/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2021 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
 *
 *****************************************************************************/

#include <mapnik/debug.hpp>
#include <mapnik/css/css_unit_value.hpp>
#include <mapnik/color_factory.hpp>
#include <mapnik/svg/svg_parser.hpp>
#include <mapnik/svg/svg_path_parser.hpp>
#include <mapnik/config_error.hpp>
#include <mapnik/safe_cast.hpp>
#include <mapnik/svg/svg_parser_exception.hpp>
#include <mapnik/util/file_io.hpp>
#include <mapnik/util/utf_conv_win.hpp>
#include <mapnik/util/dasharray_parser.hpp>
#include <mapnik/util/name_to_int.hpp>
#include <mapnik/warning.hpp>
MAPNIK_DISABLE_WARNING_PUSH
#include <mapnik/warning_ignore_agg.hpp>
#include "agg_ellipse.h"
#include "agg_rounded_rect.h"
#include "agg_span_gradient.h"
#include "agg_color_rgba.h"
#include <mapnik/warning_ignore.hpp>
#include <boost/spirit/home/x3.hpp>
#include <boost/fusion/adapted/struct.hpp>
#include <boost/fusion/include/std_pair.hpp>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/property_tree/detail/xml_parser_read_rapidxml.hpp>
MAPNIK_DISABLE_WARNING_POP

#include <string>
#include <stdexcept>
#include <vector>
#include <cstring>
#include <fstream>
#include <array>

namespace mapnik {
namespace svg {

using util::name_to_int;
using util::operator"" _case;
} // namespace svg
} // namespace mapnik

BOOST_FUSION_ADAPT_STRUCT(mapnik::svg::viewbox, (double, x0)(double, y0)(double, width)(double, height))

namespace mapnik {
namespace svg {

namespace rapidxml = boost::property_tree::detail::rapidxml;

void traverse_tree(svg_parser& parser, rapidxml::xml_node<char> const* node);
void end_element(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_path(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_element(svg_parser& parser, char const* name, rapidxml::xml_node<char> const* node);
void parse_use(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_dimensions(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_polygon(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_polyline(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_line(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_rect(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_circle(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_ellipse(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_linear_gradient(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_radial_gradient(svg_parser& parser, rapidxml::xml_node<char> const* node);
bool parse_common_gradient(svg_parser& parser,
                           std::string const& id,
                           mapnik::gradient& gr,
                           rapidxml::xml_node<char> const* node);
void parse_gradient_stop(svg_parser& parser, mapnik::gradient& gr, rapidxml::xml_node<char> const* node);
void parse_attr(svg_parser& parser, rapidxml::xml_node<char> const* node);
void parse_attr(svg_parser& parser, char const* name, char const* value);

namespace {

static std::array<unsigned, 9> const unsupported_elements{{"symbol"_case,
                                                           "marker"_case,
                                                           "view"_case,
                                                           "text"_case,
                                                           "switch"_case,
                                                           "image"_case,
                                                           "a"_case,
                                                           "clipPath"_case,
                                                           "pattern"_case}};

static std::array<unsigned, 42> const unsupported_attributes{{"alignment-baseline"_case,
                                                              "baseline-shift"_case,
                                                              "clip"_case,
                                                              "clip-path"_case,
                                                              "clip-rule"_case,
                                                              "color-interpolation"_case,
                                                              "color-interpolation-filters"_case,
                                                              "color-profile"_case,
                                                              "color-rendering"_case,
                                                              "cursor"_case,
                                                              "direction"_case,
                                                              "dominant-baseline"_case,
                                                              "enable-background"_case,
                                                              "filter"_case,
                                                              "flood-color"_case,
                                                              "flood-opacity"_case,
                                                              "font-family"_case,
                                                              "font-size-adjust"_case,
                                                              "font-stretch"_case,
                                                              "font-style"_case,
                                                              "font-variant"_case,
                                                              "font-weight"_case,
                                                              "glyph-orientation-horizontal"_case,
                                                              "glyph-orientation-vertical"_case,
                                                              "image-rendering"_case,
                                                              "kerning"_case,
                                                              "letter-spacing"_case,
                                                              "lighting-color"_case,
                                                              "marker-end"_case,
                                                              "marker-mid"_case,
                                                              "marker-start"_case,
                                                              "mask"_case,
                                                              "overflow"_case,
                                                              "pointer-events"_case,
                                                              "shape-rendering"_case,
                                                              "text-anchor"_case,
                                                              "text-decoration"_case,
                                                              "text-rendering"_case,
                                                              "unicode-bidi"_case,
                                                              "word-spacing"_case,
                                                              "writing-mode"_case}};

template<typename T>
void handle_unsupported(svg_parser& parser, T const& ar, char const* name, char const* type)
{
    unsigned element = name_to_int(name);
    for (auto const& e : ar)
    {
        if (e == element)
        {
            parser.err_handler().on_error(
              std::string("SVG support error: <" + std::string(name) + "> " + std::string(type) + " is not supported"));
            break;
        }
    }
}

namespace grammar {

namespace x3 = boost::spirit::x3;

using color_lookup_type = std::vector<std::pair<double, agg::rgba8>>;
using pairs_type = std::vector<std::pair<std::string, std::string>>;

x3::rule<class key_value_sequence_ordered_tag, pairs_type> const
  key_value_sequence_ordered("key_value_sequence_ordered");
x3::rule<class key_value_tag, std::pair<std::string, std::string>> const key_value("key_value");
x3::rule<class key_tag, std::string> const key("key");
x3::rule<class value_tag, std::string> const value("value");

auto const key_def = x3::char_("a-zA-Z_") > *x3::char_("a-zA-Z_0-9-");
auto const value_def = +(x3::char_ - ';');
auto const key_value_def = key > -(':' > value);
auto const key_value_sequence_ordered_def = key_value % ';';

BOOST_SPIRIT_DEFINE(key, value, key_value, key_value_sequence_ordered);

