text: /////////////////////////////////////////////////////////////////////////////
  // Name:        src/generic/sashwin.cpp
  // Purpose:     wxSashWindow implementation. A sash window has an optional
  //              sash on each edge, allowing it to be dragged. An event
  //              is generated when the sash is released.
  // Author:      Julian Smart
  // Modified by:
  // Created:     01/02/97
  // RCS-ID:      $Id: sashwin.cpp 51249 2008-01-16 13:50:23Z JS $
  // Copyright:   (c) Julian Smart
  // Licence:     wxWindows licence
  /////////////////////////////////////////////////////////////////////////////
  
  // For compilers that support precompilation, includes "wx.h".
  #include "wx/wxprec.h"
  
  #ifdef __BORLANDC__
      #pragma hdrstop
  #endif
  
  #if wxUSE_SASH
  
  #include "wx/sashwin.h"
  
  #ifndef WX_PRECOMP
      #include "wx/dialog.h"
      #include "wx/frame.h"
      #include "wx/settings.h"
      #include "wx/dcclient.h"
      #include "wx/dcscreen.h"
      #include "wx/math.h"
  #endif
  
  #include <stdlib.h>
  
  #include "wx/laywin.h"
  
  DEFINE_EVENT_TYPE(wxEVT_SASH_DRAGGED)
  
  IMPLEMENT_DYNAMIC_CLASS(wxSashWindow, wxWindow)
  IMPLEMENT_DYNAMIC_CLASS(wxSashEvent, wxCommandEvent)
  
  BEGIN_EVENT_TABLE(wxSashWindow, wxWindow)
      EVT_PAINT(wxSashWindow::OnPaint)
      EVT_SIZE(wxSashWindow::OnSize)
      EVT_MOUSE_EVENTS(wxSashWindow::OnMouseEvent)
  #if defined( __WXMSW__ ) || defined( __WXMAC__)
      EVT_SET_CURSOR(wxSashWindow::OnSetCursor)
  #endif // __WXMSW__ || __WXMAC__
  
  END_EVENT_TABLE()
  
  bool wxSashWindow::Create(wxWindow *parent, wxWindowID id, const wxPoint& pos,
      const wxSize& size, long style, const wxString& name)
  {
      return wxWindow::Create(parent, id, pos, size, style, name);
  }
  
  wxSashWindow::~wxSashWindow()
  {
      delete m_sashCursorWE;
      delete m_sashCursorNS;
  }
  
  void wxSashWindow::Init()
  {
      m_draggingEdge = wxSASH_NONE;
      m_dragMode = wxSASH_DRAG_NONE;
      m_oldX = 0;
      m_oldY = 0;
      m_firstX = 0;
      m_firstY = 0;
      m_borderSize = 3;
      m_extraBorderSize = 0;
      m_minimumPaneSizeX = 0;
      m_minimumPaneSizeY = 0;
      m_maximumPaneSizeX = 10000;
      m_maximumPaneSizeY = 10000;
      m_sashCursorWE = new wxCursor(wxCURSOR_SIZEWE);
      m_sashCursorNS = new wxCursor(wxCURSOR_SIZENS);
      m_mouseCaptured = false;
      m_currentCursor = NULL;
  
      // Eventually, we'll respond to colour change messages
      InitColours();
  }
  
  void wxSashWindow::OnPaint(wxPaintEvent& WXUNUSED(event))
  {
      wxPaintDC dc(this);
  
