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-----------------------------------------------------------------------
-- GtkAda - Ada95 binding for the Gimp Toolkit --
-- --
-- Copyright (C) 1998-1999 --
-- Emmanuel Briot, Joel Brobecker and Arnaud Charlet --
-- Copyright (C) 2000-2013, AdaCore --
-- --
-- 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 Gdk.Drawable; use Gdk.Drawable;
with Gdk.Event; use Gdk.Event;
with Gdk.GC; use Gdk.GC;
with Gdk.Rectangle; use Gdk.Rectangle;
with Gdk.Window; use Gdk.Window;
with Gdk; use Gdk;
with Gtk.Adjustment; use Gtk.Adjustment;
with Gtk.Box; use Gtk.Box;
with Gtk.Drawing_Area; use Gtk.Drawing_Area;
with Gtk.Scrollbar; use Gtk.Scrollbar;
with Gtk.Handlers;
with Gtk.Style;
with Gtk.Widget; use Gtk.Widget;
with Gtk; use Gtk;
package body Create_Scroll_Test is
package Adjustment_Cb is new Handlers.User_Callback
(Widget_Type => Adjustment.Gtk_Adjustment_Record,
User_Type => Drawing_Area.Gtk_Drawing_Area);
package Event_Cb is new Handlers.User_Return_Callback
(Widget_Type => Drawing_Area.Gtk_Drawing_Area_Record,
Return_Type => Gint,
User_Type => Adjustment.Gtk_Adjustment);
Scroll_Test_Pos : Gint := 0;
Scroll_Test_GC : Gdk.GC.Gdk_GC;
----------
-- Help --
----------
function Help return String is
begin
return "This demo shows how you can implement some scrolling in your"
& " applications. Most of the time, putting a widget into a"
& " @bGtk_Scrolling_Area@B will do the job. However, if the scrolling"
& " takes place on a very large region, it might be more efficient to"
& " have a widget with the minimal size visible on the screen, and"
& " simply draw the relevant region in it."
& ASCII.LF
& "As you can see in this demo, this mechanism is implemented using"
& " some @bGtk_Adjustment@B widgets, along with some"
& " @bGtk_Scrollbar@Bs."
& ASCII.LF
& "Note also that you must set the event mask in your widget so that"
& " @bexpose@B and @bconfigure@B events are correctly handled.";
end Help;
-------------------------
-- Adjustment_Change --
-------------------------
procedure Adjustment_Change
(Adj : access Adjustment.Gtk_Adjustment_Record'Class;
Widget : Drawing_Area.Gtk_Drawing_Area)
is
Source_Min : Gint := Gint (Get_Value (Adj)) - Scroll_Test_Pos;
Source_Max : Gint := Source_Min + Gint (Get_Allocation_Height (Widget));
Dest_Min : Gint := 0;
Dest_Max : Gint := Gint (Get_Allocation_Height (Widget));
Rect : Gdk_Rectangle;
Event : Gdk_Event_Expose;
Tmp : Boolean;
pragma Unreferenced (Tmp, Dest_Max);
begin
Scroll_Test_Pos := Gint (Get_Value (Adj));
if not Drawable_Is_Set (Widget) then
return;
end if;
Rect := (X => 0, Y => 0, Width => 0, Height => 0);
-- This is actually different from C, since we can not
-- create a C's GdkRectangle, only a C's GdkRectangle*
if Source_Min < 0 then
Rect.Width := Gint (Get_Allocation_Width (Widget));
Rect.Height :=
Gint'Min (-Source_Min, Gint (Get_Allocation_Height (Widget)));
Source_Min := 0;
Dest_Min := Rect.Height;
else
Rect.Y :=
Gint'Max (0, 2 * Gint (Get_Allocation_Height (Widget))
- Source_Max);
Rect.Width := Gint (Get_Allocation_Width (Widget));
Rect.Height := Gint (Get_Allocation_Height (Widget)) - Rect.Y;
Source_Max := Gint (Get_Allocation_Height (Widget));
Dest_Max := Rect.Y;
end if;
if Source_Min /= Source_Max then
if Scroll_Test_GC = Null_GC then
Gdk_New (Scroll_Test_GC, Get_Window (Widget));
Set_Exposures (Scroll_Test_GC, True);
end if;
Draw_Drawable
(Get_Window (Widget), Scroll_Test_GC,
Get_Window (Widget),
0, Source_Min,
0, Dest_Min,
Gint (Get_Allocation_Width (Widget)),
Source_Max - Source_Min);
