path_parser.dart

// Copyright (c) 2018 Dan Field

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

// Modified from flutter_svg: ^0.17.3+1
// package:flutter_svg/src/svg/parser_state.dart

import 'dart:ui';

import 'package:path_drawing/path_drawing.dart';
import 'package:xml/xml.dart';

Path xmlToPath(XmlElement elem) {
  var tag = elem.name.toString();
  return _svgPathFuncs[tag](elem);
}

typedef _PathFunc = Path Function(XmlElement elem);

const Map<String, _PathFunc> _svgPathFuncs = <String, _PathFunc>{
  'circle': _Paths.circle,
  'path': _Paths.path,
  'rect': _Paths.rect,
  'polygon': _Paths.polygon,
  'polyline': _Paths.polyline,
  'ellipse': _Paths.ellipse,
  'line': _Paths.line,
};

get validTags => _svgPathFuncs.keys.toList();

class _Paths {
  static Path circle(XmlElement elem) {
    final double cx = parseDouble(getAttribute(elem, 'cx', def: '0'));
    final double cy = parseDouble(getAttribute(elem, 'cy', def: '0'));
    final double r = parseDouble(getAttribute(elem, 'r', def: '0'));
    final Rect oval = Rect.fromCircle(center: Offset(cx, cy), radius: r);
    return Path()..addOval(oval);
  }

  static Path path(XmlElement elem) {
    final String d = getAttribute(elem, 'd');
    return parseSvgPathData(d);
  }

  static Path rect(XmlElement elem) {
    final double x = parseDouble(getAttribute(elem, 'x', def: '0'));
    final double y = parseDouble(getAttribute(elem, 'y', def: '0'));
    final double w = parseDouble(getAttribute(elem, 'width', def: '0'));
    final double h = parseDouble(getAttribute(elem, 'height', def: '0'));
    final Rect rect = Rect.fromLTWH(x, y, w, h);
    String rxRaw = getAttribute(elem, 'rx', def: null);
    String ryRaw = getAttribute(elem, 'ry', def: null);
    rxRaw ??= ryRaw;
    ryRaw ??= rxRaw;

    if (rxRaw != null && rxRaw != '') {
      final double rx = parseDouble(rxRaw);
      final double ry = parseDouble(ryRaw);

      return Path()..addRRect(RRect.fromRectXY(rect, rx, ry));
    }

    return Path()..addRect(rect);
  }

  static Path polygon(XmlElement elem) {
    return parsePathFromPoints(elem, true);
  }

  static Path polyline(XmlElement elem) {
    return parsePathFromPoints(elem, false);
  }

  static Path parsePathFromPoints(XmlElement elem, bool close) {
    final String points = getAttribute(elem, 'points');
    if (points == '') {
      return null;
    }
    final String path = 'M$points${close ? 'z' : ''}';

    return parseSvgPathData(path);
  }

  static Path ellipse(XmlElement elem) {
    final double cx = parseDouble(getAttribute(elem, 'cx', def: '0'));
    final double cy = parseDouble(getAttribute(elem, 'cy', def: '0'));
    final double rx = parseDouble(getAttribute(elem, 'rx', def: '0'));
    final double ry = parseDouble(getAttribute(elem, 'ry', def: '0'));

    final Rect r = Rect.fromLTWH(cx - rx, cy - ry, rx * 2, ry * 2);
    return Path()..addOval(r);
  }

  static Path line(XmlElement elem) {
    final double x1 = parseDouble(getAttribute(elem, 'x1', def: '0'));
    final double x2 = parseDouble(getAttribute(elem, 'x2', def: '0'));
    final double y1 = parseDouble(getAttribute(elem, 'y1', def: '0'));
    final double y2 = parseDouble(getAttribute(elem, 'y2', def: '0'));

    return Path()
      ..moveTo(x1, y1)
      ..lineTo(x2, y2);
  }
}

String getAttribute(XmlElement elem, String attr, {String def}) =>
    elem.getAttribute(attr) ?? def;

/// Parses a `String` to a `double`.
/// Passing `null` will return `null`.
/// Will strip off a `px` prefix.
double parseDouble(String maybeDouble, {bool tryParse = false}) {
  assert(tryParse != null);
  if (maybeDouble == null) {
    return null;
  }
  maybeDouble = maybeDouble.trim().replaceFirst('px', '').trim();
  if (tryParse) {
    return double.tryParse(maybeDouble);
  }
  return double.parse(maybeDouble);
}