blit and BufferedPaintDC

[Declan McMullen]

I'm screenshotting the contents of my own dc. All it had in it is an image
and some other graphical elements drawn on top. If I use a BufferedPaintDC
only it works fine,
if I use a GraphiccontextDC the blit fails.


On Tue, Apr 22, 2008 at 8:14 AM, Xavier Miller <xavier.miller at cauwe.org>
wrote:

> Hello,
>
> What do you screenshot ? If it is a graphic-accelerated application (DVD
> player, game), it will not work because the drawing is managed by the
> graphical card and not the OS.
>
> Xavier.
>
> Declan McMullen a =E9crit :
>
> > Ive tried turning off double buffering and I still get an entitrely
> > black bitmap.
> > If i set the bitmap to match another bitmap its fine, so It seems the
> > blit definitely isnt
> > copying the content of the dc to the memory dc
> >
> > Any ideas ?
> >
> > On Sun, Apr 20, 2008 at 4:42 PM, Declan McMullen <
> > declan.mcmullen at gmail.com <mailto:declan.mcmullen at gmail.com>> wrote:
> >
> >
> >    Is it possible to use blit with a double buffered paint dc ?
> >    I have the following function
> >
> >
> >    wxBitmap WorkspaceView::getScreenShot(wxDC& dc)
> >
> >    {
> >
> >    wxSize screenSize =3D dc.GetSize();
> >
> >    wxBitmap screenBitmap(screenSize.GetWidth(), screenSize.GetHeight());
> >
> >    wxMemoryDC memDC;
> >
> >    memDC.SelectObject(screenBitmap);
> >
> >    memDC.Blit(0, 0, screenSize.GetWidth(), screenSize.GetHeight(), &dc,
> >    0, 0);
> >
> >    memDC.SelectObject(wxNullBitmap);
> >
> >    return screenBitmap;
> >
> >    }
> >
> >
> >
> >    What I wanted to do with it was make a bitmap I could use for
> >    printing, i.e just put everything
> >
> >    thats on the screen into a bitmap, send that image to my printout
> >    object and print it.
> >
> >    All I'm getting though is a completely black image and I'm thinking
> >    its due to my double buffering ?
> >
> >
> >    Is it possible for me to get the contents of the buffer itself and
> >    use that ?
> >
> >
> >
> >    --    http://www.computing.dcu.ie/~dmcmullen<http://www.computing.dc=
u.ie/%7Edmcmullen>
> >    <http://www.computing.dcu.ie/%7Edmcmullen>
> >    declan.mcmullen at computing.dcu.ie
> >    <mailto:declan.mcmullen at computing.dcu.ie>
> >    School of Computing
> >    Postgrad Bay A
> >
> >
> >
> >
> > --
> > http://www.computing.dcu.ie/~dmcmullen<http://www.computing.dcu.ie/%7Ed=
mcmullen>
> > declan.mcmullen at computing.dcu.ie <mailto:
> > declan.mcmullen at computing.dcu.ie>
> > School of Computing
> > Postgrad Bay A
> >
> >
> > ------------------------------------------------------------------------
> >
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-- =

http://www.computing.dcu.ie/~dmcmullen
declan.mcmullen at computing.dcu.ie
School of Computing
Postgrad Bay A
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