ToolDock.cpp

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/**********************************************************************

  Audacity: A Digital Audio Editor

  ToolBar.cpp

  Dominic Mazzoni
  Shane T. Mueller
  Leland Lucius

*******************************************************************//*******************************************************************//**********************************************************************/

#include "../Audacity.h"
#include <wx/tokenzr.h>

// For compilers that support precompilation, includes "wx/wx.h".
#include <wx/wxprec.h>

#ifndef WX_PRECOMP
#include <wx/defs.h>
#include <wx/event.h>
#include <wx/gdicmn.h>
#include <wx/intl.h>
#include <wx/panel.h>
#include <wx/settings.h>
#include <wx/window.h>
#endif  /*  */

#include "ToolManager.h"
#include "ToolDock.h"

#include <algorithm>

#include "../AColor.h"
#include "../AllThemeResources.h"
#include "../ImageManipulation.h"
#include "../Prefs.h"
#include "../Project.h"
#include "../Theme.h"
#include "../widgets/AButton.h"
#include "../widgets/Grabber.h"

const ToolBarConfiguration::Position
   ToolBarConfiguration::UnspecifiedPosition { false };

auto ToolBarConfiguration::FindPlace(const ToolBar *bar) const
   -> Iterator
{
   auto This = const_cast<ToolBarConfiguration*>(this);
   return std::find_if(This->begin(), This->end(),
      [=](const Place &place){
         return place.pTree->pBar == bar;
      });
}

auto ToolBarConfiguration::FindPeers(const ToolBar *bar)
   -> std::pair<Forest*, Forest::iterator>
{
   auto findTree = [=](Forest &forest){
      return std::find_if(forest.begin(), forest.end(),
         [=](const Tree &tree){ return tree.pBar == bar; });
   };

   auto iter1 = findTree(mForest);
   if (iter1 != mForest.end())
      return { &mForest, iter1 };

   Forest::iterator result;
   auto iter = std::find_if(begin(), end(),
      [&](const Place &place){
         auto &children = place.pTree->children;
         return (result = findTree(children)) != children.end();
      }
   );
   if (iter != end())
      return { &iter->pTree->children, result };

   return { nullptr, Forest::iterator{} };
}

auto ToolBarConfiguration::Find(const ToolBar *bar) const -> Position
{
   auto iter = FindPlace(bar);
   if (iter == end())
      return UnspecifiedPosition;
   else
      return iter->position;
}

void ToolBarConfiguration::Insert(ToolBar *bar, Position position)
{
   if (position == UnspecifiedPosition) {
      // Add at the "end" of the layout
      // bottommost and rightmost
      Forest *pForest = &mForest;
      while (!pForest->empty())
         pForest = &pForest->back().children;
      pForest->push_back( Tree {} );
      pForest->back().pBar = bar;
   }
   else {
      // Insert at what depth?
      auto pForest = &mForest;
      if (position.rightOf) {
         const auto parent = FindPlace(position.rightOf);
         if (parent != end())
            // Insert among children of some node
            pForest = &parent->pTree->children;
      }
      else {
         // Insert a new root in the top forest
      }

      // Insert at what breadth?
      const auto begin = pForest->begin();
      auto iter = begin;
      const auto end = pForest->end();
      bool adopt = false;

      if (position.below) {
         iter = std::find_if(begin, end,
            [=](const Tree &tree){ return tree.pBar == position.below; }
         );
         if (iter != end) {
            ++iter;
            if (iter != end)
               adopt = true;
         }
         else
            // Not found, default to topmost
            iter = begin;
      }
      else
         // No previous sibling specified, so insert as first
         adopt = (iter != end);

      // Insert as a leaf, or as an internal node?
      if (adopt && position.adopt) {
         // Existing child of parent become its grandchild

         // TODO:  is it ever correct to adopt more than one, depending on
         // heights?  Could an inserted tall bar adopt two short ones?

