CHANGES.md

Release 2.1 (?? 2019) -- compared to 2.0

New minimum dependencies:

Major new features and improvements:

Public API changes:

Performance improvements:

Fixes and feature enhancements:

Build/test system improvements and platform ports:

Developer goodies / internals:

Notable documentation changes:

Release 2.0 (Dec 1, 2018) -- compared to 1.8.x

New minimum dependencies:

• On Windows compiling with MSVS, the new minimum version is MSVS 2015.

Major new features and improvements:

• ImageInput and ImageOutput static create() and open() methods now return unique_ptr rather than raw pointers. #1934, #1945 (1.9.3).
• ImageInput improvements to thread safety and concurrency, including some new API calls (see "Public API changes" section below).
• ImageBufAlgo overhaul (both C++ and Python): Add IBA functions that return image results directly rather than passing ImageBuf references as parameters for output (the old kind of calls still exist, too, and have their uses). Also in C++, change all IBA functions that took raw pointers to per-channel colors into span<> for safety. #1961 (1.9.4)
• For some readers and writers, an "IOProxy" can be passed that customizes the I/O methods. An important use of this is to write an image "file" to memory or to read an image "file" from a memory, rather than disk. Currently, OpenEXR supports this for both reading and writing, and PNG supports it for writing. You specify a pointer to the proxy via the configuration option "oiio:ioproxy". #1931 (1.9.3)
• New Image Format support:
  • OpenVDB file read (as volume images or accessing via texture3d()). #2010,2018 (1.9.4)
  • "null" images -- null reader just returns black (or constant colored) pixels, null writer just returns. This can be used for benchmarking (to eliminate all actual file I/O time), "dry run" where you want to test without creating output files. #1778 (1.9.0), #2042 (1.9.4)
• TIFF I/O of multiple scanlines or tiles at once (or whole images, as is typical use case for oiiotool and maketx) is sped up by a large factor on modern multicore systems. We've seen 10x or more faster oiiotool performance for uint8 and uint16 TIFF files using "zip" (deflate) compression, on modern 12-16 core machines. #1853 (1.9.2)
• Major refactor of Exif metadata handling, including much more complete metadata support for RAW formats and support of camera "maker notes" for Canon cameras. #1774 (1.9.0)
• New maketx option --bumpslopes specifically for converting bump maps, saves additional channels containing slope distribution moments that can be used in shaders for "bump to roughness" calculations. #1810,#1913,2005 (1.9.2), #2044 (1.9.4)
• An official FindOpenImageIO.cmake that we invite you to use in other cmake-based projects that needs to find OIIO. #2027 (1.9.4)

Public API changes:

• Python binding overhaul The Python bindings have been reimplemented with pybind11, no longer with Boost.Python. #1801 (1.9.1) In the process (partly due to what's easy or hard in pybind11, but partly just because it caused us to revisit the python APIs), there are some minor API changes, some of which are breaking! To wit:
  • All of the functions that are passed or return blocks of pixels (such as ImageInput.read_image()) now use Numpy ndarray objects indexed as [y][x][channel] (no longer using old-style Python array.array and flattened to 1D).
  • Specilized enum type ImageInput.OpenMode has been replaced by string parameters, so for example, old ImageInput.open(filename, ImageInput.Create) is now ImageInput.open (filename, "Create")
  • Any function that previously took a parameter of type TypeDesc or TypeDesc.BASETYPE now will accept a string that signifies the type. For example, ImageBuf.set_write_format("float") is now a synonym for ImageBuf.set_write_format(oiio.TypeDesc(oiio.FLOAT)).
  • For several color conversion functions, parameter names were changed from "from" to "fromspace" and "to" to "tospace" to avoid a clash with the Python reserved word from. #2084
• ImageInput API changes for thread safety and statelessness #1927 (1.9.2)
  • seek_subimage() no longer takes an ImageSpec&, to avoid the obligatory copy. (If the copy is desired, just call spec() to get it afterwards.)
  • All of the read_*() methods now have varieties that take arguments specifying the subimage and mip level. The read_native_*() methods supplied by ImageInput subclass implementations now ONLY come in the variety that takes a subimage and miplevel.
  • All of the read_*() calls that take subimage/miplevel explicitly are guaranteed to be stateless and thread-safe against each other (it's not necessary to call seek_subimage first, nor to have to lock a mutex to ensure that another thread doesn't change the subimage before you get a chance to call read). For back-compatibility, there are still versions that don't take subimage/miplevel, require a prior call to seek_subimge, and are thus not considered thread-safe.
  • New methods spec(subimage,miplevel) and spec_dimensions(s,m) let you retrieve a copy of the ImageSpec for a given subimage and MIP level (thread-safe, and without needing a prior seek_subimage) call. Note that to be stateless and thread-safe, these return a COPY of the spec, rather than the reference returned by the stateful spec() call that has no arguments and requires a prior seek_subimage. However, spec_dimensions() does not copy the channel names or the arbitrary metadata, and is thus very inexpensive if the only thing you need from the spec copy is the image dimensions and channel formats.
• ImageInput and ImageOutput create/open changes
  • The static create() and open() methods have been changed so that instead of returning an ImageInput * (or ImageOutput *) and requiring the caller to correctly manage that resource and eventually destroy it, now they return a unique_ptr that automatically deletes when it leaves scope. In the process we also clean up some edge cases on Windows where it was possible for ImageInput/ImageOutput to have been allocated in one DLL's heap but freed in a different DLL's heap, which could cause subtle heap corruption problems. #1934,#1945 (1.9.3).
• ImageBuf
  • New method set_origin() changes the pixel data window origin. #1949 (1.9.4)
  • Assignment (operator=) is now enabled for ImageBuf, both the copying and moving variety. Also, an explicit copy() method has been added that returns a full copy of the ImageBuf. #1952 (1.9.4)
  • write() method has had its arguments changed and now takes an optional TypeDesc that lets you specify a requested data type when writing the output file, rather than requiring a previous and separate call to set_write_format(). The old call signature of write() still exists, but it will be considered deprecated in the future. #1953 (1.9.4)
• ImageBufAlgo
  • In C++, functions that take raw pointers for per-channel constant values or results are deprecated, in favor of new versions that heavily rely on span<> to safely pass array references and their lengths. #1961 (1.9.4)
  • In both C++ and Python, every IBA function that takes a parameter giving an ImageBuf destination reference for results have an additional variant that directly returns an ImageBuf result. This makes much cleaner, more readable code, in cases where it's not necessary to write partial results into an existing IB. #1961 (1.9.4)
  • In C++, many IBA functions that came in multiple versions for whether certain parameters could be an image, a per-channel constant, or a single constant, have been replaced by a single version that takes a new parameter-passing helper class, Image_or_Const that will match against any of those choices. (No changes are necessary for calling programs, but it makes the header and documentation a lot simpler.) #1961 (1.9.4)
  • IBA compare(), computePixelStats(), and histogram() now directly return their result structures, intead of requiring the passing of a destination reference. #1961 (1.9.4)