      DrawBorders(dc);
      DrawSashes(dc);
  }
  
  void wxSashWindow::OnMouseEvent(wxMouseEvent& event)
  {
      wxCoord x = 0, y = 0;
      event.GetPosition(&x, &y);
  
      wxSashEdgePosition sashHit = SashHitTest(x, y);
  
      if (event.LeftDown())
      {
          CaptureMouse();
          m_mouseCaptured = true;
  
          if ( sashHit != wxSASH_NONE )
          {
              // Required for X to specify that
              // that we wish to draw on top of all windows
              // - and we optimise by specifying the area
              // for creating the overlap window.
              // Find the first frame or dialog and use this to specify
              // the area to draw on.
              wxWindow* parent = this;
  
              while (parent && !parent->IsKindOf(CLASSINFO(wxDialog)) &&
                               !parent->IsKindOf(CLASSINFO(wxFrame)))
                parent = parent->GetParent();
  
              wxScreenDC::StartDrawingOnTop(parent);
  
              // We don't say we're dragging yet; we leave that
              // decision for the Dragging() branch, to ensure
              // the user has dragged a little bit.
              m_dragMode = wxSASH_DRAG_LEFT_DOWN;
              m_draggingEdge = sashHit;
              m_firstX = x;
              m_firstY = y;
  
              if ( (sashHit == wxSASH_LEFT) || (sashHit == wxSASH_RIGHT) )
              {
                  if (m_currentCursor != m_sashCursorWE)
                  {
                      SetCursor(*m_sashCursorWE);
                  }
                  m_currentCursor = m_sashCursorWE;
              }
              else
              {
                  if (m_currentCursor != m_sashCursorNS)
                  {
                      SetCursor(*m_sashCursorNS);
                  }
                  m_currentCursor = m_sashCursorNS;
              }
          }
      }
      else if ( event.LeftUp() && m_dragMode == wxSASH_DRAG_LEFT_DOWN )
      {
          // Wasn't a proper drag
          if (m_mouseCaptured)
              ReleaseMouse();
          m_mouseCaptured = false;
  
          wxScreenDC::EndDrawingOnTop();
          m_dragMode = wxSASH_DRAG_NONE;
          m_draggingEdge = wxSASH_NONE;
      }
      else if (event.LeftUp() && m_dragMode == wxSASH_DRAG_DRAGGING)
      {
          // We can stop dragging now and see what we've got.
          m_dragMode = wxSASH_DRAG_NONE;
          if (m_mouseCaptured)
              ReleaseMouse();
          m_mouseCaptured = false;
  
          // Erase old tracker
          DrawSashTracker(m_draggingEdge, m_oldX, m_oldY);
  
          // End drawing on top (frees the window used for drawing
          // over the screen)
          wxScreenDC::EndDrawingOnTop();
  
          int w, h;
          GetSize(&w, &h);
          int xp, yp;
          GetPosition(&xp, &yp);
  
          wxSashEdgePosition edge = m_draggingEdge;
          m_draggingEdge = wxSASH_NONE;
  
          wxRect dragRect;
          wxSashDragStatus status = wxSASH_STATUS_OK;
  
          // the new height and width of the window - if -1, it didn't change
          int newHeight = wxDefaultCoord,
              newWidth = wxDefaultCoord;
  
          // NB: x and y may be negative and they're relative to the sash window
          //     upper left corner, while xp and yp are expressed in the parent
          //     window system of coordinates, so adjust them! After this
          //     adjustment, all coordinates are relative to the parent window.
          y += yp;
          x += xp;
  
          switch (edge)
          {
              case wxSASH_TOP:
                  if ( y > yp + h )
                  {
                      // top sash shouldn't get below the bottom one
                      status = wxSASH_STATUS_OUT_OF_RANGE;
                  }
                  else
                  {
                      newHeight = h - (y - yp);
                  }
                  break;
  
              case wxSASH_BOTTOM:
                  if ( y < yp )
                  {
                      // bottom sash shouldn't get above the top one
                      status = wxSASH_STATUS_OUT_OF_RANGE;
                  }
                  else
                  {
                      newHeight = y - yp;
                  }
                  break;
  
              case wxSASH_LEFT:
                  if ( x > xp + w )
                  {
                      // left sash shouldn't get beyond the right one
                      status = wxSASH_STATUS_OUT_OF_RANGE;
                  }
                  else
                  {
                      newWidth = w - (x - xp);
                  }
                  break;
  
