Java check if two rectangles overlap at any point

java math selection shapes contain
user2190492 picture user2190492 · Apr 25, 2014 · Viewed 51.3k times · Source

I have multiple rectangles and one special rectangle: the selection rect. I want to check for each rectangle if the rectangle contains at least one point which is inside the selection rectangle. Here is an image for clarity:

Selection example

Answer

ThePatelGuy picture ThePatelGuy · Aug 19, 2015

Background:

A rectangle can be defined by just one of its diagonal.
Let's say the first rectangle's diagonal is (x1, y1) to (x2, y2)
And the other rectangle's diagonal is (x3, y3) to (x4, y4)

Sample

Proceeding:

Now, if any of these 4 conditions is true, we can conclude that the rectangles are not overlapping:

  1. x3 > x2 (OR)
  2. y3 > y2 (OR)
  3. x1 > x4 (OR)
  4. y1 > y4


Otherwise, they overlap!

enter image description here

Alternatively:

The rectangles overlap if

(x1 < x4) && (x3 < x2) && (y1 < y4) && (y3 < y2)



Sample solution on Leetcode: https://leetcode.com/problems/rectangle-overlap/discuss/468548/Java-check-if-two-rectangles-overlap-at-any-point

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