AxesDivider
===========

The axes_divider module provide helper classes to adjust the axes
positions of set of images in the drawing time.

* :mod:`~mpl_toolkits.axes_grid.axes_size` provides a classese of
  units that the size of each axes will be determined. For example,
  you can specify a fixed size

* :class:`~mpl_toolkits.axes_grid.axes_size.Divider` this is the class
  that is used calculates the axes position. It divides the given
  renctangular area into several areas. You intialize the divider by
  setting the horizontal and vertical list of sizes that the division
  will be based on. You then use the new_locator method, whose return
  value is a callable object that can be used to set the axes_locator
  of the axes.


You first initialize the divider by specifying its grids, i.e., horiz and vert.

for example,::

    rect = [0.2, 0.2, 0.6, 0.6]
    horiz=[h0, h1, h2, h3]
    vert=[v0, v1, v2]
    divider = Divider(fig, rect, horiz, vert)

where, rect is a bounds of the box that will be divided and h0,..h3,
v0,..v2 need to be an instance of classes in the
:mod:`~mpl_toolkits.axes_grid.axes_size`.  They have *get_size* method
that returns a tuple of two floats. The first float is the relative
size, and the second float is the absolute size. Consider a following
grid.

+-----+-----+-----+-----+
| v0  |     |     |     |
+-----+-----+-----+-----+
| v1  |     |     |     |
+-----+-----+-----+-----+
|h0,v2| h1  | h2  | h3  |
+-----+-----+-----+-----+


* v0 => 0, 2
* v1 => 2, 0
* v2 => 3, 0

The height of the bottom row is always 2 (axes_divider internally
assumes that the unit is inch). The first and the second rows with
height ratio of 2:3. For example, if the total height of the grid 6,
then the first and second row will each occupy 2/(2+3) and 3/(2+3) of
(6-1) inches. The widths of columns (horiz) will be similarly
determined. When aspect ratio is set, the total height (or width) will
be adjusted accordingly.


The :mod:`mpl_toolkits.axes_grid.axes_size` contains several classes
that can be used to set the horiz and vert. For example, for the
vertical configuration above will be::

  from mpl_toolkits.axes_grid.axes_size import Fixed, Scaled
  vert = [Fixed(2), Scaled(2), Scaled(3)]

After you set up the divider object, then you create a locator
instance which will be given to the axes.::

     locator = divider.new_locator(nx=0, ny=1)
     ax.set_axes_locator(locator)

The return value of the new_locator method is a instance of the
AxesLocator class. It is a callable object that returns the
location and size of the cell at the first column and the second row.
You may create a locator that spans over multiple cells.::

     locator = divider.new_locator(nx=0, nx=2, ny=1)

The above locator, when called, will return the position and size of
the cells spanning the first and second column and the first row. You
may consider it as [0:2, 1].

See the example,

.. plot:: mpl_toolkits/axes_grid/figures/simple_axes_divider2.py
   :include-source:

You can adjust the size of the each axes accroding to their x or y
data limits (AxesX and AxesY), similar to the axes aspect parameter.

.. plot:: mpl_toolkits/axes_grid/figures/simple_axes_divider3.py
   :include-source:

