Avoid drawing the scroll bars if the widget is non-visible

ChangeLog

@@ -1,3 +1,6 @@
+2019-06-02  Markus Gans  <guru.mail@muenster.de>
+	* Avoid drawing the scroll bars if the widget is non-visible
+
 2019-05-27  Markus Gans  <guru.mail@muenster.de>
 	* Use the Singleton design pattern to get a single object instance 
 	  via FTerm
@@ -120,7 +123,7 @@
 	  the switch statement with a vector of lambda expressions
 
 2018-12-09  Markus Gans  <guru.mail@muenster.de>
-	* Better handling of the scrollbar maximum
+	* Better handling of the scroll bar maximum
 	* Deactivate copy constructor and assignment operator with "= delete"
 	* Use nullptr instead of 0 to initialize a pointer values
 
@@ -136,7 +139,7 @@
 	* Fix compile in optimization level 2 for newer gcc
 
 2018-11-27  Markus Gans  <guru.mail@muenster.de>
-	* Correct vertical scrollbar position after sorting in FListView
+	* Correct vertical scroll bar position after sorting in FListView
 
 2018-11-25  Markus Gans  <guru.mail@muenster.de>
 	* Version 0.5.0

src/flistbox.cpp

@@ -737,6 +737,8 @@ void FListBox::adjustSize()
   hbar->setWidth (width + nf_offset, false);
   hbar->resize();
 
+  if ( isShown() )
+  {
     if ( isHorizontallyScrollable() )
       hbar->show();
     else
@@ -746,6 +748,7 @@ void FListBox::adjustSize()
       vbar->show();
     else
       vbar->hide();
+  }
 }
 
 
@@ -1180,11 +1183,14 @@ void FListBox::recalculateHorizontalBar (std::size_t len, bool has_brackets)
     hbar->setPageSize (int(max_line_width), int(getWidth() - nf_offset - 4));
     hbar->calculateSliderValues();
 
+    if ( isShown() )
+    {
       if ( isHorizontallyScrollable() )
         hbar->show();
       else
         hbar->hide();
     }
+  }
 }
 
 //----------------------------------------------------------------------
@@ -1197,10 +1203,13 @@ void FListBox::recalculateVerticalBar (std::size_t element_count)
   vbar->setPageSize (int(element_count), int(getHeight()) - 2);
   vbar->calculateSliderValues();
 
+  if ( isShown() )
+  {
     if ( isVerticallyScrollable() )
       vbar->show();
     else
       vbar->hide();
+  }
 }
 
 //----------------------------------------------------------------------

src/flistview.cpp

@@ -1361,6 +1361,8 @@ void FListView::adjustSize()
   hbar->setWidth (width, false);
   hbar->resize();
 
+  if ( isShown() )
+  {
     if ( isHorizontallyScrollable() )
       hbar->show();
     else
@@ -1370,6 +1372,7 @@ void FListView::adjustSize()
       vbar->show();
     else
       vbar->hide();
+  }
 }
 
 
@@ -1966,11 +1969,14 @@ void FListView::recalculateHorizontalBar (std::size_t len)
     hbar->setPageSize (int(max_line_width), int(getWidth() - nf_offset) - 4);
     hbar->calculateSliderValues();
 
+    if ( isShown() )
+    {
       if ( isHorizontallyScrollable() )
         hbar->show();
       else
         hbar->hide();
     }
+  }
 }
 
 //----------------------------------------------------------------------
@@ -1983,10 +1989,13 @@ void FListView::recalculateVerticalBar (std::size_t element_count)
   vbar->setPageSize (int(element_count), int(getHeight()) - 2);
   vbar->calculateSliderValues();
 
+  if ( isShown() )
+  {
     if ( isVerticallyScrollable() )
       vbar->show();
     else
       vbar->hide();
+  }
 }
 
 //----------------------------------------------------------------------

src/fscrollview.cpp

@@ -814,6 +814,9 @@ void FScrollView::calculateScrollbarPos()
 //----------------------------------------------------------------------
 void FScrollView::setHorizontalScrollBarVisibility()
 {
+  if ( ! isShown() )
+    return;
+
   switch ( hMode )
   {
     case fc::Auto:
@@ -836,6 +839,9 @@ void FScrollView::setHorizontalScrollBarVisibility()
 //----------------------------------------------------------------------
 void FScrollView::setVerticalScrollBarVisibility()
 {
+  if ( ! isShown() )
+    return;
+
   switch ( vMode )
   {
     case fc::Auto:

src/ftermlinux.cpp

@@ -1237,13 +1237,15 @@ inline void FTermLinux::initSpecialCharacter()
 //----------------------------------------------------------------------
 sInt16 FTermLinux::getFontPos (wchar_t ucs)
 {
+  constexpr sInt16 NOT_FOUND = -1;
+
   for (std::size_t n = 0; n < screen_unicode_map.entry_ct; n++)
   {
     if ( screen_unicode_map.entries[n].unicode == ucs )
       return sInt16(screen_unicode_map.entries[n].fontpos);
   }
 
-  return -1;
+  return NOT_FOUND;
 }
 
 //----------------------------------------------------------------------