path: root/doc/tools/tiffcrop.rst

tiffcrop
========

.. program:: tiffcrop

Synopsis
--------

**tiffcrop** [ *options* ] *src1.tif* … *srcN.tif* *dst.tif*

Description
-----------

:program:`tiffcrop` processes one or more files created according
to the Tag Image File Format, Revision 6.0, specification
into one or more TIFF file(s).
:program:`tiffcrop` is most often used to extract portions of an image for processing 
with bar code recognizer or OCR software when that software cannot 
restrict the region of interest to a specific portion of the image 
or to improve efficiency when the regions of interest must be rotated.
It can also be used to subdivide all or part of a processed image into 
smaller sections and export individual images or sections of images
as separate files or separate images within one or more files derived
from the original input image or images.

The available functions can be grouped broadly into three classes:

#. Those that select individual images or sections of images from the input files.
   The options :option:`-N` for sequences or lists of individual images in the input files,
   :option:`-Z` for zones, :option:`-z` for regions, :option:`-X` and :option:`-Y` for fixed sized selections,
   :option:`-m` for margins, :option:`-U` for units, and :option:`-E` for edge reference provide a variety of 
   ways to specify portions of the input image.

#. Those that allow the individual images or selections to be exported to one or
   more output files in different groupings and control the organization of the 
   data in the output images. The options :option:`-P` for page size grouping, :option:`-S` for 
   subdivision into columns and rows and :option:`-e` for export mode options that produce
   one or more files from each input image. The options :option:`-r`, :option:`-s`, :option:`-t`, :option:`-w`  control 
   strip and tile format and sizes while :option:`-B`, :option:`-L`, :option:`-c`, :option:`-f` modify the endian addressing
   scheme, the compression options, and the bit fill sequence of images as they
   are written.

#. Those that perform some action on each image that is selected from the input file.
   The options include :option:`-R` for rotate, :option:`-I` for inversion of the photometric 
   interpretation and/or data values, and :option:`-F` to flip (mirror) the image horizontally
   or vertically.

Functions are applied to the input image(s) in the following order:
cropping, fixed area extraction, zone and region extraction, 
inversion, mirroring, rotation.

Functions are applied to the output image(s) in the following order:
export mode options for grouping zones, regions, or images into
one or more files, *or* row and column divisions with output margins,
*or* page size divisions with page orientation options.

Finally, strip, tile, byte order, output resolution, and compression options are
applied to all output images.

The output file(s) may be organized and compressed using a different
algorithm from the input files.
By default, :program:`tiffcrop` will copy all the understood tags in a TIFF
directory of an input file to the associated directory in the output file.
Options can be used to force the resultant image to be written as strips 
or tiles of data, respectively.

:program:`tiffcrop` can be used to reorganize the storage characteristics of data
in a file, and to reorganize, extract, rotate, and otherwise
process the image data as specified at the same time whereas 
:program:`tiffcp` does not alter the image data within the file.

Using the options for selecting individual input images and the
options for exporting images and/or segments defined as zones or
regions of each input image, :program:`tiffcrop` can perform the
functions of :program:`tiffcp` and :program:`tiffsplit` in a single pass
while applying multiple operations to individual selections or images.

Options
-------

.. option:: -h

  Display the syntax summary for tiffcrop.

.. option:: -v

  Report the current version and last modification date for tiffcrop.

.. option:: -N odd|even|#,#-#,#|last

  Specify one or more series or range(s) of images within each file to process.
  The words ``odd`` or ``even``
  may be used to specify all odd or even numbered images counting from one.
  Note that internally, TIFF images are numbered from zero rather than one
  but since this convention is not obvious to most users, :program:`tiffcrop` used 1
  to specify the first image in a multipage file.  The word ``last``
  may be used in place of a number in the sequence to indicate the
  final image in the file without knowing how many images there are.
  Ranges of images may be specified with a dash and multiple sets
  can be indicated by joining them in a comma-separated list. eg. use
  ``-N 1,5-7,last``
  to process the 1st, 5th through 7th, and final image in the file.

