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Functions
GtkWidget * | gtk_scale_new () |
GtkWidget * | gtk_scale_new_with_range () |
void | gtk_scale_set_digits () |
void | gtk_scale_set_draw_value () |
void | gtk_scale_set_has_origin () |
void | gtk_scale_set_value_pos () |
gint | gtk_scale_get_digits () |
gboolean | gtk_scale_get_draw_value () |
gboolean | gtk_scale_get_has_origin () |
GtkPositionType | gtk_scale_get_value_pos () |
PangoLayout * | gtk_scale_get_layout () |
void | gtk_scale_get_layout_offsets () |
void | gtk_scale_add_mark () |
void | gtk_scale_clear_marks () |
Properties
gint | digits | Read / Write |
gboolean | draw-value | Read / Write |
gboolean | has-origin | Read / Write |
GtkPositionType | value-pos | Read / Write |
Object Hierarchy
GObject ╰── GInitiallyUnowned ╰── GtkWidget ╰── GtkRange ╰── GtkScale ├── GtkHScale ╰── GtkVScale
Description
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, GtkRange, in addition to the methods for GtkScale itself.
To set the value of a scale, you would normally use gtk_range_set_value()
.
To detect changes to the value, you would normally use the
“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 gtk_scale_add_mark()
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
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scale[.fine-tune] ├── marks.top │ ├── mark │ ┊ ├── [label] │ ┊ ╰── indicator ┊ ┊ │ ╰── mark ├── 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 gtk_scale_set_has_origin()
), 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 gtk_range_set_show_fill_level()
),
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.
Functions
gtk_scale_new ()
GtkWidget * gtk_scale_new (GtkOrientation orientation
,GtkAdjustment *adjustment
);
Creates a new GtkScale.
Parameters
orientation |
the scale’s orientation. |
|
adjustment |
the GtkAdjustment which sets the range
of the scale, or |
[allow-none][nullable] |
Since: 3.0
gtk_scale_new_with_range ()
GtkWidget * gtk_scale_new_with_range (GtkOrientation orientation
,gdouble min
,gdouble max
,gdouble step
);
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 gtk_scale_set_digits()
to correct it.
Parameters
orientation |
the scale’s orientation. |
|
min |
minimum value |
|
max |
maximum value |
|
step |
step increment (tick size) used with keyboard shortcuts |
Since: 3.0
gtk_scale_set_digits ()
void gtk_scale_set_digits (GtkScale *scale
,gint digits
);
Sets the number of decimal places that are displayed in the value. Also causes the value of the adjustment to be rounded off to this number of digits, so the retrieved value matches the value the user saw.
Parameters
scale |
a GtkScale |
|
digits |
the number of decimal places to display, e.g. use 1 to display 1.0, 2 to display 1.00, etc |
gtk_scale_set_draw_value ()
void gtk_scale_set_draw_value (GtkScale *scale
,gboolean draw_value
);
Specifies whether the current value is displayed as a string next to the slider.
gtk_scale_set_has_origin ()
void gtk_scale_set_has_origin (GtkScale *scale
,gboolean has_origin
);
If has_origin
is set to TRUE
(the default),
the scale will highlight the part of the scale
between the origin (bottom or left side) of the scale
and the current value.
Since: 3.4
gtk_scale_set_value_pos ()
void gtk_scale_set_value_pos (GtkScale *scale
,GtkPositionType pos
);
Sets the position in which the current value is displayed.
gtk_scale_get_digits ()
gint
gtk_scale_get_digits (GtkScale *scale
);
Gets the number of decimal places that are displayed in the value.
gtk_scale_get_draw_value ()
gboolean
gtk_scale_get_draw_value (GtkScale *scale
);
Returns whether the current value is displayed as a string next to the slider.
gtk_scale_get_has_origin ()
gboolean
gtk_scale_get_has_origin (GtkScale *scale
);
Returns whether the scale has an origin.
Since: 3.4
gtk_scale_get_value_pos ()
GtkPositionType
gtk_scale_get_value_pos (GtkScale *scale
);
Gets the position in which the current value is displayed.
gtk_scale_get_layout ()
PangoLayout *
gtk_scale_get_layout (GtkScale *scale
);
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 PangoLayout for this scale,
or NULL
if the “draw-value” property is FALSE
.
[transfer none][nullable]
Since: 2.4
gtk_scale_get_layout_offsets ()
void gtk_scale_get_layout_offsets (GtkScale *scale
,gint *x
,gint *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 “draw-value” property is FALSE
, the return
values are undefined.
Since: 2.4
gtk_scale_add_mark ()
void gtk_scale_add_mark (GtkScale *scale
,gdouble value
,GtkPositionType position
,const gchar *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 gtk_scale_clear_marks()
.
Parameters
scale |
a GtkScale |
|
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, GTK_POS_TOP
and |
|
markup |
Text to be shown at the mark, using Pango markup, or |
[allow-none] |
Since: 2.16
gtk_scale_clear_marks ()
void
gtk_scale_clear_marks (GtkScale *scale
);
Removes any marks that have been added with gtk_scale_add_mark()
.
Since: 2.16
Property Details
The “digits”
property
“digits” gint
The number of decimal places that are displayed in the value.
Flags: Read / Write
Allowed values: [-1,64]
Default value: 1
The “draw-value”
property
“draw-value” gboolean
Whether the current value is displayed as a string next to the slider.
Flags: Read / Write
Default value: TRUE
The “has-origin”
property
“has-origin” gboolean
Whether the scale has an origin.
Flags: Read / Write
Default value: TRUE
The “value-pos”
property
“value-pos” GtkPositionType
The position in which the current value is displayed.
Flags: Read / Write
Default value: GTK_POS_TOP
Style Property Details
The “slider-length”
style property
“slider-length” gint
Length of scale's slider.
GtkScale:slider-length
has been deprecated since version 3.20 and should not be used in newly-written code.
Use min-height/min-width CSS properties on the slider element instead. The value of this style property is ignored.
Flags: Read
Allowed values: >= 0
Default value: 31
The “value-spacing”
style property
“value-spacing” gint
Space between value text and the slider/trough area.
GtkScale:value-spacing
has been deprecated since version 3.20 and should not be used in newly-written code.
Use min-height/min-width CSS properties on the value element instead. The value of this style property is ignored.
Flags: Read
Allowed values: >= 0
Default value: 2
Signal Details
The “format-value”
signal
gchar* user_function (GtkScale *scale, gdouble value, gpointer user_data)
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.
Here's an example signal handler which displays a value 1.0 as with "-->1.0<--".
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static gchar* format_value_callback (GtkScale *scale, gdouble value) { return g_strdup_printf ("-->\%0.*g<--", gtk_scale_get_digits (scale), value); } |
Parameters
scale |
the object which received the signal |
|
value |
the value to format |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last