C# Signature:
[DllImport("gdi32.dll")]
static extern int CombineRgn(IntPtr hrgnDest, IntPtr hrgnSrc1,
IntPtr hrgnSrc2, int fnCombineMode);
VB.Net Signature:
<DllImport("gdi32.dll")>
Private Shared Function CombineRgn(ByVal hrgnDest As IntPtr,
ByVal hrgnSrc1 As IntPtr, ByVal hrgnSrc2 As IntPtr,
ByVal fnCombineMode As Integer) As Integer
End Function
User-Defined Types:
public enum CombineRgnStyles:int
{
RGN_AND =1,
RGN_OR =2,
RGN_XOR =3,
RGN_DIFF =4,
RGN_COPY =5,
RGN_MIN =RGN_AND,
RGN_MAX =RGN_COPY
}
Return Values:
public const int ERROR = 0;
public const int NULLREGION = 1;
public const int SIMPLEREGION = 2;
public const int COMPLEXREGION = 3;
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
// This Sample xors the two different shapes and redraw the complete window by the resultant shapes
[DllImport("gdi32.dll")]
public static extern IntPtr CreateEllipticRgn(int nLeftRect, int nTopRect,int nRightRect, int nBottomRect);
[DllImport("user32.dll")]
static extern System.UInt16 SetWindowRgn(IntPtr hWnd, IntPtr hRgn, bool bRedraw);
[DllImport("gdi32.dll")]
static extern int CombineRgn(IntPtr hrgnDest, IntPtr hrgnSrc1,IntPtr hrgnSrc2, int fnCombineMode);
// And the code lies here
InitializeComponent();
IntPtr r1 = CreateEllipticRgn(0,0,300,300);
IntPtr r2 = CreateEllipticRgn(100,100,300,300);
IntPtr r3= CreateEllipticRgn(100,100,300,300);
CombineRgn(r3,r1,r2,0);
SetWindowRgn(this.Handle,r3,true);
// by - S.C.
Alternative Managed API:
Do you know one? Please contribute it!
