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