Noel Grandin
5357da349b
So the vclcanvas backend is in worse shape than I thought. It will take too long to get it into shape to be sure of making the next release, so revert this for now, and I will have to find another approach. This reverts the following commits commitfbefe07e4cAuthor: Michael Weghorn <m.weghorn@posteo.de> Date: Thu Feb 20 09:42:14 2025 +0100 qt: Remove now unused vcl/inc/qt6/QtSvpSurface.hxx commit595354ab7eAuthor: Julien Nabet <serval2412@yahoo.fr> Date: Wed Feb 19 21:13:49 2025 +0100 Remove also canvas/cairo in gtk4, qt6 and gtk3_kde5 commitd539f6e99eAuthor: Noel Grandin <noelgrandin@gmail.com> Date: Wed Feb 19 18:15:30 2025 +0200 fix "local variable is unused" warning commit704f61b1bdAuthor: Noel Grandin <noelgrandin@collabora.co.uk> Date: Wed Jan 29 15:35:21 2025 +0200 remove canvas/cairo and canvas/gdi and canvas/directx backends Change-Id: I0492dabf7da8c42a15720c868f161919e8dc7ae4 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/181984 Tested-by: Jenkins Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
UNO-based Graphics Backend
UNO-based graphics backend, lesser impedance to modern graphics APIs than vcl.
The canvas Framework
The canvas framework is the successor of the system GUI and graphics
backend VCL. Basic functionality is available, supplying just as much
features as necessary to provide a VCL-equivalent feature set (except
proper BiDi/CTL support).
The canvas framework consists of the following two modules, canvas and
cppcanvas. Additionally, a new generic graphics tooling is used (but
not exclusively by the canvas, Armin's drawinglayer module also make
use of it), which resides in basegfx.
The UNO API used by the canvas is primarily under
css::rendering, with css::rendering::XCanvas
being the central interface.
The slideshow Engine
The slideshow engine has replaced the former Impress-embedded
presentation framework with a fully independent UNO component, and it
is based on the canvas. Some features used there are only available
from canvas, like double-buffering, and hardware-accelerated
alpha-blending (currently not on all platforms).
Cairo canvas
Cairo canvas is one of backends of canvas component. canvas is mostly
used for slideshow rendering and also for emf+ rendering. we hoped it
will even be used by drawing layer, but it didn't happen (yet?) for
API look at offapi/com/sun/star/rendering/, the implementation is in
canvas and cppcanvas modules.
Cairo canvas backend uses Cairo library for rendering. Main advantage
is support of alpha transparency and in some cases accelerated
rendering.
The backend itself is quite old and stable, not many changes in that area lately, mostly changes for emf+ rendering, communication with vcl and bugfixes
Future Works
Look at Cairo canvas and situation when it is used
(mostly slideshow).
TODO
There still might be more cases when we can save some roundtrips when exchanging data with vcl.