Generalize scroll functions in FScrollView

ChangeLog

@@ -1,4 +1,6 @@
 2017-12-27  Markus Gans  <guru.mail@muenster.de>
+	* Generalize scroll functions in FScrollView
+	* Refactoring FScrollbar::drawBar
 	* Refactoring FLineEdit::onKeyPress
 	* Refactoring FMenu::onKeyPress
 	* Refactoring FDialog::onKeyPress

include/final/fscrollbar.h

@@ -107,7 +107,8 @@ class FScrollbar : public FWidget
     void  resize();
     void  redraw();
     void  calculateSliderValues();
-    void  drawButtons();
+    void  drawVerticalBar();
+    void  drawHorizontalBar();
     void  drawBar();
 
     // Event handlers
@@ -127,6 +128,7 @@ class FScrollbar : public FWidget
     // Methods
     void  init();
     void  draw();
+    void  drawButtons();
     sType getClickedScrollType (int, int);
     void  processMiddleButton (int, int);
     void  processScroll();

include/final/fscrollview.h

@@ -179,6 +179,7 @@ class FScrollView : public FWidget
     int               nf_offset;
     bool              border;
     bool              use_own_print_area;
+    bool              update_scrollbar;
     fc::scrollBarMode vMode;  // fc:Auto, fc::Hidden or fc::Scroll
     fc::scrollBarMode hMode;
 };

src/flistbox.cpp

@@ -195,7 +195,7 @@ void FListBox::setGeometry (int x, int y, int w, int h, bool adjust)
   if ( isNewFont() )
   {
     vbar->setGeometry (getWidth(), 2, 2, getHeight() - 2);
-    hbar->setGeometry (1, getHeight(), getWidth() - 2, 1);
+    hbar->setGeometry (1, getHeight(), getWidth() - 2 - nf_offset, 1);
   }
   else
   {
@@ -1041,7 +1041,7 @@ void FListBox::adjustSize()
   hbar->setMaximum (max_line_width - getClientWidth() + 2);
   hbar->setPageSize (max_line_width, getClientWidth() - 2);
   hbar->setY (getHeight());
-  hbar->setWidth (getClientWidth(), false);
+  hbar->setWidth (getClientWidth() + nf_offset, false);
   hbar->resize();
 
   if ( element_count <= getClientHeight() )

src/fscrollbar.cpp

@@ -106,7 +106,7 @@ void FScrollbar::setMaximum (int maximum)
 }
 
 //----------------------------------------------------------------------
-void FScrollbar::setRange(int minimum, int maximum)
+void FScrollbar::setRange (int minimum, int maximum)
 {
   min = minimum;
   max = maximum;
@@ -166,6 +166,7 @@ void FScrollbar::setOrientation (int o)
     if ( isNewFont() )
       nf = 2;
   }
+
   slider_length = bar_length = length - nf - 2;
   bar_orientation = o;
 }
@@ -249,165 +250,122 @@ void FScrollbar::calculateSliderValues()
 }
 
 //----------------------------------------------------------------------
-void FScrollbar::drawButtons()
+void FScrollbar::drawVerticalBar()
 {
-  setColor (wc.scrollbar_button_fg, wc.scrollbar_button_bg);
+  int z;
+  setColor (wc.scrollbar_fg, wc.scrollbar_bg);
+
+  for (z = 1; z <= slider_pos; z++)
+  {
+    setPrintPos (1, 1 + z);
+
+    if ( isNewFont() )
+      print (fc::NF_border_line_left);  // ⎸
+
+    if ( isMonochron() || max_color < 16 )
+      print (fc::MediumShade);  // ▒
+    else
+      print (' ');
+  }
+
+  setColor (wc.scrollbar_bg, wc.scrollbar_fg);
+
+  if ( isMonochron() )
+    setReverse(false);
+
+  for (z = 1; z <= slider_length; z++)
+  {
+    setPrintPos (1, 1 + slider_pos + z);
+
+    if ( isNewFont() )
+      print (' ');
+
+    print (' ');
+  }
+
+  if ( isMonochron() )
+    setReverse(true);
+
+  setColor (wc.scrollbar_fg, wc.scrollbar_bg);
+
+  for (z = slider_pos + slider_length + 1; z <= bar_length; z++)
+  {
+    setPrintPos (1, 1 + z);
+
+    if ( isNewFont() )
+      print (fc::NF_border_line_left);  // ⎸
+
+    if ( isMonochron() || max_color < 16 )
+      print (fc::MediumShade);
+    else
+      print (' ');
+  }
+
+  if ( isMonochron() )
+    setReverse(false);
+}
+
+//----------------------------------------------------------------------
+void FScrollbar::drawHorizontalBar()
+{
+  int z;
+  setColor (wc.scrollbar_fg, wc.scrollbar_bg);
 
