 simplest interface provided by <tt>libtiff</tt> is a
    scanline-oriented interface that can be used to read TIFF
    images that have their image data organized in strips
    (trying to use this interface to read data written in tiles
    will produce errors.)
    A scanline is a one pixel high row of image data whose width
    is the width of the image.
    Data is returned packed if the image data is stored with samples
    packed together, or as arrays of separate samples if the data
    is stored wit