Implement snap to bar.

Timeline.C

@@ -190,6 +190,23 @@ Timeline::beats_per_minute ( nframes_t when, float bpm )
     tempo_track->add( new Tempo_Point( when, bpm ) );
 }
 
+/** return the absolute pixel of the nearest measure line to /x/ */
+int
+Timeline::nearest_line ( int ix )
+{
+    for ( int x = ix - 10; x < ix + 10; ++x )
+    {
+        const int measure = ts_to_x( (double)(sample_rate * 60) / beats_per_minute( x_to_ts( x ) + xoffset ));
+
+//        const int abs_x = ts_to_x( xoffset ) + x;
+
+        if ( 0 == x % measure )
+            return x;
+    }
+
+    return -1;
+}
+
 /* draw appropriate measure lines inside the given bounding box */
 void
 Timeline::draw_measure_lines ( int X, int Y, int W, int H, Fl_Color color )

Timeline.H

@@ -106,6 +106,8 @@ struct Timeline : public Fl_Group
     float beats_per_minute ( nframes_t when ) const;
     int beats_per_bar ( nframes_t when ) const;
     void beats_per_minute ( nframes_t when, float bpm );
+    int nearest_line ( int ix );
+
     void draw_measure_lines ( int X, int Y, int W, int H, Fl_Color color );
     void position ( int X );
     void draw ( void );

Track.C

@@ -119,6 +119,14 @@ Track::snap ( Track_Widget *r )
     int rx1 = r->x();
     int rx2 = r->x() + r->w();
 
+    int nx = timeline->nearest_line( r->abs_x() );
+
+    if ( nx >= 0 )
+    {
+        r->offset( timeline->x_to_ts( nx ) );
+        return;
+    }
+
     for ( list <Track_Widget*>::iterator i = _widgets.begin(); i != _widgets.end(); i++ )
     {
         const Track_Widget *w = (*i);