<!-- ##### SECTION Title ##### -->
GtkBox

<!-- ##### SECTION Short_Description ##### -->
a base class for box containers

<!-- ##### SECTION Long_Description ##### -->
<para>
GtkBox is an abstract widget which encapsulates functionallity for a
particular kind of container, one that organizes a variable number of
widgets into a rectangular area.  GtkBox currently has two derived
classes, #GtkHBox and #GtkVBox.
</para>
<para>
The rectangular area of a GtkBox is organized into either a single row
or a single column of child widgets depending upon whether the box is
of type #GtkHBox or #GtkVBox, respectively.  Thus, all children of a
GtkBox are allocated one dimension in common, which is the height of a
row, or the width of a column.
</para>
<para>
GtkBox uses a notion of <emphasis>packing</emphasis>.  Packing refers to
adding widgets with reference to a particular position in a
#GtkContainer.  For a GtkBox, there are two reference positions: the
<emphasis>start</emphasis> and the <emphasis>end</emphasis> of the box.  For a
#GtkVBox, the start is defined as the top of the box and the end is
defined as the bottom.  For a #GtkHBox the start is defined as the
left side and the end is defined as the right side.
</para>
<para>
Use repeated calls to gtk_box_pack_start() to pack widgets into a
GtkBox from start to end.  Use gtk_box_pack_end() to add widgets from
end to start.  You may intersperse these calls and add widgets from
both ends of the same GtkBox.
</para>
<para>
Use gtk_box_pack_start_defaults() or gtk_box_pack_end_defaults()
to pack widgets into a GtkBox if you do not need to specify the
<structfield>expand</structfield>, <structfield>fill</structfield>, or
<structfield>padding</structfield> attributes of the child to be
added.
</para>
<para>
Because GtkBox is a #GtkContainer, you may also use
gtk_container_add() to insert widgets into the box, and they will be
packed as if with gtk_box_pack_start_defaults().  Use
gtk_container_remove() to remove widgets from the GtkBox.
</para>
<para>
Use gtk_box_set_homogeneous() to specify whether or not all children
of the GtkBox are forced to get the same amount of space.
</para>
<para>
Use gtk_box_set_spacing() to determine how much space will be
minimally placed between all children in the GtkBox.
</para>
<para>
Use gtk_box_reorder_child() to move a GtkBox child to a different
place in the box.
</para>
<para>
Use gtk_box_set_child_packing() to reset the
<structfield>expand</structfield>, <structfield>fill</structfield>,
and <structfield>padding</structfield> attributes of any GtkBox child.
Use gtk_box_query_child_packing() to query these fields.
</para>

<!-- ##### SECTION See_Also ##### -->
<para>
<variablelist>

<varlistentry>
<term>#GtkHBox</term>
<listitem><para>a derived class that organizes widgets into a row.</para></listitem>
</varlistentry>

<varlistentry>
<term>#GtkVBox</term>
<listitem><para>a derived class that organizes widgets into a column.</para></listitem>
</varlistentry>

<varlistentry>
<term>#GtkFrame</term>
<listitem><para>a #GtkWidget useful for drawing a border around a GtkBox.</para></listitem>
</varlistentry>

<varlistentry>
<term>#GtkTable</term>
<listitem><para>a #GtkContainer for organizing widgets into a grid,
rather than independent rows or columns.</para></listitem>
</varlistentry>

<varlistentry>
<term>#GtkLayout</term>
<listitem><para>a #GtkContainer for organizing widgets into arbitrary
layouts.</para></listitem>
</varlistentry>

</variablelist>

</para>

<!-- ##### STRUCT GtkBox ##### -->
<para>
The #GtkBox-struct describes an instance of GtkBox and contains the following fields.
(These fields should be considered read-only. They should never be set by
an application.)

