Improve focus box drawing and documentation

Add new method
  Fl_Widget::draw_focus(Fl_Boxtype t, int x, int y, int w, int h, Fl_Color bg)

  ... with background color for correct contrast testing (in Fl_Tabs)

Draw the focus box of the "tabs" of Fl_Tabs widgets with the correct
  boxtype and background color.

Make 'unsigned int visible_focus()' const so it can be used in 'const'
  methods.

Do not draw the focus box if the per-widget focus box option is off.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/Fl_Tabs.cxx b/src/Fl_Tabs.cxx
index 4c83b6476..9b626456b 100644
--- a/src/Fl_Tabs.cxx
+++ b/src/Fl_Tabs.cxx
@@ -417,7 +417,7 @@ void Fl_Tabs::draw_tab(int x1, int x2, int W, int H, Fl_Widget* o, int what) {
     o->draw_label(x1, y() + yofs, W, H - yofs, tab_align());
 
     if (Fl::focus() == this && o->visible())
-      draw_focus(box(), x1, y(), W, H);
+      draw_focus(bt, x1, y(), W, H, bc);
 
     fl_pop_clip();
   } else {
@@ -435,7 +435,7 @@ void Fl_Tabs::draw_tab(int x1, int x2, int W, int H, Fl_Widget* o, int what) {
     o->draw_label(x1, y() + h() - H, W, H - yofs, tab_align());
 
     if (Fl::focus() == this && o->visible())
-      draw_focus(box(), x1, y() + h() - H, W, H);
+      draw_focus(bt, x1, y() + h() - H, W, H, bc);
 
     fl_pop_clip();
   }