ulikoehler/UliEngineering

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Coordinate functions, mainly for 2D coordinates
"""
import numpy as np

__all__ = ["BoundingBox"]

class BoundingBox(object):
    """
    A 2D bounding box
    """
    def __init__(self, points):
        """
        Compute the upright 2D bounding box for a set of
        2D coordinates in a (n,2) numpy array.

        You can access the bbox using the
        (minx, maxx, miny, maxy) members.
        """
        if len(points.shape) != 2 or points.shape[1] != 2:
            raise ValueError("Points must be a (n,2), array but it has shape {}".format(
                points.shape))
        if points.shape[0] < 1:
            raise ValueError("Can't compute bounding box for empty coordinates")
        self.minx, self.miny = np.min(points, axis=0)
        self.maxx, self.maxy = np.max(points, axis=0)

    @property
    def width(self):
        """X-axis extent of the bounding box"""
        return self.maxx - self.minx

    @property
    def height(self):
        """Y-axis extent of the bounding box"""
        return self.maxy - self.miny

    @property
    def area(self):
        """width * height"""
        return self.width * self.height

    @property
    def aspect_ratio(self):
        """width / height"""
        return self.width / self.height

    @property
    def center(self):
        """(x,y) center point of the bounding box"""
        return (self.minx + self.width / 2, self.miny + self.height / 2)

    @property
    def max_dim(self):
        """The larger dimension: max(width, height)"""
        return max(self.width, self.height)

    @property
    def min_dim(self):
        """The larger dimension: max(width, height)"""
        return min(self.width, self.height)

    def __repr__(self):
        return "BoundingBox({}, {}, {}, {})".format(
            self.minx, self.maxx, self.miny, self.maxy)