/*=========================================================================

  Program:   ParaView
  Module:    $RCSfile$

  Copyright (c) Kitware, Inc.
  All rights reserved.
  See Copyright.txt or http://www.paraview.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "vtkSMViewLayoutProxy.h"

#include "vtkClientServerStream.h"
#include "vtkCommand.h"
#include "vtkImageData.h"
#include "vtkMemberFunctionCommand.h"
#include "vtkNew.h"
#include "vtkObjectFactory.h"
#include "vtkPVXMLElement.h"
#include "vtkSmartPointer.h"
#include "vtkSMMessage.h"
#include "vtkSMPropertyHelper.h"
#include "vtkSMProxyIterator.h"
#include "vtkSMProxyLocator.h"
#include "vtkSMProxyProperty.h"
#include "vtkSMSession.h"
#include "vtkSMSessionProxyManager.h"
#include "vtkSMTrace.h"
#include "vtkSMUtilities.h"
#include "vtkSMViewProxy.h"
#include "vtkWeakPointer.h"

#include <assert.h>
#include <algorithm>
#include <vector>

class vtkSMViewLayoutProxy::vtkInternals
{
public:
  struct Cell
    {
    vtkSMViewLayoutProxy::Direction Direction;
    double SplitFraction;
    vtkWeakPointer<vtkSMViewProxy> ViewProxy;

    Cell() :
      Direction(vtkSMViewLayoutProxy::NONE),
      SplitFraction(0.5)
    {
    }
    };


  bool IsCellValid(int location)
    {
    if (location < 0 ||
      location >= static_cast<int>(this->KDTree.size()))
      {
      return false;
      }

    if (location == 0)
      {
      return true;
      }

    // now verify that every parent node for location is a split cell.
    int parent = (static_cast<int>(location) - 1) / 2;
    while (this->KDTree[parent].Direction != vtkSMViewLayoutProxy::NONE)
      {
      if (parent == 0)
        {
        return true;
        }

      parent = (static_cast<int>(parent) - 1) / 2;
      }

    return false;
    }

  void MoveSubtree(int destination, int source)
    {
    assert(destination >= 0 && source >= 0);

    // we only support moving a subtree "up".
    assert(destination < source);

    if (source >= static_cast<int>(this->KDTree.size()) ||
      destination >= static_cast<int>(this->KDTree.size()))
      {
      return;
      }

    Cell source_cell = this->KDTree[source];
    this->KDTree[source] = Cell();
    this->MoveSubtree(2*destination+1, 2*source+1);
    this->MoveSubtree(2*destination+2, 2*source+2);
    this->KDTree[destination] = source_cell;
    }

  void Shrink()
    {
    size_t max_index = this->GetMaxChildIndex(0);
    assert(max_index < this->KDTree.size());
    this->KDTree.resize(max_index + 1);
    }

  void UpdateViewPositions(int root=0, int posx=0, int posy=0)
    {
    if (root == 0)
      {
      this->Sizes.resize(this->KDTree.size() * 2);
      this->ComputeSizes();
      }

    const Cell& cell = this->KDTree[root];
    if (cell.Direction == vtkSMViewLayoutProxy::NONE)
      {
      if (cell.ViewProxy)
        {
        int pos[2] = { posx, posy };
        vtkSMPropertyHelper(cell.ViewProxy, "ViewPosition").Set(pos, 2);
        cell.ViewProxy->UpdateProperty("ViewPosition");
        }
      //cout << "View Position: " << cell.ViewProxy  << " = "
      //  << posx << "," << posy << endl;
      }
    else
      {
      // root is a split-cell. Determine sizes for the two children.
      const int *size = &this->Sizes[2* (2*root+1)];

      if (cell.Direction == vtkSMViewLayoutProxy::HORIZONTAL)
        {
        this->UpdateViewPositions(2*root+1, posx, posy);
        this->UpdateViewPositions(2*root+2, posx + size[0], posy);
        }
      else // cell.Direction == VERTICAL
        {
        this->UpdateViewPositions(2*root+1, posx, posy);
        this->UpdateViewPositions(2*root+2, posx, posy + size[1]);
        }
      }
    }

  typedef std::vector<Cell> KDTreeType;
  KDTreeType KDTree;
  vtkCommand* Observer;

private:
  size_t GetMaxChildIndex(size_t parent)
    {
    if (this->KDTree[parent].Direction == vtkSMViewLayoutProxy::NONE)
      {
      return parent;
      }

    size_t child1 = this->GetMaxChildIndex(2*parent + 1);
    size_t child2 = this->GetMaxChildIndex(2*parent + 2);
    return std::max(child1, child2);
    }

  // temporary vector uses by ComputeSizes() and allocated by
  // UpdateViewPositions().
  std::vector<int> Sizes;

  const int *ComputeSizes(int root=0)
    {
    assert(2*root+1 < static_cast<int>(this->Sizes.size()));

    const Cell& cell = this->KDTree[root];
    if (cell.Direction == vtkSMViewLayoutProxy::NONE)
      {
      int size[2] = {0, 0};
      if (cell.ViewProxy)
        {
        vtkSMPropertyHelper(cell.ViewProxy, "ViewSize").Get(size, 2);
        }
      this->Sizes[2*root] = size[0];
      this->Sizes[2*root + 1] = size[1];
      return &this->Sizes[2*root];
      }

    const int *size0 = this->ComputeSizes(2*root+1);
    const int *size1 = this->ComputeSizes(2*root+2);

    // now double the width (or height) based on the split direction.
    if (cell.Direction == vtkSMViewLayoutProxy::HORIZONTAL)
      {
      this->Sizes[2*root] = size0[0] + size1[0];
      this->Sizes[2*root + 1] = std::max(size0[1], size1[1]);
      }
    else
      {
      this->Sizes[2*root] = std::max(size0[0], size1[0]);
      this->Sizes[2*root + 1] = size0[1] + size1[1];
      }
    return &this->Sizes[2*root];
    }
};

//============================================================================
double vtkSMViewLayoutProxy::MultiViewImageBorderColor[3] = {0.0, 0.0, 0.0};
int vtkSMViewLayoutProxy::MultiViewImageBorderWidth = 0;

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::SetMultiViewImageBorderColor(double r, double g, double b)
{
  vtkSMViewLayoutProxy::MultiViewImageBorderColor[0] = std::max(0.0, std::min(1.0, r));
  vtkSMViewLayoutProxy::MultiViewImageBorderColor[1] = std::max(0.0, std::min(1.0, g));
  vtkSMViewLayoutProxy::MultiViewImageBorderColor[2] = std::max(0.0, std::min(1.0, b));
}
//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::SetMultiViewImageBorderWidth(int width)
{
  vtkSMViewLayoutProxy::MultiViewImageBorderWidth = std::max(0, width);
}

//----------------------------------------------------------------------------
const double* vtkSMViewLayoutProxy::GetMultiViewImageBorderColor()
{
  return vtkSMViewLayoutProxy::MultiViewImageBorderColor;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::GetMultiViewImageBorderWidth()
{
  return vtkSMViewLayoutProxy::MultiViewImageBorderWidth;
}

//============================================================================
vtkStandardNewMacro(vtkSMViewLayoutProxy);
//----------------------------------------------------------------------------
vtkSMViewLayoutProxy::vtkSMViewLayoutProxy() :
  MaximizedCell(-1),
  Internals(new vtkInternals()),
  BlockUpdate(false)
{
  this->Internals->Observer = vtkMakeMemberFunctionCommand(
    *this, &vtkSMViewLayoutProxy::UpdateViewPositions);

  // Push the root element.
  this->Internals->KDTree.resize(1);
}

//----------------------------------------------------------------------------
vtkSMViewLayoutProxy::~vtkSMViewLayoutProxy()
{
  vtkMemberFunctionCommand<vtkSMViewLayoutProxy>::SafeDownCast(
    this->Internals->Observer)->Reset();
  this->Internals->Observer->Delete();
  this->Internals->Observer = NULL;
  delete this->Internals;
  this->Internals = NULL;
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::Reset()
{
  this->Internals->KDTree.clear();
  this->Internals->KDTree.resize(1);
  this->UpdateState();
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::LoadState(
  const vtkSMMessage* message, vtkSMProxyLocator* locator)
{
  this->Superclass::LoadState(message, locator);

  if (message->ExtensionSize(ProxyState::user_data) != 1)
    {
    // vtkWarningMacro("Missing ViewLayoutState");
    return;
    }

  const ProxyState_UserData& user_data =
    message->GetExtension(ProxyState::user_data, 0);
  if (user_data.key() != "ViewLayoutState")
    {
    //vtkWarningMacro("Unexpected user_data. Expecting ViewLayoutState.");
    return;
    }

  this->Internals->KDTree.clear();
  this->Internals->KDTree.resize(user_data.variant_size());

  for (int cc=0; cc < user_data.variant_size(); cc++)
    {
    vtkInternals::Cell &cell = this->Internals->KDTree[cc];
    const Variant& value = user_data.variant(cc);

    cell.SplitFraction = value.float64(0);

    switch (value.integer(0))
      {
    case HORIZONTAL:
      cell.Direction = HORIZONTAL;
      break;

    case VERTICAL:
      cell.Direction = VERTICAL;
      break;

    case NONE:
    default:
      cell.Direction = NONE;
      }

    if (locator && vtkSMProxyProperty::CanCreateProxy())
      {
      cell.ViewProxy = locator->LocateProxy(value.proxy_global_id(0));
      }
    else
      {
      cell.ViewProxy = vtkSMViewProxy::SafeDownCast(
        this->GetSession()->GetRemoteObject(value.proxy_global_id(0)));
      }
    }

  // let the world know that the layout has been reconfigured.
  this->InvokeEvent(vtkCommand::ConfigureEvent);
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::UpdateState()
{
  if (this->BlockUpdate)
    {
    return;
    }

  // ensure that the state is created correctly.
  this->CreateVTKObjects();

  // push current state.
  this->State->ClearExtension(ProxyState::user_data);

  ProxyState_UserData* user_data =
    this->State->AddExtension(ProxyState::user_data);
  user_data->set_key("ViewLayoutState");

  for (size_t cc=0; cc < this->Internals->KDTree.size(); cc++)
    {
    const vtkInternals::Cell &cell = this->Internals->KDTree[cc];

    Variant* variant = user_data->add_variant();
    variant->set_type(Variant::INT); // type is just arbitrary here.
    variant->add_integer(cell.Direction);
    variant->add_float64(cell.SplitFraction);
    variant->add_proxy_global_id(
      cell.ViewProxy? cell.ViewProxy->GetGlobalID() : 0);
    }

  this->PushState(this->State);
  this->InvokeEvent(vtkCommand::ConfigureEvent);

  this->UpdateViewPositions();
}

//----------------------------------------------------------------------------
vtkPVXMLElement* vtkSMViewLayoutProxy::SaveXMLState(
  vtkPVXMLElement* root, vtkSMPropertyIterator* iter)
{
  vtkPVXMLElement* element = this->Superclass::SaveXMLState(root, iter);
  if (!element)
    {
    return NULL;
    }

  vtkPVXMLElement* layout = vtkPVXMLElement::New();
  layout->SetName("Layout");
  layout->AddAttribute("number_of_elements",
    static_cast<int>(this->Internals->KDTree.size()));
  element->AddNestedElement(layout);
  layout->Delete();