         // Make NEW node
         Tree tree;
         tree.pBar = bar;

         // Do adoption
         tree.children.push_back(Tree{});
         auto &child = tree.children.back();
         child.pBar = iter->pBar;
         child.children.swap(iter->children);

         // Put the node in the tree
         (*iter).swap(tree);
      }
      else
         // Insert as a leaf
         pForest->insert(iter, Tree {})->pBar = bar;
   }
}

void ToolBarConfiguration::InsertAtPath
   (ToolBar *bar, const std::vector<int> &path)
{
   auto pForest = &mForest;
   Tree *pTree {};

   // Guarantee the existence of nodes
   for (auto ii : path) {
      Forest::size_type uu = std::max(0, ii);
      // This may make more than one default-constructed tree, which we
      // will fill in with some other call to InsertAtPath, or else cleanup
      // with RemoveNulls
      pForest->resize(std::max(uu + 1, pForest->size()));
      pTree = &(*pForest)[uu];
      pForest = &pTree->children;
   }

   if (pTree)
      pTree->pBar = bar;
}

void ToolBarConfiguration::Remove(Forest &forest, Forest::iterator iter)
{
   // Reparent all of the children of the deleted node
   Tree tree;
   tree.swap(*iter);
   iter = forest.erase(iter);
   auto &children = tree.children;
   auto cIter = children.rbegin(), cEnd = children.rend();
   while (cIter != cEnd) {
      iter = forest.insert(iter, Tree{});
      (*iter).swap(*cIter);
      ++cIter;
   }
}

void ToolBarConfiguration::Remove(const ToolBar *bar)
{
   auto results = FindPeers(bar);
   auto pForest = results.first;
   if (pForest) {
      // Reparent all of the children of the deleted node
      auto iter = results.second;
      wxASSERT(iter->pBar == bar);
      Remove(*pForest, iter);
   }
}

void ToolBarConfiguration::Show(ToolBar *bar)
{
   // Do not assume the bar is absent, though in practice that is always so
   if (!Contains(bar))
      Insert(bar);
}

void ToolBarConfiguration::Hide(ToolBar *bar)
{
   // Future:  might hide a bar without eliminating it from the configuration
   Remove(bar);
}

bool ToolBarConfiguration::IsRightmost(const ToolBar *bar) const
{
   auto iter = FindPlace(bar);
   auto endit = end();
   if (iter == endit)
      // not present
      return true;
   if (++iter == endit)
      // Last of all
      return true;
   if (bar->GetRect().y != iter->pTree->pBar->GetRect().y)
      // Next step in preorder traversal is not rightward to a child drawn at
      // the same height
      return true;
   return false;
}

bool ToolBarConfiguration::Read
   (ToolBarConfiguration *pConfiguration,
    Legacy *pLegacy,
    ToolBar *bar, bool &visible, bool defaultVisible)
{
   bool result = true;

   // Future: might remember visibility in the configuration, not forgetting
   // positions of hidden bars.
   gPrefs->Read( wxT("Show"), &visible, defaultVisible);

   if (pConfiguration && visible) {
      int ord;
      gPrefs->Read( wxT("Order"), &ord, -1 );
      // Index was written 1-based
      --ord;
      if (ord >= ToolBarCount)
         result = false;
      else if (ord >= 0)
      {
         // Legacy preferences
         while (pLegacy->bars.size() <= size_t(ord))
            pLegacy->bars.push_back(nullptr);
         pLegacy->bars[ord] = bar;
      }
      else {
         wxString strPath;
         gPrefs->Read( wxT("Path"), &strPath );
         if (!strPath.empty()) {
            wxStringTokenizer toker { strPath, wxT(",") };
            std::vector<int> path;
            while(toker.HasMoreTokens()) {
               auto token = toker.GetNextToken();
               auto ii = wxAtoi(token);
               path.push_back(ii);
            }
            pConfiguration->InsertAtPath(bar, path);
         }
      }
   }

   return result;
}

void ToolBarConfiguration::RemoveNulls(Forest &forest)
{
   for (size_t ii = 0; ii < forest.size(); ++ii) {
      if(forest[ii].pBar == nullptr)
         Remove(forest, forest.begin() + ii--);
   }

