lite-xl/lib/font_renderer/agg_lcd_distribution_lut.h

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// Adapted by Francesco Abbate for GSL Shell
// Original code's copyright below.
//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
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//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
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// http://www.antigrain.com
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//----------------------------------------------------------------------------
#ifndef AGG_LCD_DISTRIBUTION_LUT_INCLUDED
#define AGG_LCD_DISTRIBUTION_LUT_INCLUDED
#include <cstdlib>
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#include "agg_basics.h"
namespace agg
{
//=====================================================lcd_distribution_lut
class lcd_distribution_lut
{
public:
lcd_distribution_lut(double prim, double second, double tert)
{
double norm = 1.0 / (prim + second*2 + tert*2);
prim *= norm;
second *= norm;
tert *= norm;
for(unsigned i = 0; i < 256; i++)
{
unsigned b = (i << 8);
unsigned s = round(second * b);
unsigned t = round(tert * b);
unsigned p = b - (2*s + 2*t);
m_data[3*i + 1] = s; /* secondary */
m_data[3*i + 2] = t; /* tertiary */
m_data[3*i ] = p; /* primary */
}
}
unsigned convolution(const int8u* covers, int i0, int i_min, int i_max) const
{
unsigned sum = 0;
int k_min = (i0 >= i_min + 2 ? -2 : i_min - i0);
int k_max = (i0 <= i_max - 2 ? 2 : i_max - i0);
for (int k = k_min; k <= k_max; k++)
{
/* select the primary, secondary or tertiary channel */
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int channel = std::abs(k) % 3;
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int8u c = covers[i0 + k];
sum += m_data[3*c + channel];
}
return (sum + 128) >> 8;
}
private:
unsigned short m_data[256*3];
};
}
#endif