  for (size_t cc=0; cc < this->Internals->KDTree.size(); cc++)
    {
    const vtkInternals::Cell &cell = this->Internals->KDTree[cc];

    vtkPVXMLElement* item = vtkPVXMLElement::New();
    item->SetName("Item");
    item->AddAttribute("direction", static_cast<int>(cell.Direction));
    item->AddAttribute("fraction", cell.SplitFraction);
    item->AddAttribute("view", (cell.ViewProxy?
      static_cast<unsigned int>(cell.ViewProxy->GetGlobalID()) : 0));
    layout->AddNestedElement(item);
    item->Delete();
    }

  return element;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::LoadXMLState(
  vtkPVXMLElement* element, vtkSMProxyLocator* locator)
{
  if (!this->Superclass::LoadXMLState(element, locator))
    {
    return 0;
    }

  if (!locator)
    {
    return 1;
    }

  vtkPVXMLElement* layout = element->FindNestedElementByName("Layout");
  int number_of_elements = 0;
  if (!layout->GetScalarAttribute("number_of_elements", &number_of_elements) ||
    (number_of_elements <= 0))
    {
    vtkErrorMacro("Missing (or invalid) 'number_of_elements' attribute.");
    return 0;
    }

  if (static_cast<int>(layout->GetNumberOfNestedElements()) != number_of_elements)
    {
    vtkErrorMacro("Mismatch in number_of_elements and nested elements.");
    return 0;
    }

  this->Internals->KDTree.clear();
  this->Internals->KDTree.resize(number_of_elements);
  for (unsigned int cc = 0; cc < layout->GetNumberOfNestedElements(); cc++)
    {
    vtkPVXMLElement* item = layout->GetNestedElement(cc);
    if (item == NULL || item->GetName() == NULL ||
      strcmp(item->GetName(), "Item") != 0)
      {
      vtkErrorMacro("Invalid nested element at index : " << cc);
      return 0;
      }
    int direction, viewid;
    double fraction;
    if (!item->GetScalarAttribute("direction", &direction) ||
      !item->GetScalarAttribute("fraction", &fraction) ||
      !item->GetScalarAttribute("view", &viewid))
      {
      vtkErrorMacro("Invalid nested element at index : " << cc);
      return 0;
      }
    vtkInternals::Cell &cell = this->Internals->KDTree[cc];
    cell.Direction = ((direction == NONE)? NONE : (
        (direction == HORIZONTAL)? HORIZONTAL : VERTICAL));
    cell.SplitFraction = fraction;
    if (viewid)
      {
      cell.ViewProxy = locator->LocateProxy(viewid);
      }
    else
      {
      cell.ViewProxy = NULL;
      }
    }

  this->UpdateViewPositions();
  return 1;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::Split(int location, int direction, double fraction)
{
  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return 0;
    }

  // we don't get by value, since we resize the vector.
  vtkInternals::Cell cell = this->Internals->KDTree[location];
  if (cell.Direction != NONE)
    {
    vtkErrorMacro("Cell identified by location '" << location
      << "' is already split. Cannot split the cell again.");
    return 0;
    }

  if (direction <= NONE || direction > HORIZONTAL)
    {
    vtkErrorMacro("Invalid direction : " << direction);
    return 0;
    }

  if (fraction < 0.0 || fraction > 1.0)
    {
    vtkErrorMacro("Invalid fraction : " << fraction
      << ". Must be in the range [0, 1]");
    return 0;
    }

  SM_SCOPED_TRACE(CallMethod)
    .arg(this)
    .arg(direction == VERTICAL? "SplitVertical" : "SplitHorizontal")
    .arg(location)
    .arg(fraction)
    .arg("comment", "split cell");

  cell.Direction = (direction == VERTICAL)? VERTICAL : HORIZONTAL;
  cell.SplitFraction = fraction;

