path.js

var PathProxy = require("../core/PathProxy");

var line = require("./line");

var cubic = require("./cubic");

var quadratic = require("./quadratic");

var arc = require("./arc");

var _util = require("./util");

var normalizeRadian = _util.normalizeRadian;

var curve = require("../core/curve");

var windingLine = require("./windingLine");

var CMD = PathProxy.CMD;
var PI2 = Math.PI * 2;
var EPSILON = 1e-4;

function isAroundEqual(a, b) {
  return Math.abs(a - b) < EPSILON;
} // 临时数组


var roots = [-1, -1, -1];
var extrema = [-1, -1];

function swapExtrema() {
  var tmp = extrema[0];
  extrema[0] = extrema[1];
  extrema[1] = tmp;
}

function windingCubic(x0, y0, x1, y1, x2, y2, x3, y3, x, y) {
  // Quick reject
  if (y > y0 && y > y1 && y > y2 && y > y3 || y < y0 && y < y1 && y < y2 && y < y3) {
    return 0;
  }

  var nRoots = curve.cubicRootAt(y0, y1, y2, y3, y, roots);

  if (nRoots === 0) {
    return 0;
  } else {
    var w = 0;
    var nExtrema = -1;
    var y0_, y1_;

    for (var i = 0; i < nRoots; i++) {
      var t = roots[i]; // Avoid winding error when intersection point is the connect point of two line of polygon

      var unit = t === 0 || t === 1 ? 0.5 : 1;
      var x_ = curve.cubicAt(x0, x1, x2, x3, t);

      if (x_ < x) {
        // Quick reject
        continue;
      }

      if (nExtrema < 0) {
        nExtrema = curve.cubicExtrema(y0, y1, y2, y3, extrema);

        if (extrema[1] < extrema[0] && nExtrema > 1) {
          swapExtrema();
        }

        y0_ = curve.cubicAt(y0, y1, y2, y3, extrema[0]);

        if (nExtrema > 1) {
          y1_ = curve.cubicAt(y0, y1, y2, y3, extrema[1]);
        }
      }

      if (nExtrema == 2) {
        // 分成三段单调函数
        if (t < extrema[0]) {
          w += y0_ < y0 ? unit : -unit;
        } else if (t < extrema[1]) {
          w += y1_ < y0_ ? unit : -unit;
        } else {
          w += y3 < y1_ ? unit : -unit;
        }
      } else {
        // 分成两段单调函数
        if (t < extrema[0]) {
          w += y0_ < y0 ? unit : -unit;
        } else {
          w += y3 < y0_ ? unit : -unit;
        }
      }
    }

    return w;
  }
}

function windingQuadratic(x0, y0, x1, y1, x2, y2, x, y) {
  // Quick reject
  if (y > y0 && y > y1 && y > y2 || y < y0 && y < y1 && y < y2) {
    return 0;
  }

  var nRoots = curve.quadraticRootAt(y0, y1, y2, y, roots);

  if (nRoots === 0) {
    return 0;
  } else {
    var t = curve.quadraticExtremum(y0, y1, y2);

    if (t >= 0 && t <= 1) {
      var w = 0;
      var y_ = curve.quadraticAt(y0, y1, y2, t);

      for (var i = 0; i < nRoots; i++) {
        // Remove one endpoint.
        var unit = roots[i] === 0 || roots[i] === 1 ? 0.5 : 1;
        var x_ = curve.quadraticAt(x0, x1, x2, roots[i]);

        if (x_ < x) {
          // Quick reject
          continue;
        }

        if (roots[i] < t) {
          w += y_ < y0 ? unit : -unit;
        } else {
          w += y2 < y_ ? unit : -unit;
        }
      }

      return w;
    } else {
      // Remove one endpoint.
      var unit = roots[0] === 0 || roots[0] === 1 ? 0.5 : 1;
      var x_ = curve.quadraticAt(x0, x1, x2, roots[0]);

      if (x_ < x) {
        // Quick reject
        return 0;
      }

      return y2 < y0 ? unit : -unit;
    }
  }
} // TODO
// Arc 旋转


function windingArc(cx, cy, r, startAngle, endAngle, anticlockwise, x, y) {
  y -= cy;

  if (y > r || y < -r) {
    return 0;
  }

  var tmp = Math.sqrt(r * r - y * y);
  roots[0] = -tmp;
  roots[1] = tmp;
  var diff = Math.abs(startAngle - endAngle);

  if (diff < 1e-4) {
    return 0;
  }

  if (diff % PI2 < 1e-4) {
    // Is a circle
    startAngle = 0;
    endAngle = PI2;
    var dir = anticlockwise ? 1 : -1;

    if (x >= roots[0] + cx && x <= roots[1] + cx) {
      return dir;
    } else {
      return 0;
    }
  }

  if (anticlockwise) {
    var tmp = startAngle;
    startAngle = normalizeRadian(endAngle);
    endAngle = normalizeRadian(tmp);
  } else {
    startAngle = normalizeRadian(startAngle);
    endAngle = normalizeRadian(endAngle);
  }

  if (startAngle > endAngle) {
    endAngle += PI2;
  }

  var w = 0;

  for (var i = 0; i < 2; i++) {
    var x_ = roots[i];

    if (x_ + cx > x) {
      var angle = Math.atan2(y, x_);
      var dir = anticlockwise ? 1 : -1;

      if (angle < 0) {
        angle = PI2 + angle;
      }

      if (angle >= startAngle && angle <= endAngle || angle + PI2 >= startAngle && angle + PI2 <= endAngle) {
        if (angle > Math.PI / 2 && angle < Math.PI * 1.5) {
          dir = -dir;
        }

        w += dir;
      }
    }
  }

  return w;
}

function containPath(data, lineWidth, isStroke, x, y) {
  var w = 0;
  var xi = 0;
  var yi = 0;
  var x0 = 0;
  var y0 = 0;

  for (var i = 0; i < data.length;) {
    var cmd = data[i++]; // Begin a new subpath

    if (cmd === CMD.M && i > 1) {
      // Close previous subpath
      if (!isStroke) {
        w += windingLine(xi, yi, x0, y0, x, y);
      } // 如果被任何一个 subpath 包含
      // if (w !== 0) {
      //     return true;
      // }