-- Make sure graphics expose events are processed before
-- scrolling again
loop
Get_Graphics_Expose (Event, Get_Window (Widget));
exit when not Is_Created (Event);
Tmp := Gtk.Widget.Event (Widget, Gdk_Event (Event));
if Get_Count (Event) = 0 then
Free (Event);
exit;
end if;
Free (Event);
end loop;
end if;
if Rect.Height /= 0 then
Draw (Widget, Rect);
end if;
end Adjustment_Change;
-----------------
-- Configure --
-----------------
function Configure
(Widget : access Drawing_Area.Gtk_Drawing_Area_Record'Class;
Event : Gdk.Event.Gdk_Event;
Adj : Adjustment.Gtk_Adjustment) return Gint
is
pragma Warnings (Off, Event);
begin
Set_Page_Increment (Adj, 0.9 * Gdouble (Get_Allocation_Height (Widget)));
Set_Page_Size (Adj, Gdouble (Get_Allocation_Height (Widget)));
-- FIXME Emit_By_Name (Adj, "changed");
return 0;
end Configure;
--------------
-- Expose --
--------------
function Expose
(Widget : access Drawing_Area.Gtk_Drawing_Area_Record'Class;
Event : Gdk.Event.Gdk_Event;
Adj : Adjustment.Gtk_Adjustment)
return Gint
is
Expose_Event : constant Gdk.Event.Gdk_Event_Expose :=
Gdk.Event.Gdk_Event_Expose (Event);
Area : Gdk.Rectangle.Gdk_Rectangle;
Imin, Imax, Jmin, Jmax : Gint;
Sty : constant Gtk.Style.Gtk_Style := Get_Style (Widget);
begin
Area := Gdk.Event.Get_Area (Expose_Event);
Imin := Area.X / 10;
Imax := (Area.X + Area.Width + 9) / 10;
Jmin := (Gint (Adjustment.Get_Value (Adj)) + Area.Y) / 10;
Jmax := (Gint (Adjustment.Get_Value (Adj)) + Area.Y
+ Area.Height + 9) / 10;
Gdk.Window.Clear_Area (Window => Get_Window (Widget),
X => Area.X, Y => Area.Y,
Width => Area.Width,
Height => Area.Height);
for I in Imin .. Imax loop
for J in Jmin .. Jmax loop
if (I + J) mod 2 /= 0 then
Gdk.Drawable.Draw_Rectangle
(Drawable => Get_Window (Widget),
GC => Gtk.Style.Get_Black_GC (Sty),
Filled => True,
X => 10 * I, Y => 10 * J - Gint (Adjustment.Get_Value (Adj)),
Width => 1 + I mod 10, Height => 1 + J mod 10);
end if;
end loop; -- J
end loop; -- I
return 0;
end Expose;
-----------
-- Run --
-----------
procedure Run (Frame : access Gtk.Frame.Gtk_Frame_Record'Class) is
Hbox : Box.Gtk_Box;
Vbox : Box.Gtk_Box;
Drawing_Area : Gtk.Drawing_Area.Gtk_Drawing_Area;
Adj : Gtk.Adjustment.Gtk_Adjustment;
Scrollbar : Gtk.Scrollbar.Gtk_Scrollbar;
begin
Set_Label (Frame, "Scroll Test");
Box.Gtk_New_Vbox (Vbox, Homogeneous => False, Spacing => 0);
Add (Frame, Vbox);
Box.Gtk_New_Hbox (Hbox, Homogeneous => False, Spacing => 0);
Box.Pack_Start (In_Box => Vbox, Child => Hbox);
Gtk.Drawing_Area.Gtk_New (Drawing_Area);
Set_Size_Request (Drawing_Area, 200, 200);
Box.Pack_Start (In_Box => Hbox, Child => Drawing_Area);
Unrealize (Drawing_Area); -- Required for Set_Events
Set_Events (Widget => Drawing_Area, Events => Exposure_Mask);
Adjustment.Gtk_New (Adjustment => Adj, Value => 0.0, Lower => 0.0,
Upper => 1000.0, Step_Increment => 1.0,
Page_Increment => 180.0, Page_Size => 200.0);
Scroll_Test_Pos := 0;
Gtk.Scrollbar.Gtk_New_Vscrollbar (Widget => Scrollbar,
Adjustment => Adj);
Box.Pack_Start (In_Box => Hbox, Child => Scrollbar,
Expand => False, Fill => False);
Event_Cb.Connect
(Widget => Drawing_Area,
Name => "expose_event",
Marsh => Event_Cb.To_Marshaller (Expose'Access),
User_Data => Adj);
Event_Cb.Connect
(Widget => Drawing_Area,
Name => "configure_event",
Marsh => Event_Cb.To_Marshaller (Configure'Access),
User_Data => Adj);
Adjustment_Cb.Connect
(Widget => Adj,
Name => "value_changed",
Marsh => Adjustment_Cb.To_Marshaller (Adjustment_Change'Access),
User_Data => Drawing_Area);
Show_All (Frame);
end Run;
end Create_Scroll_Test;
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