}
}

BOOL CBtn::OnEraseBkgnd(CDC* pDC)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
return TRUE;
//return CButton::OnEraseBkgnd(pDC);
}

BOOL CBtn::PreCreateWindow(CREATESTRUCT& cs)
{
// TODO: 在此添加专用代码和/或调用基类
cs.style |= BS_OWNERDRAW;

return CButton::PreCreateWindow(cs);
}

void CBtn::OnMouseMove(UINT nFlags, CPoint point)
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
m_bMouseOver = TRUE;
if (!m_bTracking)
{
TRACKMOUSEEVENT   tme;
tme.cbSize		=   sizeof(TRACKMOUSEEVENT);
tme.dwFlags		=   TME_LEAVE|TME_HOVER; //
tme.hwndTrack   =   GetSafeHwnd();
tme.dwHoverTime	=   8;
_TrackMouseEvent(&tme);
m_bTracking = TRUE;
}
CButton::OnMouseMove(nFlags, point);
::SetCursor(AfxGetApp() ->LoadCursor(IDC_CURSOR_HAND));
}

void CBtn::OnMouseLeave()
{
// TODO: 在此添加消息处理程序代码和/或调用默认值
m_bMouseOver	=   FALSE;
m_bTracking		=   FALSE;
m_bLBtnDown		=	FALSE;
PaintParent();
CButton::OnMouseLeave();
}

void CBtn::OnMouseHover(UINT nFlags, CPoint point)
{
m_bMouseOver = TRUE;
PaintParent();
::SetCursor(AfxGetApp() ->LoadCursor(IDC_CURSOR_HAND));
}

void CBtn::PaintParent()
{
CRect   rect;
GetWindowRect(&rect);
GetParent()-> ScreenToClient(&rect);
GetParent()-> InvalidateRect(&rect);
}

BOOL CBtn::Create(LPCTSTR lpszCaption, DWORD dwStyle, const RECT& rect, CWnd* pParentWnd, UINT nID)
{
BOOL OK=CButton::Create(lpszCaption, dwStyle, rect, pParentWnd, nID);
ModifyStyleEx(0, WS_EX_TRANSPARENT);// WS_EX_LAYERED||WS_EX_TRANSPARENT
return OK;
}

void CBtn::OnLButtonDown(UINT nFlags, CPoint point)
{
m_bLBtnDown = TRUE;
PaintParent();
CButton::OnLButtonDown(nFlags, point);
::SetCursor(AfxGetApp() ->LoadCursor(IDC_CURSOR_HAND));
}

void CBtn::OnLButtonUp(UINT nFlags, CPoint point)
{
m_bLBtnDown = FALSE;
PaintParent();
CButton::OnLButtonUp(nFlags, point);
::SetCursor(AfxGetApp() ->LoadCursor(IDC_CURSOR_HAND));
}

void CBtn::OnBnDoubleclicked()
{
// TODO: 在此添加控件通知处理程序代码
::SetCursor(AfxGetApp() ->LoadCursor(IDC_CURSOR_HAND));
}

void CBtn::OnKillFocus(CWnd* pNewWnd)
{
CButton::OnKillFocus(pNewWnd);

// TODO: 在此处添加消息处理程序代码
PaintParent();
}

///头文件中添加
...
#include "Btn.h"
...
enum {emTestBtnId1=8099,emTestBtnId2,emTestBtnId3};
CBtn m_btnTest1,m_btnTest2,m_btnTest3;//test

///在构造函数初始化列表中初始化变量(IDB_PNG_BTN_TEST_*为Png图片资源ID)  
    , m_btnTest1(IDB_PNG_BTN_TEST_DOWN,
            IDB_PNG_BTN_TEST_MOUSEOVER,
            IDB_PNG_BTN_TEST_NORMAL,
            IDB_PNG_BTN_TEST_DISABLE,
            IDB_PNG_BTN_TEST_FOCUS)
    , m_btnTest2(IDB_PNG_BTN_TEST_DOWN,
            IDB_PNG_BTN_TEST_MOUSEOVER,
            IDB_PNG_BTN_TEST_NORMAL,
            IDB_PNG_BTN_TEST_DISABLE/*,IDB_PNG_BTN_TEST_FOCUS*/)
    , m_btnTest3(IDB_PNG_BTN_TEST_DOWN,
            IDB_PNG_BTN_TEST_MOUSEOVER,
            IDB_PNG_BTN_TEST_NORMAL,
            IDB_PNG_BTN_TEST_DISABLE/*,IDB_PNG_BTN_TEST_FOCUS*/)

////在OnInitDialog()函数中创建按钮
    //test
    m_btnTest1.Create(_T("test"),WS_VISIBLE | WS_CHILD/* |WS_DISABLED*/,CRect(10,10,58,58),this,emTestBtnId1);
    m_btnTest2.Create(_T("test"),WS_VISIBLE | WS_CHILD/* |WS_DISABLED*/,CRect(10,60,58,108),this,emTestBtnId2);
    m_btnTest3.Create(_T("test"),WS_VISIBLE | WS_CHILD |WS_DISABLED,CRect(10,110,58,158),this,emTestBtnId2);