PaintDone event
Remarks
Occurs immediately after the completion of the control graphical rendering. Catching this event will allow to make further rendering on the control surface through the hDC parameter.
Syntax
Visual Basic
BtnEnh1_PaintDone (ByVal hDC As Long)
Visual C++
void PaintDone (long hDC);
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Parameter
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Description
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hDC
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Handle to the screen device context: the drawback with using a screen device context is the fact that the rendering won't be flicker free. Use the SetCustomPaintFunction method in order to perform flicker free rendering.
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It's important to note that each of the available controls can have a different drawing function.
Let's see a sample that demonstrates how to paint a red circle over the button surface:
Visual Basic example
Inside a BAS module, add the following declarations that will allow accessing the Windows GDI primitives
Public Declare Function SelectObject Lib "gdi32" (ByVal hDC As Long, ByVal hObject As Long) As Long
Public Declare Function Ellipse Lib "gdi32" (ByVal hDC As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Public Declare Function DeleteObject Lib "gdi32" (ByVal hObject&) As Long
Public Declare Function CreateSolidBrush Lib "gdi32" (ByVal crColor As Long) As Long
Inside the same BAS module add the following subroutine that will perform our custom rendering
Sub MyPaintFunction(ByVal hDC As Long)
Dim brushColor As Long
Dim brushOld As Long
brushColor = CreateSolidBrush(RGB(255, 0, 0))
brushOld = SelectObject(hDC, brushColor)
Ellipse hDC, 10, 10, 50, 50
SelectObject hDC, brushOld
DeleteObject brushColor
End Sub
Inside the form code, catch the PaintDone event for the control BtnEnh1 and call the MyPaintFunction subroutine declared above
Private Sub BtnEnh1_PaintDone(ByVal hDC As Long)
MyPaintFunction hDC
End Sub
Visual C++ example
Supposing that we have a dialog box with a button identified by IDC_BTNENHCTRL1, let's add the management function for the PaintDone event
BEGIN_EVENTSINK_MAP(CMyDialog, CDialog)
//{{AFX_EVENTSINK_MAP(CMyDialog)
ON_EVENT(CMyDialog, IDC_BTNENHCTRL1, 11 /* PaintDone */, OnPaintDoneBtnenhctrl1, VTS_I4)
//}}AFX_EVENTSINK_MAP
END_EVENTSINK_MAP()
The OnPaintDoneBtnenhctrl1management function will look like this:
void CMyDialog::OnPaintDoneBtnenhctrl1(long hDC)
{
HBRUSH brushColor = ::CreateSolidBrush (RGB (255,0,0));
HBRUSH brushOld = (HBRUSH) ::SelectObject ((HDC) hDC, brushColor);
::Ellipse((HDC) hDC, 10, 10, 50, 50);
::SelectObject ((HDC) hDC, brushOld);
::DeleteObject (brushColor);
}