} // namespace grammar
} // namespace

boost::property_tree::detail::rapidxml::xml_attribute<char> const* parse_id(svg_parser& parser,
                                                                            rapidxml::xml_node<char> const* node)
{
    auto const* id_attr = node->first_attribute("xml:id");
    if (id_attr == nullptr)
        id_attr = node->first_attribute("id");

    if (id_attr && parser.node_cache_.count(id_attr->value()) == 0)
    {
        parser.node_cache_.emplace(id_attr->value(), node);
    }
    return id_attr;
}

boost::property_tree::detail::rapidxml::xml_attribute<char> const* parse_href(rapidxml::xml_node<char> const* node)
{
    auto const* attr = node->first_attribute("xlink:href");
    if (attr == nullptr)
        attr = node->first_attribute("href");
    return attr;
}

template<typename T>
mapnik::color parse_color(T& err_handler, const char* str)
{
    mapnik::color c(100, 100, 100);
    try
    {
        c = mapnik::parse_color(str);
    }
    catch (mapnik::config_error const& ex)
    {
        err_handler.on_error("SVG parse error: failed to parse <color> with value \"" + std::string(str) + "\"");
    }
    return c;
}

template<typename T>
agg::rgba8 parse_color_agg(T& err_handler, const char* str)
{
    auto c = parse_color(err_handler, str);
    return agg::rgba8(c.red(), c.green(), c.blue(), c.alpha());
}

template<typename T>
double parse_double(T& err_handler, const char* str)
{
    using namespace boost::spirit::x3;
    double val = 0.0;
    if (!parse(str, str + std::strlen(str), double_, val))
    {
        err_handler.on_error("SVG parse error: failed to parse <number> with value \"" + std::string(str) + "\"");
    }
    return val;
}

// https://www.w3.org/TR/SVG/coords.html#Units
template<typename T>
double parse_svg_value(T& parser, char const* str, bool& is_percent)
{
    namespace x3 = boost::spirit::x3;
    double val = 0.0;
    css_unit_value units;
    const char* cur = str; // phrase_parse mutates the first iterator
    const char* end = str + std::strlen(str);
    double font_size = parser.font_sizes_.back();
    bool is_percent_;
    auto apply_value = [&](auto const& ctx) {
        val = _attr(ctx);
        is_percent_ = false;
    };
    auto apply_units = [&](auto const& ctx) {
        val *= _attr(ctx);
    };
    auto apply_em = [&](auto const& ctx) {
        val *= font_size;
    };
    auto apply_percent = [&](auto const& ctx) {
        val *= 0.01;
        is_percent_ = true;
    };

    if (!x3::phrase_parse(cur,
                          end,
                          x3::double_[apply_value] >
                            -(units[apply_units] | x3::lit("em")[apply_em] | x3::lit('%')[apply_percent]),
                          x3::space) ||
        (cur != end))
    {
        val = 0.0; // restore to default on parsing failure
        parser.err_handler().on_error("SVG parse error: failed to parse <number> with value \"" + std::string(str) +
                                      "\"");
    }
    else
    {
        is_percent = is_percent_; // update only on success
    }
    return val;
}

template<typename T>
bool parse_font_size(T& parser, char const* str)
{
    namespace x3 = boost::spirit::x3;
    double val = 0.0;
    css_unit_value units;
    css_absolute_size absolute;
    css_relative_size relative;

    std::size_t size = parser.font_sizes_.size();
    double parent_font_size = size > 1 ? parser.font_sizes_[size - 2] : 10.0;
    const char* cur = str; // phrase_parse mutates the first iterator
    const char* end = str + std::strlen(str);

    auto apply_value = [&](auto const& ctx) {
        val = _attr(ctx);
    };
    auto apply_relative = [&](auto const& ctx) {
        val = parent_font_size * _attr(ctx);
    };
    auto apply_units = [&](auto const& ctx) {
        val *= _attr(ctx);
    };
    auto apply_percent = [&](auto const& ctx) {
        val = val * parent_font_size / 100.0;
    };
    auto apply_em = [&](auto const& ctx) {
        val = val * parent_font_size;
    };
    if (!x3::phrase_parse(cur,
                          end,
                          absolute[apply_value] | relative[apply_relative] |
                            x3::double_[apply_value] >
                              -(units[apply_units] | x3::lit("em")[apply_em] | x3::lit('%')[apply_percent]),
                          x3::space) ||
        (cur != end))
    {
        parser.err_handler().on_error("SVG parse error: failed to parse <font-size> with value \"" + std::string(str) +
                                      "\"");
        return false;
    }
    if (!parser.font_sizes_.empty())
        parser.font_sizes_.back() = val;
    return true;
}

template<typename T, typename V>
bool parse_viewbox(T& err_handler, char const* str, V& viewbox)
{
    namespace x3 = boost::spirit::x3;
    if (!x3::phrase_parse(str,
                          str + std::strlen(str),
                          x3::double_ > -x3::lit(',') > x3::double_ > -x3::lit(',') > x3::double_ > -x3::lit(',') >
                            x3::double_,
                          x3::space,
                          viewbox))
    {
        err_handler.on_error("SVG parse error: failed to parse <viewbox> with value \"" + std::string(str) + "\"");
        return false;
    }
    return true;
}

enum aspect_ratio_alignment {
    none = 0,
    xMinYMin,
    xMidYMin,
    xMaxYMin,
    xMinYMid,
    xMidYMid,
    xMaxYMid,
    xMinYMax,
    xMidYMax,
    xMaxYMax
};

template<typename T>
std::pair<unsigned, bool> parse_preserve_aspect_ratio(T& err_handler, char const* str)
{
    namespace x3 = boost::spirit::x3;
    x3::symbols<unsigned> align;
    align.add("none", none)("xMinYMin", xMinYMin)("xMidYMin", xMidYMin)("xMaxYMin", xMaxYMin)("xMinYMid", xMinYMid)(
      "xMidYMid",
      xMidYMid)("xMaxYMid", xMaxYMid)("xMinYMax", xMinYMax)("xMidYMax", xMidYMax)("xMaxYMax", xMaxYMax);

