VTK-5.0.0/Common/vtkScalarsToColors.cxx

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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkScalarsToColors.cxx,v $

  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 "vtkScalarsToColors.h"

#include "vtkUnsignedCharArray.h"

#include <math.h>

vtkCxxRevisionMacro(vtkScalarsToColors, "$Revision: 1.25 $");

//----------------------------------------------------------------------------
vtkScalarsToColors::vtkScalarsToColors()
{
  this->Alpha = 1.0;
  this->VectorComponent = 0;
  this->VectorMode = vtkScalarsToColors::COMPONENT;
  this->UseMagnitude = 0;
}

//----------------------------------------------------------------------------
void vtkScalarsToColors::SetVectorModeToComponent()
{
  this->SetVectorMode(vtkScalarsToColors::COMPONENT);
}

//----------------------------------------------------------------------------
void vtkScalarsToColors::SetVectorModeToMagnitude()
{
  this->SetVectorMode(vtkScalarsToColors::MAGNITUDE);
}

//----------------------------------------------------------------------------
// do not use SetMacro() because we do not want the table to rebuild.
void vtkScalarsToColors::SetAlpha(double alpha)
{
  this->Alpha = (alpha < 0.0 ? 0.0 : (alpha > 1.0 ? 1.0 : alpha));
}

//----------------------------------------------------------------------------
vtkUnsignedCharArray *vtkScalarsToColors::MapScalars(vtkDataArray *scalars,
                                                     int colorMode, int comp)
{
  vtkUnsignedCharArray *newColors;
  vtkUnsignedCharArray *colors;

  // map scalars through lookup table only if needed
  if ( colorMode == VTK_COLOR_MODE_DEFAULT && 
       (colors=vtkUnsignedCharArray::SafeDownCast(scalars)) != NULL )
    {
    newColors = this->
      ConvertUnsignedCharToRGBA(colors, colors->GetNumberOfComponents(),
                                scalars->GetNumberOfTuples());
    }
  else
    {
    newColors = vtkUnsignedCharArray::New();
    newColors->SetNumberOfComponents(4);
    newColors->SetNumberOfTuples(scalars->GetNumberOfTuples());

    // If mapper did not specify a component, use our mode.
    this->UseMagnitude = 0;
    if (comp < 0 && this->VectorMode == vtkScalarsToColors::COMPONENT)
      {
      comp = this->VectorComponent;
      }
    if (comp < 0 && this->VectorMode == vtkScalarsToColors::MAGNITUDE)
      {
      comp = 0;
      this->UseMagnitude = 1;
      }

    // Just some error checking.
    if (comp < 0)
      {
      comp = 0;
      }
    if (comp >= scalars->GetNumberOfComponents())
      {
      comp = scalars->GetNumberOfComponents()-1;
      }
    // Fill in the colors.
    this->MapScalarsThroughTable2(scalars->GetVoidPointer(comp), 
                                  newColors->GetPointer(0),
                                  scalars->GetDataType(),
                                  scalars->GetNumberOfTuples(),
                                  scalars->GetNumberOfComponents(), 
                                  VTK_RGBA);
    }//need to map

  // Here is a bit of a hack.
  // It is much faster to render RGB instead of RGBA when possible.
  // I do not want to create a 3 component color array because
  // it would be another condition.  Give the mapper a hint that
  // the colors have no alpha by setting the name.
  // When the mapper can handle 3 component color array,
  // I will change this logic to use NumberOfComponents as
  // an indicator of opacity.
  unsigned char* alphaPtr = newColors->GetPointer(0) + 3;
  vtkIdType idx, num;
  int opaque = 1;
  num = newColors->GetNumberOfTuples();
  for (idx = 0; idx < num; ++idx)
    {
    if (*alphaPtr < 255)
      {
      opaque = 0;
      }
    alphaPtr += 4;
    }
  if (opaque)
    {
    newColors->SetName("Opaque Colors");
    }

  return newColors;
}

//----------------------------------------------------------------------------
// Map a set of scalar values through the table
void vtkScalarsToColors::MapScalarsThroughTable(vtkDataArray *scalars, 
                                                unsigned char *output,
                                                int outputFormat)
{
  switch (outputFormat)
    {
    case VTK_RGBA:
    case VTK_RGB:
    case VTK_LUMINANCE_ALPHA:
    case VTK_LUMINANCE:
      break;
    default:
      vtkErrorMacro(<< "MapScalarsThroughTable: unrecognized color format");
      break;
    }

  this->MapScalarsThroughTable2(scalars->GetVoidPointer(0),
                                output,
                                scalars->GetDataType(),
                                scalars->GetNumberOfTuples(),
                                scalars->GetNumberOfComponents(),
                                outputFormat);
}

//----------------------------------------------------------------------------
vtkUnsignedCharArray *vtkScalarsToColors::ConvertUnsignedCharToRGBA(
  vtkUnsignedCharArray *colors, int numComp, int numTuples)
{
  if ( numComp == 4 && this->Alpha >= 1.0 )
    {
    colors->Register(this);
    return colors;
    }
    
  unsigned char *cptr = colors->GetPointer(0);
  vtkUnsignedCharArray *newColors = vtkUnsignedCharArray::New();
  newColors->SetNumberOfComponents(4);
  newColors->SetNumberOfTuples(numTuples);
  unsigned char *nptr = newColors->GetPointer(0);
  int i;

  if ( this->Alpha >= 1.0 )
    {
    switch (numComp)
      {
      case 1:
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr;
          *nptr++ = *cptr;
          *nptr++ = *cptr++;
          *nptr++ = 255;
          }
        break;

      case 2:
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr;
          *nptr++ = *cptr;
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          }
        break;

      case 3:
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          *nptr++ = 255;
          }
        break;

      default:
        vtkErrorMacro(<<"Cannot convert colors");
        return NULL;
      }
    }
  else //blending required
    {
    unsigned char alpha;
    switch (numComp)
      {
      case 1:
        alpha = static_cast<unsigned char>(this->Alpha*255);
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr;
          *nptr++ = *cptr;
          *nptr++ = *cptr++;
          *nptr++ = alpha;
          }
        break;

      case 2:
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr;
          *nptr++ = *cptr;
          *nptr++ = *cptr++;
          *nptr++ = static_cast<unsigned char>((*cptr)*this->Alpha); cptr++;
          }
        break;

      case 3:
        alpha = static_cast<unsigned char>(this->Alpha*255);
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          *nptr++ = alpha;
          }
        break;

      case 4:
        for (i=0; i<numTuples; i++)
          {
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          *nptr++ = *cptr++;
          *nptr++ = static_cast<unsigned char>((*cptr)*this->Alpha); cptr++;
          }
        break;

      default:
        vtkErrorMacro(<<"Cannot convert colors");
        return NULL;
      }
    }
  
  return newColors;
}

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

  os << indent << "Alpha: " << this->Alpha << endl;
  if (this->VectorMode == vtkScalarsToColors::MAGNITUDE)
    {
    os << indent << "VectorMode: Magnitude\n";
    }
  else
    {
    os << indent << "VectorMode: Component\n";
    os << indent << "VectorComponent: " << this->VectorComponent << endl;
    }
}