* @defgroup Elm_Box Box
* @ingroup Elementary
* @image html box_inheritance_tree.png
* @image latex box_inheritance_tree.eps
* @image html img/widget/box/preview-00.png
* @image latex img/widget/box/preview-00.eps width=\textwidth
* @image html img/box.png
* @image latex img/box.eps width=\textwidth
* A box arranges objects in a linear fashion, governed by a layout function
* that defines the details of this arrangement.
* By default, the box will use an internal function to set the layout to
* a single row, either vertical or horizontal. This layout is affected
* by a number of parameters, such as the homogeneous flag set by
* elm_box_homogeneous_set(), the values given by elm_box_padding_set() and
* elm_box_align_set() and the hints set to each object in the box.
* For this default layout, it's possible to change the orientation with
* elm_box_horizontal_set(). The box will start in the vertical orientation,
* placing its elements ordered from top to bottom. When horizontal is set,
* the order will go from left to right. If the box is set to be
* homogeneous, every object in it will be assigned the same space, that
* of the largest object. Padding can be used to set some spacing between
* the cell given to each object. The alignment of the box, set with
* elm_box_align_set(), determines how the bounding box of all the elements
* will be placed within the space given to the box widget itself.
* The size hints of each object also affect how they are placed and sized
* within the box. evas_object_size_hint_min_set() will give the minimum
* size the object can have, and the box will use it as the basis for all
* latter calculations. Elementary widgets set their own minimum size as
* needed, so there's rarely any need to use it manually.
* evas_object_size_hint_weight_set(), when not in homogeneous mode, is
* used to tell whether the object will be allocated the minimum size it
* needs or if the space given to it should be expanded. It's important
* to realize that expanding the size given to the object is not the same
* thing as resizing the object. It could very well end being a small
* widget floating in a much larger empty space. If not set, the weight
* for objects will normally be 0.0 for both axis, meaning the widget will
* not be expanded. To take as much space possible, set the weight to
* EVAS_HINT_EXPAND (defined to 1.0) for the desired axis to expand.
* Besides how much space each object is allocated, it's possible to control
* how the widget will be placed within that space using
* evas_object_size_hint_align_set(). By default, this value will be 0.5
* for both axis, meaning the object will be centered, but any value from
* 0.0 (left or top, for the @c x and @c y axis, respectively) to 1.0
* (right or bottom) can be used. The special value EVAS_HINT_FILL, which
* is -1.0, means the object will be resized to fill the entire space it
* was allocated.
* In addition, customized functions to define the layout can be set, which
* allow the application developer to organize the objects within the box
* in any number of ways.
* The special elm_box_layout_transition() function can be used
* to switch from one layout to another, animating the motion of the
* children of the box.
* @note Objects should not be added to box objects using _add() calls.
* Some examples on how to use boxes follow:
* @li @ref box_example_01
* @li @ref box_example_02