  // ensure that both the children (2i+1), (2i+2) can fit in the KDTree.
  if ( (2*location + 2) >= static_cast<int>(this->Internals->KDTree.size()))
    {
    this->Internals->KDTree.resize(2*location + 2 + 1);
    }

  int child_location = (2*location + 1);
  if (cell.ViewProxy)
    {
    vtkInternals::Cell &child = this->Internals->KDTree[child_location];
    child.ViewProxy = cell.ViewProxy;
    cell.ViewProxy = NULL;
    }
  this->Internals->KDTree[location] = cell;
  this->MaximizedCell = -1;
  this->UpdateState();
  return child_location;
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::AssignView(int location, vtkSMViewProxy* view)
{
  if (view == NULL)
    {
    return false;
    }

  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return false;
    }

  vtkInternals::Cell &cell = this->Internals->KDTree[location];
  if (cell.Direction != NONE)
    {
    vtkErrorMacro("Cell is not a leaf '" << location << "'."
      " Cannot assign a view to it.");
    return false;
    }

  if (cell.ViewProxy != NULL && cell.ViewProxy != view)
    {
    vtkErrorMacro("Cell is not empty.");
    return false;
    }

  SM_SCOPED_TRACE(CallMethod)
    .arg(this)
    .arg("AssignView")
    .arg(location)
    .arg(view)
    .arg("assign view to a paricular cell in the layout");

  if (cell.ViewProxy == view)
    {
    // nothing to do.
    return true;
    }

  cell.ViewProxy = view;

  if (view->GetProperty("ViewSize"))
    {
    // every time view-size changes, we update the view positions for all views.
    view->GetProperty("ViewSize")->AddObserver(
      vtkCommand::ModifiedEvent, this->Internals->Observer);
    }

  this->UpdateState();
  return true;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::AssignViewToAnyCell(
  vtkSMViewProxy* view, int location_hint)
{
  if (!view)
    {
    return 0;
    }

  int cur_location = this->GetViewLocation(view);
  if (cur_location != -1)
    {
    // already assigned to a frame. return that index.
    SM_SCOPED_TRACE(CallMethod)
      .arg(this)
      .arg("AssignView")
      .arg(cur_location)
      .arg(view)
      .arg("comment", "place view in the layout");
    return cur_location;
    }

  if (location_hint < 0)
    {
    location_hint = 0;
    }

  // If location_hint refers to an empty cell, use it.
  if (this->Internals->IsCellValid(location_hint))
    {
    int empty_cell = this->GetEmptyCell(location_hint);
    if (empty_cell >= 0)
      {
      return this->AssignView(empty_cell, view);
      }
    }
  else
    {
    // make location_hint a valid location.
    location_hint = 0;
    }

  // Find any empty cell.
  int empty_cell = this->GetEmptyCell(0);
  if (empty_cell >= 0)
    {
    return this->AssignView(empty_cell, view);
    }

  // No empty cell found, split a view, starting with the location_hint.
  Direction direction = HORIZONTAL;

  int parent = this->GetParent(location_hint);
  if (parent >= 0)
    {
    direction = this->GetSplitDirection(parent) == HORIZONTAL?
      VERTICAL: HORIZONTAL;
    }
  int split_cell = this->GetSplittableCell(location_hint, direction);
  assert(split_cell >= 0);

  bool prev = this->SetBlockUpdate(true);
  int new_cell = this->Split(split_cell, direction, 0.5);
  this->SetBlockUpdate(prev);

  if (this->GetView(new_cell) == NULL)
    {
    return this->AssignView(new_cell, view);
    }

  return this->AssignView(new_cell + 1, view);
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::RemoveView(int index)
{
  return this->RemoveView(this->GetView(index)) != -1;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::RemoveView(vtkSMViewProxy* view)
{
  if (!view)
    {
    return -1;
    }