   // Now do the same recursively
   for (auto &tree : forest)
      RemoveNulls(tree.children);
}

void ToolBarConfiguration::PostRead(Legacy &legacy)
{
   // Be sure no nodes contain NULL,
   // against the case of obsolete preferences, perhaps
   RemoveNulls(mForest);

   // Interpret what was saved in old .cfg files under "order"
   // which specified toolbar configuration simply as a sequence, not a tree
   ToolBar *prev {};
   for (auto pBar : legacy.bars) {
      if (!pBar)
         continue;

      Position position{ prev };
      Insert(pBar, position);

      prev = pBar;
   }
}

void ToolBarConfiguration::Write
   (const ToolBarConfiguration *pConfiguration, const ToolBar *bar)
{
   // Assume a path has been set in gPrefs suitable for bar
   if (pConfiguration) {
      // Write comma-separated list of numbers specifying position in the tree
      wxString strPath;
      const auto cIter = pConfiguration->FindPlace(bar);
      const auto path = cIter.GetPath();
      if (!path.empty()) {
         auto iter = path.begin(), end = path.end();
         strPath += wxString::Format(wxT("%d"), *iter++);
         while (iter != end)
            strPath += wxString::Format(wxT(",%d"), *iter++);
      }
      gPrefs->Write(wxT("Path"), strPath);

      // Remove any legacy configuration info.
      // Note:  this causes Audacity 2.1.2 and earlier to create toolbars
      // always in default position when reading a .cfg saved by Audacity
      // 2.1.3 or later
      gPrefs->DeleteEntry(wxT("Order"));
   }
   gPrefs->Write( wxT("Show"), bar->IsVisible() );
}

IMPLEMENT_CLASS( ToolDock, wxPanelWrapper );


//
// Custom event
//
//DEFINE_EVENT_TYPE( EVT_TOOLBAR_FLOAT );

BEGIN_EVENT_TABLE( ToolDock, wxPanelWrapper )
   EVT_GRABBER( wxID_ANY, ToolDock::OnGrabber )
   EVT_ERASE_BACKGROUND( ToolDock::OnErase )
   EVT_PAINT( ToolDock::OnPaint )
   EVT_SIZE( ToolDock::OnSize )
   EVT_MOUSE_EVENTS( ToolDock::OnMouseEvents )
END_EVENT_TABLE()

//
// Constructor
//
ToolDock::ToolDock( ToolManager *manager, wxWindow *parent, int dockid ):
   wxPanelWrapper( parent, dockid, wxDefaultPosition, parent->GetSize() )
{
   SetLabel( _( "ToolDock" ) );
   SetName( _( "ToolDock" ) );

   // Init
   mManager = manager;
   memset(mBars, 0, sizeof(mBars)); // otherwise uninitialized
   SetBackgroundColour(theTheme.Colour( clrMedium ));
   // Use for testing gaps
   // SetOwnBackgroundColour( wxColour( 255, 0, 0 ) );
}

//
// Destructer
//
ToolDock::~ToolDock()
{
}

//
// Remove the toolbar from our control
//
void ToolDock::Undock( ToolBar *bar )
{
   if( mConfiguration.Contains( bar ) )
   {
      mConfiguration.Remove( bar );
   }
   mBars[ bar->GetId() ] = nullptr;
}

//
// Handle ToolDock events
//
void ToolDock::Dock( ToolBar *bar, bool deflate, ToolBarConfiguration::Position position )
{
#ifndef __WXMAC__
   // Apply the deflate fix only on Mac, else you introduce the opposite bug on others
   deflate = false;
#endif

   // Adopt the toolbar into our family
   bar->Reparent( this );
   mBars[ bar->GetId() ] = bar;