.. option:: -E top|bottom|left|right

  Specify the ``top``, ``bottom``, ``left``, or ``right`` edge as the reference from
  which to calculate the width and length of crop regions or sequence
  of positions for zones. When used with the :option:`-e` option for exporting
  zones or regions, the reference edge determines how composite images
  are arranged. Using ``-E left`` or ``-E right`` causes successive zones or
  regions to be merged horizontally whereas using ``-E top`` or ``-E bottom``
  causes successive zones or regions to be arranged vertically. This
  option has no effect on export layout when multiple zones or regions
  are not being exported to composite images. Edges may be abbreviated
  to the first letter.

.. option:: -e combined|divided|image|multiple|separate

  Specify the export mode for images and selections from input images.
  The final filename on the command line is considered to be the
  destination file or filename stem for automatically generated
  sequences of files. Modes may be abbreviated to the first letter.

  .. list-table:: Export modes
    :widths: 5 20
    :header-rows: 1

    * - Export mode
      - Description

    * - combined
      - All images and selections are written to a single file with
        multiple selections from one image combined into a single image (default)
    * - divided
      - All images and selections are written to a single file
        with each selection from one image written to a new image
    * - image
      - Each input image is written to a new file (numeric filename sequence)
        with multiple selections from the image combined into one image
    * - multiple
      - Each input image is written to a new file (numeric filename sequence)
        with each selection from the image written to a new image
    * - separate
      - Individual selections from each image are written to separate files

.. option:: -U in|cm|px

  Specify the type of units to apply to dimensions for margins and
  crop regions for input and output images. Inches or centimeters
  are converted to pixels using the resolution unit specified in the
  TIFF file (which defaults to inches if not specified in the IFD).

.. option:: -m top,left,bottom,right

  Specify margins to be removed from the input image. The order must
  be *top*, *left*, *bottom*, *right* with only commas separating the elements
  of the list. Margins are scaled according to the current units and
  removed before any other extractions are computed.

.. option:: -X #

  Set the horizontal (X-axis) dimension of a region to extract relative to
  the specified origin reference. If the origin is the top or bottom
  edge, the X axis value will be assumed to start at the left edge.

.. option:: -Y #

  Set the vertical (Y-axis) dimension of a region to extract relative to
  the specified origin reference. If the origin is the left or right
  edge, the Y axis value will be assumed to start at the top.

.. option:: -Z  #:#,#:#

  Specify zones of the image designated as position X of Y equal sized portions
  measured from the reference edge,  eg 1:3 would be first third of the
  image starting from the reference edge minus any margins specified
  for the confining edges. Multiple zones can be specified as a comma
  separated list but they must reference the same edge. To extract the
  top quarter and the bottom third of an image you would use
  ``-Z 1:4,3:3``.

.. option:: -z x1,y1,x2,y2: ... :xN,yN,xN+1,yN+1

  Specify a series of coordinates to define regions for processing and exporting.
  The coordinates represent the top left and lower right corners of each region
  in the current units, eg inch, cm, or pixels. Pixels are counted from one to
  width or height and inches or cm are calculated from image resolution data.

  Each colon delimited series of four values represents the horizontal and vertical
  offsets from the top and left edges of the image, regardless of the edge specified
  with the :option:`-E` option. The first and third values represent the horizontal offsets of
  the corner points from the left edge while the second and fourth values represent
  the vertical offsets from the top edge.

.. option:: -F horiz|vert

  Flip, ie mirror, the image or extracted region horizontally or vertically.

.. option:: -R 90|180|270

  Rotate the image or extracted region 90, 180, or 270 degrees clockwise.

