python/polyline.py at master · war16641/python · GitHub

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from typing import List

from nose.tools import assert_raises

from GoodToolPython.vector3d import Vector3D, Line3D
import matplotlib.pyplot as plt
import numpy as np

class Polylines2D:
    """
    平面多段线 x递增
    """
    points_list: List[Vector3D]
    tol = 1e-15  # 判断相等的误差

    def __init__(self, name: str = ''):
        self.name = name  # 名称
        self.points_list = []

    def append(self, pt: Vector3D) -> None:
        assert isinstance(pt, Vector3D)
        if self.num_of_points > 0:
            assert pt.x > self.points_list[-1].x, '要求x坐标递增'
        self.points_list.append(pt)

    @property
    def num_of_points(self):  # 点的个数
        return len(self.points_list)

    @property
    def num_of_lines(self):  # 线的个数
        return len(self.points_list) - 1

    def get_slope_by_line_id(self, id_line=0) -> float:
        """
        返回斜率 通过线的编号
        :param id_line:线编号
        :return: 斜率 正无穷时返回'inf'
        """
        assert self.num_of_lines >= id_line, '线的编号越界'
        p1 = self.points_list[id_line]
        p2 = self.points_list[id_line + 1]
        if abs(p1.y - p2.y) < self.tol:
            slope = 'inf'  # 此时斜率为正无穷
        else:
            slope = (p1.y - p2.y) / (p1.x - p2.x)
        return slope

    def get_slope(self, x: float = 0., side='left') -> float:
        """
        通过x坐标 返回该处的斜率
        如果为无穷大 返回'inf'
        :param x:
        :param side: 指定当遇到中间节点 返回的值'left' 'right' 'stop'
        :return:
        """
        assert isinstance(x, (int, float))
        if side == 'left':
            offset = -1
        elif side == 'right':
            offset = 0
        elif side == 'stop':  # 设定 如果遇到中间点就抛出错误
            offset = -2
        else:
            raise Exception("参数错误")
        if x < self.points_list[0].x:
            raise Exception("x小于最小x值，不在多段线段上")
        for id, pt in enumerate(self.points_list):
            if x == pt.x:  # 在端点上
                if id == 0:  # 起点 返回第一条的斜率
                    return self.get_slope_by_line_id(0)
                elif id == self.num_of_points:  # 终点 返回最后一条的斜率
                    return self.get_slope_by_line_id(id - 1)
                else:  # 中间点
                    if offset == -2:
                        raise Exception("遇到中间点")
                    return self.get_slope_by_line_id(id + offset)
            elif x < pt.x:  # 在线段内部
                return self.get_slope_by_line_id(id - 1)

    def get_value(self, x: float = 0.) -> float:
        """
        获取横坐标为x时，y的值
        :param x:
        :return:
        """
        assert isinstance(x, (int, float))
        if x < self.points_list[0].x:
            raise Exception("x小于最小x值，不在多段线段上")
        for id, pt in enumerate(self.points_list):
            if pt.x >= x:  # 找到了
                elo = Line3D.make_line_by_2_points(self.points_list[id - 1], pt)
                return elo.get_point('x', x).y
        raise Exception("x大于最大x值，不在多段线上")

    def show(self):
        #使用matplot显示
        x,y=self.get_array()
        plt.plot(x,y)
        plt.show()
        pass

    def get_array(self):
        x_list=[x.x for x in self.points_list]
        y_list = [x.y for x in self.points_list]
        x=np.array(x_list)
        y=np.array(y_list)
        return x,y

if __name__ == '__main__':
    pl = Polylines2D()
    pl.append(Vector3D())
    pl.append(Vector3D(1, 1))
    assert_raises(Exception, pl.append, Vector3D(1, 1))
    assert_raises(Exception, pl.append, Vector3D(0.5, 0))
    assert 1. == pl.get_value(1)
    assert 0.5 == pl.get_value(0.5)
    assert_raises(Exception, pl.get_value, 1.1)
    assert_raises(Exception, pl.get_value, -1.1)
    pl.append(Vector3D(2, 3))
    assert pl.get_slope(0.5) == 1.
    assert pl.get_slope(1.1) == 2.
    assert pl.get_slope(1) == 1.
    assert pl.get_slope(1, side='right') == 2.
    assert pl.get_slope(0, side='left') == 1.
    assert pl.get_slope(0, side='right') == 1.
    assert pl.get_slope(2, side='left') == 2.
    assert_raises(Exception, pl.get_value, -1.1)
    assert_raises(Exception, pl.get_value, 2.1)
    assert_raises(Exception,pl.get_slope,1,'stop')
    pl.show()
    pl.show()
    pl = Polylines2D()
    pl.append(Vector3D())
    pl.show()