/**
 * libgamma -- Display server abstraction layer for gamma ramp adjustments
 * Copyright (C) 2014  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef LIBGAMMA_FAKE_QUARTZ_CG_H
#define LIBGAMMA_FAKE_QUARTZ_CG_H

#ifndef FAKE_LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS
# error Including fake-quartz-cg.h without FAKE_LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS
#endif


#ifndef __GCC__
# define __attribute__(x)
#endif


/* This header file contains some capabilities of
 * <CoreGraphics/CGDirectDisplay.h> and <CoreGraphics/CGError.h>,
 * and can be used modify gamma ramps without Mac OS X and Quartz
 * but with its API.
 * 
 * The content of this file is based on the documentation found on:
 * 
 * https://developer.apple.com/library/mac/documentation/GraphicsImaging/Reference/Quartz_Services_Ref/Reference/reference.html
 * 
 * https://developer.apple.com/library/mac/documentation/CoreGraphics/Reference/CoreGraphicsConstantsRef/Reference/reference.html#//apple_ref/c/tdef/CGError */


#include <stdint.h>


/**
 * Numerical `typedef` for errors that occur in CoreGraphics calls.
 */
typedef int32_t CGError;

/**
 * The call was successful.
 */
#define kCGErrorSuccess 0

/**
 * The data type that is used for the values in the gamma ramps.
 */
typedef float CGGammaValue;

/**
 * The data type for display ID:s.
 */
typedef uint32_t CGDirectDisplayID;


/**
 * Get a list of all online displays on the system.
 * 
 * @param   max_size      The number of elements allocated for `displays_out`.
 * @param   displays_out  List ot fill with the ID for each online display on the system.
 * @param   count_out     Output parameter for the number of elements stored in `displays_out`.
 *                        if `displays_out` is too small to fit all display ID:s,
 *                        `*count_out` will be `max_size`.
 * @return                `kCGErrorSuccess` on success, and error number of failure.
 */
CGError CGGetOnlineDisplayList(uint32_t max_size,
			       CGDirectDisplayID* restrict displays_out, uint32_t* restrict count_out);

/**
 * Set the gamma ramps for a display.
 * 
 * @param   display     The ID of the display.
 * @param   gamma_size  The number of stops in gamma ramps.
 * @param   red         The gamma ramp for the red channel.
 * @param   green       The gamma ramp for the green channel.
 * @param   blue        The gamma ramp for the blue channel.
 * @return              `kCGErrorSuccess` on success, and error number of failure.
 */
CGError CGSetDisplayTransferByTable(CGDirectDisplayID display, uint32_t gamma_size, const CGGammaValue* red,
				    const CGGammaValue* green, const CGGammaValue* blue);

/**
 * Get the current gamma ramps for a display.
 * 
 * @param   display         The ID of the display.
 * @param   gamma_size      The number of stops you have allocated for the gamma ramps.
 * @param   red             Table allocated for the gamma ramp for the red channel.
 * @param   green           Table allocated for the gamma ramp for the green channel.
 * @param   blue            Table allocated for the gamma ramp for the blue channel.
 * @param   gamma_size_out  Output parameter for the actual number of stops in the gamma ramps.
 * @return                  `kCGErrorSuccess` on success, and error number of failure.
 */
CGError CGGetDisplayTransferByTable(CGDirectDisplayID display, uint32_t gamma_size,
				    CGGammaValue* restrict red, CGGammaValue* restrict green,
				    CGGammaValue* restrict blue, uint32_t* restrict gamma_size_out);

/**
 * Restore each display's gamma ramps to the settings in ColorSync.
 */
void CGDisplayRestoreColorSyncSettings(void);

/**
 * Get the number of stops in the gamma ramps for a display.
 * 
 * @param   display  The ID of the display.
 * @return           The number of stops in the gamma ramps.
 */
uint32_t CGDisplayGammaTableCapacity(CGDirectDisplayID display) __attribute__((const));


/* The follow part most only be used when this module is used,
 * it cannot be used when the real CoreGraphics is used.
 * CoreGraphics does not have this function, it is added so
 * that there is a way to cleanly close the X connection
 * and free resources needed by this module. */

/**
 * Release resources used by the backend.
 */
void close_fake_quartz_cg(void);



#ifndef __GCC__
# undef __attribute__
#endif

#endif