  • New IBA::fit() resizes and image to just fit in the given size, but preserve its aspect ratio (padding with black as necessary). It's just like what oiiotool --fit has always done, but now you can call it directly from C++ or Python. #1993 (1.9.4)
  • New contrast_remap() allows flexible linear or sigmoidal contrast remapping. #2043 (1.9.4)
  • ImageBufAlgo::colorconvert and various ocio transformations have changed the default value of their unpremult parameter from false to true, reflecting the fact that we believe this is almost always the more correct choice. Also, if their input image is clearly marked as having unasociated alpha already, they will not bracket the color conversion with the requested unpremult/premult. #1864 (1.9.2)
  • Updated the OpenCV interoperability with new functions to_OpenCV (make an ImageBuf out of a cv::Mat) and from_OpenCV (fill in a cv::Mat with the contents of an ImageBuf). Deprecated the old from_IplImage and to_IplImage, which are very OpenCV-1.x-centric. (2.0.2)
• ImageCache/TextureSystem:
  • ImageCache and TextureSystem now have close(filename) and close_all() methods, which for one file or all files will close the files and release any open file handles (also unlocking write access to those files on Windows), but without invalidating anything it knows about the ImageSpec or any pixel tiles already read from the files, as would happen with a call to the much more drastic invalidate() or invalidate_all(). #1950 (1.9.4)
  • TextureSystem::create() has an additional optional argument that allows the caller to pass an existing app-owned custom ImageCache. #2019 (1.9.4)
  • New TextureSystem::imagecache() method returns a blind, non-owning pointer to the underlying ImageCache of that TS. #2019 (1.9.4)
  • ImageCache: extended add_tile() with an optional copy parameter (which defaults to true), which when set to false will make a tile that references an app buffer without allocating, copying, and owning the memory. In short, this makes it possible to reference existing memory holding an image array, as if it were a texture. #2012 (1.9.4)
  • ImageCache::add_file() extended with an optional replace parameter (default: false), that if true, will replace the tile and invalidate the old one. #2021 (1.9.4)
• Changes to string formatting: #2076 (2.0.1)
  • New Strutil::sprintf() and ustring::sprintf() functions are for printf-style formatted errors and warnings. You are encouraged to change your existing format() calls to sprintf(), since the original format may in a later version (2.1?) switch to Python-style formatting commands, but sprintf will continue to reliably use C printf style notation.
  • In ImageInput, ImageOutput, ImageBuf, and ErrorHandler, new errorf() and warningf() methods similarly provide printf-style formatted errors and warnings. The old error()/warning() calls will someday (maybe 2.1?) switch to Python-style formatting commands, but errorf will continue to reliably use C printf style notation.
• ColorConfig changes: ColorConfig methods now return shared pointers to ColorProcessor rather than raw pointers. It is therefore no longer required to make an explicit delete call. Created ColorProcessor objects are now internally cached, so asking for the same color transformation multiple times is no longer expensive. The ColorProcessor interface is now in color.h and can be directly used to perform transformations on individual colors (previously it was just an opaque pointer and could only be used to pass into certain IBA functions). The color space names "rgb" and "default" are now understood to be synonyms for the default "linear" color space. #1788 (1.9.0)
• Remove long-deprecated API calls:
  • ImageBuf::get_pixels/get_pixel_channels varieties deprecated since 1.6.
  • ImageBuf::set_deep_value_uint, deprecated since 1.7.
  • ImageBuf::deep_alloc, deprecated since 1.7.
  • ImageBufAlgo::colorconvert variety deprecated since 1.7.
  • ImageCache::clear, deprecated since 1.7.
  • ImageCache::add_tile variety deprecated since 1.6.
• ROI new methods: contains() #1874, #1878 (1.9.2)
• ImageBufAlgo::pixeladdr() now takes an additional optional parameter, the channel number. #1880 (1.9.2)
• Global OIIO attribute "log_times" (which defaults to 0 but can be overridden by setting the OPENIMAGEIO_LOG_TIMES environment variable), when nonzero, instruments ImageBufAlgo functions to record the number of times they are called and how much time they take to execute. A report of these times can be retrieved as a string as the "timing_report" attribute, or it will be printed to stdout automatically if the value of log_times is 2 or more at the time that the application exits. #1885 (1.9.2)
• Moved the definition of ROI from imagebuf.h to imageio.h and make most of the methods constexpr. #1906 (1.9.2)
• Rename/move of array_view to span. Deprecated array_view and moved array_view.h contents to span.h. You should change array_view<T> to span<T> and array_view<const T> to cspan<T>. #1956,2062 (1.9.4)
• ustring: removed operator int() that allowed simple int casting such as:

      ustring u, v;
      if (u || !v) { ... }
  

  This was error-prone, neither std::string nor std::string_view had the equivalent, so we are removing it. The preferred idiom is:

      if (!u.empty() || v.empty()) { ... }
  

Performance improvements:

• ImageBufAlgo::computePixelStats is now multithreaded and should improve by a large factor when running on a machine with many cores. This is particularly noticable for maketx. #1852 (1.9.2)
• Color conversions are sped up by 50% for 4 channel float images, about 30% for other combinations of channels or data formats. #1868 (1.9.2)
• ImageBuf::get_pixels() sped up by around 3x for the common case of the image being fully in memory (the slower path is now only used for ImageCache-based images). #1872 (1.9.2)
• ImageBufAlgo::copy() and crop() sped up for in-memory buffers, by about 35-45% when copying between buffers of the same type, 2-4x when copying between buffers of different data types. #1877 (1.9.2)
• ImageBufAlgo::over() when both buffers are in-memory, float, 4-channels, sped up by about 2x. #1879 (1.9.2).
• ImageBufAlgo::fill() of a constant color sped up by 1.5-2.5x (depending on the data type involved). #1886 (1.9.2)

Fixes and feature enhancements:

• oiiotool
  • --help prints important usage tips that explain command parsing, syntax of optional modifiers, and the path to PDF docs. #1811 (1.9.2)
  • --colormap has new maps "inferno", "magma", "plasma", "viridis", which are perceptually uniform, monotonically increasing luminance, look good converted to greyscale, and usable by people with color blindness. #1820 (1.9.2)
  • oiiotool no longer enables autotile by default. #1856 (1.9.2)
  • --colorconvert, --tocolorspace, and all of the --ocio commands now take an optional modifier :unpremult=1 which causes the color conversion to be internally bracketed by unpremult/premult steps (if the image has alpha and is not already marked as having unassociated alpha). You should therefore prefer --colorconvert:unpremult=1 from to rather than the more complex --unpremult --colorconvert from to -premult. #1864 (1.9.2)
  • --autocc will also cause unpremult/premult to bracket any color transformations it does automatically for read and write (if the image has alpha and does not appear to already be unassociated). #1864 (1.9.2)
  • --help prints the name of the OCIO color config file. #1869 (1.9.2)
  • Frame sequence wildcard improvements: fix handling of negative frame numbers and ranges, also the --frames command line option is not enough to trigger a loop over those frame numbers, even if no other arguments appear to have wildcard structure. #1894 (1.8.10/1.9.2)
  • --info -v now prints metadata in sorted order, making it easier to spot the existance of particular metadata. #1982 (1.9.4)
  • --no-autopremult fixed, it wasn't working properly for cases that were read directly rather than backed by ImageCache. #1984 (1.9.4)
  • New --contrast allows for contrast remapping (linear or sigmoidal). #2043 (1.9.4)
  • Improved logic for propagating the pixel data format through multiple operations, especially for files with multiple subimages. #1769 (1.9.0/1.8.6)
  • Outputs are now written to temporary files, then atomically moved to the specified filename at the end. This makes it safe for oiiotool to "overwrite" a file (i.e. oiiotool in.tif ... -o out.tif) without problematic situations where the file is truncated or overwritten before the reading is complete. #1797 (1.8.7/1.9.1)
  • Fixed problem with reading half files where very small (denormalized) half values could get squashed to float 0.0 instead of having their values preserved, if certain old versions of libopenjpeg were being used (because they set a CPU flag strangely upon library load and then never changed it back, this is a libopenjpeg bug that has since been fixed). #2048 (2.0)