    std::pair<unsigned, bool> preserve_aspect_ratio{xMidYMid, true};
    char const* cur = str; // phrase_parse mutates the first iterator
    char const* end = str + std::strlen(str);
    auto apply_align = [&](auto const& ctx) {
        preserve_aspect_ratio.first = _attr(ctx);
    };
    auto apply_slice = [&](auto const& ctx) {
        preserve_aspect_ratio.second = false;
    };
    try
    {
        x3::phrase_parse(cur,
                         end,
                         -x3::lit("defer") // only applicable to <image> which we don't support currently
                           > align[apply_align] > -(x3::lit("meet") | x3::lit("slice")[apply_slice]),
                         x3::space);
    }
    catch (x3::expectation_failure<char const*> const& ex)
    {
        err_handler.on_error("SVG parse error: failed to parse <preserveAspectRatio> with value \"" + std::string(str) +
                             "\"");
        return {xMidYMid, true}; // default
    }
    return preserve_aspect_ratio;
}

bool parse_style(char const* str, grammar::pairs_type& v)
{
    namespace x3 = boost::spirit::x3;
    return x3::phrase_parse(str, str + std::strlen(str), grammar::key_value_sequence_ordered, x3::space, v);
}

bool parse_id_from_url(char const* str, std::string& id)
{
    namespace x3 = boost::spirit::x3;
    auto extract_id = [&](auto const& ctx) {
        id += _attr(ctx);
    };
    return x3::phrase_parse(str,
                            str + std::strlen(str),
                            x3::lit("url") > '(' > '#' > *(x3::char_ - ')')[extract_id] > ')',
                            x3::space);
}

void process_css(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto const& css = parser.css_data_;
    std::unordered_map<std::string, mapnik::property_value_type> style;
    std::string element_name = node->name();
    auto itr = css.find(element_name);
    if (itr != css.end())
    {
        for (auto const& def : std::get<1>(*itr))
        {
            style[std::get<0>(def)] = std::get<1>(def);
        }
    }

    auto const* class_attr = node->first_attribute("class");
    if (class_attr != nullptr)
    {
        auto const* value = class_attr->value();
        if (std::strlen(value) > 0)
        {
            char const* first = value;
            char const* last = first + std::strlen(value);
            std::vector<std::string> classes;
            bool result = boost::spirit::x3::phrase_parse(first, last, mapnik::classes(), mapnik::skipper(), classes);
            if (result)
            {
                for (auto const& class_name : classes)
                {
                    std::string solitary_class_key = std::string(".") + class_name;
                    auto range = css.equal_range(solitary_class_key);
                    for (auto itr = range.first; itr != range.second; ++itr)
                    {
                        for (auto const& def : std::get<1>(*itr))
                        {
                            style[std::get<0>(def)] = std::get<1>(def);
                        }
                    }
                    std::string class_key = element_name + solitary_class_key;
                    range = css.equal_range(class_key);
                    for (auto itr = range.first; itr != range.second; ++itr)
                    {
                        for (auto const& def : std::get<1>(*itr))
                        {
                            style[std::get<0>(def)] = std::get<1>(def);
                        }
                    }
                }
            }
        }
    }
    auto const* id_attr = node->first_attribute("id");
    if (id_attr != nullptr)
    {
        auto const* value = id_attr->value();
        if (std::strlen(value) > 0)
        {
            std::string id_key = std::string("#") + value;
            itr = css.find(id_key);
            if (itr != css.end())
            {
                for (auto const& def : std::get<1>(*itr))
                {
                    style[std::get<0>(def)] = std::get<1>(def);
                }
            }
        }
    }
    // If style has properties, create or update style attribute
    if (style.size() > 0)
    {
        std::ostringstream ss;
        for (auto const& def : style)
        {
            auto const& r = std::get<1>(def);
            std::string val{r.begin(), r.end()};
            parse_attr(parser, std::get<0>(def).c_str(), val.c_str());
        }
    }
}

void traverse_tree(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    if (parser.ignore_)
        return;
    auto name = name_to_int(node->name());

    switch (node->type())
    {
        case rapidxml::node_element: {
            parser.font_sizes_.push_back(parser.font_sizes_.back());
            switch (name)
            {
                case "defs"_case: {
                    if (node->first_node() != nullptr)
                    {
                        parser.is_defs_ = true;
                    }
                    break;
                }
                case "clipPath"_case:
                case "symbol"_case:
                case "pattern"_case: {
                    parser.ignore_ = true;
                    break;
                }
                // the gradient tags *should* be in defs, but illustrator seems not to put them in there so
                // accept them anywhere
                case "linearGradient"_case:
                    parse_linear_gradient(parser, node);
                    break;
                case "radialGradient"_case:
                    parse_radial_gradient(parser, node);
                    break;
            }

            if (!parser.is_defs_) // FIXME
            {
                switch (name)
                {
                    case "g"_case:
                        if (node->first_node() != nullptr)
                        {
                            parser.path_.push_attr();
                            parse_id(parser, node);
                            if (parser.css_style_)
                                process_css(parser, node);
                            parse_attr(parser, node);
                            parser.path_.begin_group();
                        }
                        break;
                    case "use"_case:
                        parser.path_.push_attr();
                        parse_id(parser, node);
                        if (parser.css_style_)
                            process_css(parser, node);
                        parse_attr(parser, node);
                        if (parser.path_.cur_attr().opacity < 1.0)
                            parser.path_.begin_group();
                        parse_use(parser, node);
                        if (parser.path_.cur_attr().opacity < 1.0)
                            parser.path_.end_group();
                        parser.path_.pop_attr();
                        break;
                    default:
                        parser.path_.push_attr();
                        parse_id(parser, node);
                        if (parser.css_style_)
                            process_css(parser, node);
                        parse_attr(parser, node);
                        if (parser.path_.display())
                        {
                            if (parser.path_.cur_attr().opacity < 1.0)
                                parser.path_.begin_group();
                            parse_element(parser, node->name(), node);
                            if (parser.path_.cur_attr().opacity < 1.0)
                                parser.path_.end_group();
                        }
                        parser.path_.pop_attr();
                }
            }
            else
            {
                // save node for later
                parse_id(parser, node);
            }

