Toc Gallery Index Tree Gtk.Adjustment

Hierarchy

Description

This object represents an adjustable bounded value. It is used in many other widgets that have such internal values, like Gtk_Scrollbar, Gtk_Spin_Button, Gtk_Range, ... Modifying the value of these widgets is done through their associated adjustments.

The modification of the value is left to the user, who should call Value_Changed or Changed to emit the relevant signals.

The meaning of the most important fields can be explained on the following figure (imagine this is a scrollbar):

[-------|=================|-------------------] lower value value + page_size upper

Types

  • type Gtk_Adjustment is access all Gtk_Adjustment_Record'Class;
  • type Gtk_Adjustment_Record is new Object.Gtk_Object_Record with private;

Subprograms

  • procedure Gtk_New (Adjustment : out Gtk_Adjustment; Value : Gdouble; Lower : Gdouble; Upper : Gdouble; Step_Increment : Gdouble; Page_Increment : Gdouble; Page_Size : Gdouble);
    Create a new adjustment. Value is the initial value of the adjustment. It must be in the range (Lower .. Upper) and the adjustment's value will never be outside this range. Step_Increment is the value used to make minor adjustments, such as when the user clicks on the arrows of a scrollbar. Page_Increment is used to make major adjustments, such as when the user clicks in the through on a scrollbar. Page_Size is the size of the area that is currently visible (for instance in a Gtk_Scrolled_Window).
  • procedure Initialize (Adjustment : access Gtk_Adjustment_Record'Class; Value : Gdouble; Lower : Gdouble; Upper : Gdouble; Step_Increment : Gdouble; Page_Increment : Gdouble; Page_Size : Gdouble);
    Internal initialization function. See the section "Creating your own widgets" in the documentation.
  • function Get_Type return Gtk.Gtk_Type;
    Return the internal value associated with a Gtk_Adjustment.
  • procedure Set_Value (Adjustment : access Gtk_Adjustment_Record; Value : Gdouble);
    function Get_Value (Adjustment : access Gtk_Adjustment_Record) return Gdouble;
    Modify the current value of the adjustment. You do not need to call Value_Changed after modifying this value, this is done automatically.
  • procedure Set_Lower (Adjustment : access Gtk_Adjustment_Record; Lower : Gdouble);
    function Get_Lower (Adjustment : access Gtk_Adjustment_Record) return Gdouble;
    Modify the lower bound of the adjustment. You should call Changed after modifying this value.
  • procedure Set_Upper (Adjustment : access Gtk_Adjustment_Record; Upper : Gdouble);
    function Get_Upper (Adjustment : access Gtk_Adjustment_Record) return Gdouble;
    Modify the upper bound of the adjustment. You should call Changed after modifying this value.
  • procedure Set_Step_Increment (Adjustment : access Gtk_Adjustment_Record; Step_Increment : Gdouble);
    function Get_Step_Increment (Adjustment : access Gtk_Adjustment_Record) return Gdouble;
    Modify the step increment of the adjustment. You should call Changed after modifying this value.
  • procedure Set_Page_Increment (Adjustment : access Gtk_Adjustment_Record; Page_Increment : Gdouble);
    function Get_Page_Increment (Adjustment : access Gtk_Adjustment_Record) return Gdouble;
    Modify the page increment of the adjustment. You should call Changed after modifying this value.
  • procedure Set_Page_Size (Adjustment : access Gtk_Adjustment_Record; Page_Size : Gdouble);
    function Get_Page_Size (Adjustment : access Gtk_Adjustment_Record) return Gdouble;
    Modify the page size of the adjustment. You should call Changed after modifying this value.
  • Misc functions

  • procedure Clamp_Page (Adjustment : access Gtk_Adjustment_Record; Lower : Gdouble; Upper : Gdouble);
    Update the Adjustment value to ensure that the range between Lower and Upper is in the current page (i.e. between value and value + page_size). If the range is larger than the page size, then only the start of it will be in the current page. A "value_changed" signal will be emitted if the value is changed.
  • Signals emission

  • procedure Changed (Adjustment : access Gtk_Adjustment_Record);
    Emit the "changed" signal on Adjustment. This warns any listener that some field other than the value has been changed.
  • procedure Value_Changed (Adjustment : access Gtk_Adjustment_Record);
    Emit the "value_changed" signal on Adjustment. This warns any listener that the value has been changed.

Signals

  • changed
    procedure Handler (Adjustment : access Gtk_Adjustment_Record'Class);
    This signal is emitted every time one of the parameters is modified, except the value.
  • value_changed
    procedure Handler (Adjustment : access Gtk_Adjustment_Record'Class);
    This signal is emitted every time the value of the adjustment is modified

Properties

  • Lower_Property
    Double
    The minimum value of the adjustment
  • Page_Increment_Property
    Double
    The page increment of the adjustment
  • Page_Size_Property
    Double
    The page size of the adjustment
  • Step_Increment_Property
    Double
    The step increment of the adjustment
  • Upper_Property
    Double
    The maximum value of the adjustment
  • Value_Property
    Double
    The value of the adjustment

Alphabetical Index