/**
* 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/>.
*/
#include "ramps.h"
/**
* Test mapping function from [0, 1] float encoding value to [0, 2⁸ − 1] integer output value.
*
* @param encoding [0, 1] float encoding value.
* @return [0, 2⁸ − 1] integer output value.
*/
uint8_t invert_ramps8(float encoding)
{
double i_encoding = (double)(1.f - encoding);
double f_output = ((double)UINT8_MAX) * i_encoding;
uint8_t output = (uint8_t)f_output;
if ((i_encoding < (double)(0.25f)) && (output > UINT8_MAX / 2))
output = 0;
if ((i_encoding > (double)(0.75f)) && (output < UINT8_MAX / 2))
output = UINT8_MAX;
return output;
}
/**
* Test mapping function from [0, 1] float encoding value to [0, 2¹⁶ − 1] integer output value.
*
* @param encoding [0, 1] float encoding value.
* @return [0, 2¹⁶ − 1] integer output value.
*/
uint16_t invert_ramps16(float encoding)
{
double i_encoding = (double)(1.f - encoding);
double f_output = ((double)UINT16_MAX) * i_encoding;
uint16_t output = (uint16_t)f_output;
if ((i_encoding < (double)(0.25f)) && (output > UINT16_MAX / 2))
output = 0;
if ((i_encoding > (double)(0.75f)) && (output < UINT16_MAX / 2))
output = UINT16_MAX;
return output;
}
/**
* Test mapping function from [0, 1] float encoding value to [0, 2³² − 1] integer output value.
*
* @param encoding [0, 1] float encoding value.
* @return [0, 2³² − 1] integer output value.
*/
uint32_t invert_ramps32(float encoding)
{
double i_encoding = (double)(1.f - encoding);
double f_output = ((double)UINT32_MAX) * i_encoding;
uint32_t output = (uint32_t)f_output;
if ((i_encoding < (double)(0.25f)) && (output > UINT32_MAX / 2))
output = 0;
if ((i_encoding > (double)(0.75f)) && (output < UINT32_MAX / 2))
output = UINT32_MAX;
return output;
}
/**
* Test mapping function from [0, 1] float encoding value to [0, 2⁶⁴ − 1] integer output value.
*
* @param encoding [0, 1] float encoding value.
* @return [0, 2⁶⁴ − 1] integer output value.
*/
uint64_t invert_ramps64(float encoding)
{
double i_encoding = (double)(1.f - encoding);
double f_output = ((double)UINT64_MAX) * i_encoding;
uint64_t output = (uint64_t)f_output;
if ((i_encoding < (double)(0.25f)) && (output > UINT64_MAX / 2))
output = 0;
if ((i_encoding > (double)(0.75f)) && (output < UINT64_MAX / 2))
output = UINT64_MAX;
return output;
}
/**
* Test mapping function from [0, 1] float encoding value to [0, 1] float output value.
*
* @param encoding [0, 1] float encoding value.
* @return [0, 1] float output value.
*/
float invert_rampsf(float encoding)
{
return 1.f - encoding;
}
/**
* Test mapping function from [0, 1] double precision float encoding
* value to [0, 1] double precision float output value.
*
* @param encoding [0, 1] float encoding value.
* @return [0, 1] float output value.
*/
double invert_rampsd(double encoding)
{
return ((double)1.f) - encoding;
}
