Adding a custom offset on the bar

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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 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 was introduced in GTK+ 3.6.

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

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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.

gtk_level_bar_new ()

GtkWidget *
gtk_level_bar_new (void);

Creates a new GtkLevelBar.

Since: 3.6

gtk_level_bar_new_for_interval ()

GtkWidget *
gtk_level_bar_new_for_interval (gdouble min_value,
                                gdouble max_value);

Utility constructor that creates a new GtkLevelBar for the specified interval.

Since: 3.6

gtk_level_bar_set_mode ()

void
gtk_level_bar_set_mode (GtkLevelBar *self,
                        GtkLevelBarMode mode);

Sets the value of the “mode” property.

Since: 3.6

gtk_level_bar_get_mode ()

GtkLevelBarMode
gtk_level_bar_get_mode (GtkLevelBar *self);

Returns the value of the “mode” property.

Since: 3.6

gtk_level_bar_set_value ()

void
gtk_level_bar_set_value (GtkLevelBar *self,
                         gdouble value);

Sets the value of the “value” property.

Since: 3.6

gtk_level_bar_get_value ()

gdouble
gtk_level_bar_get_value (GtkLevelBar *self);

Returns the value of the “value” property.

Since: 3.6

gtk_level_bar_set_min_value ()

void
gtk_level_bar_set_min_value (GtkLevelBar *self,
                             gdouble value);

Sets the value of the “min-value” property.

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

Since: 3.6

gtk_level_bar_get_min_value ()

gdouble
gtk_level_bar_get_min_value (GtkLevelBar *self);

Returns the value of the “min-value” property.

Since: 3.6

gtk_level_bar_set_max_value ()

void
gtk_level_bar_set_max_value (GtkLevelBar *self,
                             gdouble value);

Sets the value of the “max-value” property.

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

Since: 3.6

gtk_level_bar_get_max_value ()

gdouble
gtk_level_bar_get_max_value (GtkLevelBar *self);

Returns the value of the “max-value” property.

Since: 3.6

gtk_level_bar_set_inverted ()

void
gtk_level_bar_set_inverted (GtkLevelBar *self,
                            gboolean inverted);

Sets the value of the “inverted” property.

Since: 3.8

gtk_level_bar_get_inverted ()

gboolean
gtk_level_bar_get_inverted (GtkLevelBar *self);

Return the value of the “inverted” property.

Since: 3.8

gtk_level_bar_add_offset_value ()

void
gtk_level_bar_add_offset_value (GtkLevelBar *self,
                                const gchar *name,
                                gdouble 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 “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 .

Since: 3.6

gtk_level_bar_remove_offset_value ()

void
gtk_level_bar_remove_offset_value (GtkLevelBar *self,
                                   const gchar *name);

Removes an offset marker previously added with gtk_level_bar_add_offset_value().

Since: 3.6

gtk_level_bar_get_offset_value ()

gboolean
gtk_level_bar_get_offset_value (GtkLevelBar *self,
                                const gchar *name,
                                gdouble *value);

Fetches the value specified for the offset marker name in self , returning TRUE in case an offset named name was found.

Since: 3.6

GTK_LEVEL_BAR_OFFSET_LOW

#define GTK_LEVEL_BAR_OFFSET_LOW  "low"

The name used for the stock low offset included by GtkLevelBar.

Since: 3.6

GTK_LEVEL_BAR_OFFSET_HIGH

#define GTK_LEVEL_BAR_OFFSET_HIGH "high"

The name used for the stock high offset included by GtkLevelBar.

Since: 3.6

GTK_LEVEL_BAR_OFFSET_FULL

#define GTK_LEVEL_BAR_OFFSET_FULL "full"

The name used for the stock full offset included by GtkLevelBar.

Since: 3.20

enum GtkLevelBarMode

Describes how GtkLevelBar contents should be rendered. Note that this enumeration could be extended with additional modes in the future.

Since: 3.6

struct GtkLevelBar

struct GtkLevelBar;

The “inverted” property

  “inverted”                 gboolean

Level bars normally grow from top to bottom or left to right. Inverted level bars grow in the opposite direction.

Flags: Read / Write

Default value: FALSE

Since: 3.8

The “max-value” property

  “max-value”                gdouble

The “max-value” property determaxes the maximum value of the interval that can be displayed by the bar.

Flags: Read / Write

Allowed values: >= 0

Default value: 1

Since: 3.6

The “min-value” property

  “min-value”                gdouble

The “min-value” property determines the minimum value of the interval that can be displayed by the bar.

Flags: Read / Write

Allowed values: >= 0

Default value: 0

Since: 3.6

The “mode” property

  “mode”                     GtkLevelBarMode

The “mode” property determines the way GtkLevelBar interprets the value properties to draw the level fill area. Specifically, when the value is GTK_LEVEL_BAR_MODE_CONTINUOUS, GtkLevelBar will draw a single block representing the current value in that area; when the value is GTK_LEVEL_BAR_MODE_DISCRETE, the widget will draw a succession of separate blocks filling the draw area, with the number of blocks being equal to the units separating the integral roundings of “min-value” and “max-value”.

Flags: Read / Write

Default value: GTK_LEVEL_BAR_MODE_CONTINUOUS

Since: 3.6

The “value” property

  “value”                    gdouble

The “value” property determines the currently filled value of the level bar.

Flags: Read / Write

Allowed values: >= 0

Default value: 0

Since: 3.6

The “min-block-height” style property

  “min-block-height”         gint

The min-block-height style property determines the minimum height for blocks filling the GtkLevelBar widget.

Flags: Read / Write

Allowed values: >= 1

Default value: 3

Since: 3.6

The “min-block-width” style property

  “min-block-width”          gint

The min-block-width style property determines the minimum width for blocks filling the GtkLevelBar widget.

Flags: Read / Write

Allowed values: >= 1

Default value: 3

Since: 3.6

The “offset-changed” signal

void
user_function (GtkLevelBar *self,
               gchar       *name,
               gpointer     user_data)

Emitted when an offset specified on the bar changes value as an effect to gtk_level_bar_add_offset_value() being called.

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.

Flags: Has Details

Since: 3.6