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GtkSizeGroup provides a mechanism for grouping a number of widgets together so they all request the same amount of space. This is typically useful when you want a column of widgets to have the same size, but you can’t use a GtkGrid widget.
In detail, the size requested for each widget in a GtkSizeGroup is
the maximum of the sizes that would have been requested for each
widget in the size group if they were not in the size group. The mode
of the size group (see gtk_size_group_set_mode()) determines whether
this applies to the horizontal size, the vertical size, or both sizes.
Note that size groups only affect the amount of space requested, not
the size that the widgets finally receive. If you want the widgets in
a GtkSizeGroup to actually be the same size, you need to pack them in
such a way that they get the size they request and not more. For
example, if you are packing your widgets into a table, you would not
include the GTK_FILL flag.
GtkSizeGroup objects are referenced by each widget in the size group,
so once you have added all widgets to a GtkSizeGroup, you can drop
the initial reference to the size group with g_object_unref(). If the
widgets in the size group are subsequently destroyed, then they will
be removed from the size group and drop their references on the size
group; when all widgets have been removed, the size group will be
freed.
Widgets can be part of multiple size groups; GTK+ will compute the
horizontal size of a widget from the horizontal requisition of all
widgets that can be reached from the widget by a chain of size groups
of type GTK_SIZE_GROUP_HORIZONTAL or GTK_SIZE_GROUP_BOTH, and the
vertical size from the vertical requisition of all widgets that can be
reached from the widget by a chain of size groups of type
GTK_SIZE_GROUP_VERTICAL or GTK_SIZE_GROUP_BOTH.
Note that only non-contextual sizes of every widget are ever consulted
by size groups (since size groups have no knowledge of what size a widget
will be allocated in one dimension, it cannot derive how much height
a widget will receive for a given width). When grouping widgets that
trade height for width in mode GTK_SIZE_GROUP_VERTICAL or GTK_SIZE_GROUP_BOTH:
the height for the minimum width will be the requested height for all
widgets in the group. The same is of course true when horizontally grouping
width for height widgets.
Widgets that trade height-for-width should set a reasonably large minimum width by way of “width-chars” for instance. Widgets with static sizes as well as widgets that grow (such as ellipsizing text) need no such considerations.
Size groups can be specified in a UI definition by placing an <object>
element with class="GtkSizeGroup" somewhere in the UI definition. The
widgets that belong to the size group are specified by a <widgets> element
that may contain multiple <widget> elements, one for each member of the
size group. The ”name” attribute gives the id of the widget.
An example of a UI definition fragment with GtkSizeGroup:
1 2 3 4 5 6 7 |
<object class="GtkSizeGroup"> <property name="mode">GTK_SIZE_GROUP_HORIZONTAL</property> <widgets> <widget name="radio1"/> <widget name="radio2"/> </widgets> </object> |
GtkSizeGroup *
gtk_size_group_new (GtkSizeGroupMode mode);
Create a new GtkSizeGroup.
void gtk_size_group_set_mode (GtkSizeGroup *size_group,GtkSizeGroupMode mode);
Sets the GtkSizeGroupMode of the size group. The mode of the size
group determines whether the widgets in the size group should
all have the same horizontal requisition (GTK_SIZE_GROUP_HORIZONTAL)
all have the same vertical requisition (GTK_SIZE_GROUP_VERTICAL),
or should all have the same requisition in both directions
(GTK_SIZE_GROUP_BOTH).
GtkSizeGroupMode
gtk_size_group_get_mode (GtkSizeGroup *size_group);
Gets the current mode of the size group. See gtk_size_group_set_mode().
void gtk_size_group_set_ignore_hidden (GtkSizeGroup *size_group,gboolean ignore_hidden);
gtk_size_group_set_ignore_hidden has been deprecated since version 3.22 and should not be used in newly-written code.
Measuring the size of hidden widgets has not worked
reliably for a long time. In most cases, they will report a size
of 0 nowadays, and thus, their size will not affect the other
size group members. In effect, size groups will always operate
as if this property was TRUE. Use a GtkStack instead to hide
widgets while still having their size taken into account.
Sets whether unmapped widgets should be ignored when calculating the size.
size_group |
||
ignore_hidden |
whether unmapped widgets should be ignored when calculating the size |
Since: 2.8
gboolean
gtk_size_group_get_ignore_hidden (GtkSizeGroup *size_group);
gtk_size_group_get_ignore_hidden has been deprecated since version 3.22 and should not be used in newly-written code.
Measuring the size of hidden widgets has not worked
reliably for a long time. In most cases, they will report a size
of 0 nowadays, and thus, their size will not affect the other
size group members. In effect, size groups will always operate
as if this property was TRUE. Use a GtkStack instead to hide
widgets while still having their size taken into account.
Returns if invisible widgets are ignored when calculating the size.
Since: 2.8
void gtk_size_group_add_widget (GtkSizeGroup *size_group,GtkWidget *widget);
Adds a widget to a GtkSizeGroup. In the future, the requisition
of the widget will be determined as the maximum of its requisition
and the requisition of the other widgets in the size group.
Whether this applies horizontally, vertically, or in both directions
depends on the mode of the size group. See gtk_size_group_set_mode().
When the widget is destroyed or no longer referenced elsewhere, it will be removed from the size group.
void gtk_size_group_remove_widget (GtkSizeGroup *size_group,GtkWidget *widget);
Removes a widget from a GtkSizeGroup.
GSList *
gtk_size_group_get_widgets (GtkSizeGroup *size_group);
Returns the list of widgets associated with size_group
.
a GSList of widgets. The list is owned by GTK+ and should not be modified.
[element-type GtkWidget][transfer none]
Since: 2.10
“ignore-hidden” property“ignore-hidden” gboolean
If TRUE, unmapped widgets are ignored when determining
the size of the group.
GtkSizeGroup:ignore-hidden has been deprecated since version 3.22 and should not be used in newly-written code.
Measuring the size of hidden widgets has not worked
reliably for a long time. In most cases, they will report a size
of 0 nowadays, and thus, their size will not affect the other
size group members. In effect, size groups will always operate
as if this property was TRUE. Use a GtkStack instead to hide
widgets while still having their size taken into account.
Owner: GtkSizeGroup
Flags: Read / Write
Default value: FALSE
Since: 2.8
“mode” property“mode” GtkSizeGroupMode
The directions in which the size group affects the requested sizes of its component widgets.
Owner: GtkSizeGroup
Flags: Read / Write
Default value: GTK_SIZE_GROUP_HORIZONTAL