GtkSorter

GtkSorter — Sorting items

Signals

void changed Run Last

Types and Values

Object Hierarchy

    GObject
    ╰── GtkSorter
        ├── GtkCustomSorter
        ├── GtkMultiSorter
        ├── GtkNumericSorter
        ├── GtkStringSorter
        ╰── GtkTreeListRowSorter

Includes

#include <gtk/gtk.h>

Description

GtkSorter is the way to describe sorting criteria. Its primary user is GtkSortListModel.

The model will use a sorter to determine the order in which its items should appear by calling gtk_sorter_compare() for pairs of items.

Sorters may change their sorting behavior through their lifetime. In that case, they call gtk_sorter_changed(), which will emit the “changed” signal to notify that the sort order is no longer valid and should be updated by calling gtk_sorter_compare() again.

GTK provides various pre-made sorter implementations for common sorting operations. GtkColumnView has built-in support for sorting lists via the “sorter” property, where the user can change the sorting by clicking on list headers.

Of course, in particular for large lists, it is also possible to subclass GtkSorter and provide one's own sorter.

Functions

gtk_sorter_compare ()

GtkOrdering
gtk_sorter_compare (GtkSorter *self,
                    gpointer item1,
                    gpointer item2);

Compares two given items according to the sort order implemented by the sorter.

Sorters implement a partial order:

  • It is reflexive, ie a = a

  • It is antisymmetric, ie if a < b and b < a, then a = b

  • It is transitive, ie given any 3 items with a ≤ b and b ≤ c, then a ≤ c

The sorter may signal it conforms to additional constraints via the return value of gtk_sorter_get_order().

Parameters

self

a GtkSorter

 

item1

first item to compare.

[type GObject][transfer none]

item2

second item to compare.

[type GObject][transfer none]

Returns

GTK_ORDERING_EQUAL if item1 == item2 , GTK_ORDERING_SMALLER if item1 < item2 , GTK_ORDERING_LARGER if item1 > item2


gtk_sorter_get_order ()

GtkSorterOrder
gtk_sorter_get_order (GtkSorter *self);

Gets the order that self conforms to. See GtkSorterOrder for details of the possible return values.

This function is intended to allow optimizations.

Parameters

self

a GtkSorter

 

Returns

The order


gtk_sorter_changed ()

void
gtk_sorter_changed (GtkSorter *self,
                    GtkSorterChange change);

Emits the “changed” signal to notify all users of the sorter that it has changed. Users of the sorter should then update the sort order via gtk_sorter_compare().

Depending on the change parameter, it may be possible to update the sort order without a full resorting. Refer to the GtkSorterChange documentation for details.

This function is intended for implementors of GtkSorter subclasses and should not be called from other functions.

Parameters

self

a GtkSorter

 

change

How the sorter changed

 

Types and Values

GtkSorter

typedef struct _GtkSorter GtkSorter;

enum GtkSorterOrder

Describes the type of order that a GtkSorter may describe.

Members

GTK_SORTER_ORDER_PARTIAL

A partial order. And GtkOrdering is possible.

 

GTK_SORTER_ORDER_NONE

No order, all elements are considered equal. gtk_sorter_compare() will only return GTK_ORDERING_EQUAL or GTK_ORDERING_INVALID.

 

GTK_SORTER_ORDER_TOTAL

A total order. gtk_sorter_compare() will only return GTK_ORDERING_EQUAL if an item is compared with itself. Two different items will never cause this value to be returned.

 

enum GtkSorterChange

Describes changes in a sorter in more detail and allows users to optimize resorting.

Members

GTK_SORTER_CHANGE_DIFFERENT

The sorter change cannot be described by any of the other enumeration values

 

GTK_SORTER_CHANGE_INVERTED

The sort order was inverted. Comparisons that returned GTK_ORDERING_SMALLER now return GTK_ORDERING_LARGER and vice versa. Other comparisons return the same values as before.

 

GTK_SORTER_CHANGE_LESS_STRICT

The sorter is less strict: Comparisons may now return GTK_ORDERING_EQUAL that did not do so before.

 

GTK_SORTER_CHANGE_MORE_STRICT

The sorter is more strict: Comparisons that did return GTK_ORDERING_EQUAL may not do so anymore.

 

Signal Details

The “changed” signal

void
user_function (GtkSorter      *self,
               GtkSorterChange change,
               gpointer        user_data)

This signal is emitted whenever the sorter changed. Users of the sorter should then update the sort order again via gtk_sorter_compare().

GtkSortListModel handles this signal automatically.

Depending on the change parameter, it may be possible to update the sort order without a full resorting. Refer to the GtkSorterChange documentation for details.

Parameters

self

The GtkSorter

 

change

how the sorter changed

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last

See Also

GtkSortListModel