------------------------------------------------------------------------------
-- --
-- Copyright (C) 1998-2000 E. Briot, J. Brobecker and A. Charlet --
-- Copyright (C) 2000-2014, AdaCore --
-- --
-- This library is free software; you can redistribute it and/or modify it --
-- under terms of the GNU General Public License as published by the Free --
-- Software Foundation; either version 3, or (at your option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- --
-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
------------------------------------------------------------------------------
-- <description>
-- The Gtk.Drawing_Area.Gtk_Drawing_Area widget is used for creating custom
-- user interface elements. It's essentially a blank widget; you can draw on
-- it. After creating a drawing area, the application may want to connect to:
--
--
--
-- *
--
-- Mouse and button press signals to respond to input from the user. (Use
-- Gtk.Widget.Add_Events to enable events you wish to receive.)
--
-- *
--
-- The Gtk.Widget.Gtk_Widget::realize signal to take any necessary actions
-- when the widget is instantiated on a particular display. (Create GDK
-- resources in response to this signal.)
--
-- *
--
-- The Gtk.Widget.Gtk_Widget::configure-event signal to take any necessary
-- actions when the widget changes size.
--
-- *
--
-- The Gtk.Widget.Gtk_Widget::draw signal to handle redrawing the contents of
-- the widget.
--
-- The following code portion demonstrates using a drawing area to display a
-- circle in the normal widget foreground color.
--
-- Note that GDK automatically clears the exposed area to the background
-- color before sending the expose event, and that drawing is implicitly
-- clipped to the exposed area.
--
-- == Simple GtkDrawingArea usage ==
--
-- gboolean
-- draw_callback (GtkWidget *widget, cairo_t *cr, gpointer data)
-- {
-- guint width, height;
-- GdkRGBA color;
-- width = gtk_widget_get_allocated_width (widget);
-- height = gtk_widget_get_allocated_height (widget);
-- cairo_arc (cr,
-- width / 2.0, height / 2.0,
-- MIN (width, height) / 2.0,
-- 0, 2 * G_PI);
-- gtk_style_context_get_color (gtk_widget_get_style_context (widget),
-- 0,
-- &color);
-- gdk_cairo_set_source_rgba (cr, &color);
-- cairo_fill (cr);
-- return FALSE;
-- }
-- [...]
-- GtkWidget *drawing_area = gtk_drawing_area_new (<!-- -->);
-- gtk_widget_set_size_request (drawing_area, 100, 100);
-- g_signal_connect (G_OBJECT (drawing_area), "draw",
-- G_CALLBACK (draw_callback), NULL);
--
-- Draw signals are normally delivered when a drawing area first comes
-- onscreen, or when it's covered by another window and then uncovered. You
-- can also force an expose event by adding to the "damage region" of the
-- drawing area's window; Gtk.Widget.Queue_Draw_Area and
-- Gdk.Window.Invalidate_Rect are equally good ways to do this. You'll then
-- get a draw signal for the invalid region.
--
-- The available routines for drawing are documented on the <link
-- linkend="gdk3-Cairo-Interaction">GDK Drawing Primitives</link> page and the
-- cairo documentation.
--
-- To receive mouse events on a drawing area, you will need to enable them
-- with Gtk.Widget.Add_Events. To receive keyboard events, you will need to
-- set the "can-focus" property on the drawing area, and you should probably
-- draw some user-visible indication that the drawing area is focused. Use
-- Gtk.Widget.Has_Focus in your expose event handler to decide whether to draw
-- the focus indicator. See Gtk.Style_Context.Render_Focus for one way to draw
-- focus.
--
-- </description>
-- <description>
-- See also the Double_Buffer widget provided in the GtkAda examples for an
-- advanced example that demonstrates how to use double buffering, to avoid
-- flickering in your drawings.
--
-- </description>
-- <group>Drawing</group>
-- <testgtk>libart_demo.adb</testgtk>
pragma Ada_2005;
pragma Warnings (Off, "*is already use-visible*");
with Glib; use Glib;
with Glib.Types; use Glib.Types;
with Gtk.Buildable; use Gtk.Buildable;
with Gtk.Widget; use Gtk.Widget;
package Gtk.Drawing_Area is
type Gtk_Drawing_Area_Record is new Gtk_Widget_Record with null record;
type Gtk_Drawing_Area is access all Gtk_Drawing_Area_Record'Class;
------------------
-- Constructors --
------------------
procedure Gtk_New (Drawing_Area : out Gtk_Drawing_Area);
procedure Initialize
(Drawing_Area : not null access Gtk_Drawing_Area_Record'Class);
-- Creates a new drawing area.
function Gtk_Drawing_Area_New return Gtk_Drawing_Area;
-- Creates a new drawing area.
function Get_Type return Glib.GType;
pragma Import (C, Get_Type, "gtk_drawing_area_get_type");
----------------
-- Interfaces --
----------------
-- This class implements several interfaces. See Glib.Types
--
-- - "Buildable"
package Implements_Gtk_Buildable is new Glib.Types.Implements
(Gtk.Buildable.Gtk_Buildable, Gtk_Drawing_Area_Record, Gtk_Drawing_Area);
function "+"
(Widget : access Gtk_Drawing_Area_Record'Class)
return Gtk.Buildable.Gtk_Buildable
renames Implements_Gtk_Buildable.To_Interface;
function "-"
(Interf : Gtk.Buildable.Gtk_Buildable)
return Gtk_Drawing_Area
renames Implements_Gtk_Buildable.To_Object;
end Gtk.Drawing_Area;