Implement new Fl_Panzoomer widget, for panning and zooming around a thumbnail instead of scrollbars.

FL/Fl_Panzoomer.H

@@ -0,0 +1,105 @@
+
+/*******************************************************************************/
+/* Copyright (C) 2012 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.  */
+/*******************************************************************************/
+
+#ifndef Fl_Panzoomer_H
+#define Fl_Panzoomer_H
+
+#include <FL/Fl_Valuator.H>
+
+class FL_EXPORT Fl_Panzoomer : public Fl_Valuator
+{
+protected:
+
+    typedef void (draw_thumbnail_view_callback_t)( int X,int Y,int W,int H,void *v );
+
+    draw_thumbnail_view_callback_t *_draw_thumbnail_view_callback;
+    void *_draw_thumbnail_view_userdata;
+
+    int _zoom;
+    bool _zoom_changed;
+    int _zoom_min;
+    int _zoom_max;
+
+    double _ymin, _ymax, _xmin, _xmax;
+    double _xpos, _ypos;
+
+    /* size of the window vertically and horizontally as a value
+     * between 0-1. */
+    double _ysize, _xsize;
+
+public:
+
+    Fl_Panzoomer ( int X, int Y, int W, int H, const char *L=0 );
+    virtual ~Fl_Panzoomer ( ) { }
+
+    virtual void draw ( void );
+    virtual int handle ( int m );
+
+    /* these behave like Fl_Scrollbar::value() */
+    /* first and total are the bounds, size is the size of the window,
+     * and pos is the leftmost edge. */
+    int x_value ( int pos, int size, int first, int total )
+        {
+            _xmin = first;
+            _xmax = total;
+            _xpos = pos;
+            _xsize = size;
+
+            redraw();
+
+            return pos;
+        }
+
+    int y_value ( int pos, int size, int first, int total )
+        {
+            _ymin = first;
+            _ymax = total;
+            _ypos = pos;
+            _ysize = size;
+
+            redraw();
+
+            return pos;
+        }
+
+    double x_value ( void ) const { return _xpos; }
+    double y_value ( void ) const { return _ypos; }
+    void x_value ( double v );
+    void y_value ( double v );
+
+    void cursor_bounds ( int &cx, int &cy, int &cw, int &ch ) const;
+
+    bool zoom_changed ( void ) const { return _zoom_changed; }
+    double zoom ( void ) const { return _zoom; }
+    void zoom ( int v );
+
+    void zoom_range ( int zmin, int zmax ) { _zoom_min = zmin; _zoom_max = zmax; }
+
+    void zoom_in ( void ) { int z = _zoom; zoom( _zoom + 1 ); if ( z != _zoom ) do_callback(); }
+    void zoom_out ( void ) { int z = _zoom; zoom( _zoom - 1 ); if ( z != _zoom ) do_callback(); }
+
+    /* set this callback if you want to display a thumbnail view of the canvas being scrolled */
+    void draw_thumbnail_view_callback( draw_thumbnail_view_callback_t *cb, void *v )
+        {
+            _draw_thumbnail_view_callback = cb;
+            _draw_thumbnail_view_userdata = v;
+        }
+};
+
+#endif

