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weston/libweston/color.h

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/*
* Copyright 2021 Collabora, Ltd.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial
* portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef WESTON_COLOR_H
#define WESTON_COLOR_H
#include <stdbool.h>
#include <stdint.h>
#include <libweston/libweston.h>
/**
* Represents a color profile description (an ICC color profile)
*
* Sub-classed by the color manager that created this.
*/
struct weston_color_profile {
struct weston_color_manager *cm;
int ref_count;
char *description;
};
/** Type or formula for a curve */
enum weston_color_curve_type {
/** Identity function, no-op */
WESTON_COLOR_CURVE_TYPE_IDENTITY = 0,
/** Three-channel, one-dimensional look-up table */
WESTON_COLOR_CURVE_TYPE_LUT_3x1D,
};
/** LUT_3x1D parameters */
struct weston_color_curve_lut_3x1d {
/**
* Approximate a color curve with three 1D LUTs
*
* A 1D LUT is a mapping from [0.0, 1.0] to arbitrary values. The first
* element in the LUT corresponds to input value 0.0, and the last
* element corresponds to input value 1.0. The step from one element
* to the next in input space is 1.0 / (len - 1). When input value is
* between two elements, linear interpolation should be used.
*
* This function fills in the given array with the LUT values.
*
* \param xform This color transformation object.
* \param len The number of elements in each 1D LUT.
* \param values Array of 3 x len elements. First R channel
* LUT, immediately followed by G channel LUT, and then B channel LUT.
*/
void
(*fill_in)(struct weston_color_transform *xform,
float *values, unsigned len);
/** Optimal 1D LUT length for storage vs. precision */
unsigned optimal_len;
};
/**
* A scalar function for color encoding and decoding
*
* This object can represent a one-dimensional function that is applied
* independently to each of the color channels. Depending on the type and
* parameterization of the curve, all color channels may use the
* same function or each may have separate parameters.
*
* This is usually used for EOTF or EOTF^-1 and to optimize a 3D LUT size
* without sacrificing precision, both in one step.
*/
struct weston_color_curve {
/** Which member of 'u' defines the curve. */
enum weston_color_curve_type type;
/** Parameters for the curve. */
union {
/* identity: no parameters */
struct weston_color_curve_lut_3x1d lut_3x1d;
} u;
};
/**
* Describes a color transformation formula
*
* Guaranteed unique, de-duplicated.
*
* Sub-classed by the color manager that created this.
*
* For a renderer to support WESTON_CAP_COLOR_OPS it must implement everything
* that this structure can represent.
*/
struct weston_color_transform {
struct weston_color_manager *cm;
int ref_count;
/* for renderer or backend to attach their own cached objects */
struct wl_signal destroy_signal;
/* Color transform is the series of steps: */
/** Step 1: color model change */
/* YCbCr→RGB conversion, but that is done elsewhere */
/** Step 2: color curve before color mapping */
struct weston_color_curve pre_curve;
/** Step 3: color mapping */
/* TBD: e.g. a 3D LUT or a matrix */
/** Step 4: color curve after color mapping */
/* struct weston_color_curve post_curve; */
};
/**
* How content color needs to be transformed
*
* This object is specific to the color properties of the weston_surface and
* weston_output it was created for. It is automatically destroyed if any
* relevant color properties change.
*
* Fundamentally this contains the color transformation from content color
* space to an output's blending color space. This is stored in field
* 'transform' with NULL value corresponding to identity transformation.
*
* For graphics pipeline optimization purposes, the field 'identity_pipeline'
* indicates whether the combination of 'transform' here and the output's
* blending color space to monitor color space transformation total to
* identity transformation. This helps detecting cases where renderer bypass
* (direct scanout) is possible.
*/
struct weston_surface_color_transform {
/** Transformation from source to blending space */
struct weston_color_transform *transform;
/** True, if source colorspace is identical to monitor color space */
bool identity_pipeline;
};
struct weston_color_manager {
/** Identifies this CMS component */
const char *name;
/** This compositor instance */
struct weston_compositor *compositor;
/** Supports the Wayland CM&HDR protocol extension? */
bool supports_client_protocol;
/** Initialize color manager */
bool
(*init)(struct weston_color_manager *cm);
/** Destroy color manager */
void
(*destroy)(struct weston_color_manager *cm);
/** Destroy a color profile after refcount fell to zero */
void
(*destroy_color_profile)(struct weston_color_profile *cprof);
/** Create a color profile from ICC data
*
* \param cm The color manager.
