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Wrong result from Rectangle.contains() in java

It appears that the contains() method in Rectangle is not inclusive to the bottom right corner.

For example the following code returns "false";

Rectangle r = new Rectangle(0,0,100,100);
System.out.println(r.contains(100, 100));
Solution

  • As quoted from the Rectangle API (Java 8):

    public Rectangle(int x, int y, int width, int height)
    Constructs a new Rectangle whose upper-left corner is specified as (x,y) and whose width and height are specified by the arguments of the same name.

    Using Width and Height with the starting Point of (0,0) means the Rectangle has points from (0,0) to (99,99) - 100 pixels of width and 100 pixels of height, based on the given starting pixel of (0,0) which is always included in the Rectangle.

    This means that (100,100) will indeed not be included in the constructed Rectangle. Based on the logic above, (100,100) will be contained in the following (verified using an online java compiler):

    Rectangle r = new Rectangle(1,1,100,100);

    References: