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# Package Gtk.Scrolled`_`Window

Gtk_Scrolled_Window is a Gtk_Bin child: it's a container the accepts a single child widget. Gtk_Scrolled_Window adds scrollbars to the child widget.

The scrolled window can work in two ways. Some widgets have native scrolling support; these widgets have "slots" for Gtk_Adjustment objects. The scrolled window installs Gtk_Adjustment objects in the child window's slots using the "set_scroll_adjustments" signal (Conceptually, these widgets implement a "Scrollable" interface).

The second way to use the scrolled window is useful with widgets that lack the "set_scroll_adjustments" signal. The Gtk_Viewport widget acts as a proxy, implementing scrollability for child widgets that lack their own scrolling capabilities.

If a widget has native scrolling abilities, it can be added to the Gtk_Scrolled_Window with Gtk.Container.Add. If a widget does not, you must first add the widget to a Gtk_Viewport, then add the Gtk_Viewport to the scrolled window. The convenience function Add_With_Viewport does exactly this, so you can ignore the presence of the viewport.

If you want to create your own new widget type that can be inserted directly into a scrolled_window, you need to specify a signal for Set_Scroll_Adjustments in the call to Gtk.Object.Initialize_Class_Record.

- Gtk.Scrolled_Window Widget Hierarchy
- Gtk.Scrolled_Window Types
- Gtk.Scrolled_Window Subprograms

## Widget Hierarchy

    Gtk_Object                    (see section Package Gtk.Object)
       \___ Gtk_Widget            (see section Package Gtk.Widget)
          \___ Gtk_Container      (see section Package Gtk.Container)
             \___ Gtk_Scrolled_Window (see section Package Gtk.Scrolled_Window)

## Types

    type Gtk_Corner_Type is
        (Corner_Top_Left,
         Corner_Bottom_Left,
         Corner_Top_Right,
         Corner_Bottom_Right);

| Type used by Set_Placement below to determine the location of the child widget with respect to the scrollbars. Corner_Top_Left means the child is in the top left, with the scrollbars underneath and to the right.

## Subprograms

    procedure Gtk_New
      (Scrolled_Window    : out    Gtk_Scrolled_Window;
       Hadjustment        :        Adjustment.Gtk_Adjustment
                           := Adjustment.Null_Adjustment;
       Vadjustment        :        Adjustment.Gtk_Adjustment
                           := Adjustment.Null_Adjustment);

| Create a new scrolled window. The two arguments are the scrolled window's horizontal and vertical adjustments; these will be shared with the scrollbars and the child widget to keep the bars in sync with the child. Usually you want to use the default value Null_Adjustment for the adjustments, which will cause the scrolled window to create them for you.

    function Get_Type              return Gtk.Gtk_Type;

| Return the internal value associated with a Gtk_Scrolled_Window.

    procedure Add_With_Viewport
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record;
       Child              : access Gtk.Widget.Gtk_Widget_Record'Class);

Used to add children without native scrolling capabilities.
This is simply a convenience function; it is equivalent to adding the unscrollable child to a viewport, then adding the viewport to the scrolled window. If a child has native scrolling, use Gtk.Container.Add instead of this function.

The viewport scrolls the child by moving its Gdk_Window, and takes the size of the child to be the size of its toplevel Gdk_Window. This will be very wrong for most widgets that support native scrolling; for example, if you add a Gtk_Clist with a viewport, the whole widget will scroll, including the column headings. Thus Gtk_Clist supports scrolling already, and should not be used with the GtkViewport proxy.

A widget supports scrolling natively if it contains a valid "set_scroll_adjustments" signal.

    function Get_Hadjustment
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record)
       return Adjustment.Gtk_Adjustment;

| Return the horizontal scrollbar's adjustment. This adjustment is used to connect the horizontal scrollbar to the child widget's horizontal scroll functionality.

    function Get_Vadjustment
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record)
       return Adjustment.Gtk_Adjustment;

| Return the vertical scrollbar's adjustment. This adjustment is used to connect the vertical scrollbar to the child widget's vertical scroll functionality.

    procedure Set_Hadjustment
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record;
       Hadjustment        :        Adjustment.Gtk_Adjustment);

| Set the Gtk_Adjustment for the horizontal scrollbar.

    procedure Set_Vadjustment
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record;
       Vadjustment        :        Adjustment.Gtk_Adjustment);

| Set the Gtk_Adjustment for the vertical scrollbar.

    procedure Set_Placement
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record;
       Window_Placement   :        Gtk_Corner_Type);

| Determine the location of the widget with respect to the scrollbars. The default is Corner_Top_Left.

    procedure Set_Policy
      (Scrolled_Window    : access Gtk_Scrolled_Window_Record;
       H_Scrollbar_Policy  : in     Enums.Gtk_Policy_Type;
       V_Scrollbar_Policy  : in     Enums.Gtk_Policy_Type);

Set the scrollbar policy for the horizontal and vertical scrollbars.
It determines when the scrollbar should appear; it is a value from the Gtk_Policy_Type enumeration. If Policy_Always, the scrollbar is always present; if Policy_Never, the scrollbar is never present; if Policy_Automatic, the scrollbar is present only if needed (that is, if the slider part of the bar would be smaller than the trough - the display is larger than the page size).

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