              case wxSASH_RIGHT:
                  if ( x < xp )
                  {
                      // and the right sash, finally, shouldn't be beyond the
                      // left one
                      status = wxSASH_STATUS_OUT_OF_RANGE;
                  }
                  else
                  {
                      newWidth = x - xp;
                  }
                  break;
  
              case wxSASH_NONE:
                  // can this happen at all?
                  break;
          }
  
          if ( newHeight == wxDefaultCoord )
          {
              // didn't change
              newHeight = h;
          }
          else
          {
              // make sure it's in m_minimumPaneSizeY..m_maximumPaneSizeY range
              newHeight = wxMax(newHeight, m_minimumPaneSizeY);
              newHeight = wxMin(newHeight, m_maximumPaneSizeY);
          }
  
          if ( newWidth == wxDefaultCoord )
          {
              // didn't change
              newWidth = w;
          }
          else
          {
              // make sure it's in m_minimumPaneSizeY..m_maximumPaneSizeY range
              newWidth = wxMax(newWidth, m_minimumPaneSizeX);
              newWidth = wxMin(newWidth, m_maximumPaneSizeX);
          }
  
          dragRect = wxRect(x, y, newWidth, newHeight);
  
          wxSashEvent eventSash(GetId(), edge);
          eventSash.SetEventObject(this);
          eventSash.SetDragStatus(status);
          eventSash.SetDragRect(dragRect);
          GetEventHandler()->ProcessEvent(eventSash);
      }
      else if ( event.LeftUp() )
      {
          if (m_mouseCaptured)
             ReleaseMouse();
          m_mouseCaptured = false;
      }
      else if ((event.Moving() || event.Leaving()) && !event.Dragging())
      {
          // Just change the cursor if required
          if ( sashHit != wxSASH_NONE )
          {
              if ( (sashHit == wxSASH_LEFT) || (sashHit == wxSASH_RIGHT) )
              {
                  if (m_currentCursor != m_sashCursorWE)
                  {
                      SetCursor(*m_sashCursorWE);
                  }
                  m_currentCursor = m_sashCursorWE;
              }
              else
              {
                  if (m_currentCursor != m_sashCursorNS)
                  {
                      SetCursor(*m_sashCursorNS);
                  }
                  m_currentCursor = m_sashCursorNS;
              }
          }
          else
          {
              SetCursor(wxNullCursor);
              m_currentCursor = NULL;
          }
      }
      else if ( event.Dragging() &&
                ((m_dragMode == wxSASH_DRAG_DRAGGING) ||
                 (m_dragMode == wxSASH_DRAG_LEFT_DOWN)) )
      {
          if ( (m_draggingEdge == wxSASH_LEFT) || (m_draggingEdge == wxSASH_RIGHT) )
          {
              if (m_currentCursor != m_sashCursorWE)
              {
                  SetCursor(*m_sashCursorWE);
              }
              m_currentCursor = m_sashCursorWE;
          }
          else
          {
              if (m_currentCursor != m_sashCursorNS)
              {
                  SetCursor(*m_sashCursorNS);
              }
              m_currentCursor = m_sashCursorNS;
          }
  
          if (m_dragMode == wxSASH_DRAG_LEFT_DOWN)
          {
              m_dragMode = wxSASH_DRAG_DRAGGING;
              DrawSashTracker(m_draggingEdge, x, y);
          }
          else
          {
              if ( m_dragMode == wxSASH_DRAG_DRAGGING )
              {
                  // Erase old tracker
                  DrawSashTracker(m_draggingEdge, m_oldX, m_oldY);
  