<informaltable pgwide=1 frame="none" role="struct">
<tgroup cols="2"><colspec colwidth="2*"><colspec colwidth="8*">
<tbody>

<row>
<entry>#GList * <structfield>children</structfield>;</entry>
<entry>a list of children belonging the GtkBox.  The data is a list of
structures of type #GtkBoxChild-struct.</entry>
</row>

<row>
<entry>#gint16 <structfield>spacing</structfield>;</entry>
<entry>the number of pixels to put between children of the GtkBox, zero
by default.  Use gtk_box_set_spacing() to set this field.</entry>
</row>

<row>
<entry>#guint <structfield>homogeneous</structfield>;</entry>
<entry>a flag that if %TRUE forces all children to get equal space in
the GtkBox; %FALSE by default.  Use gtk_box_set_homogeneous() to set this
field.</entry>
</row>
</tbody></tgroup></informaltable>
</para>


<!-- ##### STRUCT GtkBoxChild ##### -->
<para>
The #GtkBoxChild-struct holds a child widget of GtkBox and describes
how the child is to be packed into the GtkBox.  Use
gtk_box_query_child_packing() and gtk_box_set_child_packing() to query
and reset the <structfield>padding</structfield>,
<structfield>expand</structfield>, <structfield>fill</structfield>,
and <structfield>pack</structfield> fields.
</para>
<para>
#GtkBoxChild-struct contains the following fields.  (These fields
should be considered read-only. They should never be directly set by an
application.)

<informaltable pgwide=1 frame="none" role="struct">
<tgroup cols="2"><colspec colwidth="2*"><colspec colwidth="8*">
<tbody>

<row>
<entry>#GtkWidget * <structfield>widget</structfield>;</entry>
<entry>the child widget, packed into the GtkBox.</entry>
</row>

<row>
<entry>#guint16 <structfield>padding</structfield>;</entry>
<entry>the number of extra pixels to put between this child and its
neighbors, set when packed, zero by default.</entry>
</row>

<row>
<entry>#guint <structfield>expand</structfield>;</entry>
<entry>flag indicates whether extra space should be given to this
child.  Any extra space given to the parent GtkBox is divided up among
all children with this attribute set to %TRUE; set when packed, %TRUE by
default.</entry>
</row>

<row>
<entry>#guint <structfield>fill</structfield>;</entry>
<entry>flag indicates whether any extra space given to this child due to its
<structfield>expand</structfield> attribute being set is actually
allocated to the child, rather than being used as padding
around the widget; set when packed, %TRUE by default.</entry>
</row>

<row>
<entry>#guint <structfield>pack</structfield>;</entry> <entry>one of
#GtkPackType indicating whether the child is packed with reference to
the start (top/left) or end (bottom/right) of the GtkBox.</entry>
</row>
</tbody></tgroup></informaltable>
</para>

@widget: 
@padding: 
@expand: 
@fill: 
@pack: 

<!-- ##### FUNCTION gtk_box_pack_start ##### -->
<para>
Adds @child to @box, packed with reference to the start of @box.  The
@child is packed after any other child packed with reference to the
start of @box.
</para>

@box: a #GtkBox.
@child: the #GtkWidget to be added to @box.
@expand: %TRUE if the new child is to be given extra space allocated to
@box.  The extra space will be divided evenly between all children of
@box that use this option.
@fill: %TRUE if space given to @child by the @expand option is
actually allocated to @child, rather than just padding it.  This
parameter has no effect if @expand is set to %FALSE.  A child is
always allocated the full height of a #GtkHBox and the full width of a
#GtkVBox.  This option affects the other dimension.
@padding: extra space in pixels to put between this child and its
neighbors, over and above the global amount specified by
<structfield>spacing</structfield> in #GtkBox-struct.  If @child is a
widget at one of the reference ends of @box, then @padding pixels are also put
between @child and the reference edge of @box.


<!-- ##### FUNCTION gtk_box_pack_end ##### -->
<para>
Adds @child to @box, packed with reference to the end of @box.  The
@child is packed after (away from end of) any other child packed with reference to the
end of @box.
</para>

@box: a #GtkBox.
@child: the #GtkWidget to be added to @box.
@expand: %TRUE if the new child is to be given extra space allocated to
@box.  The extra space will be divided evenly between all children of
@box that use this option.
@fill: %TRUE if space given to @child by the @expand option is
actually allocated to @child, rather than just padding it.  This
parameter has no effect if @expand is set to %FALSE.  A child is
always allocated the full height of a #GtkHBox and the full width of a
#GtkVBox.  This option affects the other dimension.
@padding: extra space in pixels to put between this child and its
neighbors, over and above the global amount specified by
<structfield>spacing</structfield> in #GtkBox-struct.  If @child is a
widget at one of the reference ends of @box, then @padding pixels are also put
between @child and the reference edge of @box.


