Struct gtk4::LevelBar[][src]

pub struct LevelBar(_);
Expand description

LevelBar 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.

An example GtkLevelBar

Use set_value() to set the current value, and 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: LEVEL_BAR_OFFSET_LOW, LEVEL_BAR_OFFSET_HIGH and 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

⚠️ The following code is in c ⚠️

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-style: 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 set_min_value() and 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 LevelBarMode::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 LevelBar implementation of the Buildable 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
    ┊

LevelBar 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

LevelBar uses the AccessibleRole::Meter role.

Implements

WidgetExt, glib::ObjectExt, AccessibleExt, BuildableExt, ConstraintTargetExt, OrientableExt, WidgetExtManual, AccessibleExtManual

Implementations

Creates a new LevelBar.

Returns

a LevelBar.

Creates a new LevelBar for the specified interval.

min_value

a positive value

max_value

a positive value

Returns

a LevelBar

Creates a new builder-pattern struct instance to construct LevelBar objects.

This method returns an instance of LevelBarBuilder which can be used to create LevelBar objects.

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

When the bar value is in the interval topped by value (or between value and property::LevelBar::max-value in case the offset is the last one on the bar) a style class named level-``name will be applied when rendering the level bar fill.

If another offset marker named name exists, its value will be replaced by value.

name

the name of the new offset

value

the value for the new offset

Returns whether the levelbar is inverted.

Returns

true if the level bar is inverted

Returns the max-value of the LevelBar.

Returns

a positive value

Returns the min-value of the [LevelBar`]crate::LevelBar.

Returns

a positive value

Returns the mode of the LevelBar.

Returns

a LevelBarMode

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

name

the name of an offset in the bar

Returns

true if the specified offset is found

value

location where to store the value

Returns the value of the LevelBar.

Returns

a value in the interval between LevelBar:min-value and LevelBar:max-value

Removes an offset marker from a LevelBar.

The marker must have been previously added with add_offset_value().

name

the name of an offset in the bar

Sets whether the LevelBar is inverted.

inverted

true to invert the level bar

Sets the max-value of the LevelBar.

You probably want to update preexisting level offsets after calling this function.

value

a positive value

Sets the min-value of the LevelBar.

You probably want to update preexisting level offsets after calling this function.

value

a positive value

Sets the mode of the LevelBar.

mode

a LevelBarMode

Sets the value of the LevelBar.

value

a value in the interval between property::LevelBar::min-value and property::LevelBar::max-value

Emitted when an offset specified on the bar changes value.

This typically is the result of a add_offset_value() call.

The signal supports detailed connections; you can connect to the detailed signal “changed::x” in order to only receive callbacks when the value of offset “x” changes.

name

the name of the offset that changed value

Trait Implementations

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Compares and returns the maximum of two values. Read more

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Restrict a value to a certain interval. Read more

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Returns the type identifier of Self.

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