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/*
* Copyright (c) 2005 Adrian Page <adrian@pagenet.plus.com>
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef KIS_INTEGER_MATHS_H
#define KIS_INTEGER_MATHS_H
#define UINT8_MAX 255u
#define UINT8_MIN 0u
#define UINT16_MAX 65535u
#define UINT16_MIN 0u
#define UINT32_MAX (4294967295u)
#define UINT32_MIN 0u
#define INT16_MAX 32767
#define INT16_MIN -32768
/// take a and scale it up by 256*b/255
inline uint UINT8_SCALEBY(uint a, uint b)
{
uint c = a * b + 0x80u;
return (c >> 8) + c;
}
inline uint UINT8_MULT(uint a, uint b)
{
uint c = a * b + 0x80u;
return ((c >> 8) + c) >> 8;
}
inline uint UINT8_DIVIDE(uint a, uint b)
{
uint c = (a * UINT8_MAX + (b / 2u)) / b;
return c;
}
inline uint UINT8_BLEND(uint a, uint b, uint alpha)
{
// Basically we do a*alpha + b*(1-alpha)
// However refactored to (a-b)*alpha + b since that saves a multiplication
// Signed arithmetic is needed since a-b might be negative
int c = ((int(a) - int(b)) * int(alpha)) >> 8;
return uint(c + b);
}
inline uint UINT16_MULT(uint a, uint b)
{
uint c = a * b + 0x8000u;
return ((c >> 16) + c) >> 16;
}
inline int INT16_MULT(int a, int b)
{
return (a*b) / INT16_MAX;
}
inline uint UINT16_DIVIDE(uint a, uint b)
{
uint c = (a * UINT16_MAX + (b / 2u)) / b;
return c;
}
inline uint UINT16_BLEND(uint a, uint b, uint alpha)
{
// Basically we do a*alpha + b*(1-alpha)
// However refactored to (a-b)*alpha + b since that saves a multiplication
// Signed arithmetic is needed since a-b might be negative
int c = ((int(a) - int(b)) * int(alpha)) >> 16;
return uint(c + b);
}
inline uint UINT8_TO_UINT16(uint c)
{
return c | (c<<8);
}
inline uint UINT16_TO_UINT8(uint c)
{
//return round(c / 257.0);
//For all UINT16 this calculation is the same and a lot faster (off by c/65656 which for every c is 0)
c = c - (c >> 8) + 128;
return c >>8;
}
inline int INT16_BLEND(int a, int b, uint alpha)
{
// Basically we do a*alpha + b*(1-alpha)
// However refactored to (a-b)*alpha + b since that saves a multiplication
int c = ((int(a) - int(b)) * int(alpha)) >> 16;
return c + b;
}
#endif
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