[cairo] copy and manipulate background

[Alexander Shulgin]

On Thu, Dec 2, 2010 at 16:18, Michael Gurnett <gurnett at macbat.com> wrote:
> I was wondering if there was a simple way to copy the entire visible
> background to an image_surface.
>
> My basic idea was before I show a modal dialog was to take a "screen grab"
> of the entire screen, manipulate this (gray scale, blur, darken etc) paint
> it and then show the dialog. Once the dialog has been closed everthing needs
> to return to its previous state.
>
> Any ideas are appreciated

On which platform: Windows, X11, Mac OS X?