[wxPython-users] Reducing the size of a BufferedDC

[Christopher Barker]

Alexander 'boesi' B=F6secke wrote:
>> So what should I do to get a buffered DC with the correct size? =


I see the same problem with 2.8 on OS-X, but not with 2.6. However, =

there is a bit of odd code. I've re-written it a bit, and it seems to =

work now. You don't need to explicitly call destroy on the dc. In =

general, you don't call Destroy() in wxPython -- python's garbage =

collection handles that for you.

See enclosed.

However, the other option is to create the off-screen bitmap yourself, =

then pass it in the constructor. See the commented code in the example.

In real use, it's likely you want to keep that bitmap around anyway, so =

that your OnPaint handler can just blit it to the screen. See the =

DoubleBuffer demo in the Wiki.

also, some odd things do happen with this example, as you are creating a =

bufferedclientDC, but not drawing anything.

-Chris




-- =

Christopher Barker, Ph.D.
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Chris.Barker at noaa.gov
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# -*- coding: iso8859_15 -*-

import wx

class myFrame(wx.Frame):
    def __init__(self, parent=3DNone):
        wx.Frame.__init__(self, parent, -1, 'Test')
        self.dc =3D None
        self.panel =3D wx.Panel(self, -1)
        self.btnBuffer =3D wx.ToggleButton(self.panel, label=3D'Use Buffere=
d DC', pos=3D(0, 0))
        self.btnDC =3D wx.Button(self.panel, label=3D'Create DC', pos=3D(0,=
 25))
        self.btnDC.Bind(wx.EVT_BUTTON, self.createDC)

    def createDC(self, event=3DNone):
            self.dc =3D wx.ClientDC(self.panel)
            print 'Unbuffered Size:', self.dc.GetSize(),
            #self._buffer =3D wx.EmptyBitmap(*self.GetSize())
            if self.btnBuffer.GetValue() =3D=3D True:
                self.dc =3D wx.BufferedDC(self.dc, self.dc.GetSize())
                #self.dc =3D wx.BufferedDC(self.dc, self._buffer)
                print 'Buffered Size:', self.dc.GetSize()
            else:
                print "UnBuffered Size:", self.dc.GetSize()

app =3D wx.PySimpleApp()
frame =3D myFrame()
frame.Show()
app.MainLoop()