Michael Weghorn
238d744178
Library_simplecanvas contains the SimpleCanvasImpl class, which implements the XSimpleCanvas UNO interface and is the implementation for the "com.sun.star.rendering.SimpleCanvas" service, defined in the component file. However, none of these are actually used anywhere. Therefore, drop the simplecanvas library altogether. Change-Id: I301b3a42dfb6eacf6a9ef3a4851ed1d38f16ec66 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/208852 Tested-by: Jenkins Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
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.