  • -d chan=type logic fixed for certain cases of specifying the data types of individual channels. #2061 (2.0beta2)
  • Expression evaluation: metadata names can now be enclosed in single or double quotes if they don't follow "C" identifier naming conventions. For example, {TOP.'foo/bar'} retrieves metadata called "foo/bar" rather than trying to retrieve "foo" and divide by bar. #2068 (2.0beta2)
  • Expression evaluation: When retrieving metadata, timecode data will be expressed properly as a string ("00:00:00:00"). #2068 (2.0beta2)
• ImageBufAlgo:
  • color_map() supports new maps "inferno", "magma", "plasma", "viridis". #1820 (1.9.2)
  • Across many functions, improve channel logic when combining an image with alpha with another image without alpha. #1827 (1.9.2)
  • mad() now takes an img*color+img variety. (Previously it supported img*img+img and img*color+color.) #1866 (1.9.2)
  • New fit() is like resize but fits inside a specified window size, while preserving the aspect ratio of the image appearance. #1993.
  • New contrast_remap() allows flexible linear or sigmoidal contrast remapping. #2043 (1.9.4)
  • channel_append() is no longer limited to requiring the two input images to have the same pixel data type. #2022 (1.9.4)
  • isConstantColor(), isConstantChannel(), and isMonochrome() have added an optional threshold parameter that allows you to compute whether the image is constant or monochrome within a non-zero tolerance (the default is still 0.0, meaning checking for an exact match). #2049 (2.0.0)
  • IBA::ociodisplay() has better behavior when its "fromspace" parameter is left blank -- instead of assuming "linear" (as a space name), it assumes it's whatever space in your OCIO color config has the "linear" role. #2083 (1.8.17/2.0.1)
• ImageBuf:
  • Bug fixed in IB::copy() of rare types. #1829 (1.9.2)
  • write() automatically tells the ImageCache to 'invalidate' the file being written, so cached images will not retain the prior version of the files. #1916 (1.9.2)
  • Bug fix to ImageBuf::contains_roi() method -- it erroneously always returned true. #1997 (1.8.14/1.9.4)
• ImageCache/TextureSystem/maketx:
  • Improved stats on how long we wait for ImageInput mutexes. #1779 (1.9.0/1.8.6)
  • Improved performance of IC/TS tile and file caches under heavy contention from many threads. #1780 (1.9.0)
  • Increased the default max_tile_channels limit from 5 to 6. #1803 (1.9.1)
  • maketx: improved image hashing to avoid some (extremely rare) possible hash collisions. #1819 (1.9.2)
  • IC/TS performance improvements by changing the underlying hash table implementation. #1823,1824,1825,1826,1830 (1.9.2)
  • texture()/texture3d(): when requesting a nonexistant "subimage", return the fill color, like we do when requesting nonexistant channels (rather than nondeterministically simply not filling in the result). #1917 (1.9.2)
  • Relying on some changes to the ImageInput API, there is now much less thread locking to protect the underlying ImageInputs, and this should improve texture and image cache performance when many threads need to read tiles from the same file. #1927 (1.9.2)
  • get_image_info()/get_texture_info() is now more flexible about retrieving arrays vs aggregates, in cases where the total number of elements is correct. #1968 (1.9.4)
  • Fix uninitialized read within the texture system (only affected statistics, never gave wrong texture results). #2000 (1.9.4)
  • texture3d() transforms lookup points from world into local space if the file has a "worldtolocal" metadata giving a 4x4 matrix. #2009 (1.9.4)
  • Fix minor texture filtering bug where widely disparate "sblur" and "tblur" values could in some circumstances lead to incorrect texture filter estimation. #2052 (2.0.0)
  • ImageCache::invalidate(filename) did not properly invalidate the "fingerprint" is used to detect duplicate files. #2081 (1.8.17/2.0.1)
• iv:
  • Fix (especially on OSX) for various ways it has been broken since the shift to Qt5. #1946 (1.8.12, 1.9.4)
  • New optin --no-autopremult works like oiiotool, causes images with unassociated alpha to not be automatically premultiplied by alpha as they are read in. #1984 (1.9.4)
• All string->numeric parsing and numeric->string formatting is now locale-independent and always uses '.' as decimal marker. #1796 (1.9.0)
• Python Imagebuf.get_pixels and set_pixels bugs fixed, in the varieties that take an ROI to describe the region. #1802 (1.9.2)
• Python: Implement missing ImageOutput.open() call variety for declaring multiple subimages. #2074 (2.0.1)
• More robust parsing of XMP metadata for unknown metadata names. #1816 (1.9.2/1.8.7)
• Fix ImageSpec constructor from an ROI, display/"full" window did not get the right default origin. #1997 (1.8.14/1.9.4)
• ImageSpec::erase_attribute() fix bug where it got case-sensitivity of the search backwards when built using std::regex rather than boost::regex. #2003 (1.8.14/1.9.4)
• DPX:
  • Better catching of write errors, including filling the disk while in the process of writing a DPX file. #2072 (2.0.1)
• Field3d:
  • Prevent crashes when open fails. #1848 (1.9.2/1.8.8)
  • Fix potential mutex deadlock. #1972 (1.9.4)
• GIF:
  • Fix crash when reading GIF with comment extension but no comment data. #2001 (1.8.14/1.9.4)
• JPEG:
  • When writing, be robust to accidentally setting the "density" metadata to values larger than JPEG's 16 bit integer field will accommodate. #2002 (1.8.14/1.9.4)
  • Better detection and reporting of error conditions while reading corrupt JPEG files. #2073 (2.0.1)
• OpenEXR:
  • Gracefully detect and reject files with subsampled channels, which is a rarely-to-never-used OpenEXR feature that we don't support properly. #1849 (1.9.2/1.8.8)
  • Improved handling of UTF-8 filenames on Windows. #1941 (1.9.3, 1.8.12, 1.7.19)
• PNG:
  • Fix redundant png_write_end call. #1910 (1.9.2)
• PSD:
  • Fix parse issue of layer mask data. #1777 (1.9.2)
• RAW:
  • Add "raw:HighlightMode" configuration hint to control libraw's handling of highlight mode processing. #1851
  • Important bug fix when dealing with rotated (and vertical) images, which were not being re-oriented properly and could get strangely scrambled. #1854 (1.9.2/1.8.9)
  • Major rewrite of the way makernotes and camera-specific metadata are handled, resulting in much more (and more accurate) reporting of camera metadata. #1985 (1.9.4)
  • The "oiio:ColorSpace" metadata is now set correctly when reading raw DSLR images. And we deprecate the old "raw:ColorSpace" metadata, which is useless. #2016 (1.9.4)
  • Add "raw:aber" configuration hint to control libraw's adjustments for chromatic aberration. This data is of type "float[2]", the first value is the scale factor for red, the second for blue, and both should be very close to 1.0. #2030 (1.9.4)
• TIFF:
  • Improve performance of TIFF scanline output. #1833 (1.9.2)
  • Bug fix: read_tile() and read_tiles() input of un-premultiplied tiles botched the "shape" of the tile data array. #1907 (1.9.2/1.8.10)
  • Improvement in speed of reading headers (by removing redundant call to TIFFSetDirectory). #1922 (1.9.2)
  • When config option "oiio:UnassociatedAlpha" is nonzero (or not set -- which is the default), therefore enabling automatic premultiplication by alpha for any unassociated alpha files, it will set the metadata "tiff:UnassociatedAlpha" to indicate that the original file was unassociated. #1984 (1.9.4)
  • Bug fixes for TIFF reads of images with unassociated alpha -- there were some edge cases where they pixels failed to automatically premultiply upon read. #2032 (1.9.4)
• zfile: more careful gzopen on Windows that could crash when given bogus filename. #1839,2070 (1.9.2/1.8.8/2.0.1)
• Windows fix: Safer thread pool destruction on. #2038 (1.9.4)