   // Reset size
   bar->SetSize(
      // Undo the expansion that was applied when un-docking
      bar->GetSize().x - (deflate ? 2 * ToolBarFloatMargin : 0),
      // Don't need to adjust y the same way.
      bar->GetDockedSize().y
   );

   // Park the NEW bar in the correct berth
   if (!mConfiguration.Contains(bar) && bar->IsVisible())
      mConfiguration.Insert( bar, position );

   // Inform toolbar of change
   bar->SetDocked( this, false );

   // Rearrange our world
   if (bar->IsVisible())
      LayoutToolBars();
   Updated();
}

// Initial docking of bars
void ToolDock::LoadConfig()
{
   // Add all ordered toolbars
   for(const auto &place : GetConfiguration()) {
      auto bar = place.pTree->pBar;
      this->Dock(bar, false);
      // Show it -- hidden bars are not (yet) ever saved as part of a
      // configuration
      Expose( bar->GetId(), true );
   }
}

// A policy object for the skeleton routine below
class ToolDock::LayoutVisitor
{
public:
   virtual void ModifySize
   (ToolBar *,
    const wxRect &,
    ToolBarConfiguration::Position,
    ToolBarConfiguration::Position,
    wxSize &)
   {
   }

   virtual void Visit
   (ToolBar *ct, wxPoint point) = 0;

   virtual bool ShouldVisitSpaces() = 0;

   virtual void FinalRect
   (const wxRect &, ToolBarConfiguration::Position)
   {
   }
};

// Skeleton routine common to insertion of a toolbar, and figuring out
// width-constrained layout of toolbars
void ToolDock::VisitLayout(LayoutVisitor &visitor,
                           ToolBarConfiguration *pWrappedConfiguration)
{
   if (pWrappedConfiguration)
      pWrappedConfiguration->Clear();

   // Get size of our parent since we haven't been sized yet
   int width, height;
   GetParent()->GetClientSize( &width, &height );
   width -= toolbarGap;
   height -= toolbarGap;

   // Rectangle of space to allocate
   wxRect main{ toolbarGap, toolbarGap,
      // Allow limited width, but arbitrary height, for the root rectangle
      width, std::numeric_limits<int>::max() };

   // For recording the nested subdivisions of the rectangle
   struct Item {
      int myBarID { NoBarID };
      int parentBarID { NoBarID };
      ToolBar *lastSib {};
      ToolBar *lastWrappedChild {};
      wxRect rect;
   } layout[ ToolBarCount ];

   ToolBar *lastRoot {};
   ToolBar *lastWrappedRoot {};

   // Process all docked and visible toolbars
   for ( const auto &place : this->GetConfiguration() )
   {
      // Cache toolbar pointer
      const auto ct = place.pTree->pBar;

      // set up the chain of ancestors.
      const auto parent = place.position.rightOf;
      const auto type = ct->GetType();
      auto &newItem = layout[ type ];
      newItem.parentBarID = parent ? parent->GetType() : NoBarID;
      // Mark the slots that really were visited, for final pass through
      // the spaces.
      newItem.myBarID = type;

      const auto parentItem = parent ? &layout[ parent->GetType() ] : nullptr;
      ToolBar *prevSib;
      if (!parent) {
         prevSib = lastRoot;
         lastRoot = ct;
      }
      else {
         auto &sib = parentItem->lastSib;
         prevSib = sib;
         sib = ct;
      }
      auto prevPosition = ToolBarConfiguration::Position{ parent, prevSib };

      // Determine the size of the toolbar to fit, with advice from
      // the visitor object
      wxSize sz = ct->GetSize();
      {
         wxRect temp;
         temp.SetPosition(ct->GetParent()->ClientToScreen(ct->GetPosition()));
         temp.SetSize(sz);
         visitor.ModifySize(ct, temp, prevPosition, place.position, sz);
      }

