Windows NT/2000/XP: Included in Windows 2000 Ａnd later. Windows 95/98/Me: Unsupported. Header: Declared in Winuser.h; include Windows.h. Library: Use User32.lib
BOOL SetLayeredWindowAttributes(
HWND hwnd, // handle to the layered window
COLORREF crKey, // specifies the color key
BYTE bAlpha, // value for the blend function
DWORD dwFlags // action
);
一些常量:
WS_EX_LAYERED = 0x80000;
LWA_ALPHA = 0x2;
LWA_COLORKEY=0x1
其中dwFlags有LWA_ALPHA和LWA_COLORKEY。LWA_ALPHA被设置的话,通过bAlpha决定透明度，LWA_COLORKEY被设置的话,则指定被透明掉的颜色为crKey，其他颜色则正常显示。
注:要使使窗体拥有透明效果，首先要有WS_EX_LAYERED扩展属性(旧sdk也没有的)。
【
SetWindowLong(this->GetSafeHwnd(),GWL_EXSTYLE,
GetWindowLong(this->GetSafeHwnd(),GWL_EXSTYLE)^0x80000);
HINSTANCE hInst = LoadLibrary(/"User32.DLL/");
if(hInst)
{
typedef BOOL (WINAPI *MYFUNC)(HWND,COLORREF,BYTE,DWORD);
MYFUNC fun = NULL;
//取得SetLayeredWindowAttributes函数指针
fun=(MYFUNC)GetProcAddress(hInst, /"SetLayeredWindowAttributes/");
if(fun)
fun(this->GetSafeHwnd(),0,128,2);
FreeLibrary(hInst);
}
】
#define WS_EX_LAYERED 0x00080000
#define LWA_COLORKEY 0x00000001
#define LWA_ALPHA 0x00000002
typedef BOOL (*_SetLayeredWindowAttributes)(HWND,COLORREF,BYTE,DWORD);
_SetLayeredWindowAttributes SetLayeredWindowAttributes;
void SetLayered(HWND hWnd,int Pos)
{
SetLayeredWindowAttributes = (_SetLayeredWindowAttributes)GetProcAddress(GetModuleHandle(///"user32.dll///"),///"SetLayeredWindowAttributes///");
if ( SetLayeredWindowAttributes == NULL )
return ;
else{
__try{
SetWindowLong(hWnd,GWL_EXSTYLE,GetWindowLong(hWnd,GWL_EXSTYLE)|WS_EX_LAYERED);
SetLayeredWindowAttributes(hWnd,RGB(0,0,0),Pos,LWA_ALPHA);
}
__except(EXCEPTION_EXECUTE_HANDLER){
AfxMessageBox(///"SYSTEM FALSE///");
}
}
}