### Class

# Gtk LevelBar

since: 4.0

#### Description [src]

    final class Gtk.LevelBar : Gtk.Widget
      implements Gtk.Accessible, Gtk.AccessibleRange, Gtk.Buildable, Gtk.ConstraintTarget, Gtk.Orientable {
      /* No available fields */
    }

`GtkLevelBar` is a widget that can be used as a level indicator.

Typical use cases are displaying the strength of a password, or showing the charge level of a battery.

Use `gtk_level_bar_set_value()` to set the current value, and `gtk_level_bar_add_offset_value()` to set the value offsets at which the bar will be considered in a different state. GTK will add a few offsets by default on the level bar: `GTK_LEVEL_BAR_OFFSET_LOW`, `GTK_LEVEL_BAR_OFFSET_HIGH` and `GTK_LEVEL_BAR_OFFSET_FULL`, with values 0.25, 0.75 and 1.0 respectively.

Note that it is your responsibility to update preexisting offsets when changing the minimum or maximum value. GTK will simply clamp them to the new range.

## Adding a custom offset on the bar

    static GtkWidget *
    create_level_bar (void)
    {
      GtkWidget *widget;
      GtkLevelBar *bar;

      widget = gtk_level_bar_new ();
      bar = GTK_LEVEL_BAR (widget);

      // This changes the value of the default low offset

      gtk_level_bar_add_offset_value (bar,
                                      GTK_LEVEL_BAR_OFFSET_LOW,
                                      0.10);

      // This adds a new offset to the bar; the application will
      // be able to change its color CSS like this:
      //
      // levelbar block.my-offset {
      //   background-color: magenta;
      //   border-style: solid;
      //   border-color: black;
      //   border-width: 1px;
      // }

      gtk_level_bar_add_offset_value (bar, "my-offset", 0.60);

      return widget;
    }

The default interval of values is between zero and one, but it’s possible to modify the interval using `gtk_level_bar_set_min_value()` and `gtk_level_bar_set_max_value()`. The value will be always drawn in proportion to the admissible interval, i.e. a value of 15 with a specified interval between 10 and 20 is equivalent to a value of 0.5 with an interval between 0 and 1. When `GTK_LEVEL_BAR_MODE_DISCRETE` is used, the bar level is rendered as a finite number of separated blocks instead of a single one. The number of blocks that will be rendered is equal to the number of units specified by the admissible interval.

For instance, to build a bar rendered with five blocks, it’s sufficient to set the minimum value to 0 and the maximum value to 5 after changing the indicator mode to discrete.

# GtkLevelBar as GtkBuildable

The `GtkLevelBar` implementation of the `GtkBuildable` interface supports a custom `<offsets>` element, which can contain any number of `<offset>` elements, each of which must have “name” and “value” attributes.

# CSS nodes

    levelbar[.discrete]
    ╰── trough
        ├── block.filled.level-name
        ┊
        ├── block.empty
        ┊

`GtkLevelBar` has a main CSS node with name levelbar and one of the style classes .discrete or .continuous and a subnode with name trough. Below the trough node are a number of nodes with name block and style class .filled or .empty. In continuous mode, there is exactly one node of each, in discrete mode, the number of filled and unfilled nodes corresponds to blocks that are drawn. The block.filled nodes also get a style class .level-name corresponding to the level for the current value.

In horizontal orientation, the nodes are always arranged from left to right, regardless of text direction.

# Accessibility

`GtkLevelBar` uses the `GTK_ACCESSIBLE_ROLE_METER` role.

Available since: 4.0

#### Ancestors

- GtkWidget
- GInitiallyUnowned
- GObject

#### Implements

- GtkAccessible
- GtkAccessibleRange
- GtkBuildable
- GtkConstraintTarget
- GtkOrientable

#### Constructors

###### gtk_level_bar_new

Creates a new `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_new_for_interval

Creates a new `GtkLevelBar` for the specified interval.

since: 4.0

#### Instance methods

###### gtk_level_bar_add_offset_value

Adds a new offset marker on `self` at the position specified by `value`.

since: 4.0

###### gtk_level_bar_get_inverted

Returns whether the levelbar is inverted.

since: 4.0

###### gtk_level_bar_get_max_value

Returns the `max-value` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_get_min_value

Returns the `min-value` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_get_mode

Returns the `mode` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_get_offset_value

Fetches the value specified for the offset marker `name` in `self`.

since: 4.0

###### gtk_level_bar_get_value

Returns the `value` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_remove_offset_value

Removes an offset marker from a `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_set_inverted

Sets whether the `GtkLevelBar` is inverted.

since: 4.0

###### gtk_level_bar_set_max_value

Sets the `max-value` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_set_min_value

Sets the `min-value` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_set_mode

Sets the `mode` of the `GtkLevelBar`.

since: 4.0

###### gtk_level_bar_set_value

Sets the value of the `GtkLevelBar`.

since: 4.0

##### Methods inherited from GtkWidget (162)

Please see GtkWidget for a full list of methods.

