# Java – Stream/IntRange on 2D coordinates?

Stream/IntRange on 2D coordinates?… here is a solution to the problem.

## Stream/IntRange on 2D coordinates?

I have the following classes:

``````public class Rectangle
{
public int width, height;
public Point start;

public Rectangle(Point start, int width, int height)
{
this.start = start;
this.width = width;
this.height = height;
}
}

public class Point
{
public int x, y;

public Point(int x, int y)
{
this.x = x;
this.y = y;
}
}
``````

I want to create a method of the Rectangle class that returns a Java 8 `Stream` of type `Point`, which will stream the index position inside the rectangle. Predecessor.

``````// This is inside the rectangle class.
public Stream<Point> stream(int hstep, int vstep)
{
if the rectangle started at 0,0
and had a width and height of 100
and hstep and vstep were both 1
then the returned stream would be
0,0 -> 1,0 -> 2,0 -> ... -> 100,0 -> 0,1 -> 1,1 -> ...

If vstep was 5 and h step was 25 it would return
0,0 -> 25,0 -> 50,0 -> 75,0 -> 100,0 -> 0,5 -> 25,5 -> ...

return ...
}
``````

I

use `IntStream`, `map`, `filter`, etc. a lot, but this is much more complicated than anything I’ve tried. I don’t know how I would do something like that. Can someone guide me in the right direction?

### Solution

You can use nested `IntStreams` to generate each `Point`, and then flatten the resulting stream:

``````public Stream<Point> stream(int hstep, int vstep) {
return IntStream.range(0, height / vstep)
.mapToObj(y -> IntStream.range(0, width / hstep)
.mapToObj(x -> new Point(start.x + x * hstep, start.y + y * vstep)))
.flatMap(Function.identity());
}
``````