Build/test system improvements and platform ports:

• Fixes for Windows build. #1793, #1794 (1.9.0/1.8.6), #2025 (1.9.4)
• Fix build bug where if the makefile wrapper got CODECOV=0, it would force a "Debug" build (required for code coverage tests) even though code coverage is instructed to be off. (It would be fine if you didn't specify CODECOV at all.) #1792 (1.9.0/1.8.6)
• Build: Fix broken build when Freetype was not found or disabled. #1800 (1.8.6/1.9.1)
• Build: Boost.Python is no longer a dependency, but pybind11 is. If not found on the system, it will be automatically downloaded. #1801, #2031 (1.9.1)
• Time for a multi-core build of OIIO is reduced by 40% by refactoring some extra big modules into more bite-sized pieces. #1806 (1.9.2)
• testtex:
  • Make the "thread workout" cases all honor --handle. #1778 (1.9.0)
  • Only prints detailed stats if -v is used, and new option --invalidate will invalidate the cache when starting each threadtimes trial. #1828 (1.9.2)
  • New --anisoratio lets you choose anisotropic shape for thread working tests, and make thread_workout samples twice as big to be more typical by interpolating mip levels. #1840 (1.9.2)
  • TextureSystem stats are printed as well as ImageCache. #1840 (1.9.2)
• iv no longer requires GLEW, using QOpenGLFunctions instead. #1840 (1.9.2)
• DICOM: Fix dcmtk build errors on some platforms. Also, the minimum dcmtk version we suport is 3.6.1. #1843 (1.9.2/1.8.8)
• Build fixes for Hurd OS. #1850 (1.9.2/1.8.8)
• Clean up leak sanitizer errors. #1855 (1.9.2)
• On Unix/Linux, add explicit DL library dependency to libOpenImageIO.so itself instead of only to the binaries and test utilities. #1860 (1.9.2/1.8.8)
• The build now bundles a sample OCIO config in testsuite/common so that we can do OCIO-based unit tests. #1870 (1.9.2)
• Properly find newer openjpeg 2.3. #1871 (1.9.2)
• Fix testsuite to be Python 2/3 agnostic. #1891 (1.9.2)
• Removed USE_PYTHON3 build flag, which didn't do anything. #1891 (1.9.2)
• The PYTHON_VERSION build variable is now better at selecting among several installed versions of Python, and all the tests should work fine with Python 3.x now. #2015 (1.9.4)
• Remove some lingering support for MSVS < 2013 (which we haven't advertised as working anyway). #1887 (1.9.2)
• Windows/MSVC build fix: use the /bigobj option on some large modules that need it. #1900, #1902 (1.8.10/1.9.2)
• Add up-to-date Nuke versions to FindNuke.cmake. #1920 (1.8.11, 1.9.2)
• Allow building against ffmpeg 4.0. #1926,#1936 (1.8.11, 1.9.2)
• Disable SSE for 32 bit Windows -- problematic build issues. #1933 (1.9.3, 1.8.12, 1.7.19)
• Fixes to the EMBEDPLUGINS=0 build case, which had at some point stopped working properly. #1942 (1.9.3)
• Improvements in finding the location of OpenJPEG with Macports. #1948 (1.8.12, 1.9.4)
• Improvement finding libraw properly on Windows. #1959 (1.9.4)
• Fix warnings to allow clean gcc8 builds. #1974 (1.9.4)
• Make sure we build properly for C++17. (1.9.4)
• Check properly for minimal FFMpeg version (2.6). #1981 (1.9.4)
• New build option GLIBCXX_USE_CXX11_ABI, when set to 0 will force the old gcc string ABI (even gcc 7+ where the new ABI is the default), and if set to 1 will force the new gcc string ABI (on gcc 5-6, where old ABI is the default). If not set at all, it will respect the default choice for that compiler. #1980 (1.9.4)
• TravisCI builds now use an abbreviated test matrix for most ordinary pushes of working branches, but the full test matrix for PRs or pushes to "master" or "RB" branches. #1983 (1.9.4)
• Support compilation by clang 7.0. #1995 (1.9.4)
• Support for building against OpenEXR 2.3. #2007 (1.9.4)
• Use OpenEXR pkgconfig if available. #2008 (1.9.4)
• Allow builds outside the source tree to pass testsuite. Defaults to finding test image directories such as oiio-images, openexr-images, and libtiffpic in the usual ".." from the main OIIO source directory, but now it can be overridden with the CMake variable OIIO_TESTSUITE_IMAGEDIR. #2026 (1.9.4)
• Remove stale python examples from src/python. They were untested, undocumented, and probably no longer worked against the current APIs. #2036 (1.9.4)
• Fixes for Windows when making Unicode builds, and fix Plugin::dlopen on Windows to properly support UTF-8 filenames. #1454 (2.0.1)
• Support added for OpenCV 4.0. (2.0.1)

