TIFFsize.3tiff man page
TIFFScanlineSize, TIFFRasterScanlineSize, — return the size of various items associated with an open TIFF file
tsize_t TIFFRasterScanlineSize(TIFF *tif)
tsize_t TIFFScanlineSize(TIFF *tif)
TIFFScanlineSize returns the size in bytes of a row of data as it would be returned in a call to TIFFReadScanline, or as it would be expected in a call to TIFFWriteScanline.
TIFFRasterScanlineSize returns the size in bytes of a complete decoded and packed raster scanline. Note that this value may be different from the value returned by TIFFScanlineSize if data is stored as separate planes.
TIFFOpen(3TIFF), TIFFReadScanline(3TIFF), libtiff(3TIFF)
Libtiff library home page: http://www.simplesystems.org/libtiff/