Question

Since using the DrawArc function in GDI+ isn’t very accurate when drawing a small rounded rectangle, I am using RoundRect instead.

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
  Dim hDC As IntPtr = e.Graphics.GetHdc
  Dim rc As New Rectangle(10, 10, 64, 24)
  Dim hPen As IntPtr = Win32.CreatePen(Win32.PenStyle.PS_SOLID, 0, _
                                       ColorTranslator.ToWin32(Color.Green))
  Dim hOldPen As IntPtr = Win32.SelectObject(hDC, hPen)
  Call Win32.RoundRect(hDC, rc.Left, rc.Top, rc.Right, rc.Bottom, 10, 10)
  Win32.SelectObject(hDC, hOldPen)
  Win32.DeleteObject(hPen)
  e.Graphics.ReleaseHdc(hDC)
  MyBase.OnPaint(e)    
End Sub

This will draw a nice rounded rectangle, but it will also fill it with a white brush, erasing what I don’t want to have erased.

How can I draw this without erasing the inside of the rectangle?

Answer 1

You just need to select a stock, hollow brush before you draw the rectangle. Call GetStockObject with HOLLOW_BRUSH and then select that into the device context in the same way as you selected the pen.