# Radius & Step Size

```pycon
>>> from glcm_cupy import GLCM
>>> import numpy as np
>>> from PIL import Image
>>> ar = np.asarray(Image.open("image.jpg"))
>>> g = GLCM(radius=1, step_size=1).run(ar)
```

## Radius

(radius)=

The radius defines the window radius for each GLCM window.

If the radius is 1, we have diameter of 3 as it includes the center pixel

## Step Size

(step_size)=

The step size defines the distance between each window.

If it's diagonal, it treats a diagonal step as 1. It's not the euclidean distance.

## Checking Suitability with

If the image is too small for the radius & step size it will be rejected.

You may check the resulting shape ahead of time by

```pycon
>>> from glcm_cupy import GLCM
>>> import numpy as np
>>> from PIL import Image
>>> ar = np.asarray(Image.open("image.jpg"))
>>> shape_after = GLCM().glcm_shape(ar, step_size=..., radius=...)
```

If ``shape_after`` has any values ``<=0``, you know that it'll fail.

This is the signature of that helper function

```pycon
def glcm_shape(im_shape: Tuple, step_size: int, radius: int):
    ...
```