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GtkScale

GtkScale — Base class for GtkHScale and GtkVScale

Synopsis


#include <gtk/gtk.h>


            GtkScale;
void        gtk_scale_set_digits            (GtkScale *scale,
                                             gint digits);
void        gtk_scale_set_draw_value        (GtkScale *scale,
                                             gboolean draw_value);
void        gtk_scale_set_value_pos         (GtkScale *scale,
                                             GtkPositionType pos);
gint        gtk_scale_get_digits            (GtkScale *scale);
gboolean    gtk_scale_get_draw_value        (GtkScale *scale);
GtkPositionType gtk_scale_get_value_pos     (GtkScale *scale);
PangoLayout* gtk_scale_get_layout           (GtkScale *scale);
void        gtk_scale_get_layout_offsets    (GtkScale *scale,
                                             gint *x,
                                             gint *y);


Object Hierarchy


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

Implemented Interfaces

GtkScale implements AtkImplementorIface.

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

Signal Prototypes


"format-value"
            gchar*      user_function      (GtkScale *scale,
                                            gdouble arg1,
                                            gpointer user_data);

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 GtkScale-struct struct contains the following fields. (These fields should be considered read-only. They should never be set by an application.)

guint draw_value;non-zero if the scale's current value is displayed next to the slider.
guint value_pos;the position in which the textual value is displayed, selected from GtkPositionType.


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 :a boolean.

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

Properties

The "digits" property

  "digits"               gint                  : Read / Write

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

Allowed values: [-1,64]

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: FALSE


The "value-pos" property

  "value-pos"            GtkPositionType       : Read / Write

The position in which the current value is displayed.

Default value: GTK_POS_LEFT

Style Properties

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

Signals

The "format-value" signal

gchar*      user_function                  (GtkScale *scale,
                                            gdouble arg1,
                                            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<--".

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.
arg1 :
user_data :user data set when the signal handler was connected.
Returns :allocated string representing value