mapnik/agg/src/agg_line_profile_aa.cpp

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2006-01-31 23:09:52 +00:00
//----------------------------------------------------------------------------
// 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.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
// mcseemagg@yahoo.com
// http://www.antigrain.com
//----------------------------------------------------------------------------
#include "agg_renderer_outline_aa.h"
namespace agg
{
//---------------------------------------------------------------------
void line_profile_aa::width(double w)
{
if(w < 0.0) w = 0.0;
if(w < m_smoother_width) w += w;
else w += m_smoother_width;
w *= 0.5;
w -= m_smoother_width;
double s = m_smoother_width;
if(w < 0.0)
{
s += w;
w = 0.0;
}
set(w, s);
}
//---------------------------------------------------------------------
line_profile_aa::value_type* line_profile_aa::profile(double w)
{
m_subpixel_width = uround(w * subpixel_scale);
unsigned size = m_subpixel_width + subpixel_scale * 6;
if(size > m_size)
{
delete [] m_profile;
m_profile = new value_type[m_size = size];
}
return m_profile;
}
//---------------------------------------------------------------------
void line_profile_aa::set(double center_width, double smoother_width)
{
double base_val = 1.0;
if(center_width == 0.0) center_width = 1.0 / subpixel_scale;
if(smoother_width == 0.0) smoother_width = 1.0 / subpixel_scale;
double width = center_width + smoother_width;
if(width < m_min_width)
{
double k = width / m_min_width;
base_val *= k;
center_width /= k;
smoother_width /= k;
}
value_type* ch = profile(center_width + smoother_width);
unsigned subpixel_center_width = unsigned(center_width * subpixel_scale);
unsigned subpixel_smoother_width = unsigned(smoother_width * subpixel_scale);
value_type* ch_center = ch + subpixel_scale*2;
value_type* ch_smoother = ch_center + subpixel_center_width;
unsigned i;
unsigned val = m_gamma[unsigned(base_val * aa_mask)];
ch = ch_center;
for(i = 0; i < subpixel_center_width; i++)
{
*ch++ = (value_type)val;
}
for(i = 0; i < subpixel_smoother_width; i++)
{
*ch_smoother++ =
m_gamma[unsigned((base_val -
base_val *
(double(i) / subpixel_smoother_width)) * aa_mask)];
}
unsigned n_smoother = profile_size() -
subpixel_smoother_width -
subpixel_center_width -
subpixel_scale*2;
val = m_gamma[0];
for(i = 0; i < n_smoother; i++)
{
*ch_smoother++ = (value_type)val;
}
ch = ch_center;
for(i = 0; i < subpixel_scale*2; i++)
{
*--ch = *ch_center++;
}
}
}