                  // Draw new one
                  DrawSashTracker(m_draggingEdge, x, y);
              }
          }
          m_oldX = x;
          m_oldY = y;
      }
      else if ( event.LeftDClick() )
      {
          // Nothing
      }
      else
      {
      }
  }
  
  void wxSashWindow::OnSize(wxSizeEvent& WXUNUSED(event))
  {
      SizeWindows();
  }
  
  wxSashEdgePosition wxSashWindow::SashHitTest(int x, int y, int WXUNUSED(tolerance))
  {
      int cx, cy;
      GetClientSize(& cx, & cy);
  
      int i;
      for (i = 0; i < 4; i++)
      {
          wxSashEdge& edge = m_sashes[i];
          wxSashEdgePosition position = (wxSashEdgePosition) i ;
  
          if (edge.m_show)
          {
              switch (position)
              {
                  case wxSASH_TOP:
                  {
                      if (y >= 0 && y <= GetEdgeMargin(position))
                          return wxSASH_TOP;
                      break;
                  }
                  case wxSASH_RIGHT:
                  {
                      if ((x >= cx - GetEdgeMargin(position)) && (x <= cx))
                          return wxSASH_RIGHT;
                      break;
                  }
                  case wxSASH_BOTTOM:
                  {
                      if ((y >= cy - GetEdgeMargin(position)) && (y <= cy))
                          return wxSASH_BOTTOM;
                      break;
                  }
                  case wxSASH_LEFT:
                  {
                      if ((x <= GetEdgeMargin(position)) && (x >= 0))
                          return wxSASH_LEFT;
                      break;
                  }
                  case wxSASH_NONE:
                  {
                      break;
                  }
              }
          }
      }
      return wxSASH_NONE;
  }
  
  // Draw 3D effect borders
  void wxSashWindow::DrawBorders(wxDC& dc)
  {
      int w, h;
      GetClientSize(&w, &h);
  
      wxPen mediumShadowPen(m_mediumShadowColour, 1, wxSOLID);
      wxPen darkShadowPen(m_darkShadowColour, 1, wxSOLID);
      wxPen lightShadowPen(m_lightShadowColour, 1, wxSOLID);
      wxPen hilightPen(m_hilightColour, 1, wxSOLID);
  
      if ( GetWindowStyleFlag() & wxSW_3DBORDER )
      {
          dc.SetPen(mediumShadowPen);
          dc.DrawLine(0, 0, w-1, 0);
          dc.DrawLine(0, 0, 0, h - 1);
  
          dc.SetPen(darkShadowPen);
          dc.DrawLine(1, 1, w-2, 1);
          dc.DrawLine(1, 1, 1, h-2);
  
          dc.SetPen(hilightPen);
          dc.DrawLine(0, h-1, w-1, h-1);
          dc.DrawLine(w-1, 0, w-1, h); // Surely the maximum y pos. should be h - 1.
                                       /// Anyway, h is required for MSW.
  
          dc.SetPen(lightShadowPen);
          dc.DrawLine(w-2, 1, w-2, h-2); // Right hand side
          dc.DrawLine(1, h-2, w-1, h-2);     // Bottom
      }
      else if ( GetWindowStyleFlag() & wxSW_BORDER )
      {
          dc.SetBrush(*wxTRANSPARENT_BRUSH);
          dc.SetPen(*wxBLACK_PEN);
          dc.DrawRectangle(0, 0, w-1, h-1);
      }
  
      dc.SetPen(wxNullPen);
      dc.SetBrush(wxNullBrush);
  }
  
  void wxSashWindow::DrawSashes(wxDC& dc)
  {
      int i;
      for (i = 0; i < 4; i++)
          if (m_sashes[i].m_show)
              DrawSash((wxSashEdgePosition) i, dc);
  }
  