   if ( isNewFont() )
-  {
+    setPrintPos (3, 1);
-    setPrintPos (1,1);
-
-    if ( bar_orientation == fc::vertical )
-    {
-      print (fc::NF_rev_up_arrow1);
-      print (fc::NF_rev_up_arrow2);
-      setPrintPos (1, length);
-      print (fc::NF_rev_down_arrow1);
-      print (fc::NF_rev_down_arrow2);
-    }
-    else  // horizontal
-    {
-      print (fc::NF_rev_left_arrow1);
-      print (fc::NF_rev_left_arrow2);
-      setPrintPos (length - 1, 1);
-      print (fc::NF_rev_right_arrow1);
-      print (fc::NF_rev_right_arrow2);
-    }
-  }
   else
+    setPrintPos (2, 1);
+
+  for (; z < slider_pos; z++)
   {
-    setPrintPos (1,1);
+    if ( isNewFont() )
-
+      print (fc::NF_border_line_upper);  // ¯
-    if ( isMonochron() )
+    else if ( isMonochron() || max_color < 16 )
-      setReverse(true);
+      print (fc::MediumShade);  // ▒
-
+    else
-    if ( bar_orientation == fc::vertical )
+      print (' ');
-    {
-      print (fc::BlackUpPointingTriangle);    // ▲
-      setPrintPos (1, length);
-      print (fc::BlackDownPointingTriangle);  // ▼
-    }
-    else  // horizontal
-    {
-      print (fc::BlackLeftPointingPointer);   // ◄
-      setPrintPos (length, 1);
-      print (fc::BlackRightPointingPointer);  // ►
-    }
-
-    if ( isMonochron() )
-      setReverse(false);
   }
+
+  setColor (wc.scrollbar_bg, wc.scrollbar_fg);
+
+  if ( isMonochron() )
+    setReverse(false);
+
+  for (z = 0; z < slider_length; z++)
+    print (' ');
+
+  if ( isMonochron() )
+    setReverse(true);
+
+  setColor (wc.scrollbar_fg, wc.scrollbar_bg);
+  z = slider_pos + slider_length + 1;
+
+  for (; z <= bar_length; z++)
+  {
+    if ( isNewFont() )
+      print (fc::NF_border_line_upper);  // ¯
+    else if ( isMonochron() || max_color < 16 )
+      print (fc::MediumShade);  // ▒
+    else
+      print (' ');
+  }
+
+  if ( isMonochron() )
+    setReverse(false);
 }
 