* \param icc_data Pointer to the ICC binary data.
* \param icc_len Length of the ICC data in bytes.
* \param name_part A string to be used in describing the profile.
* \param cprof_out On success, the created object is returned here.
* On failure, untouched.
* \param errmsg On success, untouched. On failure, a pointer to a
* string describing the error is stored here. The string must be
* free()'d.
* \return True on success, false on failure.
*
* This may return a new reference to an existing color profile if
* that profile is identical to the one that would be created, apart
* from name_part.
*/
bool
(*get_color_profile_from_icc)(struct weston_color_manager *cm,
const void *icc_data,
size_t icc_len,
const char *name_part,
struct weston_color_profile **cprof_out,
char **errmsg);
/** Destroy a color transform after refcount fell to zero */
void
(*destroy_color_transform)(struct weston_color_transform *xform);
/** Get surface to output's blending space transformation
*
* \param cm The color manager.
* \param surface The surface for the source color space.
* \param output The output for the destination blending color space.
* \param surf_xform For storing the color transformation and
* additional information.
*
* The callee is responsible for increasing the reference count on the
* weston_color_transform it stores into surf_xform.
*/
bool
(*get_surface_color_transform)(struct weston_color_manager *cm,
struct weston_surface *surface,
struct weston_output *output,
struct weston_surface_color_transform *surf_xform);
/** Get output's blending space to output transformation
*
* \param cm The color manager.
* \param output The output for the destination color space.
* \param xform_out Pointer for storing the weston_color_transform.
* \return True on success, false on failure.
*
* The callee is responsible for increasing the reference count on the
* weston_color_transform it stores via xform_out. On failure, xform_out
* is untouched.
*/
bool
(*get_output_color_transform)(struct weston_color_manager *cm,
struct weston_output *output,
struct weston_color_transform **xform_out);
/** Get sRGB to output transformation
*
* \param cm The color manager.
* \param output The output for the destination color space.
* \param xform_out Pointer for storing the weston_color_transform.
* \return True on success, false on failure.
*
* The callee is responsible for increasing the reference count on the
* weston_color_transform it stores via xform_out. On failure, xform_out
* is untouched.
*/
bool
(*get_sRGB_to_output_color_transform)(struct weston_color_manager *cm,
struct weston_output *output,
struct weston_color_transform **xform_out);
/** Get sRGB to output's blending space transformation
*
* \param cm The color manager.
* \param output The output for the destination blending color space.
* \param xform_out Pointer for storing the weston_color_transform.
* \return True on success, false on failure.
*
* The callee is responsible for increasing the reference count on the
* weston_color_transform it stores via xform_out. On failure, xform_out
* is untouched.
*/
bool
(*get_sRGB_to_blend_color_transform)(struct weston_color_manager *cm,
struct weston_output *output,
struct weston_color_transform **xform_out);
};
void
weston_color_profile_init(struct weston_color_profile *cprof,
struct weston_color_manager *cm);
struct weston_color_transform *
weston_color_transform_ref(struct weston_color_transform *xform);
void
weston_color_transform_unref(struct weston_color_transform *xform);
void
weston_color_transform_init(struct weston_color_transform *xform,
struct weston_color_manager *cm);
void
weston_surface_color_transform_copy(struct weston_surface_color_transform *dst,
const struct weston_surface_color_transform *src);
void
weston_surface_color_transform_fini(struct weston_surface_color_transform *surf_xform);
struct weston_paint_node;
void
weston_paint_node_ensure_color_transform(struct weston_paint_node *pnode);
struct weston_color_manager *
weston_color_manager_noop_create(struct weston_compositor *compositor);
/* DSO module entrypoint */
struct weston_color_manager *
weston_color_manager_create(struct weston_compositor *compositor);
#endif /* WESTON_COLOR_H */