  // Draw the sash
  void wxSashWindow::DrawSash(wxSashEdgePosition edge, wxDC& dc)
  {
      int w, h;
      GetClientSize(&w, &h);
  
      wxPen facePen(m_faceColour, 1, wxSOLID);
      wxBrush faceBrush(m_faceColour, wxSOLID);
      wxPen mediumShadowPen(m_mediumShadowColour, 1, wxSOLID);
      wxPen darkShadowPen(m_darkShadowColour, 1, wxSOLID);
      wxPen lightShadowPen(m_lightShadowColour, 1, wxSOLID);
      wxPen hilightPen(m_hilightColour, 1, wxSOLID);
      wxColour blackClr(0, 0, 0);
      wxColour whiteClr(255, 255, 255);
      wxPen blackPen(blackClr, 1, wxSOLID);
      wxPen whitePen(whiteClr, 1, wxSOLID);
  
      if ( edge == wxSASH_LEFT || edge == wxSASH_RIGHT )
      {
          int sashPosition = (edge == wxSASH_LEFT) ? 0 : ( w - GetEdgeMargin(edge) );
  
          dc.SetPen(facePen);
          dc.SetBrush(faceBrush);
          dc.DrawRectangle(sashPosition, 0, GetEdgeMargin(edge), h);
  
          if (GetWindowStyleFlag() & wxSW_3DSASH)
          {
              if (edge == wxSASH_LEFT)
              {
                  // Draw a dark grey line on the left to indicate that the
                  // sash is raised
                  dc.SetPen(mediumShadowPen);
                  dc.DrawLine(GetEdgeMargin(edge), 0, GetEdgeMargin(edge), h);
              }
              else
              {
                  // Draw a highlight line on the right to indicate that the
                  // sash is raised
                  dc.SetPen(hilightPen);
                  dc.DrawLine(w - GetEdgeMargin(edge), 0, w - GetEdgeMargin(edge), h);
              }
          }
      }
      else // top or bottom
      {
          int sashPosition = (edge == wxSASH_TOP) ? 0 : ( h - GetEdgeMargin(edge) );
  
          dc.SetPen(facePen);
          dc.SetBrush(faceBrush);
          dc.DrawRectangle(0, sashPosition, w, GetEdgeMargin(edge));
  
          if (GetWindowStyleFlag() & wxSW_3DSASH)
          {
              if (edge == wxSASH_BOTTOM)
              {
                  // Draw a highlight line on the bottom to indicate that the
                  // sash is raised
                  dc.SetPen(hilightPen);
                  dc.DrawLine(0, h - GetEdgeMargin(edge), w, h - GetEdgeMargin(edge));
              }
              else
              {
                  // Draw a drak grey line on the top to indicate that the
                  // sash is raised
                  dc.SetPen(mediumShadowPen);
                  dc.DrawLine(1, GetEdgeMargin(edge), w-1, GetEdgeMargin(edge));
              }
          }
      }
  
      dc.SetPen(wxNullPen);
      dc.SetBrush(wxNullBrush);
  }
  
  // Draw the sash tracker (for whilst moving the sash)
  void wxSashWindow::DrawSashTracker(wxSashEdgePosition edge, int x, int y)
  {
      int w, h;
      GetClientSize(&w, &h);
  
      wxScreenDC screenDC;
      int x1, y1;
      int x2, y2;
  
      if ( edge == wxSASH_LEFT || edge == wxSASH_RIGHT )
      {
          x1 = x; y1 = 2;
          x2 = x; y2 = h-2;
  
          if ( (edge == wxSASH_LEFT) && (x1 > w) )
          {
              x1 = w; x2 = w;
          }
          else if ( (edge == wxSASH_RIGHT) && (x1 < 0) )
          {
              x1 = 0; x2 = 0;
          }
      }
      else
      {
          x1 = 2; y1 = y;
          x2 = w-2; y2 = y;
  
          if ( (edge == wxSASH_TOP) && (y1 > h) )
          {
              y1 = h;
              y2 = h;
          }
          else if ( (edge == wxSASH_BOTTOM) && (y1 < 0) )
          {
              y1 = 0;
              y2 = 0;
          }
      }
  