<!-- ##### FUNCTION gtk_box_pack_start_defaults ##### -->
<para>
Adds @widget to @box, packed with reference to the start of @box.  The
child is packed after any other child packed with reference to the
start of @box.
</para>
<para>
Parameters for how to pack the child @widget,
<structfield>expand</structfield>, <structfield>fill</structfield>,
and <structfield>padding</structfield> in #GtkBoxChild-struct, are given their default
values, %TRUE, %TRUE, and 0, respectively.
</para>

@box: a #GtkBox.
@widget: the #GtkWidget to be added to @box.


<!-- ##### FUNCTION gtk_box_pack_end_defaults ##### -->
<para>
Adds @widget to @box, packed with reference to the end of @box.  The
child is packed after (away from end of) any other child packed with
reference to the end of @box.
</para>
<para>
Parameters for how to pack the child @widget,
<structfield>expand</structfield>, <structfield>fill</structfield>,
and <structfield>padding</structfield> in #GtkBoxChild-struct, are given their default
values, %TRUE, %TRUE, and 0, respectively.
</para>

@box: a #GtkBox.
@widget: the #GtkWidget to be added to @box.


<!-- ##### FUNCTION gtk_box_set_homogeneous ##### -->
<para>
Sets the <structfield>homogeneous</structfield> field of
#GtkBox-struct, controlling whether or not all children of @box are
given equal space in the box.
</para>

@box: a #GtkBox.
@homogeneous: a boolean value, %TRUE to create equal allotments,
%FALSE for variable allotments.


<!-- ##### FUNCTION gtk_box_set_spacing ##### -->
<para>
Sets the <structfield>spacing</structfield> field of #GtkBox-struct,
which is the number of pixels to place between children of @box.
</para>

@box: a #GtkBox.
@spacing: the number of pixels to put between children.


<!-- ##### FUNCTION gtk_box_reorder_child ##### -->
<para>
Moves @child to a new @position in the list of @box children.  The
list is the <structfield>children</structfield> field of
#GtkBox-struct, and contains both widgets packed #GTK_PACK_START as
well as widgets packed #GTK_PACK_END, in the order that these widgets
were added to @box.
</para>
<para>
A widget's position in the @box children list determines where the
widget is packed into @box.  A child widget at some position in the
list will be packed just after all other widgets of the same packing
type that appear earlier in the list.  A negative value of @position is
interpreted as position 0.
</para>

@box: a #GtkBox.
@child: the #GtkWidget to move.
@position: the new position for @child in the
<structfield>children</structfield> list of #GtkBox-struct, starting
from 0.


<!-- ##### FUNCTION gtk_box_query_child_packing ##### -->
<para>
Returns information about how @child is packed into @box.
</para>

@box: a #GtkBox.
@child: the #GtkWidget of the child to query.
@expand: the returned value of the <structfield>expand</structfield>
field in #GtkBoxChild-struct.
@fill: the returned value of the <structfield>fill</structfield> field
in #GtkBoxChild-struct.
@padding: the returned value of the <structfield>padding</structfield>
field in #GtkBoxChild-struct.
@pack_type: the returned value of the <structfield>pack</structfield>
field in #GtkBoxChild-struct.


<!-- ##### FUNCTION gtk_box_set_child_packing ##### -->
<para>
Sets the way @child is packed into @box.
</para>

@box: a #GtkBox.
@child: the #GtkWidget of the child to set.
@expand: the new value of the <structfield>expand</structfield> field
in #GtkBoxChild-struct.
@fill: the new value of the <structfield>fill</structfield> field in
#GtkBoxChild-struct.
@padding: the new value of the <structfield>padding</structfield>
field in #GtkBoxChild-struct.
@pack_type: the new value of the <structfield>pack</structfield> field
in #GtkBoxChild-struct.


<!-- ##### ARG GtkBox:spacing ##### -->
<para>
the minimum amount of space to put between children.  Refers to the
<structfield>spacing</structfield> field of #GtkBox-struct.
</para>

<!-- ##### ARG GtkBox:homogeneous ##### -->
<para>
how to allocate space for children, equally or variably.  Refers to
the <structfield>homogeneous</structfield> field of #GtkBox-struct.
</para>

