# compare method

double compare(

1. DocumentImage cmpDocumentImage

)

Computes the difference with another image.

param cmpDocumentImage The image to compare. return Comparison result in percent (0% is same, 100% is full different). throws DocumentException An error has occurred during Document Library execution.

## Implementation

    double compare(DocumentImage cmpDocumentImage) {
      Pointer<Float> pResult = calloc();
      try {
        var err = documentSDK.id3DocumentImage_Compare(_pHandle.value, cmpDocumentImage.handle, pResult);
        if (err != DocumentError.success.value) {
          throw DocumentException(err);
        }
        final vResult = pResult.value;
        return vResult;
      } finally {
        calloc.free(pResult);
      }
    }