Make zoom to time work again.

Timeline/Scalebar.H

@@ -70,7 +70,7 @@ public:
 
     bool zoom_changed ( void ) const { return _zoom_changed; }
     double zoom ( void ) const { return _zoom; }
-    void zoom ( int v ) { _zoom = v;  }
+    void zoom ( int v ) { int z = _zoom ; _zoom = v; constrain(); maybe_do_callback( z ); }
 //    double value ( void ) const { return Fl_Slider::value(); }
     void zoom_range ( int zmin, int zmax ) { _zoom_min = zmin; _zoom_max = zmax; }
 

Timeline/Timeline.C

@@ -1061,10 +1061,14 @@ Timeline::zoom_out ( void )
 void
 Timeline::zoom ( float secs )
 {
-    const int sw = w() - vscroll->w() - Track::width();
+    const int sw = tracks->w() - Track::width();
 
-    /* FIXME: we actually need to set this in the scalebar */
-//    _fpp = (int)((secs * sample_rate()) / sw);
+    int fpp = (int)((secs * sample_rate()) / sw);
+
+    int p = 0;
+    while ( 1 << p < fpp ) p++;
+
+    hscroll->zoom( p );
 
     redraw();
 }