            if ("style"_case == name)
            {
                // <style> element is not expected to have nested elements
                // we're only interested in DATA or CDATA
                for (auto const* child = node->first_node(); child; child = child->next_sibling())
                {
                    if (child->type() == rapidxml::node_data || child->type() == rapidxml::node_cdata)
                    {
                        auto const grammar = mapnik::grammar();
                        auto const skipper = mapnik::skipper();
                        char const* first = child->value();
                        char const* last = first + child->value_size();
                        bool result = boost::spirit::x3::phrase_parse(first, last, grammar, skipper, parser.css_data_);
                        if (result && first == last && !parser.css_data_.empty())
                        {
                            parser.css_style_ = true;
                        }
                    }
                }
            }
            else
            {
                for (auto const* child = node->first_node(); child; child = child->next_sibling())
                {
                    traverse_tree(parser, child);
                }
            }

            end_element(parser, node);
        }
        break;
        default:
            break;
    }
}

void end_element(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    parser.font_sizes_.pop_back();
    auto name = name_to_int(node->name());
    if (!parser.is_defs_ && (name == "g"_case))
    {
        parser.path_.end_group();
        if (node->first_node() != nullptr)
        {
            parser.path_.pop_attr();
        }
    }
    else if (name == "svg"_case)
    {
        // if (node->first_node() != nullptr)
        //{
        // parser.path_.pop_attr();
        //}
    }
    else if (name == "defs"_case)
    {
        if (node->first_node() != nullptr)
        {
            parser.is_defs_ = false;
        }
    }
    else if (name == "clipPath"_case || name == "symbol"_case || name == "pattern"_case)
    {
        parser.ignore_ = false;
        handle_unsupported(parser, unsupported_elements, node->name(), "element");
    }
}

void parse_element(svg_parser& parser, char const* name, rapidxml::xml_node<char> const* node)
{
    switch (name_to_int(name))
    {
        case "path"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_path(parser, node);
            break;
        case "polygon"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_polygon(parser, node);
            break;
        case "polyline"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_polyline(parser, node);
            break;
        case "line"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_line(parser, node);
            break;
        case "rect"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_rect(parser, node);
            break;
        case "circle"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_circle(parser, node);
            break;
        case "ellipse"_case:
            parser.path_.transform().multiply(parser.viewbox_tr_);
            parse_ellipse(parser, node);
            break;
        case "svg"_case:
            // parser.path_.push_attr();
            parse_dimensions(parser, node);
            parse_attr(parser, node);
            parser.path_.set_opacity(parser.path_.cur_attr().opacity);
            break;
        default:
            handle_unsupported(parser, unsupported_elements, name, "element");
            break;
    }
}

void parse_stroke(svg_parser& parser, char const* value)
{
    std::string id;
    if (std::strcmp(value, "none") == 0)
    {
        parser.path_.stroke_none();
    }
    else if (parse_id_from_url(value, id))
    {
        // see if we have a known gradient stroke
        if (parser.gradient_map_.count(id) > 0)
        {
            parser.path_.add_stroke_gradient(parser.gradient_map_[id]);
        }
        else if (parser.node_cache_.count(id) > 0)
        {
            // try parsing again
            auto const* gradient_node = parser.node_cache_[id];
            traverse_tree(parser, gradient_node);
            if (parser.gradient_map_.count(id) > 0)
            {
                parser.path_.add_stroke_gradient(parser.gradient_map_[id]);
            }
            else
            {
                std::stringstream ss;
                ss << "SVG parse error: failed to locate stroke with <id> \"" << id << "\"";
                parser.err_handler().on_error(ss.str());
            }
        }
        else
        {
            std::stringstream ss;
            ss << "SVG parse error: failed to locate stroke with <id> \"" << id << "\"";
            parser.err_handler().on_error(ss.str());
        }
    }
    else
    {
        parser.path_.stroke(parse_color_agg(parser.err_handler(), value));
    }
}

void parse_fill(svg_parser& parser, char const* value)
{
    std::string id;
    if (std::strcmp(value, "none") == 0)
    {
        parser.path_.fill_none();
    }
    else if (parse_id_from_url(value, id))
    {
        // see if we have a known gradient fill
        if (parser.gradient_map_.count(id) > 0)
        {
            parser.path_.add_fill_gradient(parser.gradient_map_[id]);
        }
        else if (parser.node_cache_.count(id) > 0)
        {
            // try parsing again
            auto const* gradient_node = parser.node_cache_[id];
            traverse_tree(parser, gradient_node);
            if (parser.gradient_map_.count(id) > 0)
            {
                parser.path_.add_fill_gradient(parser.gradient_map_[id]);
            }
            else
            {
                std::stringstream ss;
                ss << "SVG parse error: failed to locate fill with <id> \"" << id << "\"";
                parser.err_handler().on_error(ss.str());
            }
        }
        else
        {
            std::stringstream ss;
            ss << "SVG parse error: failed to locate fill with <id> \"" << id << "\"";
            parser.err_handler().on_error(ss.str());
        }
    }
    else
    {
        parser.path_.fill(parse_color_agg(parser.err_handler(), value));
    }
}

void parse_transform(svg_parser& parser, char const* value)
{
    agg::trans_affine tr;
    mapnik::svg::parse_svg_transform(value, tr);
    parser.path_.transform().premultiply(tr);
}

void parse_stroke_dash(svg_parser& parser, char const* value)
{
    dash_array dash;
    if (util::parse_dasharray(value, dash))
    {
        parser.path_.dash_array(std::move(dash));
    }
}

