==================
Part Transformers
==================

Each Part can have one or more transformers.  Transformers are different from 
path transforms in that the part transformers may result in more than one 
part.  


.. code-block::

    {
        "id": "my_part1",
        "part_transformers": [
            {
                "type" : "splitter"
                ...
            }
        ],
        "components": [
            ...
        ]
    }


------------------------------------------------------------------------------------------

Splitter
========

Splitter will break a part into 2 pieces, a top and bottom, using two edges.  
This is especially useful for parts that are too large to fit on a single material. 
Each edge is passed ``from`` and ``to`` Point params to tell the edges where to render.  
The ``bleed_top`` and ``bleed_bottom`` params allow the lines to bleed over

Parameters
~~~~~~~~~~

* ``y``: The y position where the split should happen. Note, if ``y`` is set, autosplit 
    must be false or unset.
* ``auto_split``: <true|false> If true, the splitter will activate if the part does 
    not fit with the material. Splits will be in half horizontally or vertically. 
    This will perform as many individual splits as needed to fit the material size. 
    Note that if auto_split is on, then any value of ``y`` will be ignored
* ``y_offset``: this will add an extra amount to the split location (either the 
    value of ``y`` or the auto_split location.  ``y_offset`` is useful for dynamically 
    moving the split point when multiple identical layers are stacked on top of each other
    so the break points are not aligned
* ``bleed_top``: The extra amount of bleed the top piece should have.  This is useful
    for butt joints that extend into the top and bottom pieces.
    Note that if the bleed amount is not supplied, it will be calculated automatically,
    this is sufficient for most usecases. 
* ``bleed_bottom``: The extra amount of bleed the bottom piece should have.  This is useful
    for butt joints that extend into the top and bottom pieces.  
* ``plug_edge``: Each connector edge is expected to have a plug side and a socket side. 
    (though some edge types might not). The plug edge is always the bottom edge of the top piece.
* ``socket_edge``: The socket edge is always the top edge of the bottom piece.
* ``max_width``: if auto split is true this will be the max width a component can have before
    it is split.  If max_width is not supplied, material_width will be used
* ``max_height``: if auto split is true this will be the max height a component can have before
    it is split.  If max_height is not supplied, material_height will be used


.. code-block:: JSON

    {
        "type": "splitter",
        "y": "2",
        "plug_edge": {
            "id": "plug_edge",
            "type": "line"
        },
        "socket_edge": {
            "type": "line"
        }
    }


------------------------------------------------------------------------------------------


Lathe
=====

.. topic:: Examples

    * `<https://github.com/dustismo/heavyfishdesign/blob/master/designs/chess/pawn.hfd>`_
    * `<https://github.com/dustismo/heavyfishdesign/blob/master/designs/candle_holder/votive_center_struts.hfd>`_


Lathe takes a component outline and 'turns' a set of stackable parts.  Given a side view outline shape, and the shape of the piece, the lathe will calculate all the parts to stack to make the shape. 

for instance, this outline:

.. image:: _static/pawn_outline.png
  :width: 150

with repeatable:

.. image:: _static/square.png
  :width: 150

Results in:

.. image:: _static/pawn.jpg
  :width: 150


Parameters
~~~~~~~~~~

* ``repeatable``: The component which is going to be repeated. This component should use the ``lathe__width`` local variable. 
* ``material_thickness``
* ``padding_top`` Amount of space before rendering the first slice.  
* ``padding_bottom`` Amount of space from the bottom that will be the last slice
* ``lathe_variable_name`` If supplied, then the rendering of this will provide some global variables to any subsequently rendered parts.  See Global Variables

Local Variables
~~~~~~~~~~~~~~~

* ``lathe__index`` The index of the parts within this Lathe.  The top most piece is part_index 0.
* ``lathe__width`` The width of the current piece.

Global Variables
~~~~~~~~~~~~~~~~

* ``<lathe_variable_name>__total_height`` The hieght of all the lathe parts stacked
* ``<lathe_variable_name>__top_width`` The width of the top piece
* ``<lathe_variable_name>__bottom_width`` The width of the bottom piece