vtkPixelTransfer.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#ifndef vtkPixelTransfer_h
#define vtkPixelTransfer_h
 
#include "vtkCommonDataModelModule.h" // for export
#include "vtkPixelExtent.h"           // for pixel extent
#include "vtkSetGet.h"                // for macros
#include <cstring>                    // for memcpy
 
VTK_ABI_NAMESPACE_BEGIN
class VTKCOMMONDATAMODEL_EXPORT vtkPixelTransfer
{
public:
  vtkPixelTransfer() = default;
 
  static int Blit(const vtkPixelExtent& ext, int nComps, int srcType, void* srcData, int destType,
    void* destData);
 
  static int Blit(const vtkPixelExtent& srcWhole, const vtkPixelExtent& srcSubset,
    const vtkPixelExtent& destWhole, const vtkPixelExtent& destSubset, int nSrcComps, int srcType,
    void* srcData, int nDestComps, int destType, void* destData);
 
  template <typename SOURCE_TYPE, typename DEST_TYPE>
  static int Blit(const vtkPixelExtent& srcWhole, const vtkPixelExtent& srcSubset,
    const vtkPixelExtent& destWhole, const vtkPixelExtent& destSubset, int nSrcComps,
    SOURCE_TYPE* srcData, int nDestComps, DEST_TYPE* destData);
 
private:
  // distpatch helper for vtk data type enum
  template <typename SOURCE_TYPE>
  static int Blit(const vtkPixelExtent& srcWhole, const vtkPixelExtent& srcSubset,
    const vtkPixelExtent& destWhole, const vtkPixelExtent& destSubset, int nSrcComps,
    SOURCE_TYPE* srcData, int nDestComps, int destType, void* destData);
};
 
//-----------------------------------------------------------------------------
inline int vtkPixelTransfer::Blit(
  const vtkPixelExtent& ext, int nComps, int srcType, void* srcData, int destType, void* destData)
{
  return vtkPixelTransfer::Blit(
    ext, ext, ext, ext, nComps, srcType, srcData, nComps, destType, destData);
}
 
//-----------------------------------------------------------------------------
template <typename SOURCE_TYPE>
int vtkPixelTransfer::Blit(const vtkPixelExtent& srcWholeExt, const vtkPixelExtent& srcExt,
  const vtkPixelExtent& destWholeExt, const vtkPixelExtent& destExt, int nSrcComps,
  SOURCE_TYPE* srcData, int nDestComps, int destType, void* destData)
{
  // second layer of dispatch
  switch (destType)
  {
    vtkTemplateMacro(return vtkPixelTransfer::Blit(srcWholeExt, srcExt, destWholeExt, destExt,
      nSrcComps, srcData, nDestComps, (VTK_TT*)destData););
  }
  return 0;
}
 
//-----------------------------------------------------------------------------
template <typename SOURCE_TYPE, typename DEST_TYPE>
int vtkPixelTransfer::Blit(const vtkPixelExtent& srcWholeExt, const vtkPixelExtent& srcSubset,
  const vtkPixelExtent& destWholeExt, const vtkPixelExtent& destSubset, int nSrcComps,
  SOURCE_TYPE* srcData, int nDestComps, DEST_TYPE* destData)
{
  if ((srcData == nullptr) || (destData == nullptr))
  {
    return -1;
  }
  if ((srcWholeExt == srcSubset) && (destWholeExt == destSubset) && (nSrcComps == nDestComps))
  {
    // buffers are contiguous
    size_t n = srcWholeExt.Size() * nSrcComps;
    for (size_t i = 0; i < n; ++i)
    {
      destData[i] = static_cast<DEST_TYPE>(srcData[i]);
    }
  }
  else
  {
    // buffers are not contiguous
    int tmp[2];
 
    // get the dimensions of the arrays
    srcWholeExt.Size(tmp);
    int swnx = tmp[0];
 
    destWholeExt.Size(tmp);
    int dwnx = tmp[0];
 
    // move from logical extent to memory extent
    vtkPixelExtent srcExt(srcSubset);
    srcExt.Shift(srcWholeExt);
 
    vtkPixelExtent destExt(destSubset);
    destExt.Shift(destWholeExt);
 
    // get size of sub-set to copy (it's the same in src and dest)
    int nxny[2];
    srcExt.Size(nxny);
 
    // use smaller ncomps for loop index to avoid reading/writing
    // invalid mem
    int nCopyComps = nSrcComps < nDestComps ? nSrcComps : nDestComps;
 
    for (int j = 0; j < nxny[1]; ++j)
    {
      int sjj = swnx * (srcExt[2] + j) + srcExt[0];
      int djj = dwnx * (destExt[2] + j) + destExt[0];
      for (int i = 0; i < nxny[0]; ++i)
      {
        int sidx = nSrcComps * (sjj + i);
        int didx = nDestComps * (djj + i);
        // copy values from source
        for (int p = 0; p < nCopyComps; ++p)
        {
          destData[didx + p] = static_cast<DEST_TYPE>(srcData[sidx + p]);
        }
        // ensure all dest comps are initialized
        for (int p = nCopyComps; p < nDestComps; ++p)
        {
          destData[didx + p] = static_cast<DEST_TYPE>(0);
        }
      }
    }
  }
  return 0;
}
 
VTK_ABI_NAMESPACE_END
#endif
// VTK-HeaderTest-Exclude: vtkPixelTransfer.h