Class Scale

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gobject.InitiallyUnowned
org.gnome.gtk.Widget
org.gnome.gtk.Range
org.gnome.gtk.Scale
All Implemented Interfaces:
Accessible, AccessibleRange, Buildable, ConstraintTarget, Orientable, Proxy
@Generated("org.javagi.JavaGI") public class Scale extends Range implements Accessible, AccessibleRange, Buildable, ConstraintTarget, Orientable

Allows to select a numeric value with a slider control.

An example GtkScale

To use it, you’ll probably want to investigate the methods on its base class, Range, in addition to the methods for GtkScale itself. To set the value of a scale, you would normally use Range.setValue(double). To detect changes to the value, you would normally use the Gtk.Range::value-changed signal.

Note that using the same upper and lower bounds for the GtkScale (through the GtkRange methods) will hide the slider itself. This is useful for applications that want to show an undeterminate value on the scale, without changing the layout of the application (such as movie or music players).

GtkScale as GtkBuildable

GtkScale supports a custom <marks> element, which can contain multiple <mark\\> elements. The “value” and “position” attributes have the same meaning as addMark(double, PositionType, String) parameters of the same name. If the element is not empty, its content is taken as the markup to show at the mark. It can be translated with the usual ”translatable” and “context” attributes.

Shortcuts and Gestures

GtkPopoverMenu supports the following keyboard shortcuts:

  • Arrow keys, + and - will increment or decrement by step, or by page when combined with Ctrl.
  • PgUp and PgDn will increment or decrement by page.
  • Home and End will set the minimum or maximum value.

CSS nodes

scale[.fine-tune][.marks-before][.marks-after]
├── [value][.top][.right][.bottom][.left]
├── marks.top
│   ├── mark
│   ┊    ├── [label]
│   ┊    ╰── indicator
┊   ┊
│   ╰── mark
├── marks.bottom
│   ├── mark
│   ┊    ├── indicator
│   ┊    ╰── [label]
┊   ┊
│   ╰── mark
╰── trough
    ├── [fill]
    ├── [highlight]
    ╰── slider

GtkScale has a main CSS node with name scale and a subnode for its contents, with subnodes named trough and slider.

The main node gets the style class .fine-tune added when the scale is in 'fine-tuning' mode.

If the scale has an origin (see setHasOrigin(boolean)), there is a subnode with name highlight below the trough node that is used for rendering the highlighted part of the trough.

If the scale is showing a fill level (see Range.setShowFillLevel(boolean)), there is a subnode with name fill below the trough node that is used for rendering the filled in part of the trough.

If marks are present, there is a marks subnode before or after the trough node, below which each mark gets a node with name mark. The marks nodes get either the .top or .bottom style class.

The mark node has a subnode named indicator. If the mark has text, it also has a subnode named label. When the mark is either above or left of the scale, the label subnode is the first when present. Otherwise, the indicator subnode is the first.

The main CSS node gets the 'marks-before' and/or 'marks-after' style classes added depending on what marks are present.

If the scale is displaying the value (see Gtk.Scale:draw-value), there is subnode with name value. This node will get the .top or .bottom style classes similar to the marks node.

Accessibility

GtkScale uses the Gtk.AccessibleRole.slider role.

  • Constructor Details

    • Scale

      public Scale(MemorySegment address)
      Create a Scale instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • Scale

      public Scale(Orientation orientation, @Nullable Adjustment adjustment)
      Creates a new GtkScale.
      Parameters:
      orientation - the scale’s orientation.
      adjustment - the Adjustment which sets the range of the scale, or null to create a new adjustment.

    • Scale

      public Scale()
      Create a new Scale.

  • Method Details

    • getType

      public static @Nullable Type getType()
      Get the GType of the Scale class.
      Returns:
      the GType

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • asParent

      protected Scale asParent()
      Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.
      Overrides:
      asParent in class Range
      Returns:
      the instance as if it were its parent type

    • withRange

      public static Scale withRange(Orientation orientation, double min, double max, double step)

      Creates a new scale widget with a range from min to max.

      The returns scale will have the given orientation and will let the user input a number between min and max (including min and max) with the increment step. step must be nonzero; it’s the distance the slider moves when using the arrow keys to adjust the scale value.

      Note that the way in which the precision is derived works best if step is a power of ten. If the resulting precision is not suitable for your needs, use setDigits(int) to correct it.

