GI.Gtk.Objects.Scale

A GtkScale is a slider control used to select a numeric value. 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 rangeSetValue. To detect changes to the value, you would normally use the Range::value-changed signal.

Note that using the same upper and lower bounds for the Scale (through the Range 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 scaleAddMark 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.

CSS nodes

plain code

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

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 scaleSetHasOrigin), 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 rangeSetShowFillLevel), 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 contents 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 Scale:draw-value), there is subnode with name value.

Exported types

newtype Scale

Memory-managed wrapper type.

Constructors

Scale (ManagedPtr Scale)

Instances

GObject Scale

Defined in GI.Gtk.Objects.Scale

Methods

gobjectType :: IO GType

HasParentTypes Scale

Defined in GI.Gtk.Objects.Scale

type ParentTypes Scale

Defined in GI.Gtk.Objects.Scale

type ParentTypes Scale = Range ': (Widget ': (Object ': (ImplementorIface ': (Buildable ': (Orientable ': ([] :: [Type]))))))

class (GObject o, IsDescendantOf Scale o) => IsScale o

Type class for types which can be safely cast to Scale, for instance with toScale.

Instances

(GObject o, IsDescendantOf Scale o) => IsScale o

Defined in GI.Gtk.Objects.Scale

toScale :: (MonadIO m, IsScale o) => o -> m Scale

Cast to Scale, for types for which this is known to be safe. For general casts, use castTo.

noScale :: Maybe Scale

A convenience alias for Nothing :: Maybe Scale.

Methods

addMark

scaleAddMark

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> Double

value: the value at which the mark is placed, must be between the lower and upper limits of the scales’ adjustment

-> PositionType

position: where to draw the mark. For a horizontal scale, GTK_POS_TOP and PositionTypeLeft are drawn above the scale, anything else below. For a vertical scale, GTK_POS_LEFT and PositionTypeTop are drawn to the left of the scale, anything else to the right.

-> Maybe Text

markup: Text to be shown at the mark, using [Pango markup][PangoMarkupFormat], or Nothing

-> m ()

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 Nothing, text is shown next to the tick mark.

To remove marks from a scale, use scaleClearMarks.

Since: 2.16

clearMarks

scaleClearMarks

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> m ()

Removes any marks that have been added with scaleAddMark.

Since: 2.16

getDigits

scaleGetDigits

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> m Int32

Returns: the number of decimal places that are displayed

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

getDrawValue

scaleGetDrawValue

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> m Bool

Returns: whether the current value is displayed as a string

Returns whether the current value is displayed as a string next to the slider.

getHasOrigin

scaleGetHasOrigin

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> m Bool

Returns: True if the scale has an origin.

Returns whether the scale has an origin.

Since: 3.4

getLayout

scaleGetLayout

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: A Scale

-> m (Maybe Layout)

Returns: the Layout for this scale, or Nothing if the Scale:draw-value property is False.

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

Since: 2.4

getLayoutOffsets

scaleGetLayoutOffsets

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> m (Int32, Int32)

Obtains the coordinates where the scale will draw the Layout representing the text in the scale. Remember when using the Layout function you need to convert to and from pixels using PANGO_PIXELS() or SCALE.

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

Since: 2.4

getValuePos

scaleGetValuePos

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> m PositionType

Returns: the position in which the current value is displayed

Gets the position in which the current value is displayed.

new

scaleNew

Arguments

:: (HasCallStack, MonadIO m, IsAdjustment a)

=> Orientation

orientation: the scale’s orientation.

-> Maybe a

adjustment: the Adjustment which sets the range of the scale, or Nothing to create a new adjustment.

-> m Scale

Returns: a new Scale

Creates a new Scale.

Since: 3.0

newWithRange

scaleNewWithRange

Arguments

:: (HasCallStack, MonadIO m)

=> Orientation

orientation: the scale’s orientation.

-> Double

min: minimum value

-> Double

max: maximum value

-> Double

step: step increment (tick size) used with keyboard shortcuts

-> m Scale

Returns: a new Scale

Creates a new scale widget with the given orientation that lets 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 scaleSetDigits to correct it.

Since: 3.0

setDigits

scaleSetDigits

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> Int32

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

-> m ()

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 Scale:draw-value is True when the value changes. If you want to enforce rounding the value when Scale:draw-value is False, you can set Range:round-digits instead.

Note that rounding to a small number of digits can interfere with the smooth autoscrolling that is built into Scale. As an alternative, you can use the Scale::format-value signal to format the displayed value yourself.

setDrawValue

scaleSetDrawValue

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> Bool

drawValue: True to draw the value

-> m ()

Specifies whether the current value is displayed as a string next to the slider.

setHasOrigin

scaleSetHasOrigin

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> Bool

hasOrigin: True if the scale has an origin

-> m ()

If 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.

