frontend: Add common --renderer=foo argument

Rather than reinventing --use-pixman and --use-gl throughout each
backend, just have a common --renderer=foo argument which can be used to
explicitly specify the renderer.

The old arguments are still handled for backwards compatibility.

Signed-off-by: Daniel Stone <daniels@collabora.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/doc/sphinx/toc/running-weston.rst b/doc/sphinx/toc/running-weston.rst
index 7ea3ed00..9822b2fe 100644
--- a/doc/sphinx/toc/running-weston.rst
+++ b/doc/sphinx/toc/running-weston.rst
@@ -34,15 +34,12 @@ stitching them together is performed by a *renderer*. By doing so, it is
 compositing all surfaces into a single image, which is being handed out to a
 back-end, and finally, displayed on the screen.
 
-libweston has a CPU-based type of renderer by making use of the
-`Pixman <http://www.pixman.org/>`_ library, but also one that can make
-use of the GPU to do that, which uses `OpenGL ES <https://www.khronos.org/opengles/>`_
-and it is simply called the GL-renderer.
-
-Most of the back-ends provide a command line option to disable the GL-renderer,
-and use the CPU for doing that. That happens by appending to the command line
-``--use-pixman`` when running Weston. One might use the CPU-based renderer
-to exclude any other potential issues with the GL-renderer.
+libweston provides two useful renderers. One uses
+`OpenGL ES <https://www.khronos.org/opengles/>`_, which will often be accelerated
+by your GPU when suitable drivers are installed. The other uses the
+`Pixman <http://www.pixman.org>`_ library which is entirely CPU (software)
+rendered. You can select between these with the ``--renderer=gl`` and
+``--renderer=pixman`` arguments when starting Weston.
 
 Additional set-up steps
 -----------------------