tdf#163125: CairoSDPR: Take virtual OutDevs into account

Unfortunaletly we have 'virtual' OutDevs, that means their
PixelSize is bigger as they claim and they use an internal
offset. This is used to not have to create too many Windows
inside Windows (AFAIR initial reason was that Windows has
a fix number of Windows per process that can be incarnated).

The offset was/is already supported by SDPRs using
ViewInformation2D and adding ot to the ViewTransformation,
but the evtl. existing PixelSize has to be clipped against.
The fallback VclPixelProcessor2D supports that indirectly
by doing that in the OutDev commands that get called, so
it does not need to be done by that renderer.

I have now added code to support that for the
CairoPixelProcessor2D, see code and comments. It uses an
existing method of cairo to do that elegantly inside the
system-dependent code of the SDPR.

Note that the Windows SDPR D2DPixelProcessor2D will
have the same problem that will have to be solved there,
too. Since it's currently in experimental state I made
myself a note about that.

Change-Id: I68915985102bb4a63c84299f8d022ab013633510
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/173998
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@me.com>

0 files changed, 0 insertions, 0 deletions