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, 6 insertions, 1 deletions

diff --git a/FL/fl_draw.H b/FL/fl_draw.H
index 8db59b43b..66125d351 100644
--- a/FL/fl_draw.H
+++ b/FL/fl_draw.H
@@ -299,7 +299,12 @@ inline void fl_rect(Fl_Rect r) {
   fl_rect(r.x(), r.y(), r.w(), r.h());
 }
 
-/** Draw a dotted rectangle, used to indicate keyboard focus on a widget. */
+/** Draw a dotted rectangle, used to indicate keyboard focus on a widget.
+
+  This method draws the rectangle in the current color and independent of
+  the Fl::visible_focus() option. You may need to set the current color
+  with fl_color() before you call this.
+*/
 inline void fl_focus_rect(int x, int y, int w, int h) {
   fl_graphics_driver->focus_rect(x, y, w, h);
 }