NAME

         tifffastcrop - extracts (crops) a rectangular region from a tiff
       file, avoiding loading the full source image input.tif into memory.

USAGE

         tifffastcrop [options] -E x,y,w,l input.tif [output]

DESCRIPTION

       tifffastcrop  takes  a  single-image  TIFF  file, reads the rectangular region of width w,
       length l, and top left corner at position (x,y) in pixels and stores it into a  new  file.
       The  function is similar to what tiffcrop from LibTIFF does but tifffastcrop works also on
       very large TIFF files and it tries to read as little as possible  from  the  source  image
       into  memory,  whereas  many  programs open the whole image even if a very small region is
       requested. Therefore, it is much faster on large files.

       If the "output" name is provided, the result is stored into a file with that name, in  the
       format  guessed  from  the  extension  of  this filename if guess is possible (and in TIFF
       format if not), or in the format specified by options. Otherwise, the name  given  to  the
       output file is created by adding the specification of the cropped region after the name of
       the original image and before the extension.

PERFORMANCES

       In principle, cropping a (small) region from a large TIFF file can also be  achieved  with
       several  tools, as tiffcrop, ImageMagick and GraphicsMagick. However, most of the programs
       start with opening and deciphering the whole image either in memory or in a huge temporary
       file  on  the  disk, which makes them quite slow, and often unable to complete the task by
       lack of memory.

       In contrast, tifffastcrop reads as little as possible from the source image. If the  input
       file  is  a  tiled  TIFF  with  reasonable  tile size, it should read barely more than the
       cropped region. This yields speedup and guarantees successful termination of  the  process
       even  on  computers with modest memory. Eg. to crop a region of size 256x256 pixels in the
       middle of a JPEG-compressed tiled TIFF image of size 180224x70144, on a computer  with  16
       GiB  of  RAM and an i7 CPU, tifffastcrop needs 0.3 seconds while GraphicsMagick needs more
       than 80 minutes and tiffcrop and ImageMagick fail.

OPTIONS

       -v     Verbose monitoring.

       -T     Do not report TIFF errors or warnings. Under Windows, they are reported with  noisy
              dialog boxes.

       -E <x in pixels>,<y in pixels>,<width in pixels>,<length in pixels>

              Specification  of  the  rectangular  region  to extract (crop). The top left corner
              (x,y) has to be inside the source image. If the rectangle extends beyond the limits
              of the source image, its dimensions are adjusted. Example: -E 10,20,512,256 .

       -j[#]  Requests  output  of  JPEG files rather than the default TIFF. Optional number # in
              the range 0 to 100 indicates wanted JPEG quality (default is 75).

       -p[#]  Requests output of PNG files rather than the default TIFF. Optional number # in the
              range 0 to 9 indicates wanted PNG compression level (default is currently 6).

               If several of -j, -p, and -c options are given, only the last one takes effect.

       -c <method>[:opt[:opt]...]
              Requests  output  of TIFF files compressed with method. Method can be `none' for no
              compression, `jpeg', `lzw', `zip'...  as  provided  by  the  LibTIFF  library  (see
              libtiff  (3TIFF)).  By  default,  the same compression as in the input TIFF file is
              used.

               Method-specific details of the wished compression can be specified by  adding  one
              or  several group of characters starting with a colon `:' after the methods's name,
              as follows.

              Option to (TIFF compressed with) JPEG method:
               :# set compression quality level as in option -j (see above).

              LZW, Deflate (zip) and LZMA2 options:
               :# set predictor value
               :p# set compression level.

              For example, -c lzw:2 to get LZW-encoded  data  with  horizontal  differencing,  -c
              zip:3:p9  for  Deflate  encoding  with maximum compression level and floating point
              predictor, -c jpeg:r:50 for JPEG-encoded RGB data at quality 50%.

               If several of -j, -p, and -c options are given, only the last one takes effect.

SEE ALSO

       tiffsplittiles(1), tiffmakemosaic(1), tiffsplit(1), tiffcrop(1), libtiff(3TIFF)

       Home Page
       http://www.imnc.in2p3.fr/pagesperso/deroulers/software/largetifftools/

AUTHOR

       Christophe Deroulers