 //----------------------------------------------------------------------
 void FScrollbar::drawBar()
 {
-  int z;
-
   if ( slider_pos == current_slider_pos || length < 3 )
     return;
 
   if ( bar_orientation == fc::vertical )
-  {
+    drawVerticalBar();
-    setColor (wc.scrollbar_fg, wc.scrollbar_bg);
-
-    for (z = 1; z <= slider_pos; z++)
-    {
-      setPrintPos (1, 1 + z);
-
-      if ( isNewFont() )
-        print (fc::NF_border_line_left);  // ⎸
-
-      if ( isMonochron() || max_color < 16 )
-        print (fc::MediumShade);  // ▒
-      else
-        print (' ');
-    }
-
-    setColor (wc.scrollbar_bg, wc.scrollbar_fg);
-
-    if ( isMonochron() )
-      setReverse(false);
-
-    for (z = 1; z <= slider_length; z++)
-    {
-      setPrintPos (1, 1 + slider_pos + z);
-
-      if ( isNewFont() )
-        print (' ');
-
-      print (' ');
-    }
-
-    if ( isMonochron() )
-      setReverse(true);
-
-    setColor (wc.scrollbar_fg, wc.scrollbar_bg);
-
-    for (z = slider_pos + slider_length + 1; z <= bar_length; z++)
-    {
-      setPrintPos (1, 1 + z);
-
-      if ( isNewFont() )
-        print (fc::NF_border_line_left);  // ⎸
-
-      if ( isMonochron() || max_color < 16 )
-        print (fc::MediumShade);
-      else
-        print (' ');
-    }
-  }
   else  // horizontal
-  {
+    drawHorizontalBar();
-    setColor (wc.scrollbar_fg, wc.scrollbar_bg);
-    z = 0;
-
-    if ( isNewFont() )
-      setPrintPos (3 + z, 1);
-    else
-      setPrintPos (2 + z, 1);
-
-    for (; z < slider_pos; z++)
-    {
-      if ( isNewFont() )
-        print (fc::NF_border_line_upper);  // ¯
-      else if ( isMonochron() || max_color < 16 )
-        print (fc::MediumShade);  // ▒
-      else
-        print (' ');
-    }
-
-    setColor (wc.scrollbar_bg, wc.scrollbar_fg);
-
-    if ( isMonochron() )
-      setReverse(false);
-
-    z = 0;
-
-    for (; z < slider_length; z++)
-      print (' ');
-
-    if ( isMonochron() )
-      setReverse(true);
-
-    setColor (wc.scrollbar_fg, wc.scrollbar_bg);
-    z = slider_pos + slider_length + 1;
-
-    for (; z <= bar_length; z++)
-    {
-      if ( isNewFont() )
-        print (fc::NF_border_line_upper);  // ¯
-      else if ( isMonochron() || max_color < 16 )
-        print (fc::MediumShade);  // ▒
-      else
-        print (' ');
-    }
-  }
 
   current_slider_pos = slider_pos;
-
-  if ( isMonochron() )
-    setReverse(false);
 }
 
 //----------------------------------------------------------------------
@@ -431,7 +389,7 @@ void FScrollbar::onMouseDown (FMouseEvent* ev)
     return;
   }
 
-  // process LeftButton
+  // Process left button
   scroll_type = getClickedScrollType(mouse_x, mouse_y);
 
   if ( scroll_type == FScrollbar::noScroll )
@@ -519,7 +477,7 @@ void FScrollbar::onMouseMove (FMouseEvent* ev)
     return;
   }
 
-  // process LeftButton
+  // Process left button
   new_scroll_type = getClickedScrollType(mouse_x, mouse_y);
 
   if ( scroll_type == FScrollbar::scrollJump )
@@ -639,6 +597,57 @@ void FScrollbar::draw()
   drawBar();
 }
 