  int index = 0;
  for (vtkInternals::KDTreeType::iterator iter =
    this->Internals->KDTree.begin();
    iter != this->Internals->KDTree.end(); ++iter, ++index)
    {
    if (iter->ViewProxy == view)
      {
      if (iter->ViewProxy->GetProperty("ViewSize"))
        {
        iter->ViewProxy->GetProperty("ViewSize")->RemoveObserver(
          this->Internals->Observer);
        }
      iter->ViewProxy = NULL;
      this->UpdateState();
      return index;
      }
    }

  return -1;
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::SwapCells(int location1, int location2)
{
  if (!this->Internals->IsCellValid(location1) ||
    !this->Internals->IsCellValid(location2))
    {
    vtkErrorMacro("Invalid locations specified.");
    return false;
    }

  SM_SCOPED_TRACE(CallMethod)
    .arg(this)
    .arg("SwapCells")
    .arg(location1)
    .arg(location2)
    .arg("comment", "swap view locations");

  vtkInternals::Cell &cell1 = this->Internals->KDTree[location1];
  vtkInternals::Cell &cell2 = this->Internals->KDTree[location2];
  if (cell1.Direction == NONE && cell2.Direction == NONE)
    {
    vtkSMViewProxy* temp1 = cell1.ViewProxy;
    cell1.ViewProxy = cell2.ViewProxy;
    cell2.ViewProxy = temp1;
    this->UpdateState();
    return true;
    }

  return false;
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::Collapse(int location)
{
  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return false;
    }

  vtkInternals::Cell &cell = this->Internals->KDTree[location];
  if (cell.Direction != NONE)
    {
    vtkErrorMacro("Only leaf cells can be collapsed.");
    return false;
    }
  
  if (cell.ViewProxy != NULL)
    {
    vtkErrorMacro("Only empty cells can be collapsed.");
    return false;
    }

  if (location == 0)
    {
    // sure, trying to collapse the root node...whatever!!!
    return true;
    }

  SM_SCOPED_TRACE(CallMethod)
    .arg(this)
    .arg("Collapse")
    .arg(location)
    .arg("comment", "close an empty frame");

  int parent = (location - 1) / 2;
  int sibling = ((location % 2) == 0)? (2*parent + 1) : (2*parent + 2);

  this->Internals->MoveSubtree(parent, sibling);
  this->Internals->Shrink();
  this->MaximizedCell = -1;
  this->UpdateState();
  return true;
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::IsSplitCell(int location)
{
  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return false;
    }

  const vtkInternals::Cell &cell = this->Internals->KDTree[location];
  return (cell.Direction != NONE);
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::GetEmptyCell(int root)
{
  vtkInternals::Cell &cell = this->Internals->KDTree[root];
  if (cell.Direction == NONE && cell.ViewProxy == NULL)
    {
    return root;
    }
  else if (cell.Direction == HORIZONTAL ||
    cell.Direction == VERTICAL)
    {
    int child0 = 2*root + 1;
    int empty_cell = this->GetEmptyCell(child0);
    if (empty_cell >= 0)
      {
      return empty_cell;
      }
    int child1 = 2*root + 2;
    empty_cell = this->GetEmptyCell(child1);
    if (empty_cell >= 0)
      {
      return empty_cell;
      }
    }
  return -1;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::GetSplittableCell(int root,
  vtkSMViewLayoutProxy::Direction& suggested_direction)
{
  vtkInternals::Cell &cell = this->Internals->KDTree[root];
  if (cell.Direction == NONE)
    {
    return root;
    }
  else if (cell.Direction == HORIZONTAL ||
    cell.Direction == VERTICAL)
    {
    suggested_direction = cell.Direction == HORIZONTAL?
      VERTICAL : HORIZONTAL;
    int child0 = 2*root + 1;
    return this->GetSplittableCell(child0, suggested_direction);
    }
  return -1;
}