void parse_attr(svg_parser& parser, char const* name, char const* value)
{
    switch (name_to_int(name))
    {
        case "transform"_case:
            parse_transform(parser, value);
            break;
        case "fill"_case:
            parse_fill(parser, value);
            break;
        case "fill-opacity"_case:
            parser.path_.fill_opacity(parse_double(parser.err_handler(), value));
            break;
        case "fill-rule"_case:
            if (std::strcmp(value, "evenodd") == 0)
            {
                parser.path_.even_odd(true);
            }
            break;
        case "stroke"_case:
            parse_stroke(parser, value);
            break;
        case "stroke-width"_case: {
            bool percent = false;
            double stroke_width = parse_svg_value(parser, value, percent);
            if (percent && parser.vbox_)
                stroke_width *= parser.normalized_diagonal_;
            parser.path_.stroke_width(stroke_width);
            break;
        }
        case "stroke-opacity"_case:
            parser.path_.stroke_opacity(parse_double(parser.err_handler(), value));
            break;
        case "stroke-linecap"_case:
            if (std::strcmp(value, "butt") == 0)
                parser.path_.line_cap(agg::butt_cap);
            else if (std::strcmp(value, "round") == 0)
                parser.path_.line_cap(agg::round_cap);
            else if (std::strcmp(value, "square") == 0)
                parser.path_.line_cap(agg::square_cap);
            break;
        case "stroke-linejoin"_case:
            if (std::strcmp(value, "miter") == 0)
                parser.path_.line_join(agg::miter_join);
            else if (std::strcmp(value, "round") == 0)
                parser.path_.line_join(agg::round_join);
            else if (std::strcmp(value, "bevel") == 0)
                parser.path_.line_join(agg::bevel_join);
            break;
        case "stroke-miterlimit"_case:
            parser.path_.miter_limit(parse_double(parser.err_handler(), value));
            break;
        case "stroke-dasharray"_case:
            parse_stroke_dash(parser, value);
            break;
        case "stroke-dashoffset"_case:
            parser.path_.dash_offset(parse_double(parser.err_handler(), value));
            break;
        case "opacity"_case:
            parser.path_.opacity(parse_double(parser.err_handler(), value));
            break;
        case "visibility"_case:
            parser.path_.visibility(std::strcmp(value, "hidden") != 0);
            break;
        case "display"_case:
            if (std::strcmp(value, "none") == 0)
            {
                parser.path_.display(false);
            }
            break;
        case "font-size"_case: {
            parse_font_size(parser, value);
            break;
        }
        default:
            handle_unsupported(parser, unsupported_attributes, name, "attribute");
            break;
    }
}

void parse_attr(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    parser.path_.opacity(1.0); // default path opacity = 1.0
    for (rapidxml::xml_attribute<char> const* attr = node->first_attribute(); attr; attr = attr->next_attribute())
    {
        auto const* name = attr->name();
        if (std::strcmp(name, "style") == 0)
        {
            using cont_type = std::vector<std::pair<std::string, std::string>>;
            using value_type = cont_type::value_type;
            cont_type vec;
            parse_style(attr->value(), vec);
            for (value_type kv : vec)
            {
                parse_attr(parser, kv.first.c_str(), kv.second.c_str());
            }
        }
        else
        {
            parse_attr(parser, name, attr->value());
        }
    }
}

void parse_dimensions(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    // https://www.w3.org/TR/SVG11/struct.html#SVGElement
    double width = 1;  // 100%
    double height = 1; // 100%
    viewbox vbox = {0, 0, 0, 0};
    bool has_percent_height = true;
    bool has_percent_width = true;

    auto const* width_attr = node->first_attribute("width");
    if (width_attr)
    {
        width = parse_svg_value(parser, width_attr->value(), has_percent_width);
    }
    auto const* height_attr = node->first_attribute("height");
    if (height_attr)
    {
        height = parse_svg_value(parser, height_attr->value(), has_percent_height);
    }
    parser.vbox_ = viewbox{0, 0, width, height};
    auto const* viewbox_attr = node->first_attribute("viewBox");
    if (viewbox_attr && parse_viewbox(parser.err_handler(), viewbox_attr->value(), vbox))
    {
        agg::trans_affine t{};
        parser.vbox_ = vbox;
        parser.normalized_diagonal_ = std::sqrt(vbox.width * vbox.width + vbox.height * vbox.height) / std::sqrt(2.0);

        if (has_percent_width)
            width = vbox.width * width;
        else if (!width_attr || width == 0)
            width = vbox.width;
        if (has_percent_height)
            height = vbox.height * height;
        else if (!height_attr || height == 0)
            height = vbox.height;

        if (width > 0 && height > 0 && vbox.width > 0 && vbox.height > 0)
        {
            std::pair<unsigned, bool> preserve_aspect_ratio{xMidYMid, true};
            auto const* aspect_ratio_attr = node->first_attribute("preserveAspectRatio");
            if (aspect_ratio_attr)
            {
                preserve_aspect_ratio = parse_preserve_aspect_ratio(parser.err_handler(), aspect_ratio_attr->value());
            }

            double sx = width / vbox.width;
            double sy = height / vbox.height;
            double scale = preserve_aspect_ratio.second ? std::min(sx, sy) : std::max(sx, sy);
            switch (preserve_aspect_ratio.first)
            {
                case none:
                    t = agg::trans_affine_scaling(sx, sy) * t;
                    break;
                case xMinYMin:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    break;
                case xMinYMid:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(0, -0.5 * (vbox.height - height / scale)) * t;
                    break;
                case xMinYMax:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(0, -1.0 * (vbox.height - height / scale)) * t;
                    break;
                case xMidYMin:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(-0.5 * (vbox.width - width / scale), 0.0) * t;
                    break;
                case xMidYMid: // (the default)
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(-0.5 * (vbox.width - width / scale),
                                                      -0.5 * (vbox.height - height / scale)) *
                        t;
                    break;
                case xMidYMax:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(-0.5 * (vbox.width - width / scale),
                                                      -1.0 * (vbox.height - height / scale)) *
                        t;
                    break;
                case xMaxYMin:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(-1.0 * (vbox.width - width / scale), 0.0) * t;
                    break;
                case xMaxYMid:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(-1.0 * (vbox.width - width / scale),
                                                      -0.5 * (vbox.height - height / scale)) *
                        t;
                    break;
                case xMaxYMax:
                    t = agg::trans_affine_scaling(scale, scale) * t;
                    t = agg::trans_affine_translation(-1.0 * (vbox.width - width / scale),
                                                      -1.0 * (vbox.height - height / scale)) *
                        t;
                    break;
            };
        }
        t = agg::trans_affine_translation(-vbox.x0, -vbox.y0) * t;
        parser.viewbox_tr_ = t;
    }
    else if (width == 0 || height == 0 || has_percent_width || has_percent_height)
    {
        std::stringstream ss;
        ss << "SVG parse error: can't infer valid image dimensions from width:\"";
        if (has_percent_width)
            ss << width * 100 << "%";
        else
            ss << width;
        ss << "\" height:\"";
        if (has_percent_height)
            ss << height * 100 << "%";
        else
            ss << height;
        ss << "\"";
        parser.err_handler().on_error(ss.str());
        parser.path_.set_dimensions(0, 0);
        return;
    }
    parser.path_.set_dimensions(width, height);
}

