Initialize LittleCMS and use it to generate the sRGB EOTF and inverse
curves. Use these curves to define the blending color space as optical
(linear) sRGB by assuming that both content and output color spaces are
sRGB.
As a consequence, this causes Weston to do "gamma correct blending", as
in, blend in light linear space which should avoid distorting colors in
alpha gradients, when color-lcms is active.
This makes use of the 3x1D LUT support added in gl-renderer earlier, and
shows how the color manager is responsible for re-using existing color
transformation objects.
Co-authored-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
This creates the color-lcms plugin that in the future will be using
Little CMS as the color matching module, processing ICC profiles, and
producing HDR tone mappings.
Right now, this new plugin is functionally equivalent to the no-op color
manager, except it already links to lcms2 and checks that the renderer
supports color operations.
Color-lcms is a libweston plugin that is loaded with explicit
weston_compositor API. This does not currently allow loading alternative
color manager plugins. External color manager plugins might be
considered in the future when the libweston APIs around color management
stabilize.
This libweston plugin uses the same build option as the old cms-static
Weston plugins, as they both need lcms2. The minimum version for lcms2
was chosen by what Debian Buster provides today and for no other reason.
This plugin intends to support the Wayland CM&HDR protocol extension and
hence sets supports_client_protocol to true. This will expose the
protocol extension to clients when it gets implemented.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Pekka Paalanen