      // Inflate the size to leave margins
      int tw = sz.GetWidth() + toolbarGap;
      int th = sz.GetHeight() + toolbarGap;

      // Choose the rectangle to subdivide
      // Find a box that we fit in by going up the tree as needed --
      // thus when parent space is exhausted, fall back on ancestors --
      // so if the tree has too much depth for the width of the
      // window, the toolbars may "wrap."
      // Can always fall back to the main rectangle even if the bar is too
      // wide.
      auto pItem = parentItem;
      auto pRect = pItem ? &pItem->rect : &main;
      while (pRect != &main)
      {
         // Get out if it will fit
         bool bTooWide = tw > pRect->GetWidth();
         // We'd like to be able to add a tall toolbar in at the start of a row,
         // even if there isn't enough height for it.
         // If so, we'd have to at least change how we calculate 'bTooHigh'.
         bool bTooHigh = th > pRect->GetHeight();
         //bTooHigh &= stack[stkcnt].GetWidth() < (width - toolbarGap);
         //bTooHigh = false;

         if (!bTooWide && !bTooHigh)
            break;

         if (pItem->parentBarID == NoBarID) {
            pItem = nullptr;
            pRect = &main;
         }
         else {
            pItem = &layout[ pItem->parentBarID ];
            pRect = &pItem->rect;
         }
      }

      // Record where the toolbar wrapped
      ToolBar *& sib = pItem ? pItem->lastWrappedChild : lastWrappedRoot;
      ToolBarConfiguration::Position newPosition {
         pItem ? this->mBars[ pItem->myBarID ] : nullptr,
         sib
      };
      sib = ct;
      if (pWrappedConfiguration)
         pWrappedConfiguration->Insert(ct, newPosition);

      // Place the toolbar at the upper left part of the rectangle.
      const auto cpos = pRect->GetPosition();
      visitor.Visit(ct, cpos);

      // Allocate an upper portion of the rectangle to this bar.
      pRect->y += th;
      pRect->height -= th;

      // A right portion of that upper portion remains available for
      // descendant bars and is remembered in the layout array.
      int x = cpos.x + tw;
      newItem.rect = wxRect{ x, cpos.y, width - x, th };
   }

   if (visitor.ShouldVisitSpaces()) {
      // Visit the fringe where NEW leaves of the tree could go

      // Find the items with leftover spaces
      const auto end = std::remove_if(layout, layout + ToolBarCount,
         [](const Item &item){
            return item.myBarID == NoBarID || item.rect.IsEmpty();
         }
      );
      // Sort top to bottom for definiteness, though perhaps not really needed
      std::sort(layout, end,
         [](const Item &lhs, const Item &rhs){
            return lhs.rect.y < rhs.rect.y;
         }
      );
      for (auto iter = layout; iter != end; ++iter) {
         const auto &item = *iter;
         const auto &rect = item.rect;

         auto globalRect = rect;
         globalRect.SetPosition( this->ClientToScreen(rect.GetPosition()) );

         // Let the visitor determine size
         wxSize sz {};
         ToolBarConfiguration::Position
            position { this->mBars[ item.myBarID ], item.lastWrappedChild },
            prevPosition {};
         visitor.ModifySize(nullptr, globalRect, prevPosition, position, sz);
         int tw = sz.GetWidth() + toolbarGap;
         int th = sz.GetHeight() + toolbarGap;

         // Test fit
         bool bTooWide = tw > rect.GetWidth();
         bool bTooHigh = th > rect.GetHeight();
         if (!bTooWide && !bTooHigh) {
            // Call visitor again to confirm the placement
            const auto cpos = rect.GetPosition();
            visitor.Visit(nullptr, cpos);
         }
      }
   }

   // Report the final bounding box of all the bars, and a position where
   // you can insert a NEW bar at bottom left.
   ToolBarConfiguration::Position finalPosition { nullptr, lastRoot };
   visitor.FinalRect(
      wxRect { toolbarGap, toolbarGap, main.width, main.y }, finalPosition
   );
}