Since: 3.4

setValuePos

scaleSetValuePos

Arguments

:: (HasCallStack, MonadIO m, IsScale a)

=> a

scale: a Scale

-> PositionType

pos: the position in which the current value is displayed

-> m ()

Sets the position in which the current value is displayed.

Properties

digits

No description available in the introspection data.

constructScaleDigits :: IsScale o => Int32 -> IO (GValueConstruct o)

Construct a GValueConstruct with valid value for the “digits” property. This is rarely needed directly, but it is used by new.

getScaleDigits :: (MonadIO m, IsScale o) => o -> m Int32

Get the value of the “digits” property. When overloading is enabled, this is equivalent to

get scale #digits

setScaleDigits :: (MonadIO m, IsScale o) => o -> Int32 -> m ()

Set the value of the “digits” property. When overloading is enabled, this is equivalent to

set scale [ #digits := value ]

drawValue

No description available in the introspection data.

constructScaleDrawValue :: IsScale o => Bool -> IO (GValueConstruct o)

Construct a GValueConstruct with valid value for the “draw-value” property. This is rarely needed directly, but it is used by new.

getScaleDrawValue :: (MonadIO m, IsScale o) => o -> m Bool

Get the value of the “draw-value” property. When overloading is enabled, this is equivalent to

get scale #drawValue

setScaleDrawValue :: (MonadIO m, IsScale o) => o -> Bool -> m ()

Set the value of the “draw-value” property. When overloading is enabled, this is equivalent to

set scale [ #drawValue := value ]

hasOrigin

No description available in the introspection data.

constructScaleHasOrigin :: IsScale o => Bool -> IO (GValueConstruct o)

Construct a GValueConstruct with valid value for the “has-origin” property. This is rarely needed directly, but it is used by new.

getScaleHasOrigin :: (MonadIO m, IsScale o) => o -> m Bool

Get the value of the “has-origin” property. When overloading is enabled, this is equivalent to

get scale #hasOrigin

setScaleHasOrigin :: (MonadIO m, IsScale o) => o -> Bool -> m ()

Set the value of the “has-origin” property. When overloading is enabled, this is equivalent to

set scale [ #hasOrigin := value ]

valuePos

No description available in the introspection data.

constructScaleValuePos :: IsScale o => PositionType -> IO (GValueConstruct o)

Construct a GValueConstruct with valid value for the “value-pos” property. This is rarely needed directly, but it is used by new.

getScaleValuePos :: (MonadIO m, IsScale o) => o -> m PositionType

Get the value of the “value-pos” property. When overloading is enabled, this is equivalent to

get scale #valuePos

setScaleValuePos :: (MonadIO m, IsScale o) => o -> PositionType -> m ()

Set the value of the “value-pos” property. When overloading is enabled, this is equivalent to

set scale [ #valuePos := value ]

Signals

formatValue

type C_ScaleFormatValueCallback = Ptr () -> CDouble -> Ptr () -> IO CString

Type for the callback on the (unwrapped) C side.

type ScaleFormatValueCallback

Arguments

 = Double

value: the value to format

-> IO Text

Returns: allocated string representing value

Signal which allows you to change how the scale value is displayed. Connect a signal handler which returns an allocated string representing value. That string will then be used to display the scale's value.

If no user-provided handlers are installed, the value will be displayed on its own, rounded according to the value of the Scale:digits property.

Here's an example signal handler which displays a value 1.0 as with "-->1.0<--".

C code

static gchar*
format_value_callback (GtkScale *scale,
                       gdouble   value)
{
  return g_strdup_printf ("-->\%0.*g<--",
                          gtk_scale_get_digits (scale), value);
 }

afterScaleFormatValue :: (IsScale a, MonadIO m) => a -> ScaleFormatValueCallback -> m SignalHandlerId

Connect a signal handler for the “format-value” signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after scale #formatValue callback

genClosure_ScaleFormatValue :: MonadIO m => ScaleFormatValueCallback -> m (GClosure C_ScaleFormatValueCallback)

Wrap the callback into a GClosure.

mk_ScaleFormatValueCallback :: C_ScaleFormatValueCallback -> IO (FunPtr C_ScaleFormatValueCallback)

Generate a function pointer callable from C code, from a C_ScaleFormatValueCallback.

noScaleFormatValueCallback :: Maybe ScaleFormatValueCallback

A convenience synonym for Nothing :: Maybe ScaleFormatValueCallback.

onScaleFormatValue :: (IsScale a, MonadIO m) => a -> ScaleFormatValueCallback -> m SignalHandlerId

Connect a signal handler for the “format-value” signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on scale #formatValue callback

wrap_ScaleFormatValueCallback :: ScaleFormatValueCallback -> C_ScaleFormatValueCallback

Wrap a ScaleFormatValueCallback into a C_ScaleFormatValueCallback.