Make turtle.pensize smarter

Feature or enhancement

Proposal:

The turtle.pensize doc says:

turtle.pensize(width=None)
    Parameters:

        width – a positive number

However, if you put a non-positive number, the function will accept it without any error or warning.

Afterwards, a draw action (like forward) will raise an exception. See below.

>>> import turtle
>>> turtle.pensize(-1)
>>> turtle.forward(100)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 8, in forward
  File "/home/adorilson/anaconda3/lib/python3.12/turtle.py", line 1636, in forward
    self._go(distance)
  File "/home/adorilson/anaconda3/lib/python3.12/turtle.py", line 1597, in _go
    self._goto(ende)
  File "/home/adorilson/anaconda3/lib/python3.12/turtle.py", line 3248, in _goto
    screen._drawline(self.drawingLineItem,
  File "/home/adorilson/anaconda3/lib/python3.12/turtle.py", line 543, in _drawline
    self.cv.itemconfigure(lineitem, width=width)
  File "<string>", line 1, in itemconfigure
  File "/home/adorilson/anaconda3/lib/python3.12/tkinter/__init__.py", line 2988, in itemconfigure
    return self._configure(('itemconfigure', tagOrId), cnf, kw)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/adorilson/anaconda3/lib/python3.12/tkinter/__init__.py", line 1712, in _configure
    self.tk.call(_flatten((self._w, cmd)) + self._options(cnf))
_tkinter.TclError: bad screen distance "-1"
>>>

My suggestion is pensize (and probably others) raises a TurtleGraphicsError if the width argument is less than 1.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

https://discuss.python.org/t/improving-the-turtle-library/61840/18

Linked PRs

• gh-135268

Commencez dans turtle.py, au niveau de l’implémentation de pensize, et comparez la façon dont elle traite l’exigence documentée d’une largeur positive avec l’échec signalé de forward. Consultez la discussion liée et gh-135268 avant de continuer ; le travail est terminé lorsque les largeurs non positives invalides sont traitées au moment de pensize, au lieu d’échouer lors d’une action de dessin ultérieure.