Description
The
Gtk_Gamma_Curve widget is a child of Gtk_Curve specifically for editing
gamma curves, which are used in graphics applications such as the Gimp.
The Gamma_Curve widget shows a curve which the user can edit with the mouse
just like a Gtk_Curve widget. On the right of the curve it also displays 5
buttons, 3 of which change between the 3 curve modes (spline, linear and
free), and the other 2 set the curve to a particular gamma value, or reset
it to a straight line.
Subprograms
-
procedure Gtk_New (Gamma_Curve : out Gtk_Gamma_Curve);
-
procedure Initialize (Gamma_Curve : access Gtk_Gamma_Curve_Record'Class);
-
-
-
function Get_Gamma
(Gamma_Curve : access Gtk_Gamma_Curve_Record) return Gfloat;
Testgtk source code
This code is part of testgtk, a demo application packaged with GtkAda. Testgtk demonstrates the various widgets of GtkAda
-----------------------------------------------------------------------
-- GtkAda - Ada95 binding for the Gimp Toolkit --
-- --
-- Copyright (C) 1998-1999 --
-- Emmanuel Briot, Joel Brobecker and Arnaud Charlet --
-- --
-- This library is free software; you can redistribute it and/or --
-- modify it under the terms of the GNU General Public --
-- License as published by the Free Software Foundation; either --
-- version 2 of the License, 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 --
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
-- General Public License for more details. --
-- --
-- You should have received a copy of the GNU General Public --
-- License along with this library; if not, write to the --
-- Free Software Foundation, Inc., 59 Temple Place - Suite 330, --
-- Boston, MA 02111-1307, USA. --
-- --
--
--
--
--
--
--
--
-----------------------------------------------------------------------
with Glib;
use Glib;
with Gtk.Box;
use Gtk.Box;
with Gtk.Button;
use Gtk.Button;
with Gtk.Curve;
use Gtk.Curve;
with Gtk.Gamma_Curve;
use Gtk.Gamma_Curve;
with Gtk.Handlers;
use Gtk.Handlers;
with Gtk;
use Gtk;
with Ada.Numerics.Generic_Elementary_Functions;
with Ada.Text_IO;
package body Create_Gamma_Curve
is
package Float_P
is new Ada.Numerics.Generic_Elementary_Functions (Gfloat);
package Gamma_Cb
is new Handlers.Callback (Gtk_Button_Record);
Count : Gint := 0;
Curve : Gtk_Gamma_Curve;
----------
-- Help --
----------
function Help
return String
is
begin
return "A very specific widget to edit a curve. This
is based on a "
& " @bGtk_Curve@B, a modified version
of the @bGtk_Drawing_Area@B."
& " You problably won't need to
use this...";
end Help;
------------------
-- Change_Curve --
------------------
procedure Change_Curve (Button :
access Gtk_Button_Record'Class)
is
pragma Warnings (Off, Button);
Max :
constant Gint := 127 + (Count
mod 4) * 128;
Vec : Gfloat_Array (1 .. Positive (Max));
begin
if (Count
mod 4 /= 3)
then
Ada.Text_IO.Put_Line ("Redrawing the window
with "
& Gint'Image (Max)
& " points");
end if;
Set_Range (Get_Curve (Curve), 0.0, Gfloat (Max), 0.0, Gfloat (Max));
for J
in Vec'Range
loop
Vec (J) := (127.0 / Float_P.Sqrt (Gfloat (Max)))
* Float_P.Sqrt (Gfloat (J));
end loop;
Set_Vector (Get_Curve (Curve), Vec);
Count := Count + 1;
end Change_Curve;
---------
-- Run --
---------
procedure Run (Frame :
access Gtk.Frame.Gtk_Frame_Record'Class)
is
Button : Gtk_Button;
Box : Gtk_Box;
begin
Set_Label (Frame, "Gamma Curve");
Gtk_New_Vbox (Box, Homogeneous => False, Spacing => 0);
Add (Frame, Box);
Gtk_New (Curve);
Pack_Start (Box, Curve, False, False);
Gtk_New (Button, "Change mode");
Pack_Start (Box, Button, False, False);
Gamma_Cb.Connect (Button, "clicked",
Gamma_Cb.To_Marshaller (Change_Curve'Access));
Gamma_Cb.Emit_By_Name (Button, "clicked");
Show_All (Frame);
end Run;
end Create_Gamma_Curve;