+//----------------------------------------------------------------------
+void FScrollbar::drawButtons()
+{
+  setColor (wc.scrollbar_button_fg, wc.scrollbar_button_bg);
+
+  if ( isNewFont() )
+  {
+    setPrintPos (1,1);
+
+    if ( bar_orientation == fc::vertical )
+    {
+      print (fc::NF_rev_up_arrow1);
+      print (fc::NF_rev_up_arrow2);
+      setPrintPos (1, length);
+      print (fc::NF_rev_down_arrow1);
+      print (fc::NF_rev_down_arrow2);
+    }
+    else  // horizontal
+    {
+      print (fc::NF_rev_left_arrow1);
+      print (fc::NF_rev_left_arrow2);
+      setPrintPos (length - 1, 1);
+      print (fc::NF_rev_right_arrow1);
+      print (fc::NF_rev_right_arrow2);
+    }
+  }
+  else
+  {
+    setPrintPos (1,1);
+
+    if ( isMonochron() )
+      setReverse(true);
+
+    if ( bar_orientation == fc::vertical )
+    {
+      print (fc::BlackUpPointingTriangle);    // ▲
+      setPrintPos (1, length);
+      print (fc::BlackDownPointingTriangle);  // ▼
+    }
+    else  // horizontal
+    {
+      print (fc::BlackLeftPointingPointer);   // ◄
+      setPrintPos (length, 1);
+      print (fc::BlackRightPointingPointer);  // ►
+    }
+
+    if ( isMonochron() )
+      setReverse(false);
+  }
+}
+
 //----------------------------------------------------------------------
 FScrollbar::sType FScrollbar::getClickedScrollType (int x, int y)
 {

src/fscrollview.cpp

@@ -41,6 +41,7 @@ FScrollView::FScrollView (FWidget* parent)
   , nf_offset(0)
   , border(true)
   , use_own_print_area(false)
+  , update_scrollbar(true)
   , vMode(fc::Auto)
   , hMode(fc::Auto)
 {
@@ -330,10 +331,14 @@ void FScrollView::scrollTo (int x, int y)
 {
   short& xoffset = viewport_geometry.x1_ref();
   short& yoffset = viewport_geometry.y1_ref();
+  short  xoffset_before = xoffset;
+  short  yoffset_before = yoffset;
   short  xoffset_end = short(getScrollWidth() - getViewportWidth());
   short  yoffset_end = short(getScrollHeight() - getViewportHeight());
   int    save_width = viewport_geometry.getWidth();
   int    save_height = viewport_geometry.getHeight();
+  bool   changeX = false;
+  bool   changeY = false;
   x--;
   y--;
 
@@ -355,25 +360,48 @@ void FScrollView::scrollTo (int x, int y)
   if ( xoffset > xoffset_end )
     xoffset = xoffset_end;
 
-  viewport_geometry.setWidth(save_width);
+  changeX = bool(xoffset_before != xoffset);
-  viewport_geometry.setHeight(save_height);
+  changeY = bool(yoffset_before != yoffset);
+
+  if ( ! isVisible() || ! viewport || ! (changeX || changeY) )
+    return;
+
+  if ( changeX )
+  {
+    viewport_geometry.setWidth(save_width);
+    setTopPadding (1 - yoffset);
+    setBottomPadding (1 - (yoffset_end - yoffset));
+
+    if ( update_scrollbar )
+    {
+      hbar->setValue (xoffset);
+      drawHBar();
+    }
+  }
+
+  if ( changeY )
+  {
+    viewport_geometry.setHeight(save_height);
+    setLeftPadding (1 - xoffset);
+    setRightPadding (1 - (xoffset_end - xoffset) + nf_offset);
+
+    if ( update_scrollbar )
+    {
+      vbar->setValue (yoffset);
+      drawVBar();
+    }
+  }
+
   viewport->has_changes = true;
-  setTopPadding (1 - yoffset);
-  setLeftPadding (1 - xoffset);
-  setBottomPadding (1 - (yoffset_end - yoffset));
-  setRightPadding (1 - (xoffset_end - xoffset) + nf_offset);
   copy2area();
-  hbar->setValue (xoffset);
-  vbar->setValue (yoffset);
-  drawHBar();
-  drawVBar();
   updateTerminal();
+
 }
 
 //----------------------------------------------------------------------
 void FScrollView::scrollBy (int dx, int dy)
 {
-  scrollTo (getScrollX() + dx, getScrollY() + dy);
+  scrollTo (1 + getScrollX() + dx, 1 + getScrollY() + dy);
 }
 
