Get Square corners from 2 points

Question

I have 2 values and want to create a rectangle from it.

enter image description here

So let's say:

1 = 1,1
2 = 10,8

So I want to calculate the upper left corner which would result in 1,8 and the lower right corner which would be 10,1. How can I achieve this with Java? Are there any libraries for this or is it even possible with the standard equipment?

That wouldn't be a square. Do you mean a rectangle with sides that are exactly vertical or horizontal (not crooked)? — nanofarad, Nov 24 '14 at 11:31
There shouldn't be any need for a library, beyond maybe a really simple `Point` class that contains an x coordinate and a y coordinate. — nanofarad, Nov 24 '14 at 11:35
Your example values don't make any sense. If you have point 1 at x=1,y=1 and point 2 at x=10,y=8, you already have the upper left corner and lower right corner. — Boann, Nov 24 '14 at 11:36
@hexafraction, I thought all rectangles have straight, not crooked lines. Or are we talking about hyperspace i.e. a galaxy far, far away? — CocoNess, Nov 24 '14 at 11:36

Boann · Answer 1 · 2014-11-24T11:49:11.997

All you need to do is take the min/max x/y of the existing points:

Point p1 = ...
Point p2 = ...

Point upperLeft  = new Point(Math.min(p1.x, p2.x), Math.min(p1.y, p2.y));
Point lowerRight = new Point(Math.max(p1.x, p2.x), Math.max(p1.y, p2.y));

Note: This assumes x increases as you go right and y increases as you go down. If you have y increasing as you go up, change to:

Point upperLeft  = new Point(Math.min(p1.x, p2.x), Math.max(p1.y, p2.y));
Point lowerRight = new Point(Math.max(p1.x, p2.x), Math.min(p1.y, p2.y));

score 1 · Accepted Answer · answered Nov 24 '14 at 11:34

1

Based on your diagram and example, you want a rectangle with vertical and horizontal sides. If you look at your current example, all you did was take x1 and y2 for one of the points, and x2/y1 for the other point.

So, given Points p1 and p2, you could do as follows:

Point p3 = new Point(p1.x, p2.y);
Point p4 = new Point(p2.x, p1.y);

Of course, if you do not have Point objects you can just use the numbers as variables accordingly.

answered Nov 24 '14 at 11:34

nanofarad

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Awesome thanks alot! Veerryyy bad at math I guess... Thank you! – user754730 Nov 24 '14 at 11:45

score 1 · Answer 3 · answered Nov 24 '14 at 11:40

here is some code to start with:

public class Test {
    public static void main(String[] args) {
        int x1, x2, x3, x4, y1, y2, y3, y4;
        x1 = 1; y1 = 1;
        x3 = 10; y3 = 8;

        x4 = x1;y4 = y3;
        x2 = x3; y2 = y1;

        System.out.println("(x4,y4)=("+ x4 + "," + y4 + ")\t\t (x3,y3)=(" + x3 + "," + y3+")");
        System.out.println("(x1,y1)=("+ x1 + "," + y1 + ")\t\t (x2,y2)=(" + x2 + "," + y2+")");

    }
}

Result is:

(x4,y4)=(1,8)        (x3,y3)=(10,8)
(x1,y1)=(1,1)        (x2,y2)=(10,1)

Get Square corners from 2 points

3 Answers3