Changes in TIFF v4.6.0
======================

.. table:: References
    :widths: auto

    ======================  ==========================================
    Current Version         v4.6.0 (:tag:`v4.6.0`)
    Previous Version        :doc:`v4.5.1 <v4.5.1>`
    Master Download Site    `<https://download.osgeo.org/libtiff/>`_
    Master HTTP Site #1     `<http://www.simplesystems.org/libtiff/>`_
    Master HTTP Site #2     `<https://libtiff.gitlab.io/libtiff/>`_
    ======================  ==========================================

This document provides a summary of significant changes made to the
software between the *previous* and *current* versions (see
above). A fully-detailed change summary is provided by the :file:`ChangeLog` file
included in the release package and by the Git commit history:

Major changes
-------------

.. warning::

    This version removes a big number of utilities that have suffered from lack
    of maintenance over the years and were the source of various reported
    security issues.
    See "Removed functionality" below for the list of removed utilities.
    Starting with libtiff v4.6.0, the source code for most TIFF tools (except tiffinfo,
    tiffdump, tiffcp and tiffset) was discontinued, due to the lack of contributors
    able to address reported security issues.
    tiff2ps and tiff2pdf source code has been moved in a unsupported category,
    no longer built by default, but are still part of the the source
    distribution. Other retired utilities are in a archive/ directory, only
    available in the libtiff git repository.
    Issues related to unsupported and archived tools will no longer be accepted
    in the libtiff bug tracker.


Software configuration changes
------------------------------

* TiffConfig.cmake.in: set TIFF_INCLUDE_DIR, TIFF_INCLUDE_DIRS and
  TIFF_LIBRARIES for compatibility with FindTIFF.cmake as shipped by CMake
  (fixes :issue:`589`)

* Update CMake and autoconf scripts to consistently update LibTIFF version
  defines and references in various files when version definition in
  configure.ac has been changed.

  - Move in tiffvers.h from libtiff source directory to libtiff build directory.
  - Remove unused version information from tif_config.h
  - With every CMake build the version defines (e.g. 4.5.1) within tiffvers.h
    are consistently updated from configure.ac. The version release-date is
    taken from file RELEASE-DATE.
  - The files VERSION and RELEASE-DATE are only updated with a special CMake
    target build: cmake --build . --target tiff_release.
  - For autotools, version information is updated from configure.ac with
    ./autogen.sh. LIBTIFF_RELEASE_DATE is taken form file RELEASE-DATE.
  - ./configure generates tiffvers.h with the cached version information and
    LIBTIFF_RELEASE_DATE.
  - "make release" updates tiffvers.h and VERSION file with cached version info
    and RELEASE-DATE file and tiffves.h with the current date.

* CMake: fix build with -Dstrip-chopping=off (fixes :issue:`600`)

Library changes
---------------

New/improved functionalities:

* Fix using ``__attribute__`` libtiff with clang-for-windows

API/ABI breaks:

* None

Bug fixes:

* WebP decoder: validate WebP blob width, height, band count against TIFF
  parameters to avoid use of uninitialized variable, or decoding corrupted
  content without explicit error (fixes :issue:`581`,  :issue:`582`).

* WebP codec: turn exact mode when creating lossless files to avoid altering
  R,G,B values in areas where alpha=0 (https://github.com/OSGeo/gdal/issues/8038)

* Fix TransferFunction writing of only two transfer functions.

* TIFFReadDirectoryCheckOrder: avoid integer overflow. When it occurs, it
  should be harmless in practice though
  (https://gitlab.com/libtiff/libtiff/-/merge_requests/512)

Documentation
-------------

* TiffField functions documentation updated with return behaviour for not
  defined tags and determination of write-/read-count size.

Tools changes
-------------

Removed functionality:

* The following tools are no longer compiled and have been moved to archive/tools:

  - fax2ps
  - fax2tiff
  - pal2rgb
  - ppm2tiff
  - raw2tiff
  - rgb2ycbcr
  - thumbnail
  - tiff2bw
  - tiff2rgba
  - tiffcmp
  - tiffcrop
  - tiffdither
  - tiffgt
  - tiffmedian

* The following tools are no longer compiled by default: tiff2ps and tiff2pdf.
  They have been moved to tools/unsupported. 
  They can be built by setting ``--enable-tools-unsupported`` for autoconf,
  or ``-Dtiff-tools-unsupported`` for CMake, but as the name imply, they are
  no longer supported by upstream. Packagers are suggested *not* to enable those
  options.

* tiffcp: remove -i option (ignore errors), because almost all
  fuzzer issues were consequential errors from ignored errors because of the
  "-i" option.

New/improved functionality:

* None

Bug fixes:

* tiffset: fix #597: warning: comparison of integer expressions of different
  signedness. (fixes :issue:`597`)

* tiffcp: fix memory corruption (overflow) on hostile images
  (fixes :issue:`591`)

Test changes
------------

* Add missing test_write_read_tags.c and test_transferfunction_write_read.c
  in tarball (fixes :issue:`585`) and correct "long" issue.

* Don't use "long" because can be int32_t or int64_t, depending on compiler and
  system.

Changes to contributed and unsupported tools
--------------------------------------------

* raw2tiff: fix integer overflow and bypass of the check (fixes :issue:`592`)