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/* This file is part of the libdepixelize project
Copyright (C) 2013 Vinícius dos Santos Oliveira <vini.ipsmaker@gmail.com>
GNU Lesser General Public License Usage
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.
You should have received a copy of the GNU Lesser General Public License
along with this library. If not, see <http://www.gnu.org/licenses/>.
GNU General Public License Usage
Alternatively, this library may be used 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.
You should have received a copy of the GNU General Public License along with
this library. If not, see <http://www.gnu.org/licenses/>.
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
Lesser General Public License for more details.
*/
#ifndef LIBDEPIXELIZE_TRACER_YUV_H
#define LIBDEPIXELIZE_TRACER_YUV_H
#include <glib.h>
namespace Tracer {
namespace colorspace {
/**
* The same algorithm used in hqx filter
*/
inline void rgb2yuv(guint8 r, guint8 g, guint8 b,
guint8 &y, guint8 &u, guint8 &v)
{
y = 0.299 * r + 0.587 * g + 0.114 * b;
u = guint16(-0.169 * r - 0.331 * g + 0.5 * b) + 128;
v = guint16(0.5 * r - 0.419 * g - 0.081 * b) + 128;
}
inline void rgb2yuv(const guint8 rgb[], guint8 yuv[])
{
rgb2yuv(rgb[0], rgb[1], rgb[2], yuv[0], yuv[1], yuv[2]);
}
inline bool same_color(const guint8 (&a)[4], const guint8 (&b)[4])
{
return (a[0] == b[0]
&& a[1] == b[1]
&& a[2] == b[2]
&& a[3] == b[3]);
}
inline bool dissimilar_colors(const guint8 a[], const guint8 b[])
{
// C uses row-major order, so
// A[2][3] = { {1, 2, 3}, {4, 5, 6} } = {1, 2, 3, 4, 5, 6}
guint8 yuv[2][3];
rgb2yuv(a, yuv[0]);
rgb2yuv(b, yuv[1]);
// Magic numbers taken from hqx algorithm
// Only used to describe the level of tolerance
return abs(yuv[0][0] - yuv[1][0]) > 0x30
|| abs(yuv[0][1] - yuv[1][1]) > 7
|| abs(yuv[0][2] - yuv[1][2]) > 6;
}
inline bool similar_colors(const guint8 a[], const guint8 b[])
{
return !dissimilar_colors(a, b);
}
inline bool shading_edge(const guint8 a[], const guint8 b[])
{
// C uses row-major order, so
// A[2][3] = { {1, 2, 3}, {4, 5, 6} } = {1, 2, 3, 4, 5, 6}
guint8 yuv[2][3];
rgb2yuv(a, yuv[0]);
rgb2yuv(b, yuv[1]);
// Magic numbers taken from Kopf-Lischinski algorithm
// Only used to describe the level of tolerance
return abs(yuv[0][0] - yuv[1][0]) <= 100
&& abs(yuv[0][1] - yuv[1][1]) <= 100
&& abs(yuv[0][2] - yuv[1][2]) <= 100;
}
inline bool contour_edge(const guint8 a[], const guint8 b[])
{
return !shading_edge(a, b);
}
} // namespace colorspace
} // namespace Tracer
#endif // LIBDEPIXELIZE_TRACER_YUV_H
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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