//----------------------------------------------------------------------------
vtkSMViewLayoutProxy::Direction vtkSMViewLayoutProxy::GetSplitDirection(
  int location)
{
  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return NONE;
    }

  return this->Internals->KDTree[location].Direction;
}

//----------------------------------------------------------------------------
double vtkSMViewLayoutProxy::GetSplitFraction(int location)
{
  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return NONE;
    }

  return this->Internals->KDTree[location].SplitFraction;
}

//----------------------------------------------------------------------------
vtkSMViewProxy* vtkSMViewLayoutProxy::GetView(int location)
{
  if (!this->Internals->IsCellValid(location))
    {
    vtkErrorMacro("Invalid location '" << location << "' specified.");
    return NULL;
    }

  return this->Internals->KDTree[location].ViewProxy;
}

//----------------------------------------------------------------------------
int vtkSMViewLayoutProxy::GetViewLocation(vtkSMViewProxy* view)
{
  int index = 0;
  for (vtkInternals::KDTreeType::iterator iter =
    this->Internals->KDTree.begin();
    iter != this->Internals->KDTree.end(); ++iter, ++index)
    {
    if (iter->ViewProxy == view)
      {
      return index;
      }
    }
  return -1;
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::SetSplitFraction(int location, double val)
{
  if (val < 0.0 || val > 1.0)
    {
    vtkErrorMacro("Invalid fraction : " << val
      << ". Must be in the range [0, 1]");
    return 0;
    }

  if (!this->IsSplitCell(location))
    {
    return false;
    }


  SM_SCOPED_TRACE(CallMethod)
    .arg(this)
    .arg("SetSplitFraction")
    .arg(location)
    .arg(val)
    .arg("comment", "resize frame");

  if (this->Internals->KDTree[location].SplitFraction != val)
    {
    this->Internals->KDTree[location].SplitFraction = val;
    this->MaximizedCell = -1;
    this->UpdateState();
    }

  return true;
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::UpdateViewPositions()
{
  if (this->MaximizedCell == -1)
    {
    this->Internals->UpdateViewPositions();
    }
  else
    {
    // simply set all ViewPositions to 0.
    for (vtkInternals::KDTreeType::iterator iter =
      this->Internals->KDTree.begin();
      iter != this->Internals->KDTree.end();
      ++iter)
      {
      if (iter->ViewProxy.GetPointer() != NULL)
        {
        int pos[2] = {0, 0};
        vtkSMPropertyHelper(iter->ViewProxy, "ViewPosition").Set(pos, 2);
        iter->ViewProxy->UpdateProperty("ViewPosition");
        }
      }
    }
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::ShowViewsOnTileDisplay()
{
  this->CreateVTKObjects();

  vtkSMProxy* proxy = this->GetSessionProxyManager()->NewProxy(
    "misc", "InternalViewLayoutHelper");
  proxy->UpdateVTKObjects();

  vtkClientServerStream stream;
  stream << vtkClientServerStream::Invoke
         << VTKOBJECT(proxy)
         << "ResetTileDisplay"
         << vtkClientServerStream::End;
  for (vtkInternals::KDTreeType::iterator iter =
    this->Internals->KDTree.begin();
    iter != this->Internals->KDTree.end();
    ++iter)
    {
    if (iter->ViewProxy.GetPointer() != NULL)
      {
      stream << vtkClientServerStream::Invoke
        << VTKOBJECT(proxy)
        << "ShowOnTileDisplay"
        << static_cast<unsigned int>(iter->ViewProxy->GetGlobalID())
        << vtkClientServerStream::End;
      }
    }
  this->GetSession()->ExecuteStream(
    proxy->GetLocation(), stream, false);
  proxy->Delete();
}

//----------------------------------------------------------------------------
bool vtkSMViewLayoutProxy::MaximizeCell(int location)
{
  if (this->Internals->IsCellValid(location) == false ||
    this->IsSplitCell(location))
    {
    return false;
    }

  this->MaximizedCell = location;
  this->UpdateState();
  return true;
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::RestoreMaximizedState()
{
  if (this->MaximizedCell != -1)
    {
    this->MaximizedCell = -1;
    this->UpdateState();
    }
}

