tdf#130857 qt weld: Add QtInstanceDrawingArea basics

Add a new QtInstanceDrawingArea class as the weld::DrawingArea
implementation using native Qt widgets.

Initially only add the "basic structure" (most of the actual
functionality of drawing will be added separately):

* Add the QtInstanceDrawingArea class with most methods
currently still unimplemented and triggering an assert
when they get called.
* Add a `ScopedVclPtrInstance<VirtualDevice> m_xDevice`
member and return that in `QtInstanceDrawingArea::get_ref_device`,
as the gtk3 implementation (GtkInstanceDrawingArea) does.
* Let QtBuilder::makeObject create a QLabel for a
"GtkDrawingArea" object for now. That label will hold
a pixmap (which should be sufficient for simple cases
at least).
* Let QtInstanceBuilder::weld_drawing_area return an
instance of the new class.

Change-Id: I5d509ccd9f5a7a826a166958af4a92ff01cc0225
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/176171
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Tested-by: Jenkins

0 files changed, 0 insertions, 0 deletions