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

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
@@ -747,6 +749,7 @@ void FListBox::adjustSize()
     else
       vbar->hide();
   }
+}
 
 
 // private methods of FListBox
@@ -1180,12 +1183,15 @@ 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();
     }
   }
+}
 
 //----------------------------------------------------------------------
 void FListBox::recalculateVerticalBar (std::size_t element_count)
@@ -1197,11 +1203,14 @@ 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();
   }
+}
 
 //----------------------------------------------------------------------
 inline void FListBox::getWidgetFocus()

src/flistview.cpp

@@ -1361,6 +1361,8 @@ void FListView::adjustSize()
   hbar->setWidth (width, false);
   hbar->resize();
 
+  if ( isShown() )
+  {
     if ( isHorizontallyScrollable() )
       hbar->show();
     else
@@ -1371,6 +1373,7 @@ void FListView::adjustSize()
     else
       vbar->hide();
   }
+}
 
 
 // private methods of FListView
@@ -1966,12 +1969,15 @@ 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();
     }
   }
+}
 
 //----------------------------------------------------------------------
 void FListView::recalculateVerticalBar (std::size_t element_count)
@@ -1983,11 +1989,14 @@ 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();
   }
+}
 
 //----------------------------------------------------------------------
 void FListView::mouseHeaderClicked()

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;
 }
 
 //----------------------------------------------------------------------