//----------------------------------------------------------------------------
vtkImageData* vtkSMViewLayoutProxy::CaptureWindow(int magnification)
{
  if (this->MaximizedCell != -1)
    {
    vtkSMViewProxy* view = this->GetView(this->MaximizedCell);
    if (view)
      {
      return view->CaptureWindow(magnification);
      }
    vtkErrorMacro("No view present in the layout.");
    return NULL;
    }

  this->UpdateState();

  int extent[6] = {VTK_INT_MAX, VTK_INT_MIN,
    VTK_INT_MAX, VTK_INT_MIN, VTK_INT_MAX, VTK_INT_MIN};

  std::vector<vtkSmartPointer<vtkImageData> > images;
  for (vtkInternals::KDTreeType::iterator iter =
    this->Internals->KDTree.begin();
    iter != this->Internals->KDTree.end(); ++iter)
    {
    if (iter->ViewProxy.GetPointer())
      {
      vtkImageData* image = iter->ViewProxy->CaptureWindow(magnification);
      if (image)
        {
        const int* image_extent = image->GetExtent();
        extent[0] = std::min(extent[0], image_extent[0]);
        extent[2] = std::min(extent[2], image_extent[2]);
        extent[4] = std::min(extent[4], image_extent[4]);
        extent[1] = std::max(extent[1], image_extent[1]);
        extent[3] = std::max(extent[3], image_extent[3]);
        extent[5] = std::max(extent[5], image_extent[5]);

        images.push_back(image);
        image->FastDelete();
        }
      }
    }

  if (images.size() == 0)
    {
    vtkErrorMacro("No view present in the layout.");
    return NULL;
    }

  int numComponents = vtkSMViewProxy::GetTransparentBackground()? 4 : 3;
  vtkImageData* image = vtkImageData::New();
  image->SetExtent(extent);
  image->AllocateScalars(VTK_UNSIGNED_CHAR, numComponents);

  unsigned char* image_data =
    reinterpret_cast<unsigned char*>(image->GetScalarPointer());
  std::fill(
    image_data, image_data + image->GetNumberOfPoints() * numComponents,
    static_cast<unsigned char>(0));

  unsigned char color[3];
  color[0] = static_cast<unsigned char>(vtkSMViewLayoutProxy::MultiViewImageBorderColor[0] *  0xff);
  color[1] = static_cast<unsigned char>(vtkSMViewLayoutProxy::MultiViewImageBorderColor[1] *  0xff);
  color[2] = static_cast<unsigned char>(vtkSMViewLayoutProxy::MultiViewImageBorderColor[2] *  0xff);
  for (size_t cc=0; cc < images.size(); cc++)
    {
    vtkSMUtilities::Merge(image, images[cc],
      vtkSMViewLayoutProxy::MultiViewImageBorderWidth, color);
    }

  return image;
}

//----------------------------------------------------------------------------
vtkSMViewLayoutProxy* vtkSMViewLayoutProxy::FindLayout(
  vtkSMViewProxy* view, const char* reggroup/*=layouts*/)
{
  if (!view)
    {
    return NULL;
    }
  vtkSMSessionProxyManager* pxm = view->GetSessionProxyManager();
  vtkNew<vtkSMProxyIterator> iter;
  iter->SetSessionProxyManager(pxm);
  iter->SetModeToOneGroup();
  for (iter->Begin(reggroup); !iter->IsAtEnd(); iter->Next())
    {
    vtkSMViewLayoutProxy* layout = vtkSMViewLayoutProxy::SafeDownCast(iter->GetProxy());
    if (layout != NULL && layout->GetViewLocation(view) != -1)
      {
      return layout;
      }
    }
  return NULL;
}

//----------------------------------------------------------------------------
void vtkSMViewLayoutProxy::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os, indent);
}