.. option:: -I [black|white|data|both]

  Invert color space, eg dark to light for bilevel and grayscale images.
  This can be used to modify negative images to positive or to correct
  images that have the ``PHOTOMETRIC_INTERPRETATION`` tag set incorrectly.
  If the value is black or white, the ``PHOTOMETRIC_INTERPRETATION`` tag is set to
  MinIsBlack or MinIsWhite, without altering the image data. If the argument
  is data or both, the data values of the image are modified. Specifying both
  inverts the data and the ``PHOTOMETRIC_INTERPRETATION`` tag, whereas using data
  inverts the data but not the ``PHOTOMETRIC_INTERPRETATION`` tag.
  No support for modifying the color space of color images in this release.

.. option:: -H #

  Set the horizontal resolution of output images to *#*,
  expressed in the current units.

.. option:: -V #

  Set the vertical resolution of the output images to *#*
  expressed in the current units.

.. option:: -J #

  Set the horizontal margin of an output page size to *#*
  expressed in the current units when sectioning image into *columns* × *rows*
  subimages using the :option:`-S` ``cols:rows`` option.

.. option:: -K #

  Set the vertical margin of an output page size to *#* 
  expressed in the current units when sectioning image into *columns* × *rows*
  subimages using the :option:`-S` ``cols:rows`` option.

.. option:: -O portrait|landscape|auto

  Set the output orientation of the pages or sections.
  Auto will use the arrangement that requires the fewest pages.
  This option is only meaningful in conjunction with the :option:`-P`
  option to format an image to fit on a specific paper size.

.. option:: -P page

  Format the output images to fit on page size paper. Use
  ``-P list`` to show the supported page sizes and dimensions.
  You can define a custom page size by entering the width and length of the
  page in the current units with the following format ``#.#x#.#``.

.. option:: -S cols:rows

  Divide each image into cols across and rows down equal sections.

.. option:: -B

  Force output to be written with Big-Endian byte order.
  This option only has an effect when the output file is created or
  overwritten and not when it is appended to.

.. option:: -C

  Suppress the use of "strip chopping" when reading images
  that have a single strip/tile of uncompressed data.

.. option:: -c

  Specify the compression to use for data written to the output file:
  :command:`-c none` for no compression,
  :command:`-c packbits` for PackBits compression,
  :command:`-c lzw` for Lempel-Ziv & Welch compression,
  :command:`-c jpeg` for baseline JPEG compression.
  :command:`-c zip` for Deflate compression,
  :command:`-c g3` for CCITT Group 3 (T.4) compression,
  :command:`-c g4` for CCITT Group 4 (T.6) compression.
  By default :program:`tiffcrop` will compress data according to the value of the
  ``Compression`` tag found in the source file.

  The CCITT Group 3 and Group 4 compression algorithms can only
  be used with bilevel data.

  Group 3 compression can be specified together with several
  T.4-specific options:
  ``1d`` for 1-dimensional encoding,
  ``2d`` for 2-dimensional encoding,
  ``fill`` to force each encoded scanline to be zero-filled so that the
  terminating EOL code lies on a byte boundary.
  Group 3-specific options are specified by appending a ``:``-separated
  list to the ``g3`` option; e.g. ``-c g3:2d:fill``
  to get 2D-encoded data with byte-aligned EOL codes.

  LZW compression can be specified together with a ``predictor``
  value. A predictor value of 2 causes
  each scanline of the output image to undergo horizontal
  differencing before it is encoded; a value
  of 1 forces each scanline to be encoded without differencing.
  LZW-specific options are specified by appending a ``:``-separated
  list to the ``lzw`` option; e.g. ``-c lzw:2`` for LZW
  compression with horizontal differencing.

.. option:: -f

  Specify the bit fill order to use in writing output data.
  By default, :program:`tiffcrop`
  will create a new file with the same fill order as the original.
  Specifying
  ``-f lsb2msb``
  will force data to be written with the ``FillOrder`` tag set to
  ``LSB2MSB``, while
  ``-f msb2lsb`` will force data to be written with the ``FillOrder``
  tag set to ``MSB2LSB``.

.. option:: -i

  Ignore non-fatal read errors and continue processing of the input file.