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

##### Methods inherited from GtkAccessible (19)

###### gtk_accessible_announce

Requests the user’s screen reader to announce the given message.

since: 4.14

###### gtk_accessible_get_accessible_parent

Retrieves the accessible parent for an accessible object.

since: 4.10

###### gtk_accessible_get_accessible_role

Retrieves the accessible role of an accessible object.

since: 4.0

###### gtk_accessible_get_at_context

Retrieves the accessible implementation for the given `GtkAccessible`.

since: 4.10

###### gtk_accessible_get_bounds

Queries the coordinates and dimensions of this accessible.

since: 4.10

###### gtk_accessible_get_first_accessible_child

Retrieves the first accessible child of an accessible object.

since: 4.10

###### gtk_accessible_get_next_accessible_sibling

Retrieves the next accessible sibling of an accessible object.

since: 4.10

###### gtk_accessible_get_platform_state

Query a platform state, such as focus.

since: 4.10

###### gtk_accessible_reset_property

Resets the accessible `property` to its default value.

since: 4.0

###### gtk_accessible_reset_relation

Resets the accessible `relation` to its default value.

since: 4.0

###### gtk_accessible_reset_state

Resets the accessible `state` to its default value.

since: 4.0

###### gtk_accessible_set_accessible_parent

Sets the parent and sibling of an accessible object.

since: 4.10

###### gtk_accessible_update_next_accessible_sibling

Updates the next accessible sibling of `self`.

since: 4.10

###### gtk_accessible_update_property

Updates a list of accessible properties.

since: 4.0

###### gtk_accessible_update_property_value

Updates an array of accessible properties.

since: 4.0

###### gtk_accessible_update_relation

Updates a list of accessible relations.

since: 4.0

###### gtk_accessible_update_relation_value

Updates an array of accessible relations.

since: 4.0

###### gtk_accessible_update_state

Updates a list of accessible states. See the `GtkAccessibleState` documentation for the value types of accessible states.

since: 4.0

###### gtk_accessible_update_state_value

Updates an array of accessible states.

since: 4.0

##### Methods inherited from GtkBuildable (1)

###### gtk_buildable_get_buildable_id

Gets the ID of the `buildable` object.

since: 4.0

##### Methods inherited from GtkOrientable (2)

###### gtk_orientable_get_orientation

Retrieves the orientation of the `orientable`.

since: 4.0

###### gtk_orientable_set_orientation

Sets the orientation of the `orientable`.

since: 4.0

#### Properties

###### Gtk.LevelBar:inverted

Whether the `GtkLeveBar` is inverted.

since: 4.0

###### Gtk.LevelBar:max-value

Determines the maximum value of the interval that can be displayed by the bar.

since: 4.0

###### Gtk.LevelBar:min-value

Determines the minimum value of the interval that can be displayed by the bar.

since: 4.0

###### Gtk.LevelBar:mode

Determines the way `GtkLevelBar` interprets the value properties to draw the level fill area.

since: 4.0

###### Gtk.LevelBar:value

Determines the currently filled value of the level bar.

since: 4.0

##### Properties inherited from GtkWidget (34)

###### Gtk.Widget:can-focus

Whether the widget or any of its descendents can accept the input focus.

since: 4.0

###### Gtk.Widget:can-target

Whether the widget can receive pointer events.

since: 4.0

###### Gtk.Widget:css-classes

A list of css classes applied to this widget.

since: 4.0

###### Gtk.Widget:css-name

The name of this widget in the CSS tree.

since: 4.0

###### Gtk.Widget:cursor

The cursor used by `widget`.

since: 4.0

###### Gtk.Widget:focus-on-click

Whether the widget should grab focus when it is clicked with the mouse.

since: 4.0

###### Gtk.Widget:focusable

Whether this widget itself will accept the input focus.

since: 4.0

###### Gtk.Widget:halign

How to distribute horizontal space if widget gets extra space.