void parse_path(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto const* attr = node->first_attribute("d");
    if (attr != nullptr)
    {
        auto const* value = attr->value();
        if (std::strlen(value) > 0)
        {
            parser.path_.begin_path();

            if (!mapnik::svg::parse_path(value, parser.path_))
            {
                auto const* id_attr = parse_id(parser, node);
                if (id_attr)
                {
                    parser.err_handler().on_error(std::string("SVG parse error: failed to parse <path> with <id> \"") +
                                                  id_attr->value() + "\"");
                }
                else
                {
                    parser.err_handler().on_error(std::string("SVG parse error: failed to parse <path>"));
                }
            }
            parser.path_.end_path();
        }
    }
}

void parse_use(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto* attr = parse_href(node);
    if (attr)
    {
        auto const* value = attr->value();
        if (std::strlen(value) > 1 && value[0] == '#')
        {
            std::string id(&value[1]);
            if (parser.node_cache_.count(id) > 0)
            {
                auto const* base_node = parser.node_cache_[id];
                double x = 0.0;
                double y = 0.0;
                double w = 0.0;
                double h = 0.0;
                bool percent = false;
                attr = node->first_attribute("x");
                if (attr != nullptr)
                {
                    x = parse_svg_value(parser, attr->value(), percent);
                }

                attr = node->first_attribute("y");
                if (attr != nullptr)
                {
                    y = parse_svg_value(parser, attr->value(), percent);
                }

                attr = node->first_attribute("width");
                if (attr != nullptr)
                {
                    w = parse_svg_value(parser, attr->value(), percent);
                    if (percent)
                        w *= parser.path_.width();
                }
                attr = node->first_attribute("height");
                if (attr)
                {
                    h = parse_svg_value(parser, attr->value(), percent);
                    if (percent)
                        h *= parser.path_.height();
                }
                if (w < 0.0)
                {
                    std::stringstream ss;
                    ss << "SVG validation error: invalid <use> width \"" << w << "\"";
                    parser.err_handler().on_error(ss.str());
                }
                else if (h < 0.0)
                {
                    std::stringstream ss;
                    ss << "SVG validation error: invalid <use> height \"" << w << "\"";
                    parser.err_handler().on_error(ss.str());
                }
                agg::trans_affine t{};
                if (!node->first_attribute("transform") && w != 0.0 && h != 0.0)
                {
                    // FIXME
                    double scale = std::min(double(w / parser.path_.width()), double(h / parser.path_.height()));
                    t *= agg::trans_affine_scaling(scale);
                }
                t *= agg::trans_affine_translation(x, y);
                parser.path_.transform().premultiply(t);
                traverse_tree(parser, base_node);
            }
        }
    }
}

void parse_polygon(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto const* attr = node->first_attribute("points");
    if (attr != nullptr)
    {
        parser.path_.begin_path();
        if (!mapnik::svg::parse_points(attr->value(), parser.path_))
        {
            parser.err_handler().on_error(std::string("SVG parse error: failed to parse <polygon> points"));
        }
        parser.path_.close_subpath();
        parser.path_.end_path();
    }
}

void parse_polyline(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto const* attr = node->first_attribute("points");
    if (attr != nullptr)
    {
        parser.path_.begin_path();
        if (!mapnik::svg::parse_points(attr->value(), parser.path_))
        {
            parser.err_handler().on_error(std::string("SVG parse error: failed to parse <polyline> points"));
        }
        parser.path_.end_path();
    }
}

void parse_line(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    double x1 = 0.0;
    double y1 = 0.0;
    double x2 = 0.0;
    double y2 = 0.0;
    bool percent = false;
    auto const* x1_attr = node->first_attribute("x1");
    if (x1_attr)
    {
        x1 = parse_svg_value(parser, x1_attr->value(), percent);
        if (percent && parser.vbox_)
            x1 *= parser.vbox_->width;
    }
    auto const* y1_attr = node->first_attribute("y1");
    if (y1_attr)
    {
        y1 = parse_svg_value(parser, y1_attr->value(), percent);
        if (percent && parser.vbox_)
            y1 *= parser.vbox_->height;
    }

    auto const* x2_attr = node->first_attribute("x2");
    if (x2_attr)
    {
        x2 = parse_svg_value(parser, x2_attr->value(), percent);
        if (percent && parser.vbox_)
            x2 *= parser.vbox_->width;
    }
    auto const* y2_attr = node->first_attribute("y2");
    if (y2_attr)
    {
        y2 = parse_svg_value(parser, y2_attr->value(), percent);
        if (percent && parser.vbox_)
            y2 *= parser.vbox_->height;
    }
    parser.path_.begin_path();
    parser.path_.move_to(x1, y1);
    parser.path_.line_to(x2, y2);
    parser.path_.end_path();
}

void parse_circle(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    double cx = 0.0;
    double cy = 0.0;
    double r = 0.0;
    bool percent = false;
    auto* attr = node->first_attribute("cx");
    if (attr != nullptr)
    {
        cx = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            cx *= parser.vbox_->width;
    }

    attr = node->first_attribute("cy");
    if (attr != nullptr)
    {
        cy = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            cy *= parser.vbox_->height;
    }

    attr = node->first_attribute("r");
    if (attr != nullptr)
    {
        r = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            r *= parser.normalized_diagonal_;
    }

    if (r != 0.0)
    {
        if (r < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <circle> radius \"" << r << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else
        {
            parser.path_.begin_path();
            agg::ellipse c(cx, cy, r, r);
            parser.path_.storage().concat_path(c);
            parser.path_.end_path();
        }
    }
}

void parse_ellipse(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    double cx = 0.0;
    double cy = 0.0;
    double rx = 0.0;
    double ry = 0.0;
    bool percent = false;
    auto* attr = node->first_attribute("cx");
    if (attr != nullptr)
    {
        cx = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            cx *= parser.vbox_->width;
    }

