Rewrite Panel navigation logic so it makes more sense

Rather than calculating distances between widget centers it now considers
the closeness of their edges.  It's not perfect but better than before.

diff --git a/source/panel.cpp b/source/panel.cpp
index 7e34c5947a7c7f4e0f93822eac08707c0ba3f104..dc2808ed4bf5a237d97aad9cd1ec75e068ac7580 100644 (file)
--- a/source/panel.cpp
+++ b/source/panel.cpp
@@ -66,49 +66,31 @@ bool Panel::navigate(Navigation nav)
 
        if(nav==NAV_UP || nav==NAV_DOWN || nav==NAV_LEFT || nav==NAV_RIGHT)
        {
-               int x = geom.w/2;
-               int y = geom.h/2;
+               int nav_x = (nav==NAV_RIGHT ? 1 : nav==NAV_LEFT ? -1 : 0);
+               int nav_y = (nav==NAV_UP ? 1 : nav==NAV_DOWN ? -1 : 0);
+
+               int origin_x, origin_y, origin_dim;
                if(input_focus)
                {
                        const Geometry &fgeom = input_focus->get_geometry();
-                       x = fgeom.x+fgeom.w/2;
-                       y = fgeom.y+fgeom.h/2;
+                       origin_x = fgeom.x+(nav_x*0.5+0.5)*fgeom.w;
+                       origin_y = fgeom.y+(nav_y*0.5+0.5)*fgeom.h;
+                       origin_dim = abs(nav_x)*fgeom.h+abs(nav_y)*fgeom.w;
                }
-               else if(nav==NAV_UP)
-                       y = 0;
-               else if(nav==NAV_DOWN)
-                       y = geom.h;
-               else if(nav==NAV_RIGHT)
-                       x = 0;
-               else if(nav==NAV_LEFT)
-                       x = geom.w;
-
-               Widget *sibling = 0;
-               int best_score = 0;
-               for(list<Child *>::const_iterator i=children.begin(); i!=children.end(); ++i)
+               else
                {
-                       if((*i)->widget==input_focus || !(*i)->widget->is_focusable())
-                               continue;
-
-                       const Geometry &cgeom = (*i)->widget->get_geometry();
-                       int dx = cgeom.x+cgeom.w/2-x;
-                       int dy = cgeom.y+cgeom.h/2-y;
-
-                       int score = -1;
-                       if(nav==NAV_UP && dy>0)
-                               score = dy+abs(dx)*4;
-                       else if(nav==NAV_DOWN && dy<0)
-                               score = -dy+abs(dx)*4;
-                       else if(nav==NAV_RIGHT && dx>0)
-                               score = dx+abs(dy)*4;
-                       else if(nav==NAV_LEFT && dx<0)
-                               score = -dx+abs(dy)*4;
-
-                       if(score>0 && (!sibling || score<best_score))
-                       {
-                               sibling = (*i)->widget;
-                               best_score = score;
-                       }
+                       origin_x = geom.w*(0.5-nav_x*0.5);
+                       origin_y = geom.h*(0.5-nav_y*0.5);
+                       origin_dim = abs(nav_x)*geom.h+abs(nav_y)*geom.w;
+               }
+
+               Widget *sibling = find_next_child(origin_x, origin_y, origin_dim, nav_x, nav_y);
+               if(!sibling && input_focus)
+               {
+                       const Geometry &fgeom = input_focus->get_geometry();
+                       origin_x -= fgeom.w*(nav_x*0.5);
+                       origin_y -= fgeom.h*(nav_y*0.5);
+                       sibling = find_next_child(origin_x, origin_y, origin_dim, nav_x, nav_y);
                }
 
                if(sibling)
@@ -123,6 +105,49 @@ bool Panel::navigate(Navigation nav)
        return false;
 }
 
+Widget *Panel::find_next_child(int origin_x, int origin_y, int origin_dim, int nav_x, int nav_y) const
+{
+       Widget *sibling = 0;
+       int best_score = 0;
+       for(list<Child *>::const_iterator i=children.begin(); i!=children.end(); ++i)
+       {
+               if((*i)->widget==input_focus || !(*i)->widget->is_focusable())
+                       continue;
+
+               const Geometry &cgeom = (*i)->widget->get_geometry();
+               int dx = compute_delta(cgeom.x, cgeom.w, origin_x, origin_dim, nav_x);
+               int dy = compute_delta(cgeom.y, cgeom.h, origin_y, origin_dim, nav_y);
+
+               int score = -1;
+               if(nav_y && nav_y*dy>=0)
+                       score = nav_y*dy+abs(dx)*4;
+               else if(nav_x && nav_x*dx>=0)
+                       score = nav_x*dx+abs(dy)*4;
+
+               if(score>=0 && (!sibling || score<best_score))
+               {
+                       sibling = (*i)->widget;
+                       best_score = score;
+               }
+       }
+
+       return sibling;
+}
+
+int Panel::compute_delta(int pos, int dim, int origin_pos, int origin_dim, int nav)
+{
+       if(nav<0)
+               return pos+dim-origin_pos;
+       else if(nav>0)
+               return pos-origin_pos;
+       else if(pos+dim<origin_pos-origin_dim/2)
+               return pos+dim+origin_dim/2-origin_pos;
+       else if(pos>origin_pos+origin_dim/2)
+               return pos-origin_pos-origin_dim/2;
+       else
+               return 0;
+}
+
 void Panel::on_geometry_change()
 {
        if(layout)

diff --git a/source/panel.h b/source/panel.h
index ebe765ddcf5f541c8d661231b1957536999978a8..2bc7a5ffdfa01ff7ce80af7a16f67d3afb54e1b4 100644 (file)
--- a/source/panel.h
+++ b/source/panel.h
@@ -73,8 +73,10 @@ protected:
 
 public:
        virtual bool navigate(Navigation);
-
 protected:
+       Widget *find_next_child(int, int, int, int, int) const;
+       static int compute_delta(int, int, int, int, int);
+
        virtual void on_geometry_change();
        virtual void on_child_added(Widget &);
        virtual void on_child_removed(Widget &);