.. option:: -k size

  Set maximum memory allocation size (in MiB). The default is 256MiB.
  Set to 0 to disable the limit.

.. option:: -l

  Specify the length of a tile (in pixels).
  :program:`tiffcrop` attempts to set the tile dimensions so
  that no more than 8 kilobytes of data appear in a tile.

.. option:: -L

  Force output to be written with Little-Endian byte order.
  This option only has an effect when the output file is created or
  overwritten and not when it is appended to.

.. option:: -M

  Suppress the use of memory-mapped files when reading images.

.. option:: -p

  Specify the planar configuration to use in writing image data
  that has more than one sample per pixel.
  By default, :program:`tiffcrop`
  will create a new file with the same planar configuration as
  the original.
  Specifying :command:`-p contig`
  will force data to be written with multi-sample data packed
  together, while
  :command:`-p separate`
  will force samples to be written in separate planes.

.. option:: -r

  Specify the number of rows (scanlines) in each strip of data
  written to the output file.
  By default (or when value **0** is specified), :program:`tiffcrop`
  attempts to set the rows/strip that no more than 8 kilobytes of 
  data appear in a strip. If you specify the special value
  **-1** it will results in infinite number of the rows per strip. The entire image
  will be the one strip in that case.

.. option:: -s

  Force the output file to be written with data organized in strips
  (rather than tiles).

.. option:: -t

  Force the output file to be written with data organized in tiles
  (rather than strips).

.. option:: -w

  Specify the width of a tile (in pixels).
  :program:`tiffcrop` attempts to set the tile dimensions so
  that no more than 8 kilobytes of data appear in a tile.

.. option:: -D opt1:value1,opt2:value2,opt3:value3:opt4:value4

  Debug and dump facility

  Display program progress and/or dump raw data to non-TIFF files.
  Options include the following and must be joined as a comma
  separated list. The use of this option is generally limited to
  program debugging and development of future options. An equal sign
  may be substituted for the colon in option:value pairs.

  ``debug:N``:

    Display limited program progress indicators where larger *N*
    increases the level of detail.

  ``format:txt|raw``:

    Format any logged data as ASCII text or raw binary 
    values. ASCII text dumps include strings of ones and zeroes representing
    the binary values in the image data plus identifying headers.

  ``level:N``:

    Specify the level of detail presented in the dump files.
    This can vary from dumps of the entire input or output image data to dumps
    of data processed by specific functions. Current range of levels is 1 to 3.

  ``input:full-path-to-directory/input-dumpname``:

  ``output:full-path-to-directory/output-dumpname``:

    When dump files are being written, each image will be written to a separate
    file with the name built by adding a numeric sequence value to the dumpname
    and an extension of :file:`.txt` for ASCII dumps or :file:`.bin` for binary dumps.

  The four debug/dump options are independent, though it makes little sense to
  specify a dump file without specifying a detail level.

  Note: :program:`tiffcrop` may be compiled with :command:`-DDEVELMODE` to enable
  additional very low level debug reporting.

Examples
--------

The following concatenates two files and writes the result using LZW
encoding:

.. highlight:: shell

::

    tiffcrop -c lzw a.tif b.tif result.tif

To convert a G3 1d-encoded TIFF to a single strip of G4-encoded data the following might be used:

::

    tiffcrop -c g4 -r 10000 g3.tif g4.tif

(1000 is just a number that is larger than the number of rows in
the source file.)