    attr = node->first_attribute("cy");
    if (attr)
    {
        cy = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            cy *= parser.vbox_->height;
    }

    attr = node->first_attribute("rx");
    if (attr != nullptr)
    {
        rx = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            rx *= parser.normalized_diagonal_;
    }

    attr = node->first_attribute("ry");
    if (attr != nullptr)
    {
        ry = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            ry *= parser.normalized_diagonal_;
    }

    if (rx != 0.0 && ry != 0.0)
    {
        if (rx < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <ellipse> rx \"" << rx << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else if (ry < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <ellipse> ry \"" << ry << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else
        {
            parser.path_.begin_path();
            agg::ellipse c(cx, cy, rx, ry);
            parser.path_.storage().concat_path(c);
            parser.path_.end_path();
        }
    }
}

void parse_rect(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    // http://www.w3.org/TR/SVGTiny12/shapes.html#RectElement
    double x = 0.0;
    double y = 0.0;
    double w = 0.0;
    double h = 0.0;
    double rx = 0.0;
    double ry = 0.0;
    bool percent = false;
    auto* attr = node->first_attribute("x");
    if (attr != nullptr)
    {
        x = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            x *= parser.vbox_->width;
    }

    attr = node->first_attribute("y");
    if (attr != nullptr)
    {
        y = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            y *= parser.vbox_->height;
    }

    attr = node->first_attribute("width");
    if (attr != nullptr)
    {
        w = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            w *= parser.vbox_->width;
    }
    attr = node->first_attribute("height");
    if (attr)
    {
        h = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            h *= parser.vbox_->height;
    }

    bool rounded = true;
    attr = node->first_attribute("rx");
    if (attr != nullptr)
    {
        rx = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            rx *= parser.vbox_->width;
        if (rx > 0.5 * w)
            rx = 0.5 * w;
    }
    else
        rounded = false;

    attr = node->first_attribute("ry");
    if (attr != nullptr)
    {
        ry = parse_svg_value(parser, attr->value(), percent);
        if (percent && parser.vbox_)
            ry *= parser.vbox_->height;
        if (ry > 0.5 * h)
            ry = 0.5 * h;
        if (!rounded)
        {
            rx = ry;
            rounded = true;
        }
    }
    else if (rounded)
    {
        ry = rx;
    }

    if (w != 0.0 && h != 0.0)
    {
        if (w < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <rect> width \"" << w << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else if (h < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <rect> height \"" << h << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else if (rx < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <rect> rx \"" << rx << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else if (ry < 0.0)
        {
            std::stringstream ss;
            ss << "SVG validation error: invalid <rect> ry \"" << ry << "\"";
            parser.err_handler().on_error(ss.str());
        }
        else
        {
            parser.path_.begin_path();

            if (rounded)
            {
                agg::rounded_rect r;
                r.rect(x, y, x + w, y + h);
                r.radius(rx, ry);
                parser.path_.storage().concat_path(r);
            }
            else
            {
                parser.path_.move_to(x, y);
                parser.path_.line_to(x + w, y);
                parser.path_.line_to(x + w, y + h);
                parser.path_.line_to(x, y + h);
                parser.path_.close_subpath();
            }
            parser.path_.end_path();
        }
    }
}

void parse_gradient_stop(svg_parser& parser, mapnik::gradient& gr, rapidxml::xml_node<char> const* node)
{
    double offset = 0.0;
    mapnik::color stop_color{0, 0, 0, 255};
    double opacity = 1.0;

    auto* attr = node->first_attribute("offset");
    if (attr != nullptr)
    {
        bool percent = false;
        offset = parse_svg_value(parser, attr->value(), percent);
    }

    attr = node->first_attribute("style");
    if (attr != nullptr)
    {
        using cont_type = std::vector<std::pair<std::string, std::string>>;
        using value_type = cont_type::value_type;
        cont_type vec;
        parse_style(attr->value(), vec);

        for (value_type kv : vec)
        {
            if (kv.first == "stop-color")
            {
                stop_color = parse_color(parser.err_handler(), kv.second.c_str());
            }
            else if (kv.first == "stop-opacity")
            {
                opacity = parse_double(parser.err_handler(), kv.second.c_str());
            }
        }
    }

    attr = node->first_attribute("stop-color");
    if (attr != nullptr)
    {
        stop_color = parse_color(parser.err_handler(), attr->value());
    }

    attr = node->first_attribute("stop-opacity");
    if (attr != nullptr)
    {
        opacity = parse_double(parser.err_handler(), attr->value());
    }

    stop_color.set_alpha(static_cast<uint8_t>(opacity * 255));
    gr.add_stop(offset, stop_color);
}

bool parse_common_gradient(svg_parser& parser,
                           std::string const& id,
                           mapnik::gradient& gr,
                           rapidxml::xml_node<char> const* node)
{
    // check if we should inherit from another tag
    auto* attr = parse_href(node);
    if (attr != nullptr)
    {
        auto const* value = attr->value();
        if (std::strlen(value) > 1 && value[0] == '#')
        {
            std::string linkid(&value[1]); // FIXME !!!
            if (parser.gradient_map_.count(linkid))
            {
                gr = parser.gradient_map_[linkid];
            }
            else
            {
                // save node for later
                parser.node_cache_.emplace(id, node);
                return false;
            }
        }
    }

    attr = node->first_attribute("gradientUnits");
    if (attr != nullptr)
    {
        if (std::strcmp(attr->value(), "userSpaceOnUse") == 0)
        {
            gr.set_units(USER_SPACE_ON_USE);
        }
        else
        {
            gr.set_units(OBJECT_BOUNDING_BOX);
        }
    }

    attr = node->first_attribute("gradientTransform");
    if (attr != nullptr)
    {
        agg::trans_affine tr;
        mapnik::svg::parse_svg_transform(attr->value(), tr);
        gr.set_transform(tr);
    }
    return true;
}

void parse_radial_gradient(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto* attr = parse_id(parser, node);
    if (attr == nullptr)
        return;
    std::string id = attr->value();

