gp_gamma_correction.h File Reference

Gamma and sRGB corrections. More...

#include <stdint.h>
#include <core/gp_types.h>
#include <core/gp_pixel.gen.h>
#include <core/gp_gamma_correction.gen.h>

Go to the source code of this file.

Data Structures
struct	gp_correction_desc
	A correction description. More...
struct	gp_gamma_table
	A lookup gamma table. More...
struct	gp_gamma
	A correction tables for all pixel channels. More...

Typedefs
typedef enum gp_correction_type	gp_correction_type
	A list of supported correction types.
typedef struct gp_correction_desc	gp_correction_desc
	A correction description.
typedef struct gp_gamma_table	gp_gamma_table
	A lookup gamma table.
typedef struct gp_gamma	gp_gamma
	A correction tables for all pixel channels.

Enumerations
enum	gp_correction_type { GP_CORRECTION_TYPE_GAMMA , GP_CORRECTION_TYPE_SRGB }
	A list of supported correction types. More...

Functions
gp_gamma *	gp_correction_acquire (gp_pixel_type pixel_type, gp_correction_desc *corr_desc)
	Acquires a gamma, sRGB, ... correction tables for a given pixel type.
gp_gamma *	gp_gamma_incref (gp_gamma *gamma)
	Increases reference counters.
void	gp_gamma_decref (gp_gamma *self)
	Decreases reference counters.
const char *	gp_correction_type_name (gp_correction_type type)
	Returns correction name.
void	gp_gamma_print (const gp_gamma *self)
	Prints info about gamma table into the stdout.
static uint8_t	gp_lin16_to_srgb8 (uint16_t val)
	Converts 16 bit linear value to 8 bit sRGB.
static uint16_t	gp_srgb8_to_lin16 (uint8_t val)
	Converts 8 bit sRGB to 16 bit linear value.

Detailed Description

Gamma and sRGB corrections.

Definition in file gp_gamma_correction.h.

Typedef Documentation

gp_gamma

typedef struct gp_gamma gp_gamma

A correction tables for all pixel channels.

Contains pointers to lookup tables for each pixel channel for linearization and inverse transformation. Linearization produces a values with a few more bits, e.g. for 8bit value you end up with at least 10bits to correctly encode the linearized values.

Function Documentation

gp_correction_acquire()

gp_gamma * gp_correction_acquire	(	gp_pixel_type	pixel_type,
		gp_correction_desc *	corr_desc
	)

Acquires a gamma, sRGB, ... correction tables for a given pixel type.

Parameters

pixel_type	A pixel type to build the tables for
corr_desc	A correction description.

Returns

Correction tables.

gp_correction_type_name()

const char * gp_correction_type_name

(

gp_correction_type

type

)

Returns correction name.

Parameters

type	A correction type.

Returns

A correction name.

gp_gamma_decref()

void gp_gamma_decref

(

gp_gamma *

self

)

Decreases reference counters.

Decreases reference counters and frees the table if counters drop to zero.

Parameters

self	A gamma table.

gp_gamma_incref()

gp_gamma * gp_gamma_incref

(

gp_gamma *

gamma

)

Increases reference counters.

Increases reference counters for gamma tables. Each time a pixmap is duplicated or new pixmap is created as a result of filters the newly created pixmap needs to inherit the gamma correction tables.

Parameters

gamma

A gamma table.

Returns

A pointer to the gamma table passed as argument.

gp_gamma_print()

void gp_gamma_print

(

const gp_gamma *

self

)

Prints info about gamma table into the stdout.

Parameters

self	A gamma table.

gp_lin16_to_srgb8()

static uint8_t gp_lin16_to_srgb8 ( uint16_t  val )

inlinestatic

Converts 16 bit linear value to 8 bit sRGB.

Parameters

val	A linear 16 bit value.

Returns

A sRGB 8 bit value.

Definition at line 223 of file gp_gamma_correction.h.

gp_srgb8_to_lin16()

static uint16_t gp_srgb8_to_lin16 ( uint8_t  val )

inlinestatic

Converts 8 bit sRGB to 16 bit linear value.

Parameters

val	A 8 bit sRGB value.

Returns

A 16 bit linear value.

Definition at line 234 of file gp_gamma_correction.h.