mapnik/include/mapnik/renderer_common/clipping_extent.hpp

49 lines
1.7 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2014 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
*
*****************************************************************************/
#ifndef MAPNIK_CLIPPING_EXTENT_HPP
#define MAPNIK_CLIPPING_EXTENT_HPP
#include <mapnik/box2d.hpp>
namespace mapnik {
template <typename T>
box2d<double> clipping_extent(T const& common)
{
if (common.t_.offset() > 0)
{
box2d<double> box = common.query_extent_;
double scale = static_cast<double>(common.query_extent_.width())/static_cast<double>(common.width_);
// 3 is used here because at least 3 was needed for the 'style-level-compositing-tiled-0,1' visual test to pass
// TODO - add more tests to hone in on a more robust #
scale *= common.t_.offset() * 3;
box.pad(scale);
return box;
}
return common.query_extent_;
}
} // namespace mapnik
#endif // MAPNIK_CLIPPING_EXTENT_HPP