Full Image Support When Linking to C Libraries

LibraryLink is extended to support Image objects being directly sent to/from external libraries.

Here is an example to create a sepia effect from a given image represented in a 32 bit real data type. See the complete example here.

static void isepia(raw_t_real32 *out, raw_t_real32 *in, mint width, 
        mint height, mint channels) {
  for (mint ii = 0; ii < height; ii++) {
    for (mint jj = 0; jj < width; jj++) {
      for (mint kk = 0; kk < channels; kk++) {
        mint index = channels * (ii * width + jj);
        raw_t_real32 r = in[index + 0];
        ...
        out[index + 0] = r * static_cast<raw_t_real32>(0.393) +
                                 g * static_cast<raw_t_real32>(0.769) +
                                 b * static_cast<raw_t_real32>(0.189);
        ...
        for (int ii = 3; ii < channels; ii++) {
          out[index + ii] = in[index + ii];
        }
      }
    }
  }
  return;
}

EXTERN_C DLLEXPORT int speia(WolframLibraryData libData, mint Argc,
    MArgument *Args, MArgument res) {
    ...
    data_in = imgFuns->MImage_getReal32Data(image_in);
    data_out = imgFuns->MImage_getReal32Data(image_out);
    ...
    ispeia(data_out, data_in, width, height, channels);
    MArgument_setMImage(res, image_out);
    return LIBRARY_NO_ERROR;
}

Load the function from the library.

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