since: 4.0

###### Gtk.Widget:has-default

Whether the widget is the default widget.

since: 4.0

###### Gtk.Widget:has-focus

Whether the widget has the input focus.

since: 4.0

###### Gtk.Widget:has-tooltip

Enables or disables the emission of the ::query-tooltip signal on `widget`.

since: 4.0

###### Gtk.Widget:height-request

Override for height request of the widget.

since: 4.0

###### Gtk.Widget:hexpand

Whether to expand horizontally.

since: 4.0

###### Gtk.Widget:hexpand-set

Whether to use the `hexpand` property.

since: 4.0

###### Gtk.Widget:layout-manager

The `GtkLayoutManager` instance to use to compute the preferred size of the widget, and allocate its children.

since: 4.0

###### Gtk.Widget:margin-bottom

Margin on bottom side of widget.

since: 4.0

###### Gtk.Widget:margin-end

Margin on end of widget, horizontally.

since: 4.0

###### Gtk.Widget:margin-start

Margin on start of widget, horizontally.

since: 4.0

###### Gtk.Widget:margin-top

Margin on top side of widget.

since: 4.0

###### Gtk.Widget:name

The name of the widget.

since: 4.0

###### Gtk.Widget:opacity

The requested opacity of the widget.

since: 4.0

###### Gtk.Widget:overflow

How content outside the widget’s content area is treated.

since: 4.0

###### Gtk.Widget:parent

The parent widget of this widget.

since: 4.0

###### Gtk.Widget:receives-default

Whether the widget will receive the default action when it is focused.

since: 4.0

###### Gtk.Widget:root

The `GtkRoot` widget of the widget tree containing this widget.

since: 4.0

###### Gtk.Widget:scale-factor

The scale factor of the widget.

since: 4.0

###### Gtk.Widget:sensitive

Whether the widget responds to input.

since: 4.0

###### Gtk.Widget:tooltip-markup

Sets the text of tooltip to be the given string, which is marked up with Pango markup.

since: 4.0

###### Gtk.Widget:tooltip-text

Sets the text of tooltip to be the given string.

since: 4.0

###### Gtk.Widget:valign

How to distribute vertical space if widget gets extra space.

since: 4.0

###### Gtk.Widget:vexpand

Whether to expand vertically.

since: 4.0

###### Gtk.Widget:vexpand-set

Whether to use the `vexpand` property.

since: 4.0

###### Gtk.Widget:visible

Whether the widget is visible.

since: 4.0

###### Gtk.Widget:width-request

Override for width request of the widget.

since: 4.0

##### Properties inherited from GtkAccessible (1)

###### GtkAccessible:accessible-role

The accessible role of the given `GtkAccessible` implementation.

since: 4.0

##### Properties inherited from GtkOrientable (1)

###### GtkOrientable:orientation

The orientation of the orientable.

since: 4.0

#### Signals

###### Gtk.LevelBar::offset-changed

Emitted when an offset specified on the bar changes value.

since: 4.0

##### Signals inherited from GtkWidget (13)

###### GtkWidget::destroy

Signals that all holders of a reference to the widget should release the reference that they hold.

since: 4.0

###### GtkWidget::direction-changed

Emitted when the text direction of a widget changes.

since: 4.0

###### GtkWidget::hide

Emitted when `widget` is hidden.

since: 4.0

###### GtkWidget::keynav-failed

Emitted if keyboard navigation fails.

since: 4.0

###### GtkWidget::map

Emitted when `widget` is going to be mapped.

since: 4.0

###### GtkWidget::mnemonic-activate

Emitted when a widget is activated via a mnemonic.

since: 4.0

###### GtkWidget::move-focus

Emitted when the focus is moved.

since: 4.0

###### GtkWidget::query-tooltip

Emitted when the widget’s tooltip is about to be shown.

since: 4.0

###### GtkWidget::realize

Emitted when `widget` is associated with a `GdkSurface`.

since: 4.0

###### GtkWidget::show

Emitted when `widget` is shown.

since: 4.0

###### GtkWidget::state-flags-changed

Emitted when the widget state changes.

since: 4.0

###### GtkWidget::unmap

Emitted when `widget` is going to be unmapped.

since: 4.0

###### GtkWidget::unrealize

Emitted when the `GdkSurface` associated with `widget` is destroyed.

since: 4.0

##### Signals inherited from GObject (1)

###### GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.

since: 2.0