      Parameters:
      orientation - the scale’s orientation.
      min - minimum value
      max - maximum value
      step - step increment (tick size) used with keyboard shortcuts
      Returns:
      a new GtkScale

    • addMark

      public void addMark(double value, PositionType position, @Nullable String markup)

      Adds a mark at value.

      A mark is indicated visually by drawing a tick mark next to the scale, and GTK makes it easy for the user to position the scale exactly at the marks value.

      If markup is not null, text is shown next to the tick mark.

      To remove marks from a scale, use clearMarks().

      Parameters:
      value - the value at which the mark is placed, must be between the lower and upper limits of the scales’ adjustment
      position - where to draw the mark. For a horizontal scale, PositionType.TOP and PositionType.LEFT are drawn above the scale, anything else below. For a vertical scale, PositionType.LEFT and PositionType.TOP are drawn to the left of the scale, anything else to the right.
      markup - Text to be shown at the mark, using Pango markup

    • clearMarks

      public void clearMarks()
      Removes any marks that have been added.

    • getDigits

      public int getDigits()
      Gets the number of decimal places that are displayed in the value.
      Returns:
      the number of decimal places that are displayed

    • getDrawValue

      public boolean getDrawValue()
      Returns whether the current value is displayed as a string next to the slider.
      Returns:
      whether the current value is displayed as a string

    • getHasOrigin

      public boolean getHasOrigin()
      Returns whether the scale has an origin.
      Returns:
      true if the scale has an origin.

    • getLayout

      public @Nullable Layout getLayout()

      Gets the PangoLayout used to display the scale.

      The returned object is owned by the scale so does not need to be freed by the caller.

      Returns:
      the Layout for this scale, or null if the Gtk.Scale:draw-value property is false.

    • getLayoutOffsets

      public void getLayoutOffsets(@Nullable Out<Integer> x, @Nullable Out<Integer> y)

      Obtains the coordinates where the scale will draw the PangoLayout representing the text in the scale.

      Remember when using the PangoLayout function you need to convert to and from pixels using PANGO_PIXELS() or PANGO_SCALE.

      If the Gtk.Scale:draw-value property is false, the return values are undefined.

      Parameters:
      x - location to store X offset of layout
      y - location to store Y offset of layout

    • getValuePos

      public PositionType getValuePos()
      Gets the position in which the current value is displayed.
      Returns:
      the position in which the current value is displayed

    • setDigits

      public void setDigits(int digits)

      Sets the number of decimal places that are displayed in the value.

      Also causes the value of the adjustment to be rounded to this number of digits, so the retrieved value matches the displayed one, if Gtk.Scale:draw-value is true when the value changes. If you want to enforce rounding the value when Gtk.Scale:draw-value is false, you can set Gtk.Range:round-digits instead.

      Note that rounding to a small number of digits can interfere with the smooth autoscrolling that is built into GtkScale. As an alternative, you can use setFormatValueFunc(ScaleFormatValueFunc) to format the displayed value yourself.

      Parameters:
      digits - the number of decimal places to display, e.g. use 1 to display 1.0, 2 to display 1.00, etc

    • setDrawValue

      public void setDrawValue(boolean drawValue)
      Specifies whether the current value is displayed as a string next to the slider.
      Parameters:
      drawValue - true to draw the value

    • setFormatValueFunc

      public void setFormatValueFunc(@Nullable ScaleFormatValueFunc func)

      func allows you to change how the scale value is displayed.

      The given function will return an allocated string representing value. That string will then be used to display the scale's value.

      If NULL is passed as func, the value will be displayed on its own, rounded according to the value of the Gtk.Scale:digits property.

      Parameters:
      func - function that formats the value

    • setHasOrigin

      public void setHasOrigin(boolean hasOrigin)

      Sets whether the scale has an origin.

      If Gtk.Scale:has-origin is set to true (the default), the scale will highlight the part of the trough between the origin (bottom or left side) and the current value.

      Parameters:
      hasOrigin - true if the scale has an origin

    • setValuePos

      public void setValuePos(PositionType pos)
      Sets the position in which the current value is displayed.
      Parameters:
      pos - the position in which the current value is displayed

    • builder

      public static Scale.Builder<? extends Scale.Builder> builder()
      A Scale.Builder object constructs a Scale with the specified properties. Use the various set...() methods to set properties, and finish construction with Scale.Builder.build().
      Returns:
      the builder object