mapnik/src/color.cpp
2016-02-22 15:38:15 +01:00

131 lines
3.9 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2015 Artem Pavlenko
*
* 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.
*
* 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
// mapnik
#include <mapnik/color.hpp>
#include <mapnik/color_factory.hpp>
#include <mapnik/config_error.hpp>
#pragma GCC diagnostic push
#include <mapnik/warning_ignore.hpp>
#include <boost/spirit/include/karma.hpp>
#pragma GCC diagnostic pop
namespace mapnik {
color::color(std::string const& str, bool premultiplied)
{
*this = parse_color(str);
premultiplied_ = premultiplied;
}
std::string color::to_string() const
{
namespace karma = boost::spirit::karma;
boost::spirit::karma::eps_type eps;
boost::spirit::karma::double_type double_;
boost::spirit::karma::uint_generator<uint8_t,10> color_;
std::string str;
std::back_insert_iterator<std::string> sink(str);
karma::generate(sink, eps(alpha() < 255)
// begin grammar
<< "rgba("
<< color_(red()) << ','
<< color_(green()) << ','
<< color_(blue()) << ','
<< double_(alpha()/255.0) << ')'
|
"rgb("
<< color_(red()) << ','
<< color_(green()) << ','
<< color_(blue()) << ')'
// end grammar
);
return str;
}
std::string color::to_hex_string() const
{
namespace karma = boost::spirit::karma;
boost::spirit::karma::hex_type hex;
boost::spirit::karma::eps_type eps;
boost::spirit::karma::right_align_type right_align;
std::string str;
std::back_insert_iterator<std::string> sink(str);
karma::generate(sink,
// begin grammar
'#'
<< right_align(2,'0')[hex(red())]
<< right_align(2,'0')[hex(green())]
<< right_align(2,'0')[hex(blue())]
<< eps(alpha() < 255) << right_align(2,'0')[hex(alpha())]
// end grammar
);
return str;
}
namespace {
static std::uint8_t multiply(std::uint8_t c, std::uint8_t a)
{
std::uint32_t t = c * a + 128;
return std::uint8_t(((t >> 8) + t) >> 8);
}
}
bool color::premultiply()
{
if (premultiplied_) return false;
if (alpha_ != 255)
{
red_ = multiply(red_, alpha_);
green_ = multiply(green_, alpha_);
blue_ = multiply(blue_, alpha_);
}
premultiplied_ = true;
return true;
}
bool color::demultiply()
{
if (!premultiplied_) return false;
if (alpha_ < 255)
{
if (alpha_ == 0)
{
red_ = green_ = blue_ = 0;
}
else
{
std::uint32_t r = (std::uint32_t(red_) * 255) / alpha_;
std::uint32_t g = (std::uint32_t(green_) * 255) / alpha_;
std::uint32_t b = (std::uint32_t(blue_) * 255) / alpha_;
red_ = (r > 255) ? 255 : r;
green_ = (g > 255) ? 255 : g;
blue_ = (b > 255) ? 255 : b;
}
}
premultiplied_ = false;
return true;
}
}