• Pekka Paalanen's avatar
    pixman: make shadow buffer optional · 26ded94a
    Pekka Paalanen authored
    Add a flag to pixman-renderer for initializing the output with a shadow
    framebuffer. All backends were getting the shadow implcitly, so all
    backends are modified to ask for the shadow explicitly.
    Using a shadow buffer is usually beneficial, because read-modify-write
    cycles (blending) into a scanout-capable buffer may be very slow. The
    scanout framebuffer may also have reduced color depth, making blending
    and read-back produce inferior results.
    In some use cases though the shadow buffer might be just an extra copy
    hurting more than it helps. Whether it helps or hurts depends on the
    platform and the workload. Therefore let the backends control whether
    pixman-renderer uses a shadow buffer for an output or not.
    Signed-off-by: Pekka Paalanen's avatarPekka Paalanen <pekka.paalanen@collabora.co.uk>
    Signed-off-by: default avatarFabien Lahoudere <fabien.lahoudere@collabora.com>
    Reviewed-by: default avatarIan Ray <ian.ray@ge.com>
compositor-x11.c 51.1 KB