Implement Fl_Packscroller, an alternative to Fl_Scroll better suited to containing vertical Fl_Packs.

FL/Fl_Packscroller.H

@@ -0,0 +1,195 @@
+
+/*******************************************************************************/
+/* Copyright (C) 2010 Jonathan Moore Liles                                     */
+/*                                                                             */
+/* This program 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 program 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 program; see the file COPYING.  If not,write to the Free Software */
+/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+/*******************************************************************************/
+
+/* Scrolling group suitable for containing a single child (a
+ * pack). When the Fl_Packscroller is resized, the child will be resized
+ * too. No scrollbars are displayed, but the widget responds to
+ * FL_MOUSEWHEEL events. */
+
+#pragma once
+
+#include <FL/Fl_Group.H>
+#include <FL/fl_draw.H>
+#include <FL/Fl.H>
+
+/* FIXME: Optimize scroll */
+
+class Fl_Packscroller : public Fl_Group
+{
+
+    int _increment;
+    int _yposition;
+    static const int sbh = 15;                                  /* scroll button height */
+
+public:
+
+    Fl_Packscroller ( int X, int Y, int W, int H, const char *L = 0 ) : Fl_Group( X, Y, W, H, L )
+        {
+            clip_children( 1 );
+
+            _increment = 30;
+            _yposition = 0;
+
+//            color( FL_WHITE );
+        }
+
+    int increment ( void ) const { return _increment; }
+    void increment ( int v ) { _increment = v; }
+
+    void yposition ( int v )
+        {
+            if ( ! children() )
+                return;
+
+            int Y = v;
+
+            if ( Y > 0 )
+                Y = 0;
+
+            const int H = h() - (sbh * 2);
+
+            Fl_Widget *o = child( 0 );
+
+            if ( o->h() > H &&
+                 Y + o->h() < H )
+                Y = H - o->h();
+            else if ( o->h() < H )
+                Y = 0;
+
+            if ( _yposition != Y )
+            {
+                _yposition = Y;
+
+                damage( FL_DAMAGE_SCROLL );
+            }
+        }
+
+    int yposition ( void ) const
+        {
+            if ( children() )
+                return child( 0 )->y() - (y() + sbh);
+
+            return 0;
+        }
+
+    void bbox ( int &X, int &Y, int &W, int &H )
+        {
+            X = x();
+            Y = y() + sbh;
+            W = w();
+            H = h() - (sbh * 2);
+        }
+
+    virtual void
+    draw ( void )
+        {
+            if ( ! children() )
+                return;
+
+            if ( ! fl_not_clipped( x(), y(), w(), h() ) )
+                return;
+
+//            draw_box();
+
+            Fl_Widget *o = child( 0 );
+
+            o->position( x(), y() + sbh + _yposition );
+
+            if ( damage() != FL_DAMAGE_CHILD )
+            {
+                fl_rectf( x(), y(), w(), h(), color() );
+
+                fl_font( FL_HELVETICA, 12 );
+
+                if ( o->y() != y() + sbh )
+                {
+                    fl_draw_box( box(), x(), y(), w(), sbh, color() );
+                    fl_color( FL_BLACK );
+                    fl_draw( "@2<", x(), y(), w(), sbh, FL_ALIGN_CENTER );
+                }
+
+                if ( o->h() > h() - (sbh * 2) && o->y() + o->h() != y() + h() - sbh )
+                {
+                    fl_draw_box( box(), x(), y() + h() - sbh, w(), sbh, color() );
+                    fl_color( FL_BLACK );
+                    fl_draw( "@2>", x(), y() + h() - sbh, w(), sbh, FL_ALIGN_CENTER );
+                }
+
+            }
+
+            fl_push_clip( x(), y() + sbh, w(), h() - (sbh * 2 ) );
+
+            draw_children();
+
+            fl_pop_clip();
+        }
+
+    virtual int
+    handle ( int m )
+        {
+            switch ( m )
+            {
+                case FL_PUSH:
+                {
+                    if ( Fl::event_button1() )
+                    {
+                        if ( Fl::event_inside( x(), y(), w(), sbh ) )
+                        {
+                            yposition( yposition() + ( h() / 4 ) );
+                            return 1;
+                        }
+                        else if ( Fl::event_inside(  x(), y() + h() - sbh, w(), sbh ) )
+                        {
+                            yposition( yposition() - (h() / 4 ) );
+                            return 1;
+                        }
+
+                        return Fl_Group::handle( m );
+                    }
+                }
+                case FL_ENTER:
+                case FL_LEAVE:
+                    return 1;
+                case FL_FOCUS:
+                    return 1;
+                case FL_KEYBOARD:
+                {
+                    if ( Fl::event_key() == FL_Up )
+                    {
+                        yposition( yposition() + ( h() / 4 ) );
+                        return 1;
+                    }
+                    else if ( Fl::event_key() == FL_Down )
+                    {
+                        yposition( yposition() - (h() / 4 ) );
+                        return 1;
+                    }
+                    return Fl_Group::handle( m );
+                }
+                case FL_MOUSEWHEEL:
+                {
+                    yposition( yposition() - ( Fl::event_dy() * _increment ) );
+
+                    return 1;
+                }
+            }
+
+            return Fl_Group::handle( m );
+        }
+};