BoundingBox.cpp

#include "BoundingBox.h"

BoundingBox::BoundingBox(vector<Point> points) : 
    top_left(points[(0)]), bottom_right(points[1]) {
    if (top_left.x > bottom_right.x || top_left.y > bottom_right.y) {
        string msg("Invalid points for BoundingBox.  Bottom right must have (x,y) >= top right point.");
        cerr << msg.c_str() << endl;
        throw runtime_error(msg);
    }
}

bool BoundingBox::operator==(const BoundingBox& other) const {
    return top_left == other.top_left && bottom_right == other.bottom_right;
}

int BoundingBox::area() {
    return (bottom_right.x - top_left.x) * (bottom_right.y - top_left.y);
}

bool BoundingBox::contains(BoundingBox other) {
    return top_left.x <= other.top_left.x && top_left.y <= other.top_left.y
        && bottom_right.x >= other.bottom_right.x && bottom_right.y >= other.bottom_right.y;
}

BoundingBox.h

#pragma once

#include <vector>
#include <iostream>

using namespace std;

// An [x/y] coordinate, relative to an upper left origin (positive Y is down, positive X to the right)
class Point {
public:
    // Instantiate a Point with default values
    Point() : x(0), y(0) {}

    // Instantiate a Point with provided values
    Point(int x, int y) : x(x), y(y) {}

    // Compares two Points for equality
    bool operator==(const Point & other) const {
        return x == other.x && y == other.y;
    }

    // X coordinate
    int x;

    // Y coordinate
    int y;
};

// A rectangular region defined by two points - a top left corner and a bottom right corner.  
class BoundingBox {
public:

    // Initializes a BoundingBox from a vector of Points.
    // The element at index 0 is used as the top left corner, and the 
    // element at index 1 is used as the bottom right corner.
    // Throws if the bottom right corner's (x,y) coordinates are 
    // not >= than the upper left's ones
    BoundingBox(vector<Point> corners);

    // Compares two BoundingBoxes for equality
    bool operator==(const BoundingBox& other) const;

    // Returns the top left Point of the bounding box
    Point getTopLeft() { return top_left; }

    // Returns the bottom right Point of the bounding box
    Point getBottomRight() { return bottom_right; }

    /// Calculates the area of the bounding box
    int area();

    /// Determines if one BoundingBox contains another
    /// <returns>true if this BoundingBox contains other</returns>
    bool contains(BoundingBox other);

private:
    Point top_left;
    Point bottom_right;
};