The Gtk.Fixed.Gtk_Fixed widget is a container which can place child widgets at fixed positions and with fixed sizes, given in pixels. Gtk.Fixed.Gtk_Fixed performs no automatic layout management.
For most applications, you should not use this container! It keeps you from having to learn about the other GTK+ containers, but it results in broken applications. With Gtk.Fixed.Gtk_Fixed, the following things will result in truncated text, overlapping widgets, and other display bugs:
Themes, which may change widget sizes.
Fonts other than the one you used to write the app will of course change
the size of widgets containing text; keep in mind that users may use a larger font because of difficulty reading the default, or they may be using a different OS that provides different fonts.
Translation of text into other languages changes its size. Also, display
of non-English text will use a different font in many cases.
In addition, Gtk.Fixed.Gtk_Fixed does not pay attention to text direction and thus may produce unwanted results if your app is run under right-to-left languages such as Hebrew or Arabic. That is: normally GTK+ will order containers appropriately for the text direction, e.g. to put labels to the right of the thing they label when using an RTL language, but it can't do that with Gtk.Fixed.Gtk_Fixed. So if you need to reorder widgets depending on the text direction, you would need to manually detect it and adjust child positions accordingly.
Finally, fixed positioning makes it kind of annoying to add/remove GUI elements, since you have to reposition all the other elements. This is a long-term maintenance problem for your application.
If you know none of these things are an issue for your application, and prefer the simplicity of Gtk.Fixed.Gtk_Fixed, by all means use the widget. But you should be aware of the tradeoffs.
See also Gtk.Layout.Gtk_Layout, which shares the ability to perform fixed positioning of child widgets and additionally adds custom drawing and scrollability.
<screenshot>gtk-fixed</screenshot> <group>Layout containers</group> <testgtk>create_fixed.adb</testgtk>
function "+"
(Widget : access Gtk_Fixed_Record'Class)
return Gtk.Buildable.Gtk_Buildable
function "-"
(Interf : Gtk.Buildable.Gtk_Buildable)
return Gtk_Fixed
function Get_Type return Glib.GType
type Gtk_Fixed is access all Gtk_Fixed_Record'Class;
function Gtk_Fixed_New return Gtk_Fixed
Creates a new Gtk.Fixed.Gtk_Fixed.
type Gtk_Fixed_Record is new Gtk_Container_Record with null record;
procedure Gtk_New (Fixed : out Gtk_Fixed)
Creates a new Gtk.Fixed.Gtk_Fixed. Initialize does nothing if the object was already created with another call to Initialize* or G_New.
package Implements_Gtk_Buildable is new Glib.Types.Implements
(Gtk.Buildable.Gtk_Buildable, Gtk_Fixed_Record, Gtk_Fixed);
procedure Initialize (Fixed : not null access Gtk_Fixed_Record'Class)
Creates a new Gtk.Fixed.Gtk_Fixed. Initialize does nothing if the object was already created with another call to Initialize* or G_New.
procedure Move
(Fixed : not null access Gtk_Fixed_Record;
Widget : not null access Gtk.Widget.Gtk_Widget_Record'Class;
X : Glib.Gint;
Y : Glib.Gint)
Move a child of a GtkFixed container to the given position. X indicates the horizontal position to place the widget at. Y is the vertical position to place the widget at.
the child widget.
the horizontal position to move the widget to.
the vertical position to move the widget to.
procedure Put
(Fixed : not null access Gtk_Fixed_Record;
Widget : not null access Gtk.Widget.Gtk_Widget_Record'Class;
X : Glib.Gint;
Y : Glib.Gint)
Add Widget to a Fixed container at the given position. X indicates the horizontal position to place the widget at. Y is the vertical position to place the widget at.
the widget to add.
the horizontal position to place the widget at.
the vertical position to place the widget at.