    mapnik::gradient gr;
    if (!parse_common_gradient(parser, id, gr, node))
        return;
    double cx = 0.5;
    double cy = 0.5;
    double fx = 0.5;
    double fy = 0.5;
    double r = 0.5;
    bool has_percent = false;

    attr = node->first_attribute("cx");
    if (attr != nullptr)
    {
        cx = parse_svg_value(parser, attr->value(), has_percent);
    }
    else if (gr.get_units() == USER_SPACE_ON_USE)
    {
        cx = 0.5 * (parser.vbox_ ? parser.vbox_->width : parser.path_.width()); // 50%
    }

    attr = node->first_attribute("cy");
    if (attr != nullptr)
    {
        cy = parse_svg_value(parser, attr->value(), has_percent);
    }
    else if (gr.get_units() == USER_SPACE_ON_USE)
    {
        cy = 0.5 * (parser.vbox_ ? parser.vbox_->height : parser.path_.height()); // 50%
    }

    attr = node->first_attribute("fx");
    if (attr != nullptr)
    {
        fx = parse_svg_value(parser, attr->value(), has_percent);
    }
    else
    {
        fx = cx;
    }
    attr = node->first_attribute("fy");
    if (attr != nullptr)
    {
        fy = parse_svg_value(parser, attr->value(), has_percent);
    }
    else
    {
        fy = cy;
    }
    attr = node->first_attribute("r");
    if (attr != nullptr)
    {
        r = parse_svg_value(parser, attr->value(), has_percent);
    }
    else if (gr.get_units() == USER_SPACE_ON_USE)
    {
        r = 0.5 * parser.normalized_diagonal_; // 50%
    }

    gr.set_gradient_type(RADIAL);
    gr.set_control_points(fx, fy, cx, cy, r);

    // parse stops
    for (auto const* child = node->first_node(); child; child = child->next_sibling())
    {
        if (std::strcmp(child->name(), "stop") == 0)
        {
            parse_gradient_stop(parser, gr, child);
        }
    }
    parser.gradient_map_[id] = gr;
}

void parse_linear_gradient(svg_parser& parser, rapidxml::xml_node<char> const* node)
{
    auto const* attr = parse_id(parser, node);
    if (attr == nullptr)
        return;

    std::string id = attr->value();
    mapnik::gradient gr;
    if (!parse_common_gradient(parser, id, gr, node))
        return;

    double x1 = 0.0;
    double y1 = 0.0;
    double x2 = 1.0;
    double y2 = 0.0;

    bool has_percent = true;
    attr = node->first_attribute("x1");
    if (attr != nullptr)
    {
        x1 = parse_svg_value(parser, attr->value(), has_percent);
    }

    attr = node->first_attribute("y1");
    if (attr != nullptr)
    {
        y1 = parse_svg_value(parser, attr->value(), has_percent);
    }

    attr = node->first_attribute("x2");
    if (attr != nullptr)
    {
        x2 = parse_svg_value(parser, attr->value(), has_percent);
    }

    attr = node->first_attribute("y2");
    if (attr != nullptr)
    {
        y2 = parse_svg_value(parser, attr->value(), has_percent);
    }
    // this logic for detecting %'s will not support mixed coordinates.
    if (has_percent && gr.get_units() == USER_SPACE_ON_USE)
    {
        gr.set_units(USER_SPACE_ON_USE_BOUNDING_BOX);
    }
    gr.set_gradient_type(LINEAR);
    gr.set_control_points(x1, y1, x2, y2);

    // parse stops
    for (auto const* child = node->first_node(); child; child = child->next_sibling())
    {
        if (std::strcmp(child->name(), "stop") == 0)
        {
            parse_gradient_stop(parser, gr, child);
        }
    }
    parser.gradient_map_[id] = gr;
}

svg_parser::svg_parser(svg_converter_type& path, bool strict)
    : path_(path)
    , is_defs_(false)
    , ignore_(false)
    , css_style_(false)
    , err_handler_(strict)
{
    font_sizes_.push_back(10.0);
}

svg_parser::~svg_parser() {}

void svg_parser::parse(std::string const& filename)
{
#ifdef _WIN32
    std::basic_ifstream<char> stream(mapnik::utf8_to_utf16(filename));
#else
    std::basic_ifstream<char> stream(filename.c_str());
#endif
    if (!stream)
    {
        std::stringstream ss;
        ss << "SVG error: unable to open \"" << filename << "\"";
        throw std::runtime_error(ss.str());
    }

    stream.unsetf(std::ios::skipws);
    std::vector<char> buffer(std::istreambuf_iterator<char>(stream.rdbuf()), std::istreambuf_iterator<char>());
    buffer.push_back(0);

    const int flags = rapidxml::parse_trim_whitespace | rapidxml::parse_validate_closing_tags;
    rapidxml::xml_document<> doc;
    try
    {
        doc.parse<flags>(buffer.data());
    }
    catch (rapidxml::parse_error const& ex)
    {
        std::stringstream ss;
        ss << "SVG error: unable to parse \"" << filename << "\"";
        throw std::runtime_error(ss.str());
    }

    for (rapidxml::xml_node<char> const* child = doc.first_node(); child; child = child->next_sibling())
    {
        traverse_tree(*this, child);
    }
}

void svg_parser::parse_from_string(std::string const& svg)
{
    const int flags = rapidxml::parse_trim_whitespace | rapidxml::parse_validate_closing_tags;
    rapidxml::xml_document<> doc;
    std::vector<char> buffer(svg.begin(), svg.end());
    buffer.push_back(0);
    try
    {
        doc.parse<flags>(buffer.data());
    }
    catch (rapidxml::parse_error const& ex)
    {
        std::stringstream ss;
        std::string str = (svg.length() > 1024) ? svg.substr(0, 1024) + "..." : svg;
        ss << "SVG error: unable to parse \"" << str << "\"";
        throw std::runtime_error(ss.str());
    }
    for (rapidxml::xml_node<char> const* child = doc.first_node(); child; child = child->next_sibling())
    {
        traverse_tree(*this, child);
    }
}

svg_parser::error_handler& svg_parser::err_handler()
{
    return err_handler_;
}

} // namespace svg
} // namespace mapnik