//
// Layout the toolbars
//
void ToolDock::LayoutToolBars()
{
   struct SizeSetter final : public LayoutVisitor
   {
      SizeSetter (ToolDock *d) : dock{ d } {}

      void Visit
         (ToolBar *bar, wxPoint point)
         override
      {
         // Place the toolbar
         if(bar)
            bar->SetPosition( point );
      }

      bool ShouldVisitSpaces() override
      {
         return false;
      }

      virtual void FinalRect
         (const wxRect &rect, ToolBarConfiguration::Position)
         override
      {
         // Set the final size of the dock window
         dock->SetMinSize( rect.GetSize() );
      }

      ToolDock *dock;
   } sizeSetter {
      this
   };
   VisitLayout(sizeSetter, &mWrappedConfiguration);

   // Set tab order
   {
      ToolBar *lt{};
      for ( const auto &place : GetConfiguration() ) {
         auto ct = place.pTree->pBar;
         if( lt )
            ct->MoveAfterInTabOrder( lt );
         lt = ct;
      }
   }

   // Clean things up
   Refresh( false );
}

// Determine the position where a NEW bar would be placed
//
// 'rect' will be the rectangle for the dock marker (black triangle)
ToolBarConfiguration::Position
   ToolDock::PositionBar( ToolBar *t, const wxPoint & pos, wxRect & rect )
{
   // Set width and size, but we must still find x and y.
   rect = t->GetRect();

   using Position = ToolBarConfiguration::Position;
   Position result { ToolBarConfiguration::UnspecifiedPosition };
   struct Inserter : public LayoutVisitor
   {
      struct Stop {};

      Inserter(Position &p, wxRect &r, const wxPoint &pt, ToolBar *t)
         : result(p), rect(r), point(pt), tb(t)
      {}

      void ModifySize
         (ToolBar *ct,
          const wxRect &rect,
          ToolBarConfiguration::Position prevPosition,
          ToolBarConfiguration::Position position,
          wxSize &sz)
         override
      {
         // Maybe insert the NEW bar if it hasn't already been done
         // and is in the right place.

         // Does the location fall within this bar?
         if (rect.Contains(point))
         {
            sz = tb->GetDockedSize();
            // Choose a position always, if there is a bar to displace.
            // Else, only if the fit is possible.
            if (ct || (sz.x <= rect.width && sz.y <= rect.height)) {
               // May choose current or previous.
               if (ct &&
                   (sz.y < rect.height ||
                    point.y < (rect.GetTop() + rect.GetBottom()) / 2))
                  // "Wedge" the bar into a crack alone, not adopting others,
                  // if either a short bar displaces a tall one, or else
                  // the displacing bar is at least at tall, but the pointer is
                  // in the upper half of the box.
                  usedPrev = true, result = prevPosition, result.adopt = false;
               else
                  result = position;
            }
            // Now wait until the other callback below to discover x and y
         }
      }

      void Visit
         (ToolBar *, wxPoint point)
         override
      {
         if (result != ToolBarConfiguration::UnspecifiedPosition) {
            // If we've placed it, we're done.
            rect.x = point.x;
            rect.y = point.y;
            if (usedPrev)
               rect.y -= tb->GetDockedSize().GetHeight() / 2;

            throw Stop {};
         }
      }

      bool ShouldVisitSpaces() override
      {
         return true;
      }

      void FinalRect
         (const wxRect &finalRect, ToolBarConfiguration::Position finalPosition)
         override
      {
         if (result == ToolBarConfiguration::UnspecifiedPosition) {
            // Default of all other placements.
            result = finalPosition;
            wxPoint point { finalRect.GetLeft(), finalRect.GetBottom() };
            rect.SetPosition(point);
         }
      }


