text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    vtkTextRenderer.cxx
  
    Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
    All rights reserved.
    See Copyright.txt or http://www.kitware.com/Copyright.htm 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 "vtkTextRenderer.h"
  
  #include "vtkImageData.h"
  #include "vtkObjectFactory.h"
  #include "vtkPath.h"
  #include "vtkStdString.h"
  #include "vtkTextProperty.h"
  #include "vtkUnicodeString.h"
  
  #include <vtksys/RegularExpression.hxx>
  
  #ifdef VTK_DEBUG_LEAKS
  #include "vtkDebugLeaks.h"
  #endif
  
  //----------------------------------------------------------------------------
  // The singleton, and the singleton cleanup
  vtkTextRenderer *vtkTextRenderer::Instance = NULL;
  vtkTextRendererCleanup vtkTextRenderer::Cleanup;
  
  //----------------------------------------------------------------------------
  vtkTextRendererCleanup::vtkTextRendererCleanup()
  {
  }
  
  //----------------------------------------------------------------------------
  vtkTextRendererCleanup::~vtkTextRendererCleanup()
  {
    vtkTextRenderer::SetInstance(NULL);
  }
  
  //----------------------------------------------------------------------------
  void vtkTextRenderer::PrintSelf(ostream &os, vtkIndent indent)
  {
    this->Superclass::PrintSelf(os, indent);
  
    os << indent << "Instance: " << vtkTextRenderer::Instance << endl;
    os << indent << "HasFreeType: " << this->HasFreeType << endl;
    os << indent << "HasMathText: " << this->HasMathText << endl;
    os << indent << "MathTextRegExp: " << this->MathTextRegExp << endl;
    os << indent << "MathTextRegExp2: " << this->MathTextRegExp2 << endl;
  }
  
  //----------------------------------------------------------------------------
  vtkTextRenderer *vtkTextRenderer::New()
  {
    vtkTextRenderer *instance = vtkTextRenderer::GetInstance();
    if (instance)
      {
      instance->Register(NULL);
      }
    return instance;
  }
  
  //----------------------------------------------------------------------------
  vtkTextRenderer *vtkTextRenderer::GetInstance()
  {
    if (vtkTextRenderer::Instance)
      {
      return vtkTextRenderer::Instance;
      }
  
    vtkTextRenderer::Instance = static_cast<vtkTextRenderer*>(
          vtkObjectFactory::CreateInstance("vtkTextRenderer"));
  
    // Clean up any leaked references from vtkDebugLeaks if needed
  #ifdef VTK_DEBUG_LEAKS
    if (!vtkTextRenderer::Instance)
      {
      vtkDebugLeaks::DestructClass("vtkTextRenderer");
      }
  #endif
  
    return vtkTextRenderer::Instance;
  }
  
  //----------------------------------------------------------------------------
  void vtkTextRenderer::SetInstance(vtkTextRenderer *instance)
  {
    if (vtkTextRenderer::Instance == instance)
      {
      return;
      }
  
    if (vtkTextRenderer::Instance)
      {
      vtkTextRenderer::Instance->Delete();
      }
  
    vtkTextRenderer::Instance = instance;
  
    if (instance)
      {
      instance->Register(NULL);
      }
  }
  
  //----------------------------------------------------------------------------
  vtkTextRenderer::vtkTextRenderer()
    : MathTextRegExp(new vtksys::RegularExpression("[^\\]\\$.+[^\\]\\$")),
      MathTextRegExp2(new vtksys::RegularExpression("^\\$.+[^\\]\\$")),
      HasFreeType(false),
      HasMathText(false),
      DefaultBackend(Detect)
  {
  }
  
  //----------------------------------------------------------------------------
  vtkTextRenderer::~vtkTextRenderer()
  {
    delete this->MathTextRegExp;
    delete this->MathTextRegExp2;
  }
  
  //----------------------------------------------------------------------------
  int vtkTextRenderer::DetectBackend(const vtkStdString &str)
  {
    if (!str.empty())
      {
      // the vtksys::RegularExpression class doesn't support {...|...} "or"
      // branching, so we check the first character to see which regexp to use:
      //
      // Find unescaped "$...$" patterns where "$" is not the first character:
      //   MathTextRegExp  = "[^\\]\\$.+[^\\]\\$"
      // Find unescaped "$...$" patterns where "$" is the first character:
      //   MathTextRegExp2 = "^\\$.+[^\\]\\$"
      if ((str[0] == '$' && this->MathTextRegExp2->find(str)) ||
          this->MathTextRegExp->find(str))
        {
        return static_cast<int>(MathText);
        }
      }
    return static_cast<int>(FreeType);
  }
  
  //----------------------------------------------------------------------------
  int vtkTextRenderer::DetectBackend(const vtkUnicodeString &str)
  {
    if (!str.empty())
      {
      // the vtksys::RegularExpression class doesn't support {...|...} "or"
      // branching, so we check the first character to see which regexp to use:
      //
      // Find unescaped "$...$" patterns where "$" is not the first character:
      //   MathTextRegExp  = "[^\\]\\$.+[^\\]\\$"
      // Find unescaped "$...$" patterns where "$" is the first character:
      //   MathTextRegExp2 = "^\\$.+[^\\]\\$"
      if ((str[0] == '$' && this->MathTextRegExp2->find(str.utf8_str())) ||
          this->MathTextRegExp->find(str.utf8_str()))
        {
        return static_cast<int>(MathText);
        }
      }
    return static_cast<int>(FreeType);
  }
  
  //----------------------------------------------------------------------------
  void vtkTextRenderer::CleanUpFreeTypeEscapes(vtkStdString &str)
  {
    size_t ind = str.find("\\$");
    while (ind != std::string::npos)
      {
      str.replace(ind, 2, "$");
      ind = str.find("\\$", ind + 1);
      }
  }
  
  //----------------------------------------------------------------------------
  void vtkTextRenderer::CleanUpFreeTypeEscapes(vtkUnicodeString &str)
  {
    // vtkUnicodeString has only a subset of the std::string API available, so
    // this method is more complex than the std::string overload.
    vtkUnicodeString::const_iterator begin = str.begin();
    vtkUnicodeString::const_iterator end = str.end();
    vtkUnicodeString tmp;
  
    for (vtkUnicodeString::const_iterator it = begin; it != end; ++it)
      {
      if (*it != '\\')
        {
        continue;
        }
  
      // No operator+ in the unicode string iterator. Copy and advance it:
      vtkUnicodeString::const_iterator nextChar = it;
      std::advance(nextChar, 1);
      if (*nextChar != '$')
        {
        continue;
        }
  
      // We found a "\$" in the string. Append [begin, it) into tmp.
      tmp.append(begin, it);
  
      // Add the dollar sign
      tmp.append(vtkUnicodeString::from_utf8("$"));
  
      // Reset the iterators to continue checking the rest of the string.
      begin = it;
      std::advance(it, 1);
      std::advance(begin, 2);
      }
  
    // Append the last bit of the string to tmp
    tmp.append(begin, end);
  
    // Update the input with the cleaned up string:
    str = tmp;
  }
  