To extract a selected set of images from a multi-image TIFF file 
use the :option:`-N` option described above. Thus, to copy the 1st and 3rd
images of image file :file:`album.tif` to :file:`result.tif`:

::

    tiffcrop -N 1,3 album.tif result.tif

Invert a bilevel image scan of a microfilmed document and crop off margins of
0.25 inches on the left and right, 0.5 inch on the top, and 0.75 inch on the
bottom. From the remaining portion of the image, select the second and third
quarters, ie, one half of the area left from the center to each margin:

::

    tiffcrop -U in -m 0.5,0.25,0.75,0.25 -E left -Z 2:4,3:4 -I both MicrofilmNegative.tif MicrofilmPostiveCenter.tif

Extract only the final image of a large Architectural E sized 
multipage TIFF file and rotate it 90 degrees clockwise while 
reformatting the output to fit on tabloid sized sheets with one 
quarter of an inch on each side:

::

    tiffcrop -N last -R 90 -O auto -P tabloid -U in -J 0.25 -K 0.25 -H 300 -V 300 Big-PlatMap.tif BigPlatMap-Tabloid.tif 

The output images will have a specified resolution of 300 dpi in both
directions. The orientation of each page will be determined by whichever
choice requires the fewest pages. To specify a specific orientation, use
the portrait or landscape option. The paper size option does not resample
the image. It breaks each original image into a series of smaller images
that will fit on the target paper size at the specified resolution.

Extract two regions 2048 pixels wide by 2048 pixels high from each page of
a multi-page input file and write each region to a separate output file:

::

    tiffcrop -U px -z 1,1,2048,2048:1,2049,2048,4097 -e separate  CheckScans.tiff Check

The output file names will use the stem :file:`Check` with a numeric suffix which is
incremented for each region of each image, eg :file:`Check-001.tiff`,
:file:`Check-002.tiff` … :file:`Check-NNN.tiff`. To produce a unique file for each page
of the input image with one new image for each region of the input image on that page
change the export option to ``-e multiple``.

Notes
-----

In general, bilevel, grayscale, palette and RGB(A) data with bit depths
from 1 to 32 bits should work in both interleaved and separate plane
formats. Unlike :program:`tiffcp`, :program:`tiffcrop` can read and write tiled images with
bits per sample that are not a multiple of 8 in both interleaved and
separate planar format. Floating point data types are supported at 
bit depths of 16, 24, 32 and 64 bits per sample. 

Not all images can be converted from one compression scheme to another.
Data with some photometric interpretations and/or bit depths are tied to 
specific compression schemes and vice-versa, e.g. Group 3/4 compression
is only usable for bilevel data. JPEG compression is only usable on 8
bit per sample data (or 12 bit if :program:`libtiff`
was compiled with 12 bit JPEG support). Support for OJPEG compressed 
images is problematic at best. Since OJPEG compression is no longer 
supported for writing images with LibTIFF, these images will be updated
to the newer JPEG compression when they are copied or processed. This
may cause the image to appear color shifted or distorted after conversion.
In some cases, it is possible to remove the original compression from 
image data using the option ``-c none``.

:program:`tiffcrop` does not currently provide options to up or downsample data to 
different bit depths or convert data from one photometric interpretation 
to another, e.g. 16 bits per sample to 8 bits per sample or RGB to grayscale. 

:program:`tiffcrop` is very loosely derived from code in :program:`tiffcp`
with extensive modifications and additions to support the selection of input 
images and regions and the exporting of them to one or more output files in 
various groupings. The image manipulation routines are entirely new and 
additional ones may be added in the future. It will handle tiled images with 
bit depths that are not a multiple of eight that tiffcp may refuse to read.

:program:`tiffcrop` was designed to handle large files containing many moderate sized images
with memory usage that is independent of the number of images in the file.
In order to support compression modes that are not based on individual 
scanlines, e.g. JPEG, it now reads images by strip or tile rather than by 
individual scanlines. In addition to the memory required by the input and
output buffers associated with :program:`libtiff`
one or more buffers at least as large as the largest image to be read are
required. The design favors large volume document processing uses over 
scientific or graphical manipulation of large datasets as might be found 
in research or remote sensing scenarios.

See also
--------

:doc:`pal2rgb` (1),
:doc:`tiffinfo` (1),
:doc:`tiffcmp` (1),
:doc:`tiffcp` (1),
:doc:`tiffmedian` (1),
:doc:`tiffsplit` (1),
:doc:`/functions/libtiff` (3tiff)