VB Forum / Win API / September 2007

Alessandro Baraldi <ik2zok@libero.it> schrieb im Beitrag
<1190414523.951336.27690@50g2000hsm.googlegroups.com>...

Why don't you read the documentation? It states that the frame of the
rectangle will be drawn with the current pen (not brush!) and that its
interior will be filled with the current brush. So you have to create a
brush with the colour you need, select it into the DC, and then draw the
rectangle. And don't forget to replace the brush afterwards with the DC's
original brush.

In GDI you'd need to use a clipping region to accomplish this, here's a demo:

'***
Private Declare Function CreateRoundRectRgn Lib "GDI32.dll" ( _
   ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, _
   ByVal Y2 As Long, ByVal X3 As Long, ByVal Y3 As Long) As Long
Private Declare Function SelectClipRgn Lib "GDI32.dll" ( _
   ByVal hDC As Long, ByVal hRgn As Long) As Long
Private Declare Function GetClientRect Lib "User32.dll" ( _
   ByVal hWnd As Long, ByRef lpRect As RectAPI) As Long
Private Declare Function InflateRect Lib "User32.dll" ( _
   ByRef lpRect As RectAPI, ByVal X As Long, ByVal Y As Long) As Long
Private Declare Function DeleteObject Lib "GDI32.dll" (ByVal hObject As Long) As Long
Private Declare Function RoundRect Lib "GDI32.dll" ( _
   ByVal hDC As Long, ByVal X1 As Long, ByVal Y1 As Long, _
   ByVal X2 As Long, ByVal Y2 As Long, ByVal X3 As Long, ByVal Y3 As Long) As Long
Private Declare Function CreatePen Lib "GDI32.dll" ( _
   ByVal nPenStyle As Long, ByVal nWidth As Long, ByVal crColor As Long) As Long
Private Declare Function GetStockObject Lib "GDI32.dll" (ByVal nIndex As Long) As Long
Private Declare Function SelectObject Lib "GDI32.dll" ( _
   ByVal hDC As Long, ByVal hObject As Long) As Long

Private Type RectAPI
   Left As Long
   Top As Long
   Right As Long
   Bottom As Long
End Type

Private Const PS_SOLID As Long = &H0
Private Const NULL_BRUSH As Long = &H5

Private Sub Form_Paint()
   Dim ClientArea As RectAPI
   Dim hClipRgn As Long
   Dim hPen As Long, hOldPen As Long
   Dim hDC As Long

   Const CornerSize As Long = 32

   hDC = Me.hDC

   ' Get the form's size and shrink by 5 pixels
   Call GetClientRect(Me.hwnd, ClientArea)
   Call InflateRect(ClientArea, -5, -5)

   ' Create and selection clipping region for fill
   hClipRgn = CreateRoundRectRgn(ClientArea.Left, ClientArea.Top, _
       ClientArea.Right + 1, ClientArea.Bottom + 1, CornerSize, CornerSize)
   Call SelectClipRgn(hDC, hClipRgn)

   ' Draw gradient fill
   Call DrawRectGrad(hDC, _
       NewTriVertex(ClientArea.Left, ClientArea.Top, vb3DHighlight), _
       NewTriVertex(ClientArea.Right, ClientArea.Bottom, vb3DShadow), False)

   ' Deselect and destroy clipping region
   Call SelectClipRgn(hDC, 0&)
   Call DeleteObject(hClipRgn)

   ' Draw border
   hPen = CreatePen(PS_SOLID, 0, vbBlack)
   hOldPen = SelectObject(hDC, hPen)
   Call RoundRect(hDC, ClientArea.Left, ClientArea.Top, _
       ClientArea.Right, ClientArea.Bottom, CornerSize, CornerSize)
   Call SelectObject(hDC, hOldPen)
   Call DeleteObject(hPen)
End Sub

Private Sub Form_Resize()
   ' Re-paint on resize, ugly, but ok for demo
   Call Me.Refresh
End Sub
'***

I'm using my gradient drawing library (available on my site if you're feeling lazy too!) for this demo to save some
declarations and filling out the TRIVERTEX structures, but you can easily replace this in your own code with a
GradientFill() which it uses internally anyway.
If you're not happy with this implementation then if GDI+ is an option to you or if you're already using it in your
project then you can use a LinearGradientBrush to perform the fill.  Rounded rectangles are not natively supported by
the library (for some reason??), however you can use a GraphicsPath and a series of Arc's to create the profile that way
then FillPath/DrawPath to draw it.
Hope this helps,

   Mike

- Microsoft Visual Basic MVP -
E-Mail: EDais@mvps.org
WWW: Http://EDais.mvps.org/