執行效果

實現方法

1.給按鈕加上BS_OWNERDRAW樣式
2.過載DrawItem函式,在這裡繪製按鈕
3.關鍵之處就是把父視窗的背景複製到按鈕上,實現視覺上的透明
4.最後通過AlphaBlend實現半透明.

實現原始碼

// MyButton.h
#pragma once


// CMyButton

class CMyButton : public CButton
{
	DECLARE_DYNAMIC(CMyButton)

public:
	CMyButton();
	virtual ~CMyButton();
public:
	void SetBkColor(COLORREF color);
	void SetTextColor(COLORREF color);
private:
	bool m_bOver;
	bool m_bDown;
	bool m_bDisable;
	bool m_bTracking;
	COLORREF m_bkColor;
	COLORREF m_textColor;
protected:
	DECLARE_MESSAGE_MAP()
	virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
	virtual void PreSubclassWindow();
public:
	virtual void DrawItem(LPDRAWITEMSTRUCT /*lpDrawItemStruct*/);
	afx_msg void OnMouseMove(UINT nFlags, CPoint point);
	afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
	afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
	afx_msg LRESULT OnMouseLeave(WPARAM wParam, LPARAM lParam);
	afx_msg LRESULT OnMouseHover(WPARAM wParam, LPARAM lParam);
	afx_msg void OnEnable(BOOL bEnable);
private:
	void ButtonInit();
	void DrawButton();
	void DrawButton(HDC hDestDC);
};

// MyButton.cpp : 實現檔案
//

#include "stdafx.h"
#include "AlphaButton.h"
#include "MyButton.h"
#include "MainDlg.h"

// CMyButton

IMPLEMENT_DYNAMIC(CMyButton, CButton)

CMyButton::CMyButton()
{
	m_bkColor=0xFFFFFF;
	m_textColor=0x000000;
}

CMyButton::~CMyButton()
{
}


BEGIN_MESSAGE_MAP(CMyButton, CButton)
	ON_WM_MOUSEMOVE()
	ON_WM_LBUTTONDOWN()
	ON_WM_LBUTTONUP()
	ON_MESSAGE(WM_MOUSELEAVE, OnMouseLeave)
	ON_MESSAGE(WM_MOUSEHOVER, OnMouseHover)
	ON_WM_ENABLE()
END_MESSAGE_MAP()



// CMyButton 訊息處理程式

void CMyButton::SetBkColor(COLORREF color)
{
	m_bkColor=color;
}
void CMyButton::SetTextColor(COLORREF color)
{
	m_textColor=color;
}

BOOL CMyButton::PreCreateWindow(CREATESTRUCT& cs)
{
	BOOL bRet=CButton::PreCreateWindow(cs);
	ButtonInit();
	return bRet;
}

void CMyButton::PreSubclassWindow()
{
	CButton::PreSubclassWindow();
	ButtonInit();
}
void CMyButton::ButtonInit()
{
	m_bTracking=false;
	m_bOver=m_bDown=m_bDisable=false;
	m_bDisable=IsWindowEnabled()?FALSE:TRUE;
	ModifyStyle(NULL,BS_OWNERDRAW);
}

void CMyButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{

	DrawButton(lpDrawItemStruct->hDC);
}

void CMyButton::OnMouseMove(UINT nFlags, CPoint point)
{
	if (!m_bTracking)
	{
		m_bOver = TRUE;
		TRACKMOUSEEVENT tme;
		tme.cbSize = sizeof(tme);
		tme.hwndTrack = m_hWnd;
		tme.dwFlags = TME_LEAVE | TME_HOVER;
		tme.dwHoverTime = 50;
		m_bTracking = (bool)_TrackMouseEvent(&tme);
	}

	CButton::OnMouseMove(nFlags, point);
}

void CMyButton::OnLButtonDown(UINT nFlags, CPoint point)
{
	m_bDown=TRUE;

	CButton::OnLButtonDown(nFlags, point);
}

void CMyButton::OnLButtonUp(UINT nFlags, CPoint point)
{
	m_bDown=FALSE;
	CButton::OnLButtonUp(nFlags, point);
}
LRESULT CMyButton::OnMouseLeave(WPARAM wParam, LPARAM lParam)
{
	m_bOver = FALSE;
	m_bTracking = FALSE;
	m_bDown=FALSE;
	InvalidateRect(NULL, FALSE);
	return 0;
}

