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/* This file is part of GEGL editor -- a gtk frontend for GEGL
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
* Copyright (C) 2005, 2008 Øyvind Kolås
*/
#include "config.h"
#include "gegl-path-smooth.h"
#include <gegl.h>
#include "gegl-path.h"
#include <math.h>
static GeglPathList *
points_to_bezier_path (gdouble coord_x[],
gdouble coord_y[],
gint n_coords)
{
GeglPathList *ret = NULL;
gint i;
gdouble smooth_value;
smooth_value = 0.8;
if (!n_coords)
return NULL;
ret = gegl_path_list_append (ret, 'M', coord_x[0], coord_y[0]);
for (i=1;i<n_coords;i++)
{
gdouble x2 = coord_x[i];
gdouble y2 = coord_y[i];
gdouble x0,y0,x1,y1,x3,y3;
if (i==1)
{
x0=coord_x[i-1];
y0=coord_y[i-1];
x1 = coord_x[i-1];
y1 = coord_y[i-1];
}
else
{
x0=coord_x[i-2];
y0=coord_y[i-2];
x1 = coord_x[i-1];
y1 = coord_y[i-1];
}
if (i+1 < n_coords)
{
x3 = coord_x[i+1];
y3 = coord_y[i+1];
}
else
{
x3 = coord_x[i];
y3 = coord_y[i];
}
{
gdouble xc1 = (x0 + x1) / 2.0;
gdouble yc1 = (y0 + y1) / 2.0;
gdouble xc2 = (x1 + x2) / 2.0;
gdouble yc2 = (y1 + y2) / 2.0;
gdouble xc3 = (x2 + x3) / 2.0;
gdouble yc3 = (y2 + y3) / 2.0;
gdouble len1 = sqrt( (x1-x0) * (x1-x0) + (y1-y0) * (y1-y0) );
gdouble len2 = sqrt( (x2-x1) * (x2-x1) + (y2-y1) * (y2-y1) );
gdouble len3 = sqrt( (x3-x2) * (x3-x2) + (y3-y2) * (y3-y2) );
gdouble k1 = len1 / (len1 + len2);
gdouble k2 = len2 / (len2 + len3);
gdouble xm1 = xc1 + (xc2 - xc1) * k1;
gdouble ym1 = yc1 + (yc2 - yc1) * k1;
gdouble xm2 = xc2 + (xc3 - xc2) * k2;
gdouble ym2 = yc2 + (yc3 - yc2) * k2;
gdouble ctrl1_x = xm1 + (xc2 - xm1) * smooth_value + x1 - xm1;
gdouble ctrl1_y = ym1 + (yc2 - ym1) * smooth_value + y1 - ym1;
gdouble ctrl2_x = xm2 + (xc2 - xm2) * smooth_value + x2 - xm2;
gdouble ctrl2_y = ym2 + (yc2 - ym2) * smooth_value + y2 - ym2;
if (i==n_coords-1)
{
ctrl2_x = x2;
ctrl2_y = y2;
}
ret = gegl_path_list_append (ret, 'C', ctrl1_x, ctrl1_y,
ctrl2_x, ctrl2_y,
x2, y2);
}
}
return ret;
}
static GeglPathList *gegl_path_smooth_flatten (GeglPathList *original)
{
GeglPathList *ret;
GeglPathList *iter;
gdouble *coordsx;
gdouble *coordsy;
gboolean is_smooth_path = TRUE;
gint count;
gint i;
/* first we do a run through the path checking it's length
* and determining whether we can flatten the incoming path
*/
for (count=0,iter = original; iter; iter=iter->next)
{
switch (iter->d.type)
{
case '*':
break;
default:
is_smooth_path=FALSE;
break;
}
count ++;
}
if (!is_smooth_path)
{
return original;
}
coordsx = g_new0 (gdouble, count);
coordsy = g_new0 (gdouble, count);
for (i=0, iter = original; iter; iter=iter->next, i++)
{
coordsx[i] = iter->d.point[0].x;
coordsy[i] = iter->d.point[0].y;
}
ret = points_to_bezier_path (coordsx, coordsy, count);
g_free (coordsx);
g_free (coordsy);
return ret;
}
void gegl_path_smooth_init (void)
{
static gboolean done = FALSE;
if (done)
return;
done = TRUE;
gegl_path_add_type ('*', 2, "path");
gegl_path_add_flattener (gegl_path_smooth_flatten);
}
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