PhysicalTurtle 0.1

Physical Turtle

This is an extension for the Python turtle module that provides a physical space for a turtle to inhabit. The initial aim is to provide areas of solid space that the turtle cannot move into.

The Turtle class is extended with the following methods and attributes. This list may change as the first version of this package is developed.

Attributes:

• touch_left, touch_right, touch_front, touch_back

  Each one returns True if the Turtle would not be able to move in that direction.

• last_distance

  The distance travelled in the preceding forward or backward movement. Since the turtle is not able to move through a solid area this distance may be less than the distance originally called for.

Methods:

• pen_set_solid()

  Set a pen property so that any movement of the turtle with the pen down creates a solid area. The pen colour is not affected, so that the lines shown on the screen correspond to lines of solidity in the physical space.

  The solid area created by the turtle move is a rectangle corresponding to the length of the move and the width of the pen.

  No solid area is drawn in the pen is up.

  The action of filling a polygon with a colour does not create solid space.

• pen_unset_solid()

  Reverses the action of pen_set_solid so that turtle movement does not create solid areas.

The extension provides a new rule that says a turtle cannot cross a line that has been drawn with pen_set_solid. The turtle is allowed to move up to the soild line and the attribute last_distance gives the distance actually moved.

There are two exceptions to this rule:

• A turtle with pen up is allowed to move anywhere. This is allows the turtle to move to any place on the screen and is required for placing the turtle into an enclosed space.

• A turtle with pen solid is allowed to move anywhere. This is specifically designed to allow drawing a solid shape where one edge must be drawn contiguously with another. (If this was not allowed, the second line would not be drawn because it would be trapped by at the end of the first line.)

Installation

Get the version straight from the Python Package Index:

pip install physical_turtle

Or Get the latest version from Bit Bucket:

https://bitbucket.org/mikedeplume/physical-turtle

If you do download the repository, don’t forget to put the physical_turtle package on your PYTHON_PATH. The easiest way to do this is to go into the directory and type:

python setup.py install

License

The package uses the MIT license:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Use

The package is intended as a one for one replacement for the builtin turtle module. Any existing turtle software that you have should work just as before if you replace:

from trurtle import ...

with:

from physical_turtle import ...

From that perspective, there is nothing much new to learn.

Example

At the Python prompt:

>>> from physical_turtle.example_random import run_me
>>> run_me()

And watch the turtle bounce randomly around an enclosed space.