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(C++) ImageToVector

 

Graphics code snippet to convert a VCL TImage to a 2D std::vector. To do the opposite, use VectorToImage.

 

#include <cassert>
#include <vector>
#include <vcl.h>

//Creates a 2D-std::vector (y-x-ordered) from a TImage
//From http://www.richelbilderbeek.nl/CppImageToVector.htm
const std::vector<std::vector<int> > ImageToVector(const TImage * const image)
{
  assert(image!=0 && "Image must not be NULL");
  assert(image->Picture->Bitmap!=0 && "Bitmap must not be NULL");
  assert(image->Picture->Bitmap->PixelFormat == pf24bit && "Bitmap must be 24 bit");

  const int width  = image->Picture->Bitmap->Width;
  const int height = image->Picture->Bitmap->Height;

  std::vector<std::vector<int> > v(height, std::vector<int>(width));

  for (int y=0; y!=height; ++y)
  {
    assert(y >= 0);
    assert(y < static_cast<int>(v.size()));
    std::vector<int>& vLine = v[y];
    const unsigned char * const line
      = static_cast<const unsigned char *>(image->Picture->Bitmap->ScanLine[y]);
    for (int x=0; x!=width; ++x)
    {
      assert(x >= 0);
      assert(x < static_cast<int>(vLine.size()));
      const double grey = static_cast<double>(line[x*3+0] + line[x*3+1] + line[x*3+2])
        / 3.0;
      vLine[x] = grey;
      assert(grey>=0.0 && grey<256.0);
    }
  }
  return v;
}

 

 

 

 

 

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