[issue40283] Documentation of turtle.circle()

[Mike Weilgart]

Change by Mike Weilgart :


--
keywords: +patch
nosy: +Weildcard
nosy_count: 6.0 -> 7.0
pull_requests: +20107
stage: needs patch -> patch review
pull_request: https://github.com/python/cpython/pull/20928

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue40283] Documentation of turtle.circle()

[Frank Henigman]

Change by Frank Henigman :


--
nosy: +fjh

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue40283] Documentation of turtle.circle()

[Florian Dahlitz]

Florian Dahlitz  added the comment:

I tested it and can confirm the findings from @cajetan.rodrigues. However, this 
does not seem to be _not_ documented. The documentation clearly states that 
using a positive value for radius results in a counter-clockwise direction, 
whereas a negative number results in a clockwise direction. This is true.

Now, let's have a look at using radius _together_ with extent, which is not 
(clearly) documented as this point. Using a positive value results in the same 
direction, but in a not full drawn circle. This seems intuitive and is 
documented:

If extent is not given, draw the entire circle.
If extent is not a full circle, one endpoint of the arc is the current pen 
position.

Using a negative value changes the direction of radius, which does also seem 
reasonable and intuitive.

My suggestion is not to replace "radius" by "extent" as suggested by @guchao as 
it is IMHO wrong. But I agree that it would be good to leave a note there or to 
add examples demonstrating the behaviour of different (signed) values of radius 
and extent, so the intent and behaviour is clearly documented.

--
nosy: +DahlitzFlorian

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue40283] Documentation of turtle.circle()

[Cajetan Rodrigues]

Cajetan Rodrigues  added the comment:

When I checked, I found the following:

turtle.circle(50, 50)   # counter-clockwise
turtle.circle(-50, -50) # counter-clockwise
turtle.circle(-50, 50)  # clockwise
turtle.circle(50, -50)  # clockwise

So it seems both radius and extent need to be of the same signage to effect a 
counter-clockwise draw. However, for the 2 cases where extent is negative, the 
draw happens through the turtle's tail rather than the head. Looks weird.

--
nosy: +cajetan.rodrigues

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue40283] Documentation of turtle.circle()

[Terry J. Reedy]

Terry J. Reedy  added the comment:

It would be bizarre if the current doc were correct, but have you verified by 
experiment that the change is correct?

The patch itself would be trivial, hence the keyword addition.  PR author can 
request that I review.

--
keywords: +easy, newcomer friendly
nosy: +terry.reedy
stage:  -> needs patch
type: resource usage -> behavior
versions: +Python 3.7, Python 3.8, Python 3.9

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue40283] Documentation of turtle.circle()

[guchao]

New submission from guchao :

refer to circle() in the url: 
https://docs.python.org/2/library/turtle.html#turtle.circle

[current]
... Draw the arc in counterclockwise direction if radius is positive, otherwise 
in clockwise direction. 

[suggestion]
... Draw the arc in counterclockwise direction if extent is positive, otherwise 
in clockwise direction. 

[explanation]
It should be "extent" , instead of "radius", that affects the direction.

--
assignee: docs@python
components: Documentation
messages: 366401
nosy: docs@python, guchao
priority: normal
severity: normal
status: open
title: Documentation of turtle.circle()
type: resource usage

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com