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GtkScale

GtkScale — Base class for GtkHScale and GtkVScale

Object Hierarchy

  GObject
   +----GInitiallyUnowned
         +----GtkObject
               +----GtkWidget
                     +----GtkRange
                           +----GtkScale
                                 +----GtkHScale
                                 +----GtkVScale

Implemented Interfaces

GtkScale implements AtkImplementorIface, GtkBuildable and GtkOrientable.

Properties

  "digits"                   gint                  : Read / Write
  "draw-value"               gboolean              : Read / Write
  "value-pos"                GtkPositionType       : Read / Write

Style Properties

  "slider-length"            gint                  : Read
  "value-spacing"            gint                  : Read

Signals

  "format-value"                                   : Run Last

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.

The GtkScale widget is an abstract class, used only for deriving the subclasses GtkHScale and GtkVScale. To create a scale widget, call gtk_hscale_new_with_range() or gtk_vscale_new_with_range().

Details

GtkScale

typedef struct _GtkScale GtkScale;

The fields of the GtkScale struct should only be accessed via the accessor functions.


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.

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.

scale :

a GtkScale

draw_value :

TRUE to draw the value

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.

scale :

a GtkScale

pos :

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.

scale :

a GtkScale

Returns :

the number of decimal places that are displayed

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.

scale :

a GtkScale

Returns :

whether the current value is displayed as a string

gtk_scale_get_value_pos ()

GtkPositionType     gtk_scale_get_value_pos             (GtkScale *scale);

Gets the position in which the current value is displayed.

scale :

a GtkScale

Returns :

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.

scale :

A GtkScale

Returns :

the PangoLayout for this scale, or NULL if the "draw-value" property is FALSE.

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.

scale :

a GtkScale

x :

location to store X offset of layout, or NULL

y :

location to store Y offset of layout, or NULL

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().

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 is drawn above the scale, anything else below. For a vertical scale, GTK_POS_LEFT is drawn to the left of the scale, anything else to the right.

markup :

Text to be shown at the mark, using Pango markup, or NULL

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().

scale :

a GtkScale

Since 2.16

Property Details

The "digits" property

  "digits"                   gint                  : Read / Write

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

Allowed values: [G_MAXULONG,64]

Default value: 1


The "draw-value" property

  "draw-value"               gboolean              : Read / Write

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

Default value: TRUE


The "value-pos" property

  "value-pos"                GtkPositionType       : Read / Write

The position in which the current value is displayed.

Default value: GTK_POS_TOP

Style Property Details

The "slider-length" style property

  "slider-length"            gint                  : Read

Length of scale's slider.

Allowed values: >= 0

Default value: 31


The "value-spacing" style property

  "value-spacing"            gint                  : Read

Space between value text and the slider/trough area.

Allowed values: >= 0

Default value: 2

Signal Details

The "format-value" signal

gchar*              user_function                      (GtkScale *scale,
                                                        gdouble   value,
                                                        gpointer  user_data)      : Run Last

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<--".

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

scale :

the object which received the signal

value :

the value to format

user_data :

user data set when the signal handler was connected.

Returns :

allocated string representing value