SetLayeredWindowAttributes function user32
Sets the opacity and transparency color key of a layered window.
BOOL SetLayeredWindowAttributes(
HWND hwnd,
COLORREF crKey,
BYTE bAlpha,
DWORD dwFlags
);
Implementation
int SetLayeredWindowAttributes(int hwnd, int crKey, int bAlpha, int dwFlags) =>
_SetLayeredWindowAttributes(hwnd, crKey, bAlpha, dwFlags);