      Position &result;
      wxRect &rect;
      const wxPoint point;
      ToolBar *const tb;
      bool usedPrev { false };
   } inserter {
      result, rect, pos, t
   };

   try { this->VisitLayout(inserter); } catch (const Inserter::Stop&) {}

   // rect is decided
   return result;
}

void ToolDock::WrapConfiguration(ToolBarConfiguration &backup)
{
   backup.Clear();
   backup.Swap(mConfiguration);
   mConfiguration.Swap(mWrappedConfiguration);
}

void ToolDock::RestoreConfiguration(ToolBarConfiguration &backup)
{
   mWrappedConfiguration.Clear();
   mWrappedConfiguration.Swap(mConfiguration);
   mConfiguration.Swap(backup);
}

//
// Set the visible/hidden state of a toolbar
//
void ToolDock::Expose( int type, bool show )
{
   ToolBar *t = mBars[ type ];

   // Maintain the docked array
   const auto shown = mConfiguration.Shows( t );
   if( show && !shown )
      mConfiguration.Show( t );
   else if( !show && shown )
      mConfiguration.Hide( t );

   // Make it (dis)appear
   t->Expose( show );

   // Update the layout
   LayoutToolBars();
   Updated();
}

//
// Queues an EVT_TOOLBAR_UPDATED command event to notify any
// interested parties of an updated toolbar or dock layout
//
void ToolDock::Updated()
{
   // Queue an update event
   wxCommandEvent e( EVT_TOOLBAR_UPDATED, GetId() );
   GetParent()->GetEventHandler()->AddPendingEvent( e );
}

//
// Handle grabber clicking
//
void ToolDock::OnGrabber( GrabberEvent & event )
{
   // auto pos = event.GetPosition();
   if (!event.IsEscaping()) {
      // Pass it on to the manager since it isn't in the handling hierarchy
      mManager->ProcessEvent( event );
   }
}

//
// Handle sizing
//
void ToolDock::OnSize( wxSizeEvent & WXUNUSED(event) )
{
//   event.Skip();
}

//
// Prevent flicker
//
void ToolDock::OnErase( wxEraseEvent & WXUNUSED(event) )
{
   // Ignore it to prevent flashing
}

//
// Repaint toolbar gap lines
//
void ToolDock::OnPaint( wxPaintEvent & WXUNUSED(event) )
{
   // Don't use a wxBufferedPaintDC() here.  It produces a bogus
   // background on Windows and GTK.
   wxPaintDC dc( this );

   // Start with a clean background
   //
   // Under GTK, we don't set the toolbar background to the background
   // colour in the system theme.  Instead we use our own colour.

   dc.SetBackground( wxBrush( theTheme.Colour( clrMedium )));
   dc.Clear();

   // Set the gap color
   AColor::Dark( &dc, false );

   // Draw the initial horizontal and vertical gaps
   wxSize sz = GetClientSize();

   AColor::Line(dc, 0, 0, sz.GetWidth(), 0 );
   AColor::Line(dc, 0, 0, 0, sz.GetHeight() );

   // Draw the gap between each bar
   for (const auto &place : GetConfiguration())
   {
      auto toolbar = place.pTree->pBar;
      if (!toolbar)
         continue;

      wxRect r = toolbar->GetRect();

      // Draw a horizontal line under the bar extending to the right edge of
      // the dock
      AColor::Line( dc,
                   r.GetLeft(),
                   r.GetBottom() + 1,
                   sz.GetWidth(),
                   r.GetBottom() + 1 );

      // For all bars but the last...
      // ...and for bars that aren't the last in a row, draw a
      // vertical gap line
      if (!mConfiguration.IsRightmost(toolbar)) {
         AColor::Line(dc,
            r.GetRight() + 1,
            r.GetTop(),
            r.GetRight() + 1,
            r.GetBottom() + 1 );
      }
   }
}

void ToolDock::OnMouseEvents(wxMouseEvent &event)
{
   // Do this hack so scrubber can detect mouse drags anywhere
   event.ResumePropagation(wxEVENT_PROPAGATE_MAX);
   event.Skip();
}