Enforce power of two zoom levels.

Timeline/Scalebar.H

@@ -27,12 +27,12 @@
 
 class Scalebar : public Fl_Scrollbar
 {
-    double _zoom;
+    int _zoom;
 
     bool _zoom_changed;
 
-    double _zoom_min;
-    double _zoom_max;
+    int _zoom_min;
+    int _zoom_max;
 
     void constrain ( void )
         {
@@ -60,9 +60,9 @@ public:
 
     Scalebar ( int X, int Y, int W, int H ) : Fl_Scrollbar ( X, Y, W, H )
         {
-            _zoom = 1.0f;
+            _zoom = 1;
             _zoom_min = 0;
-            _zoom_max = 256;
+            _zoom_max = 4;
             _zoom_changed = false;
 
             step( 1 );
@@ -70,12 +70,12 @@ public:
 
     bool zoom_changed ( void ) const { return _zoom_changed; }
     double zoom ( void ) const { return _zoom; }
-    void zoom ( double v ) { _zoom = v;  }
+    void zoom ( int v ) { _zoom = v;  }
 //    double value ( void ) const { return Fl_Slider::value(); }
-    void zoom_range ( double zmin, double zmax ) { _zoom_min = zmin; _zoom_max = zmax; }
+    void zoom_range ( int zmin, int zmax ) { _zoom_min = zmin; _zoom_max = zmax; }
 
-    void zoom_out ( void ) { int z = _zoom; _zoom *= 2; constrain(); maybe_do_callback( z ); }
-    void zoom_in ( void ) {int z = _zoom; _zoom /= 2; constrain(); maybe_do_callback( z ); }
+    void zoom_out ( void ) { int z = _zoom; ++_zoom; constrain(); maybe_do_callback( z ); }
+    void zoom_in ( void ) {int z = _zoom; --_zoom; constrain(); maybe_do_callback( z ); }
 
     int
     handle ( int m )
@@ -91,12 +91,7 @@ public:
 
                     double z = _zoom;
 
-                    if ( d < 0 )
-                        while ( d++ )
-                            _zoom /= 2;
-                    else
-                        while ( d-- )
-                            _zoom *= 2;
+                    _zoom += d;
 
                     constrain();
 

Timeline/Timeline.C

@@ -65,7 +65,7 @@ Timeline::cb_scroll ( Fl_Widget *w )
     {
         if ( hscroll->zoom_changed() )
         {
-            _fpp = hscroll->zoom() * 1;
+            _fpp = hscroll->zoom();
 
 //            hscroll->range( 0, ts_to_x( _length ) - tracks->w() - Track::width() );
             const int tw = tracks->w() - Track::width() - vscroll->w();
@@ -94,8 +94,11 @@ Timeline::Timeline ( int X, int Y, int W, int H, const char* L ) : Fl_Overlay_Wi
 
         o->range( 0, 48000 * 300 );
 //        o->zoom_range( 1, 16384 );
-        o->zoom_range( 1, 65536 << 4 );
-        o->zoom( 256 );
+//        o->zoom_range( 1, 65536 << 4 );
+        o->zoom_range( 1, 20 );
+
+        o->zoom( 8 );
+
         o->type( FL_HORIZONTAL );
         o->callback( cb_scroll, this );
 
@@ -155,7 +158,7 @@ Timeline::Timeline ( int X, int Y, int W, int H, const char* L ) : Fl_Overlay_Wi
 
     {
 //        sample_rate() = engine->sample_rate();
-        _fpp = 256;
+        _fpp = 8;
 //        _length = sample_rate() * 60 * 2;
         /* FIXME: hack */
         _length = -1;
@@ -914,7 +917,7 @@ Timeline::zoom ( float secs )
     const int sw = w() - vscroll->w() - Track::width();
 
     /* FIXME: we actually need to set this in the scalebar */
-    _fpp = (int)((secs * sample_rate()) / sw);
+//    _fpp = (int)((secs * sample_rate()) / sw);
 
     redraw();
 }

Timeline/Timeline.H

@@ -98,7 +98,7 @@ class Timeline : public Fl_Overlay_Window, public RWLock
     static void cb_scroll ( Fl_Widget *w, void *v );
     void cb_scroll ( Fl_Widget *w );
 
-    float _fpp;                                                  /* frames per pixel */
+    int _fpp;                                                 /* frames per pixel, power of two */
     nframes_t _length;
 
 
@@ -127,11 +127,11 @@ public:
 
     Timeline ( int X, int Y, int W, int H, const char *L=0 );
 
-    float fpp ( void ) const { return _fpp; }
+    nframes_t fpp ( void ) const { return 1 << _fpp; }
     nframes_t length ( void ) const { return _length; }
     nframes_t sample_rate ( void ) const { return engine->sample_rate(); }
-    int ts_to_x( nframes_t ts ) const { return  ts / _fpp; }
-    nframes_t x_to_ts ( int x ) const { return x * _fpp; }
+    int ts_to_x( nframes_t ts ) const { return  ts >> _fpp; }
+    nframes_t x_to_ts ( int x ) const { return x << _fpp; }
 
     float beats_per_minute ( nframes_t when ) const;
     int beats_per_bar ( nframes_t when ) const;