gdialpha.h

#ifndef __GDIALPHA__H__
#define __GDIALPHA__H__
#ifdef _WIN32
 
#include "utilities-def.h"
#include <windows.h>
 
SNSBEGIN
 
#define  MAX_ALPHABUF    1<<16
 
typedef struct tagALPHAINFO
{
    BITMAP bm;
    LPBYTE lpBuf;
    RECT    rc;
    tagALPHAINFO()
    {
        lpBuf=NULL;
        rc.left=rc.top=rc.right=rc.bottom=0;
    }
} ALPHAINFO,* LPALPHAINFO;
 
class UTILITIES_API CGdiAlpha
{
private:
    static BYTE s_byAlphaBack[MAX_ALPHABUF];
 
    static LPBYTE ALPHABACKUP(BITMAP *pBitmap,int x,int y,int cx,int cy);
    //恢复位图的Alpha通道
    static void ALPHARESTORE(BITMAP *pBitmap,int x,int y,int cx,int cy,LPBYTE lpAlpha);
public:
 
    static BOOL AlphaBackup(HDC hdc,LPCRECT pRect,ALPHAINFO &alphaInfo);
 
    static void AlphaRestore(ALPHAINFO &alphaInfo);
};
 
SNSEND
 
#endif //_WIN32
#endif // __GDIALPHA__H__