 //----------------------------------------------------------------------
@@ -409,161 +437,73 @@ void FScrollView::draw()
 //----------------------------------------------------------------------
 void FScrollView::onKeyPress (FKeyEvent* ev)
 {
-  int    key = ev->key();
+  short yoffset_end = short(getScrollHeight() - getViewportHeight());
-  short& xoffset = viewport_geometry.x1_ref();
-  short& yoffset = viewport_geometry.y1_ref();
-  short  xoffset_before = xoffset;
-  short  yoffset_before = yoffset;
-  short  xoffset_end = short(getScrollWidth() - getViewportWidth());
-  short  yoffset_end = short(getScrollHeight() - getViewportHeight());
-  int    save_width = viewport_geometry.getWidth();
-  int    save_height = viewport_geometry.getHeight();
 
-  switch ( key )
+  switch ( ev->key() )
   {
     case fc::Fkey_up:
-      if ( yoffset > 0 )
+      scrollBy (0, -1);
-        yoffset--;
-
       ev->accept();
       break;
 
     case fc::Fkey_down:
-      if ( yoffset < yoffset_end )
+      scrollBy (0, 1);
-        yoffset++;
-
       ev->accept();
       break;
 
     case fc::Fkey_left:
-      if ( xoffset > 0 )
+      scrollBy (-1, 0);
-        xoffset--;
-
       ev->accept();
       break;
 
     case fc::Fkey_right:
-      if ( xoffset < xoffset_end )
+      scrollBy (1, 0);
-        xoffset++;
-
       ev->accept();
       break;
 
     case fc::Fkey_ppage:
-      yoffset -= getViewportHeight();
+      scrollBy (0, -getViewportHeight());
-
-      if ( yoffset < 0 )
-        yoffset = 0;
-
       ev->accept();
       break;
 
     case fc::Fkey_npage:
-      yoffset += getViewportHeight();
+      scrollBy (0, getViewportHeight());
-
-      if ( yoffset > yoffset_end )
-        yoffset = yoffset_end;
-
       ev->accept();
       break;
 
     case fc::Fkey_home:
-      yoffset = 0;
+      scrollToY (1);
       ev->accept();
       break;
 
     case fc::Fkey_end:
-      yoffset = yoffset_end;
+      scrollToY (1 + yoffset_end);
       ev->accept();
       break;
 
     default:
       break;
   }
-
-  if ( ev->isAccepted() )
-  {
-    bool hasChanges = false;
-
-    if ( isVisible() && viewport
-      && (xoffset_before != xoffset || yoffset_before != yoffset) )
-    {
-      viewport_geometry.setWidth(save_width);
-      viewport_geometry.setHeight(save_height);
-      viewport->has_changes = true;
-      setTopPadding (1 - yoffset);
-      setLeftPadding (1 - xoffset);
-      setBottomPadding (1 - (yoffset_end - yoffset));
-      setRightPadding (1 - (xoffset_end - xoffset) + nf_offset);
-      copy2area();
-      hasChanges = true;
-      vbar->setValue (yoffset);
-      hbar->setValue (xoffset);
-      drawVBar();
-      drawHBar();
-    }
-
-    if ( hasChanges )
-      updateTerminal();
-  }
 }
 
 //----------------------------------------------------------------------
 void FScrollView::onWheel (FWheelEvent* ev)
 {
-  bool   hasChanges = false;
+  short  distance = 4;
-  short& yoffset = viewport_geometry.y1_ref();
-  short  yoffset_before = yoffset;
-  short  yoffset_end = short(getScrollHeight() - getViewportHeight());
-  int    save_height = viewport_geometry.getHeight();
-  int    wheel = ev->getWheel();
 
