cam: kms_sink: Scale the frame buffer to full screen if supported

The KMS sink currently displays the frame buffer on the top-left corner
of the screen, resulting in either a black area on the bottom and right
sides (if the frame buffer is smaller than the display resolution) of in
a restricted field of view (if the frame buffer is larger than the
display resolution). Improve this by scaling the frame buffer to full
screen if supported, and aligning the crop rectangle to the frame buffer
center if the field of view needs to be restricted.

The implementation test for possible composition options, from best to
worst. The tests are performed when the camera is started, as testing
atomic commits requires access to frame buffer objects, which are not
available at configure time. Changing this would require either a large
refactoring of the cam application to provide frame buffers earlier, or
extending the KMS API to support testing commits with dummy buffer
objects. Both are candidates for later development.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

0 files changed, 0 insertions, 0 deletions