[wxPython] Additional drawing in OnPaint while base class draws the rest

wxPython Users
1

Additional drawing in OnPaint while base class draws the rest
Hello all,

I’m working on a layout design application similar to wxDesigner. The user can create and arrange controls on a panel. I’m trying to get selected controls to draw a box around themselves. I’m trying to do this by handling EVT_PAINT thusly:

def OnPaint(self, event):

    if self.selected:

        dc = wxPaintDC(self)

        (width, height) = self.GetClientSizeTuple()

        dc.SetPen(self.selectedPen)

        dc.DrawRectangle(0, 0, width, height)

   

    event.Skip()

The problem is, for some control types, like wxBitmapButton, the creation of the wxPaintDC object appears to stop the base class from drawing itself. I end up with a white rectangle instead of a button with a box drawn inside it. I’d like for the base class to handle most of the drawing… I just want to add to it. Any ideas?

For reference, here is some more source code:

class UserCtrl(Ctrl):

def __init__(self, wxType, *_args, **_kwargs):

    argList = [self]

    argList.extend(_args)

   

    apply(wxType.__init__, argList, _kwargs)

   

    self.selected = 1

    self.selectedPen = wxPen(wxSystemSettings_GetSystemColour(wxSYS_COLOUR_BTNHIGHLIGHT), 1, wxDOT)

    EVT_PAINT(self, self.OnPaint)

def OnPaint(self, event):

    if self.selected:

        dc = wxPaintDC(self)

        (width, height) = self.GetClientSizeTuple()

        dc.SetPen(self.selectedPen)

        dc.DrawRectangle(0, 0, width, height)

   

    event.Skip()

class UserBitmapButton(wxBitmapButton, UserCtrl):

def __init__(self, *_args, **_kwargs):

    UserCtrl.__init__(self, wxBitmapButton, *_args, **_kwargs)
···

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2

I'm working on a layout design application similar to wxDesigner. The user
can create and arrange controls on a panel. I'm trying to get selected
controls to draw a box around themselves. I'm trying to do this by

handling

EVT_PAINT thusly:

    def OnPaint(self, event):
        if self.selected:
            dc = wxPaintDC(self)
            (width, height) = self.GetClientSizeTuple()
            dc.SetPen(self.selectedPen)
            dc.DrawRectangle(0, 0, width, height)

        event.Skip()

The problem is, for some control types, like wxBitmapButton, the creation

of

the wxPaintDC object appears to stop the base class from drawing itself. I
end up with a white rectangle instead of a button with a box drawn inside
it. I'd like for the base class to handle most of the drawing... I just

want

to add to it. Any ideas?

I think that the best that can be done is to set a flag and then do your
painting with a wxClientDC in an idle handler. That way the OnPaint will
return and let the system do the default drawing and then before too long
your handler will be called to do it's own drawing.

···

--
Robin Dunn
Software Craftsman
robin@AllDunn.com Java give you jitters?
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