How to use the @antv/coord/lib/index.Polar function in @antv/coord

it('_getAxisCfg when gridAlign is middle.', function() {
      as.options = {
        b: {
          grid: {
            align: 'center'
          }
        }
      };
      const coord = new Coord.Polar({
        start,
        end
      });
      coord.reflect('y');
      const axisCfg = as._getAxisCfg(coord, scaleY, scaleX, 'y');

      expect(axisCfg.ticks.length).to.equal(10);
      expect(axisCfg.grid).not.to.be.empty;
      expect(axisCfg.grid.type).to.equal('circle');
      expect(axisCfg.grid.items.length).to.equal(12); // fixed: fill gaps
      expect(axisCfg.grid.items[0]._id).not.to.be.undefined;
      expect(axisCfg.grid.items[0].points.length).to.equal(12);
    });
  });

it('_getRadiusCfg', function() {
      const coord = new Coord.Polar({
        start,
        end
      });
      const radiusCfg = as._getRadiusCfg(coord);
      expect(radiusCfg.factor).to.equal(-1);
      expect(radiusCfg.start).to.eql({
        x: 250,
        y: 250
      });
      expect(radiusCfg.end).to.eql({
        x: 250.00000000000003,
        y: 0
      });
    });

it('_getRadiusCfg when coord is transpose.', function() {
      const coord = new Coord.Polar({
        start,
        end,
        startAngle: 1 / (3 * Math.PI),
        endAngle: Math.PI
      });
      coord.transpose();
      const radiusCfg = as._getRadiusCfg(coord);
      expect(radiusCfg.factor).to.equal(1);
      expect(radiusCfg.start).to.eql({
        x: 250.70494165327872,
        y: 124.94090329888789
      });
      expect(radiusCfg.end).to.eql({
        x: 500.00000000000006,
        y: 151.49164063853073
      });

it('_getCircleCfg when coord is reflectY.', function() {
      const coord = new Coord.Polar({
        start,
        end,
        startAngle: 1 / (3 * Math.PI),
        endAngle: Math.PI
      });
      coord.reflect('y');
      const circleCfg = as._getCircleCfg(coord);

      expect(circleCfg.startAngle).to.equal(0.10610329539459758);
      expect(circleCfg.endAngle).to.equal(3.141592653589794);
      expect(circleCfg.center).to.eql({
        x: 250.70494165327872,
        y: 124.94090329888789
      });
    });

it('get axis position polar', function() {
      const coord = new Coord.Polar({
        start,
        end
      });

      let position = as._getAxisPosition(coord, 'x');
      expect(position).to.equal('circle');
      position = as._getAxisPosition(coord, 'y');
      expect(position).to.equal('radius');
    });

it('_getCircleCfg', function() {
      const coord = new Coord.Polar({
        start,
        end
      });
      const circleCfg = as._getCircleCfg(coord);

      expect(circleCfg.startAngle).to.equal(-1.5707963267948966);
      expect(circleCfg.endAngle).to.equal(4.71238898038469);
      expect(circleCfg.radius).to.equal(250);
      expect(circleCfg.inner).to.equal(0);
      expect(circleCfg.center).to.eql({ x: 250, y: 250 });
    });

it('get axis position polar transpose', function() {
      const coord = new Coord.Polar({
        start,
        end
      });
      coord.transpose();

      let position = as._getAxisPosition(coord, 'x');
      expect(position).to.equal('radius');
      position = as._getAxisPosition(coord, 'y');
      expect(position).to.equal('circle');
    });
  });

it('draw area in polar', function() {
    const coord1 = new Coord.Polar({
      start: {
        x: 0,
        y: 0
      },
      end: {
        x: 500,
        y: 500
      }
    });
    geom.reset();
    geom.set('coord', coord1);
    geom.position('a*b').color('c');
    geom.init();
    geom.paint();
    expect(shapeContainer.getCount()).equal(1);
    expect(shapeContainer.getFirst().attr('path').length).equal(9);

it('锐角扇形 宽画布 反向', () => {
    const width = 800;
    const height = 400;
    const startAngle = Math.PI * (10 / 6);
    const endAngle = Math.PI * (8 / 6);

    const coord = new Coord.Polar({
      start: { x: 0, y: height },
      end: { x: width, y: 0 },
      startAngle,
      endAngle
    });
    for (let i = startAngle; i <= endAngle; i += Math.PI / 180) {
      const point = {
        x: Math.cos(i) * coord.radius + coord.center.x,
        y: Math.sin(i) * coord.radius + coord.center.y
      };
      expect(point.x >= 0 && point.x <= width).to.be.true;
      expect(point.y >= 0 && point.y <= height).to.be.true;
    }
    expect(coord.center.y >= 0 && coord.center.y <= height).to.be.true;
    expect(coord.center.x >= 0 && coord.center.x <= width).to.be.true;
  });

it('_getCircleCfg when coord is transposed.', function() {
      const coord = new Coord.Polar({
        start,
        end,
        innerRadius: 0.5
      });
      coord.transpose();

      const circleCfg = as._getCircleCfg(coord);
      expect(circleCfg.startAngle).to.equal(-1.5707963267948966);
      expect(circleCfg.endAngle).to.equal(4.71238898038469);
      expect(circleCfg.radius).to.equal(250);
      expect(circleCfg.inner).to.equal(0.5);
      expect(circleCfg.center).to.eql({
        x: 250,
        y: 250
      });
    });