使用SetLayeredWindowAttributes API 實現透明視窗

//bAlpha form 0 to 255<br />//When bAlpha is 0, the window is completely transparent.<br />//When bAlpha is 255, the window is opaque.<br />BOOL SetWindowAlpha(HWND hwnd, BYTE bAlpha)<br />{<br /> BOOL bRet = 0;<br /> HMODULE hModule = GetModuleHandle(_T("User32.dll"));<br /> if(hModule)<br /> {<br /> #ifndef WS_EX_LAYERED<br /> #define WS_EX_LAYERED 0x00080000UL<br /> #endif //WS_EX_LAYERED</p><p> #ifndef LWA_ALPHA<br /> #define LWA_ALPHA 2<br /> #endif</p><p> typedef BOOL (WINAPI *pSETLAYEREDWINDOWATTRIBUTES)(<br /> HWND, COLORREF, BYTE, DWORD);<br /> pSETLAYEREDWINDOWATTRIBUTES pSetLayeredWindowAttributes =<br /> (pSETLAYEREDWINDOWATTRIBUTES)::GetProcAddress(hModule,<br /> "SetLayeredWindowAttributes");<br /> if(pSetLayeredWindowAttributes)<br /> {<br /> // Set WS_EX_LAYERED on this window<br /> SetWindowLong(hwnd, GWL_EXSTYLE,<br /> GetWindowLong(hwnd, GWL_EXSTYLE) | WS_EX_LAYERED);</p><p> // Make this window bAlpha<br /> pSetLayeredWindowAttributes(hwnd, 0, bAlpha, LWA_ALPHA);<br /> return bRet;<br /> }<br /> }<br /> return bRet;<br />}<br />