mapnik/src/image_scaling.cpp

202 lines
8.7 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/image.hpp>
#include <mapnik/image_scaling.hpp>
#include <mapnik/image_scaling_traits.hpp>
#pragma GCC diagnostic push
#include <mapnik/warning_ignore.hpp>
#include <boost/assign/list_of.hpp>
#include <boost/bimap.hpp>
#pragma GCC diagnostic pop
#pragma GCC diagnostic push
#include <mapnik/warning_ignore_agg.hpp>
#include "agg_image_accessors.h"
#include "agg_pixfmt_rgba.h"
#include "agg_pixfmt_gray.h"
#include "agg_color_rgba.h"
#include "agg_rasterizer_scanline_aa.h"
#include "agg_renderer_scanline.h"
#include "agg_rendering_buffer.h"
#include "agg_scanline_u.h"
#include "agg_span_allocator.h"
#include "agg_span_image_filter_gray.h"
#include "agg_span_image_filter_rgba.h"
#include "agg_span_interpolator_linear.h"
#include "agg_trans_affine.h"
#include "agg_image_filters.h"
#pragma GCC diagnostic pop
namespace mapnik
{
using scaling_method_lookup_type = boost::bimap<scaling_method_e, std::string>;
static const scaling_method_lookup_type scaling_lookup = boost::assign::list_of<scaling_method_lookup_type::relation>
(SCALING_NEAR,"near")
(SCALING_BILINEAR,"bilinear")
(SCALING_BICUBIC,"bicubic")
(SCALING_SPLINE16,"spline16")
(SCALING_SPLINE36,"spline36")
(SCALING_HANNING,"hanning")
(SCALING_HAMMING,"hamming")
(SCALING_HERMITE,"hermite")
(SCALING_KAISER,"kaiser")
(SCALING_QUADRIC,"quadric")
(SCALING_CATROM,"catrom")
(SCALING_GAUSSIAN,"gaussian")
(SCALING_BESSEL,"bessel")
(SCALING_MITCHELL,"mitchell")
(SCALING_SINC,"sinc")
(SCALING_LANCZOS,"lanczos")
(SCALING_BLACKMAN,"blackman")
;
boost::optional<scaling_method_e> scaling_method_from_string(std::string const& name)
{
boost::optional<scaling_method_e> mode;
scaling_method_lookup_type::right_const_iterator right_iter = scaling_lookup.right.find(name);
if (right_iter != scaling_lookup.right.end())
{
mode.reset(right_iter->second);
}
return mode;
}
boost::optional<std::string> scaling_method_to_string(scaling_method_e scaling_method)
{
boost::optional<std::string> mode;
scaling_method_lookup_type::left_const_iterator left_iter = scaling_lookup.left.find(scaling_method);
if (left_iter != scaling_lookup.left.end())
{
mode.reset(left_iter->second);
}
return mode;
}
template <typename T>
void scale_image_agg(T & target, T const& source, scaling_method_e scaling_method,
double image_ratio_x, double image_ratio_y, double x_off_f, double y_off_f,
double filter_factor, boost::optional<double> const & nodata_value)
{
// "the image filters should work namely in the premultiplied color space"
// http://old.nabble.com/Re:--AGG--Basic-image-transformations-p1110665.html
// "Yes, you need to use premultiplied images only. Only in this case the simple weighted averaging works correctly in the image fitering."
// http://permalink.gmane.org/gmane.comp.graphics.agg/3443
using image_type = T;
using pixel_type = typename image_type::pixel_type;
using pixfmt_pre = typename detail::agg_scaling_traits<image_type>::pixfmt_pre;
using color_type = typename detail::agg_scaling_traits<image_type>::color_type;
using img_src_type = typename detail::agg_scaling_traits<image_type>::img_src_type;
using interpolator_type = typename detail::agg_scaling_traits<image_type>::interpolator_type;
using renderer_base_pre = agg::renderer_base<pixfmt_pre>;
constexpr std::size_t pixel_size = sizeof(pixel_type);
// define some stuff we'll use soon
agg::rasterizer_scanline_aa<> ras;
agg::scanline_u8 sl;
agg::span_allocator<color_type> sa;
// initialize source AGG buffer
agg::rendering_buffer rbuf_src(const_cast<unsigned char*>(source.bytes()),
source.width(), source.height(), source.width() * pixel_size);
pixfmt_pre pixf_src(rbuf_src);
img_src_type img_src(pixf_src);
// initialize destination AGG buffer (with transparency)
agg::rendering_buffer rbuf_dst(target.bytes(), target.width(), target.height(), target.width() * pixel_size);
pixfmt_pre pixf_dst(rbuf_dst);
renderer_base_pre rb_dst_pre(pixf_dst);
// create a scaling matrix
agg::trans_affine img_mtx;
img_mtx *= agg::trans_affine_translation(x_off_f, y_off_f);
img_mtx /= agg::trans_affine_scaling(image_ratio_x, image_ratio_y);
// create a linear interpolator for our scaling matrix
interpolator_type interpolator(img_mtx);
// draw an anticlockwise polygon to render our image into
double scaled_width = target.width();
double scaled_height = target.height();
ras.reset();
ras.move_to_d(0.0, 0.0);
ras.line_to_d(scaled_width, 0.0);
ras.line_to_d(scaled_width, scaled_height);
ras.line_to_d(0.0, scaled_height);
if (scaling_method == SCALING_NEAR)
{
using span_gen_type = typename detail::agg_scaling_traits<image_type>::span_image_filter;
span_gen_type sg(img_src, interpolator);
agg::render_scanlines_aa(ras, sl, rb_dst_pre, sa, sg);
}
else
{
using span_gen_type = typename detail::agg_scaling_traits<image_type>::span_image_resample_affine;
agg::image_filter_lut filter;
detail::set_scaling_method(filter, scaling_method, filter_factor);
boost::optional<typename span_gen_type::value_type> nodata;
if (nodata_value)
{
nodata = nodata_value;
}
span_gen_type sg(img_src, interpolator, filter, nodata);
agg::render_scanlines_aa(ras, sl, rb_dst_pre, sa, sg);
}
}
template MAPNIK_DECL void scale_image_agg(image_rgba8 &, image_rgba8 const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray8 &, image_gray8 const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray8s &, image_gray8s const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray16 &, image_gray16 const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray16s &, image_gray16s const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray32 &, image_gray32 const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray32s &, image_gray32s const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray32f &, image_gray32f const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray64 &, image_gray64 const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray64s &, image_gray64s const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
template MAPNIK_DECL void scale_image_agg(image_gray64f &, image_gray64f const&, scaling_method_e,
double, double , double, double , double, boost::optional<double> const &);
}