    }

    if (i == 1) {
      // 如果第一个命令是 L, C, Q
      // 则 previous point 同绘制命令的第一个 point
      //
      // 第一个命令为 Arc 的情况下会在后面特殊处理
      xi = data[i];
      yi = data[i + 1];
      x0 = xi;
      y0 = yi;
    }

    switch (cmd) {
      case CMD.M:
        // moveTo 命令重新创建一个新的 subpath, 并且更新新的起点
        // 在 closePath 的时候使用
        x0 = data[i++];
        y0 = data[i++];
        xi = x0;
        yi = y0;
        break;

      case CMD.L:
        if (isStroke) {
          if (line.containStroke(xi, yi, data[i], data[i + 1], lineWidth, x, y)) {
            return true;
          }
        } else {
          // NOTE 在第一个命令为 L, C, Q 的时候会计算出 NaN
          w += windingLine(xi, yi, data[i], data[i + 1], x, y) || 0;
        }

        xi = data[i++];
        yi = data[i++];
        break;

      case CMD.C:
        if (isStroke) {
          if (cubic.containStroke(xi, yi, data[i++], data[i++], data[i++], data[i++], data[i], data[i + 1], lineWidth, x, y)) {
            return true;
          }
        } else {
          w += windingCubic(xi, yi, data[i++], data[i++], data[i++], data[i++], data[i], data[i + 1], x, y) || 0;
        }

        xi = data[i++];
        yi = data[i++];
        break;

      case CMD.Q:
        if (isStroke) {
          if (quadratic.containStroke(xi, yi, data[i++], data[i++], data[i], data[i + 1], lineWidth, x, y)) {
            return true;
          }
        } else {
          w += windingQuadratic(xi, yi, data[i++], data[i++], data[i], data[i + 1], x, y) || 0;
        }

        xi = data[i++];
        yi = data[i++];
        break;

      case CMD.A:
        // TODO Arc 判断的开销比较大
        var cx = data[i++];
        var cy = data[i++];
        var rx = data[i++];
        var ry = data[i++];
        var theta = data[i++];
        var dTheta = data[i++]; // TODO Arc 旋转

        var psi = data[i++];
        var anticlockwise = 1 - data[i++];
        var x1 = Math.cos(theta) * rx + cx;
        var y1 = Math.sin(theta) * ry + cy; // 不是直接使用 arc 命令

        if (i > 1) {
          w += windingLine(xi, yi, x1, y1, x, y);
        } else {
          // 第一个命令起点还未定义
          x0 = x1;
          y0 = y1;
        } // zr 使用scale来模拟椭圆, 这里也对x做一定的缩放


        var _x = (x - cx) * ry / rx + cx;

        if (isStroke) {
          if (arc.containStroke(cx, cy, ry, theta, theta + dTheta, anticlockwise, lineWidth, _x, y)) {
            return true;
          }
        } else {
          w += windingArc(cx, cy, ry, theta, theta + dTheta, anticlockwise, _x, y);
        }

        xi = Math.cos(theta + dTheta) * rx + cx;
        yi = Math.sin(theta + dTheta) * ry + cy;
        break;

      case CMD.R:
        x0 = xi = data[i++];
        y0 = yi = data[i++];
        var width = data[i++];
        var height = data[i++];
        var x1 = x0 + width;
        var y1 = y0 + height;

        if (isStroke) {
          if (line.containStroke(x0, y0, x1, y0, lineWidth, x, y) || line.containStroke(x1, y0, x1, y1, lineWidth, x, y) || line.containStroke(x1, y1, x0, y1, lineWidth, x, y) || line.containStroke(x0, y1, x0, y0, lineWidth, x, y)) {
            return true;
          }
        } else {
          // FIXME Clockwise ?
          w += windingLine(x1, y0, x1, y1, x, y);
          w += windingLine(x0, y1, x0, y0, x, y);
        }

        break;

      case CMD.Z:
        if (isStroke) {
          if (line.containStroke(xi, yi, x0, y0, lineWidth, x, y)) {
            return true;
          }
        } else {
          // Close a subpath
          w += windingLine(xi, yi, x0, y0, x, y); // 如果被任何一个 subpath 包含
          // FIXME subpaths may overlap
          // if (w !== 0) {
          //     return true;
          // }
        }

        xi = x0;
        yi = y0;
        break;
    }
  }

  if (!isStroke && !isAroundEqual(yi, y0)) {
    w += windingLine(xi, yi, x0, y0, x, y) || 0;
  }

  return w !== 0;
}

function contain(pathData, x, y) {
  return containPath(pathData, 0, false, x, y);
}

function containStroke(pathData, lineWidth, x, y) {
  return containPath(pathData, lineWidth, true, x, y);
}

exports.contain = contain;
exports.containStroke = containStroke;