-  switch ( wheel )
+  switch ( ev->getWheel() )
   {
     case fc::WheelUp:
-      if ( yoffset == 0 )
+      scrollBy (0, -distance);
-        break;
-
-      yoffset -= 4;
-
-      if ( yoffset < 0 )
-        yoffset = 0;
-
       break;
 
     case fc::WheelDown:
-      {
+      scrollBy (0, distance);
-        if ( yoffset_end < 0 )
-          yoffset_end = 0;
-
-        if ( yoffset == yoffset_end )
-          break;
-
-        yoffset += 4;
-
-        if ( yoffset > yoffset_end )
-          yoffset = yoffset_end;
-      }
       break;
 
     default:
       break;
   }
-
-  if ( isVisible() && viewport && yoffset_before != yoffset )
-  {
-    viewport_geometry.setHeight(save_height);
-    viewport->has_changes = true;
-    setTopPadding (1 - yoffset);
-    setBottomPadding (1 - (yoffset_end - yoffset));
-    copy2area();
-    hasChanges = true;
-    vbar->setValue (yoffset);
-    drawVBar();
-  }
-
-  if ( hasChanges )
-    updateTerminal();
 }
 
 //----------------------------------------------------------------------
@@ -942,14 +882,19 @@ void FScrollView::setViewportCursor()
 //----------------------------------------------------------------------
 void FScrollView::cb_VBarChange (FWidget*, data_ptr)
 {
-  FScrollbar::sType scrollType;
+  FScrollbar::sType scrollType = vbar->getScrollType();
-  bool   hasChanges = false;
+  short distance = 1;
-  short  distance = 1;
+  short wheel_distance = 4;
-  short& yoffset = viewport_geometry.y1_ref();
+
-  short  yoffset_before = yoffset;
+  if ( scrollType >= FScrollbar::scrollStepBackward
-  short  yoffset_end = short(getScrollHeight() - getViewportHeight());
+    && scrollType <= FScrollbar::scrollWheelDown )
-  int    save_height = viewport_geometry.getHeight();
+  {
-  scrollType = vbar->getScrollType();
+    update_scrollbar = true;
+  }
+  else
+  {
+    update_scrollbar = false;
+  }
 
   switch ( scrollType )
   {
@@ -960,101 +905,48 @@ void FScrollView::cb_VBarChange (FWidget*, data_ptr)
       distance = short(getViewportHeight());
       // fall through
     case FScrollbar::scrollStepBackward:
-      yoffset -= distance;
+      scrollBy (0, -distance);
-
-      if ( yoffset < 0 )
-        yoffset = 0;
-
       break;
 
     case FScrollbar::scrollPageForward:
       distance = short(getViewportHeight());
       // fall through
     case FScrollbar::scrollStepForward:
-      yoffset += distance;
+      scrollBy (0, distance);
-
-      if ( yoffset > yoffset_end )
-        yoffset = yoffset_end;
-
       break;
 
     case FScrollbar::scrollJump:
-    {
+      scrollToY (1 + short(vbar->getValue()));
-      short val = short(vbar->getValue());
-
-      if ( yoffset == val )
-        break;
-
-      yoffset = val;
-
-      if ( yoffset > yoffset_end )
-        yoffset = yoffset_end;
-
-      if ( yoffset < 0 )
-        yoffset = 0;
-
       break;
-    }
 
     case FScrollbar::scrollWheelUp:
-      if ( yoffset == 0 )
+      scrollBy (0, -wheel_distance);
-        break;
-
-      yoffset -= 4;
-
-      if ( yoffset < 0 )
-        yoffset = 0;
-
       break;
 
     case FScrollbar::scrollWheelDown:
-      if ( yoffset_end < 0 )
+      scrollBy (0, wheel_distance);
-        yoffset_end = 0;
-
-      if ( yoffset == yoffset_end )
-        break;
-
-      yoffset += 4;
-
-      if ( yoffset > yoffset_end )
-        yoffset = yoffset_end;
-
       break;
   }
 