Developer goodies / internals:

• Formatting with clang-format: All submissions are expected to be formatted using our standard clang-format rules. Please run make clang-format prior to submitting code. The TravisCI tests include one entry just to check that the formatting conforms, and will fail if it doesn't, printing the diffs that would bring it to proper formatting. (Note: for small changes, if you don't have clang-format locally, it's ok to submit, then use the diffs from the failures to fix it by hand and resubmit and update.) #2059,2064,2065,2067,2069.
• argparse.h:
  • Add pre- and post-option help printing callbacks. #1811 (1.9.2)
  • Changed to PIMPL to hide implementation from the public headers. Also modernized internals, no raw new/delete. #1858 (1.9.2)
• array_view.h:
  • Added begin(), end(), cbegin(), cend() methods, and new constructors from pointer pairs and from std::array. (1.9.0/1.8.6)
  • Deprecated, moved contents to span.h. You should change array_view<T> to span<T> and array_view<const T> to cspan<T>. #1956 (1.9.4)
• color.h: add guards to make this header safe for Cuda compilation. #1905 (1.9.2/1.8.10)
• filesystem.h:
  • IOProxy classes that can abstract file operations for custom I/O substitutions. #1931 (1.9.3)
  • Proper UTF-8 filenames for unique_path() and temp_directory(), and general UTF-8 cleanup/simplification. #1940 (1.9.3, 1.8.12, 1.7.19)
• fmath.h:
  • Now defines preprocessor symbol OIIO_FMATH_H so other files can easily detect if it has been included. (1.9.0/1.8.6)
  • Modify to allow Cuda compilation/use of this header. #1888,#1896 (1.9.2/1.8.10)
  • Improve numeric approximation of fast_atan() and fast_atan2(). #1943 (1.9.3)
  • fast_cbrt() is a fast approximate cube root (maximum error 8e-14, about 3 times faster than pow computes cube roots). #1955 (1.9.4)
• function_view.h: Overhauled fixed with an alternate implementation borrowed from LLVM. (1.9.4)
• hash.h: add guards to make this header safe for Cuda compilation. #1905 (1.9.2/1.8.10)
• imageio.h: convert_image() and parallel_convert_image have been simplified to remove optional alpha_channel and z_channel parameters that were never actually used. The old versions are still present but are deprecated. #2088 (2.0.1)
• parallel.h:
  • parallel_options passed to many functions. #1807 (1.9.2)
  • More careful avoidance of threads not recursively using the thread pool (which could lead to deadlocks). #1807 (1.9.2)
  • Internals refactor of task_set #1883 (1.9.2).
  • Make the thread pool better behaved in times if pool congestion -- if there are already way too many items in the task queue, the caller may do the work itself rather than add to the end and have to wait too long to get results. #1884 (1.9.2)
• paramlist.h:
  • ParamValue class has added get_int_indexed() and get_float_indexed() methods. #1773 (1.9.0/1.8.6)
  • ParamValue restructured to allow additional common data types to store internally rather than requre an allocation. #1812 (1.9.2)
  • New ParamList convenience methods: remove(), constains(), add_or_replace(). #1813 (1.9.2)
• platform.h:
  • New OIIO_FALLTHROUGH and OIIO_NODISCARD macros, and renamed OIIO_UNUSED_OK to OIIO_MAYBE_UNUSED (to match C++17 naming). #2041
• simd.h:
  • Fixed build break when AVX512VL is enabled. #1781 (1.9.0/1.8.6)
  • Minor fixes especially for avx512. #1846 (1.9.2/1.8.8) #1873,#1893 (1.9.2)
• span.h:
  • Used to be array_view. Now it's span<> and span_strided. Also, cspan<T> is a handy alias for span<const T>. #1956 (1.9.4)
  • Added begin(), end(), cbegin(), cend() methods, and new constructors from pointer pairs and from std::array. (1.9.0/1.8.6)
  • Added == and != to span and span_strided. #2037 (1.9.4)
• strutil.h:
  • All string->numeric parsing and numeric->string formatting is now locale-independent and always uses '.' as decimal marker. #1796 (1.9.0)
  • New Strutil::stof(), stoi(), stoui(), stod() functions for easy parsing of strings to numbers. Also tests Strutil::string_is_int() and string_is_float(). #1796 (1.9.0)
  • New to_string<> utility template. #1814 (1.9.2)
  • Fix to strtof, strtod for non-C locales. #1918 (1.8.11, 1.9.2)
  • New iless() is case-insensitive locale-independent string_view ordering comparison. Also added StringIEqual, StringLess, StringILess functors. (1.9.4)
  • join() is now a template that can act on any iterable container of objects that allow stream output. #2033 (1.9.4)
  • New splits()/splitsv() that direction returns a vector of std::string or string_view, respectively. #2033 (1.9.4)
  • A second version of extract_from_list_string that directly returns a std::vector (instead of being passed as a param). #2033 (1.9.4)
  • parse_string now accepts single quotes as well as double quotes to enclose a quoted string. #2066 (2.0beta2)
  • Fix Strutil::vsnprintf detection of encoding errors on Windows. #2082 (1.8.17/2.0.1)
• thread.h:
  • Reimplementaiton of spin_rw_mutex has much better performance when many threads are accessing at once, especially if most of them are reader threads. #1787 (1.9.0)
  • task_set: add wait_for_task() method that waits for just one task in the set to finish (versus wait() that waits for all). #1847 (1.9.2)
  • Fix rare crash in thread pool when lowering the number of threads. #2013 (1.9.4/1.8.15)
• unittest.h:
  • Made references to Strutil fully qualified in OIIO namespace, so that unittest.h can be more easily used outside of the OIIO codebase. #1791 (1.9.0)
  • OIIO_CHECK_EQUAL_APPROX - fix namespace ambiguity. #1998 (1.9.4)
  • OIIO_CHECK_EQUAL now can compare two std::vectors. #2033 (1.9.4)
  • Make unit test errors respect whether stdout is a terminal when deciding whether to print in color. #2045
• Extensive use of C++11 final and override decorators of virtual methods in our internals, especially ImageInput and ImageOutput. #1904 (1.9.2)

Notable documentation changes:

• A new LICENSE-THIRD-PARTY.md file reproduces the full open source licenses of all code that we distribute with OIIO, incorporate, or derive code from. They are have very similar license terms to the main OIIO license ("New BSD") -- MIT, Mozilla, Apache 2.0, or public domain. OIIO does not use any GPL or other "viral" licenesed code that would change license terms of any code that didn't come directly from those packages.
• The CHANGES.md file was getting truly enormous, so we have split the release notes from the 0.x and 1.x releases into separate files found in src/doc. So CHANGES.md only documents 2.0 and beyond.

---

For older release notes, see:

• CHANGES-0.x.
• CHANGES-1.x.