Class LevelBar

All Implemented Interfaces:
PointerInterface

public class LevelBar extends Widget
`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.

![An example GtkLevelBar](levelbar.png)

Use [method@Gtk.LevelBar.set_value] to set the current value, and
[method@Gtk.LevelBar.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

```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 [method@Gtk.LevelBar.set_min_value] and
[method@Gtk.LevelBar.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.

https://docs.gtk.org/gtk4/class.LevelBar.html

  • Field Details

  • Constructor Details

    • LevelBar

      public LevelBar(PointerContainer pointer)
    • LevelBar

      public LevelBar()
      Creates a new `GtkLevelBar`.
  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()
    • newForIntervalLevelBar

      public static LevelBar newForIntervalLevelBar(double min_value, double max_value)
      Creates a new `GtkLevelBar` for the specified interval.
      Parameters:
      min_value - a positive value
      max_value - a positive value
      Returns:
      a `GtkLevelBar`
    • addOffsetValue

      public void addOffsetValue(@Nonnull Str name, double value)
      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@Gtk.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.
      Parameters:
      name - the name of the new offset
      value - the value for the new offset
    • addOffsetValue

      public void addOffsetValue(String name, double value)
      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@Gtk.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.
      Parameters:
      name - the name of the new offset
      value - the value for the new offset
    • getInverted

      public boolean getInverted()
      Returns whether the levelbar is inverted.
      Returns:
      %TRUE if the level bar is inverted
    • getMaxValue

      public double getMaxValue()
      Returns the `max-value` of the `GtkLevelBar`.
      Returns:
      a positive value
    • getMinValue

      public double getMinValue()
      Returns the `min-value of the `GtkLevelBar`.
      Returns:
      a positive value
    • getMode

      public int getMode()
      Returns the `mode` of the `GtkLevelBar`.
      Returns:
      a `GtkLevelBarMode`
    • getValue

      public double getValue()
      Returns the `value` of the `GtkLevelBar`.
      Returns:
      a value in the interval between [property@Gtk.LevelBar:min-value[ and [property@Gtk.LevelBar:max-value]
    • removeOffsetValue

      public void removeOffsetValue(@Nullable Str name)
      Removes an offset marker from a `GtkLevelBar`.

      The marker must have been previously added with
      [method@Gtk.LevelBar.add_offset_value].
      Parameters:
      name - the name of an offset in the bar
    • removeOffsetValue

      public void removeOffsetValue(String name)
      Removes an offset marker from a `GtkLevelBar`.

      The marker must have been previously added with
      [method@Gtk.LevelBar.add_offset_value].
      Parameters:
      name - the name of an offset in the bar
    • setInverted

      public void setInverted(boolean inverted)
      Sets whether the `GtkLevelBar` is inverted.
      Parameters:
      inverted - %TRUE to invert the level bar
    • setMaxValue

      public void setMaxValue(double value)
      Sets the `max-value` of the `GtkLevelBar`.

      You probably want to update preexisting level offsets after calling
      this function.
      Parameters:
      value - a positive value
    • setMinValue

      public void setMinValue(double value)
      Sets the `min-value` of the `GtkLevelBar`.

      You probably want to update preexisting level offsets after calling
      this function.
      Parameters:
      value - a positive value
    • setMode

      public void setMode(int mode)
      Sets the `mode` of the `GtkLevelBar`.
      Parameters:
      mode - a `GtkLevelBarMode`
    • setValue

      public void setValue(double value)
      Sets the value of the `GtkLevelBar`.
      Parameters:
      value - a value in the interval between [property@Gtk.LevelBar:min-value] and [property@Gtk.LevelBar:max-value]
    • onOffsetChanged

      public SignalHandler onOffsetChanged(LevelBar.OnOffsetChanged signal)
      Connect to signal "offset-changed".
      See LevelBar.OnOffsetChanged.onOffsetChanged(ch.bailu.gtk.type.Str) for signal description.
      Field SIGNAL_ON_OFFSET_CHANGED contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.
    • asAccessible

      public Accessible asAccessible()
      Implements interface Accessible. Call this to get access to interface functions.
      Overrides:
      asAccessible in class Widget
      Returns:
      Accessible
    • asBuildable

      public Buildable asBuildable()
      Implements interface Buildable. Call this to get access to interface functions.
      Overrides:
      asBuildable in class Widget
      Returns:
      Buildable
    • asConstraintTarget

      public ConstraintTarget asConstraintTarget()
      Implements interface ConstraintTarget. Call this to get access to interface functions.
      Overrides:
      asConstraintTarget in class Widget
      Returns:
      ConstraintTarget
    • asOrientable

      public Orientable asOrientable()
      Implements interface Orientable. Call this to get access to interface functions.
      Returns:
      Orientable
    • getTypeID

      public static long getTypeID()
    • getParentTypeID

      public static long getParentTypeID()
    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()
    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()
    • getInstanceSize

      public static int getInstanceSize()