-  if ( isVisible() && viewport && yoffset_before != yoffset )
+  update_scrollbar = true;
-  {
-    viewport_geometry.setHeight(save_height);
-    viewport->has_changes = true;
-    setTopPadding (1 - yoffset);
-    setBottomPadding (1 - (yoffset_end - yoffset));
-    copy2area();
-    hasChanges = true;
-  }
-
-  if ( scrollType >= FScrollbar::scrollStepBackward
-    && scrollType <= FScrollbar::scrollWheelDown
-    && hasChanges )
-  {
-    vbar->setValue (yoffset);
-    drawVBar();
-  }
-
-  if ( hasChanges )
-    updateTerminal();
 }
 
 //----------------------------------------------------------------------
 void FScrollView::cb_HBarChange (FWidget*, data_ptr)
 {
-  FScrollbar::sType scrollType;
+  FScrollbar::sType scrollType = hbar->getScrollType();
-  bool   hasChanges = false;
   short  distance = 1;
-  short& xoffset = viewport_geometry.x1_ref();
+  short wheel_distance = 4;
-  short  xoffset_before = xoffset;
+
-  short  xoffset_end = short(getScrollWidth() - getViewportWidth());
+  if ( scrollType >= FScrollbar::scrollStepBackward
-  int    save_width = viewport_geometry.getWidth();
+    && scrollType <= FScrollbar::scrollWheelDown )
-  scrollType = hbar->getScrollType();
+  {
+    update_scrollbar = true;
+  }
+  else
+  {
+    update_scrollbar = false;
+  }
 
   switch ( scrollType )
   {
@@ -1065,88 +957,30 @@ void FScrollView::cb_HBarChange (FWidget*, data_ptr)
       distance = short(getViewportWidth());
       // fall through
     case FScrollbar::scrollStepBackward:
-      xoffset -= distance;
+      scrollBy (-distance, 0);
-
-      if ( xoffset < 0 )
-        xoffset = 0;
-
       break;
 
     case FScrollbar::scrollPageForward:
       distance = short(getViewportWidth());
       // fall through
     case FScrollbar::scrollStepForward:
-      xoffset += distance;
+      scrollBy (distance, 0);
-
-      if ( xoffset > xoffset_end )
-        xoffset = xoffset_end;
-
-      if ( xoffset < 0 )
-        xoffset = 0;
-
       break;
 
     case FScrollbar::scrollJump:
-    {
+      scrollToX (1 + short(hbar->getValue()));
-      short val = short(hbar->getValue());
-
-      if ( xoffset == val )
-        break;
-
-      xoffset = val;
-
-      if ( xoffset > xoffset_end )
-        xoffset = xoffset_end;
-
-      if ( xoffset < 0 )
-        xoffset = 0;
-
       break;
-    }
 
     case FScrollbar::scrollWheelUp:
-      if ( xoffset == 0 )
+      scrollBy (-wheel_distance, 0);
-        break;
-
-      xoffset -= 4;
-
-      if ( xoffset < 0 )
-        xoffset = 0;
-
       break;
 
     case FScrollbar::scrollWheelDown:
-      if ( xoffset == xoffset_end )
+      scrollBy (wheel_distance, 0);
-        break;
-
-      xoffset += 4;
-
-      if ( xoffset > xoffset_end )
-        xoffset = xoffset_end;
-
       break;
   }
 
-  if ( isVisible() && viewport && xoffset_before != xoffset )
+  update_scrollbar = true;
-  {
-    viewport_geometry.setWidth(save_width);
-    viewport->has_changes = true;
-    setLeftPadding (1 - xoffset);
-    setRightPadding (1 - (xoffset_end - xoffset) + nf_offset);
-    copy2area();
-    hasChanges = true;
-  }
-
-  if ( scrollType >= FScrollbar::scrollStepBackward
-    && scrollType <= FScrollbar::scrollWheelDown
-    && hasChanges )
-  {
-    hbar->setValue (xoffset);
-    drawHBar();
-  }
-
-  if ( hasChanges )
-    updateTerminal();
 }
 
 //----------------------------------------------------------------------