scope grabbableGrayPixels.

import java.awt.image.DataBufferByte;

static Bool #succeeded;

static Throwable #error;

sbool #enable = true;

static GrabbableGrayPixels grabbableGrayPixels(BufferedImage img) {

  if (img == null || !enable) null;

  try {

    var result = grabbableGrayPixels_impl(img);

    succeeded = result != null;

    ret result;

  } on fail e {

    error = e;

    succeeded = false;

  }

}

static GrabbableGrayPixels grabbableGrayPixels_impl(BufferedImage img) {

  Raster raster = img.getRaster();

  SampleModel sampleModel = raster.getSampleModel();

  if (!sampleModel instanceof PixelInterleavedSampleModel) null;

  cast sampleModel to PixelInterleavedSampleModel;

  DataBufferByte dataBuffer = cast raster.getDataBuffer();

  assertEquals(1, dataBuffer.getNumBanks());

  assertEquals(DataBuffer.TYPE_BYTE, dataBuffer.getDataType());

  // Let's at this point assume the raster data is gray and not a palette

  int w = img.getWidth(), h = img.getHeight();

  int scanlineStride = sampleModel.getScanlineStride();

  byte[] pixels = dataBuffer.getData();

  int offset = dataBuffer.getOffset();

  int translateX = raster.getSampleModelTranslateX();

  int translateY = raster.getSampleModelTranslateY();

  offset += -translateX-translateY*scanlineStride;

  ret GrabbableGrayPixels(pixels, w, h, offset, scanlineStride);

}