      ClientToScreen(&x1, &y1);
      ClientToScreen(&x2, &y2);
  
      wxPen sashTrackerPen(*wxBLACK, 2, wxSOLID);
  
      screenDC.SetLogicalFunction(wxINVERT);
      screenDC.SetPen(sashTrackerPen);
      screenDC.SetBrush(*wxTRANSPARENT_BRUSH);
  
      screenDC.DrawLine(x1, y1, x2, y2);
  
      screenDC.SetLogicalFunction(wxCOPY);
  
      screenDC.SetPen(wxNullPen);
      screenDC.SetBrush(wxNullBrush);
  }
  
  // Position and size subwindows.
  // Note that the border size applies to each subwindow, not
  // including the edges next to the sash.
  void wxSashWindow::SizeWindows()
  {
      int cw, ch;
      GetClientSize(&cw, &ch);
  
      if (GetChildren().GetCount() == 1)
      {
          wxWindow* child = GetChildren().GetFirst()->GetData();
  
          int x = 0;
          int y = 0;
          int width = cw;
          int height = ch;
  
          // Top
          if (m_sashes[0].m_show)
          {
              y = m_borderSize;
              height -= m_borderSize;
          }
          y += m_extraBorderSize;
  
          // Left
          if (m_sashes[3].m_show)
          {
              x = m_borderSize;
              width -= m_borderSize;
          }
          x += m_extraBorderSize;
  
          // Right
          if (m_sashes[1].m_show)
          {
              width -= m_borderSize;
          }
          width -= 2*m_extraBorderSize;
  
          // Bottom
          if (m_sashes[2].m_show)
          {
              height -= m_borderSize;
          }
          height -= 2*m_extraBorderSize;
  
          child->SetSize(x, y, width, height);
      }
      else if (GetChildren().GetCount() > 1)
      {
          // Perhaps multiple children are themselves sash windows.
          // TODO: this doesn't really work because the subwindows sizes/positions
          // must be set to leave a gap for the parent's sash (hit-test and decorations).
          // Perhaps we can allow for this within LayoutWindow, testing whether the parent
          // is a sash window, and if so, allowing some space for the edges.
          wxLayoutAlgorithm layout;
          layout.LayoutWindow(this);
      }
  
      wxClientDC dc(this);
      DrawBorders(dc);
      DrawSashes(dc);
  }
  
  // Initialize colours
  void wxSashWindow::InitColours()
  {
      // Shadow colours
      m_faceColour = wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE);
      m_mediumShadowColour = wxSystemSettings::GetColour(wxSYS_COLOUR_3DSHADOW);
      m_darkShadowColour = wxSystemSettings::GetColour(wxSYS_COLOUR_3DDKSHADOW);
      m_lightShadowColour = wxSystemSettings::GetColour(wxSYS_COLOUR_3DLIGHT);
      m_hilightColour = wxSystemSettings::GetColour(wxSYS_COLOUR_3DHILIGHT);
  }
  
  void wxSashWindow::SetSashVisible(wxSashEdgePosition edge, bool sash)
  {
       m_sashes[edge].m_show = sash;
       if (sash)
          m_sashes[edge].m_margin = m_borderSize;
       else
          m_sashes[edge].m_margin = 0;
  }
  
  #if defined( __WXMSW__ ) || defined( __WXMAC__)
  
  // this is currently called (and needed) under MSW only...
  void wxSashWindow::OnSetCursor(wxSetCursorEvent& event)
  {
      // if we don't do it, the resizing cursor might be set for child window:
      // and like this we explicitly say that our cursor should not be used for
      // children windows which overlap us
  
      if ( SashHitTest(event.GetX(), event.GetY()) != wxSASH_NONE)
      {
          // default processing is ok
          event.Skip();
      }
      //else: do nothing, in particular, don't call Skip()
  }
  
  #endif // __WXMSW__ || __WXMAC__
  
  #endif // wxUSE_SASH
  