Yalantis/uCrop · error · CImgIOException

load_analyze(): Unable to load datatype %d in file '%s'

Error message

load_analyze(): Unable to load datatype %d in file '%s'

What it means

The Analyze/NIfTI datatype field in the header maps to known storage codes (2=uint8, 4=int16, 8=int32, 16=float32, 32/64=complex, 128=RGB, 256=int8, 512=uint16, 768=uint32, 1024=float64...). If the datatype value does not match any implemented case, load_analyze() throws after closing the file. Newer NIfTI datatype codes (e.g. 2304 RGB, 256/768 in very old CImg builds, or NIfTI-2 codes) may be unsupported by the bundled CImg version.

Source

Thrown at ucrop/src/main/jni/CImg.h:58514

        delete[] buffer;
      } break;
      case 16 : {
        float *const buffer = new float[pdim];
        cimg::fread(buffer,pdim,nfile);
        if (endian) cimg::invert_endianness(buffer,pdim);
        cimg_foroff(*this,off) _data[off] = (T)(buffer[off]*scalefactor);
        delete[] buffer;
      } break;
      case 64 : {
        double *const buffer = new double[pdim];
        cimg::fread(buffer,pdim,nfile);
        if (endian) cimg::invert_endianness(buffer,pdim);
        cimg_foroff(*this,off) _data[off] = (T)(buffer[off]*scalefactor);
        delete[] buffer;
      } break;
      default :
        if (!file) cimg::fclose(nfile);
        throw CImgIOException(_cimg_instance
                              "load_analyze(): Unable to load datatype %d in file '%s'",
                              cimg_instance,
                              datatype,filename?filename:"(FILE*)");
      }
      if (!file) cimg::fclose(nfile);
      return *this;
    }

    //! Load image from a .cimg[z] file.
    /**
      \param filename Filename, as a C-string.
      \param axis Appending axis, if file contains multiple images. Can be <tt>{ 'x' | 'y' | 'z' | 'c' }</tt>.
      \param align Appending alignment.
    **/
    CImg<T>& load_cimg(const char *const filename, const char axis='z', const float align=0) {
      CImgList<T> list;
      list.load_cimg(filename);
      if (list._width==1) return list[0].move_to(*this);

View on GitHub (pinned to f788b534b4)

Solutions

1. Inspect datatype in the header (offset 70 in NIfTI-1/Analyze) and convert the volume to a supported type (e.g. int16/float32) with a converter tool (fslchfiletype, nibabel).
2. Update the CImg.h snapshot in ucrop/src/main/jni to a newer version supporting more datatypes.
3. If datatype==0, re-export with a proper writer; the field was never set.
4. Read the pixel data manually with known dims/datatype and construct the CImg yourself as a workaround.
5. Catch CImgIOException in batch pipelines and quarantine unsupported volumes for conversion.

Example fix

# before: datatype 2304 (RGB) unsupported by old CImg
# after: convert to uint8/int16 first
$ fslchfiletype NIFTI_PAIR in.nii out   # or with nibabel:
import nibabel as nib
img = nib.load('in.nii'); nib.save(nib.Nifti1Image(img.get_fdata().mean(-1).astype('int16'), img.affine), 'out.nii')

bool datatypeSupported(std::FILE* hdr) {
  // datatype at offset 70 in NIfTI-1/Analyze header
  int dt = 0; if (std::fseek(hdr, 70, SEEK_SET) != 0) return false;
  if (std::fread(&dt, sizeof(int), 1, hdr) != 1) return false;
  switch (dt) { case 1: case 2: case 4: case 8: case 16: case 32: case 64:
  case 128: case 256: case 512: case 768: case 1024: return true; default: return false; }
}

bool isSupportedDatatype(int datatype) { return datatype != 0 && datatype <= 1024 && (datatype & (datatype - 1)) == 0 || datatype == 128; }

try { img.load_analyze(path); }
catch (CImgIOException& e) {
  fprintf(stderr, "Unsupported datatype — converting volume\n");
  convertWithNibabelOrFsl(path); // external conversion fallback
}

When it happens

Trigger: Header declares a datatype code outside the switch handled by this CImg build — e.g. datatype=2304 (NIfTI RGB24), datatype=0 (unknown), or a corrupted/zeroed datatype field; encountered via load()/load_analyze() on an .img/.hdr/.nii volume.

Common situations: Images exported by newer conversion tools (dcm2niix with RGB, INT8, or float128 outputs) fed to an old CImg snapshot; headers hand-edited or zero-filled by buggy writers; NIfTI-2 files parsed as NIfTI-1 shifting the datatype field.

Related errors

• load_analyze(): Invalid Analyze7.5 or NIFTI header in file '
• load_analyze(): Invalid header size (%u) specified in file '
• load_analyze(): Cannot read header (of size %u) in file '%s'
• _cvmat2cimg() : pixel type '%s' is not supported.
• cimg::SDL3_attr(): %s

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/03935c7814d87f39. Report an issue: GitHub.