# Clicking on element in ElementArrayStim? "contains" function for elementArrayStim implementation

**URL:** <https://discourse.psychopy.org/t/clicking-on-element-in-elementarraystim-contains-function-for-elementarraystim-implementation/3002>\
**Category:** Coding\
**Tags:** screen\
**Created:** [September 4, 2017, 11:03pm UTC](https://discourse.psychopy.org/t/clicking-on-element-in-elementarraystim-contains-function-for-elementarraystim-implementation/3002 "2017-09-04T23:03:41Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![Stefan\_Uddenberg](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/stefan_uddenberg/32/5698_2.png) [@Stefan\_Uddenberg](https://discourse.psychopy.org/u/Stefan_Uddenberg)\
**Post date:** [September 5, 2017, 3:48am UTC](https://discourse.psychopy.org/t/clicking-on-element-in-elementarraystim-contains-function-for-elementarraystim-implementation/3002/2 "2017-09-05T03:48:05Z")

</div>

I think I figured it out! Can anyone think of a faster way to do this? I don’t like having to iterate over the array in the final step…

```auto
from psychopy import visual, monitors, core, event, os, data, gui, misc, logging
from random import shuffle
import time, math, random
import numpy as np

try:
	import matplotlib
	if matplotlib. __version__ > '1.2':
		from matplotlib.path import Path as mplPath
	else:
		from matplotlib import nxutils
	haveMatplotlib = True
except Exception:
	haveMatplotlib = False

## Porting psychopy's contains function to elementArrayStim
def contains(thisElementArrayStim, x, y=None, units=None):
	"""Returns True if a point x,y is inside the stimulus' border.

	Can accept variety of input options:
		+ two separate args, x and y
		+ one arg (list, tuple or array) containing two vals (x,y)
		+ an object with a getPos() method that returns x,y, such
			as a :class:`~psychopy.event.Mouse`.

	Returns `True` if the point is within the area defined either by its
	`border` attribute (if one defined), or its `vertices` attribute if
	there is no .border. This method handles
	complex shapes, including concavities and self-crossings.

	Note that, if your stimulus uses a mask (such as a Gaussian) then
	this is not accounted for by the `contains` method; the extent of the
	stimulus is determined purely by the size, position (pos), and
	orientation (ori) settings (and by the vertices for shape stimuli).

	See Coder demos: shapeContains.py
	"""
	# get the object in pixels
	if hasattr(x, 'border'):
		xy = x._borderPix # access only once - this is a property
		units = 'pix' # we can forget about the units
	elif hasattr(x, 'verticesPix'):
		# access only once - this is a property (slower to access)
		xy = x.verticesPix
		units = 'pix' # we can forget about the units
	elif hasattr(x, 'getPos'):
		xy = x.getPos()
		units = x.units
	elif type(x) in [list, tuple, np.ndarray]:
		xy = np.array(x)
	else:
		xy = np.array((x, y))
	# try to work out what units x,y has
	if units is None:
		if hasattr(xy, 'units'):
			units = xy.units
		else:
			units = thisElementArrayStim.units
	if units != 'pix':
		xy = convertToPix(xy, pos=(0, 0), units=units, win=thisElementArrayStim.win)
	# ourself in pixels
	if hasattr(thisElementArrayStim, 'border'):
		poly = thisElementArrayStim._borderPix # e.g., outline vertices
	else:
		poly = thisElementArrayStim.verticesPix[:, :, 0:2] # e.g., tesselated vertices

	return any( np.fromiter( ( pointInPolygon(thisPoly, xy[0], xy[1]) for thisPoly in poly[theseTargetIndices] ), np.bool ) )

```

---

_[View the full topic](https://discourse.psychopy.org/t/clicking-on-element-in-elementarraystim-contains-function-for-elementarraystim-implementation/3002)._