LRESULT CMyButton::OnMouseHover(WPARAM wParam, LPARAM lParam)
{
	m_bOver = TRUE;
	InvalidateRect(NULL);
	return 0;
}
void CMyButton::DrawButton()
{
	HDC hDC=::GetDC(m_hWnd);
	DrawButton(hDC);
	::ReleaseDC(m_hWnd,hDC);
}
void CMyButton::DrawButton(HDC hDestDC)
{
	CRect rc;
	GetClientRect(rc);
	int nWindth=rc.Width();
	int nHeight=rc.Height();
	HDC hDC=CreateCompatibleDC(hDestDC);//建立相容DC,採用雙緩衝畫出
	HDC hMaskDC=CreateCompatibleDC(hDestDC);
	HBITMAP hBitmap=CreateCompatibleBitmap(hDestDC,nWindth,nHeight);
	HBITMAP hMaskBitmap=CreateCompatibleBitmap(hDestDC,nWindth,nHeight);
	HBITMAP hOldBitmap=(HBITMAP)SelectObject(hDC,hBitmap);
	HBITMAP hOldMaskBitmap=(HBITMAP)SelectObject(hMaskDC,hMaskBitmap);
	SetBkMode(hDC,TRANSPARENT);

	//把父視窗的背景圖複製到按鈕的DC上,實現視覺透明----------------
	CMainDlg* pParent=(CMainDlg*)GetParent();
	CPoint pt(0,0);
	MapWindowPoints(pParent,&pt,1);
	pParent->m_bkImage.BitBlt(hDC,rc,pt,SRCCOPY);


	//-------------------------------------------------------------
	int nAlpha=100;//0--255
	int nOffset=0;

	HBRUSH hbr=CreateSolidBrush(m_bkColor);
	FillRect(hMaskDC,&rc,hbr);
	DeleteObject(hbr);

	if(m_bDisable){
		nAlpha=100;
	}else if(m_bDown){
		nAlpha=180;
		nOffset=1;
	}else if(m_bOver){
		nAlpha=150;
	}else{
		nAlpha=100;
	}
	BLENDFUNCTION blend;
	memset( &blend, 0, sizeof( blend) );
	blend.BlendOp= AC_SRC_OVER;
	blend.SourceConstantAlpha= nAlpha; // 透明度 最大255

	HRGN hRgn=CreateRoundRectRgn(0,0,nWindth,nHeight,3,3);
	SelectClipRgn (hDC,hRgn);
	AlphaBlend (hDC,0,0,nWindth,nHeight,hMaskDC, 0,0,nWindth,nHeight,blend);

	CString strText;
	GetWindowText(strText);
	if(strText!=_T("")){
		rc.InflateRect(-2,-2);
		rc.OffsetRect(nOffset,nOffset);
		HFONT hFont=(HFONT)SendMessage(WM_GETFONT);
		if(!hFont)hFont=(HFONT)GetStockObject(DEFAULT_GUI_FONT);
		HFONT hOldFont=(HFONT)SelectObject(hDC,hFont);
		::SetTextColor(hDC,m_textColor);
		::DrawText(hDC,strText,-1,&rc,DT_SINGLELINE|DT_CENTER|DT_VCENTER|DT_WORD_ELLIPSIS);
		::SelectObject(hDC,hOldFont);
	}
	SelectClipRgn (hDC,NULL);
	DeleteObject(hRgn);
	//複製到控制元件的DC上------------------------
	BitBlt(hDestDC,0,0,nWindth,nHeight,hDC,0,0,SRCCOPY);
	//刪除資源,釋放記憶體-----------------------
	SelectObject(hDC,hOldBitmap);
	DeleteObject(hBitmap);
	DeleteDC(hDC);
	SelectObject(hMaskDC,hOldMaskBitmap);
	DeleteObject(hMaskBitmap);
	DeleteDC(hMaskDC);

}
void CMyButton::OnEnable(BOOL bEnable)
{
	CButton::OnEnable(bEnable);
	m_bDisable=IsWindowEnabled()?FALSE:TRUE;
	DrawButton();
}

原始碼下載:http://download.csdn.net/detail/cometnet/4955726

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