src/Fl_Panzoomer.cxx

@@ -0,0 +1,244 @@
+
+/*******************************************************************************/
+/* Copyright (C) 2012 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.  */
+/*******************************************************************************/
+
+#include <FL/Fl.H>
+#include <FL/fl_draw.H>
+#include <FL/Fl_Panzoomer.H>
+
+Fl_Panzoomer::Fl_Panzoomer ( int X, int Y, int W, int H, const char *L ) :
+    Fl_Valuator( X,Y,W,H,L )
+{
+    _zoom = 1;
+    _zoom_min = 0;
+    _zoom_max = 4;
+    _zoom_changed = false;
+
+    _ymin = _ymax = _xmin = _xmax = _ysize = _xsize =
+    _xpos = _ypos = 0;
+
+    step( 1 );
+}
+
+void
+Fl_Panzoomer::x_value ( double v ) { 
+    if ( _xpos == v )
+        return;
+
+    _xpos = v;
+        if ( _xpos < _xmin )
+            _xpos = _xmin;
+        else if ( _xpos > _xmax - _xsize)
+            _xpos = _xmax - _xsize;
+
+        damage( FL_DAMAGE_USER1 );
+    }
+
+void
+Fl_Panzoomer::y_value ( double v ) {
+        if ( _ypos == v )
+            return;
+
+        _ypos = v; 
+        
+        if ( _ypos < _ymin )
+            _ypos = _ymin;
+        else if ( _ypos > _ymax - _ysize )
+            _ypos = _ymax - _ysize;
+
+        damage( FL_DAMAGE_USER1 );
+    }
+
+void
+Fl_Panzoomer::zoom ( int v )
+{
+        int z = _zoom;
+
+        _zoom = v;
+
+        if ( _zoom > _zoom_max )
+            _zoom = _zoom_max;
+        else
+            if ( _zoom < _zoom_min )
+                _zoom = _zoom_min;
+
+        if ( z != _zoom )
+        {
+            _zoom_changed = true;
+            do_callback();
+            _zoom_changed = false;
+        }
+}
+
+void
+Fl_Panzoomer::draw ( void )
+{
+    type( FL_HORIZONTAL );
+
+    fl_draw_box( box(), x(),y(),w(),h(), color());
+//    fl_rectf( x(),y(),w(),h(), color() );
+
+    fl_push_clip( x(), y(), w(), h());
+
+    int X,Y,W,H;
+    
+    X = x() + Fl::box_dx( box() );
+    Y = y() + Fl::box_dy( box() );
+    W = w() - Fl::box_dw( box() );
+    H = h() - Fl::box_dh( box() );
+    
+    if ( _draw_thumbnail_view_callback )
+        _draw_thumbnail_view_callback( X,Y,W,H, _draw_thumbnail_view_userdata );
+
+    int cx,cy,cw,ch;
+
+    cursor_bounds( cx,cy,cw,ch );
+
+    fl_rectf( cx,cy,cw,ch,
+              fl_color_add_alpha( FL_WHITE, 50 ));
+
+    fl_rect( cx,cy,cw,ch,
+              fl_color_add_alpha( FL_WHITE, 80 ));
+    
+    fl_pop_clip();
+
+    draw_label();
+}
+
+void
+Fl_Panzoomer::cursor_bounds ( int &cx, int &cy, int &cw, int &ch ) const
+{
+    int X,Y,W,H;
+    
+    X = x() + Fl::box_dx( box() );
+    Y = y() + Fl::box_dy( box() );
+    W = w() - Fl::box_dw( box() );
+    H = h() - Fl::box_dh( box() );
+
+    double hval;
+    if ( _xmin == _xmax )
+        hval = 0.5;
+    else 
+    {
+        hval = (_xpos-_xmin)/(_xmax-_xmin);
+
+        if (hval > 1.0) hval = 1.0;
+        else if (hval < 0.0) hval = 0.0;
+    }
+
+    double vval;
+    if ( _ymin == _ymax )
+        vval = 0.5;
+    else 
+    {
+        vval = (_ypos-_ymin)/(_ymax-_ymin);
+
+        if (vval > 1.0) vval = 1.0;
+        else if (vval < 0.0) vval = 0.0;
+    }
+
+    cx = X + (hval) * W + .5;
+    cy = _ymax ? Y + (vval) * H + .5 : Y;
+    cw = W * (_xsize/_xmax);
+    ch = _ymax ? H * (_ysize/_ymax) : H;
+}
+
+int
+Fl_Panzoomer::handle ( int m )
+{
+    static int xoffset;
+    static int yoffset;
+    static bool drag;
+
+    switch ( m )
+    {
+        case FL_ENTER:
+        case FL_LEAVE:
+            return 1;
+        case FL_PUSH:
+        {
+            int cx,cy,cw,ch;
+
+            cursor_bounds( cx,cy,cw,ch );
+
+            xoffset = Fl::event_x() - cx;
+            yoffset = Fl::event_y() - cy;
+
+            if ( Fl::event_inside( cx,cy,cw,ch ) &&
+                 Fl::event_button1() )
+                drag = true;
+
+            return 1;
+        }
+        case FL_DRAG:
+        {
+            int cx,cy,cw,ch;
+            
+            cursor_bounds( cx,cy,cw,ch );
+            
+            if ( drag )
+            {
+                x_value((((double)Fl::event_x() - x() - xoffset) / w()) * _xmax);
+                y_value( (((double)Fl::event_y() - y() - yoffset) / h()) * _ymax );
+                
+                if ( when() & FL_WHEN_CHANGED )
+                    do_callback();
+            }
+            
+            return 1;
+            break;
+        }
+        case FL_MOUSEWHEEL:
+        {
+            int d = Fl::event_dy();
+
+            if ( Fl::event_ctrl() )
+            {                
+                zoom( _zoom + d );
+                
+                return 1;
+            }
+            else if (!Fl::event_alt() && !Fl::event_shift())
+            {
+                y_value( _ypos + ( (double)d*5 / h() ) * _ymax );
+                
+                if ( when() & FL_WHEN_CHANGED )
+                    do_callback();
+
+                return 1;
+            }
+            return 0;
+            break;
+        }
+        case FL_RELEASE:
+        {
+            if ( drag )
+            {
+                drag = false;
+
+                if ( when() & FL_WHEN_RELEASE )
+                    do_callback();
+            }
+            
+            return 1;
+        }
+    }
+
+    return 0;
+}
+

src/Makefile

@@ -69,6 +69,7 @@ CPPFILES = \
 	Fl_Overlay_Window.cxx \
 	Fl_Pack.cxx \
 	Fl_Paged_Device.cxx \
+	Fl_Panzoomer.cxx \
 	Fl_Pixmap.cxx \
 	Fl_Positioner.cxx \
 	Fl_Preferences.cxx \