1# Release Notes
2
3All notable changes to [Boost.GIL](https://github.com/boostorg/gil/) project will be documented in this file.
4The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
5
6## [Unreleased]
7
8## [1.72.0] - 2019-12-11
9
10### Added
11- GSoC 2019: Lanczos resampling for image down scaling ([PR #309](https://github.com/boostorg/gil/pull/309)).
12- GSoC 2019: Methods for binary thresholding, inverted binary thresholding and truncation thresholding ([PR #313](https://github.com/boostorg/gil/pull/313)).
13- GSoC 2019: Otsu thresholding method ([PR #314](https://github.com/boostorg/gil/pull/314)).
14- GSoC 2019: Adaptive thresholding using mean or gaussian-weighted sum of the neighbourhood area ([PR #315](https://github.com/boostorg/gil/pull/315)).
15- GSoC 2019: Harris response calculation (corner detector without non-maximum filtering) ([PR #350](https://github.com/boostorg/gil/pull/350)).
16- GSoC 2019: Hessian corner detector ([PR #364](https://github.com/boostorg/gil/pull/364)).
17- GSoC 2019: Types for defining 2D kernel, `kernel_2d` and `kernel_2d_fixed`, in Numeric extension ([PR #361](https://github.com/boostorg/gil/pull/361)).
18- GSoC 2019: Implementation of 2D convolution as new function `convolve_2d` ([PR #367](https://github.com/boostorg/gil/pull/367)).
19- GSoC 2019: Box filtering using the average filter ([PR #383](https://github.com/boostorg/gil/pull/383)).
20- GSoC 2019: Blur function based on normalized mean filter ([PR #383](https://github.com/boostorg/gil/pull/383)).
21- GSoC 2019: Sobel and Scharr operators ([PR #392](https://github.com/boostorg/gil/pull/392)).
22- GSoC 2019: Median filter to remove noise from image ([PR #393](https://github.com/boostorg/gil/pull/393)).
23- Continued adding new test cases and significantly improved overall test coverage.
24- Documented purpose of `cached_location_t` ([PR #287](https://github.com/boostorg/gil/pull/287)).
25- Function `convolve_1d` in Numeric extension for convenient use of `convolve_rows` and `convolve_cols` ([PR #347](https://github.com/boostorg/gil/pull/347) and [PR #367](https://github.com/boostorg/gil/pull/367)).
26- Function `extend_boundary` in Numeric extension to perform image boundary extension ([PR #386](https://github.com/boostorg/gil/pull/386)).
27- Project release notes maintained in Markdown file `RELEASES.md` ([PR #404](https://github.com/boostorg/gil/pull/404)).
28
29### Changed
30- Move all tests, core features and extensions, inside `test/` directory ([PR #302](https://github.com/boostorg/gil/pull/302)).
31
32### Removed
33- Replace Boost.MPL with Boost.MP11 ([PR #274](https://github.com/boostorg/gil/pull/274)).
34- Removed use of Boost.TypeTraits ([PR #274](https://github.com/boostorg/gil/pull/274)).
35- Dropped support for GCC <= 4.8 ([PR #296](https://github.com/boostorg/gil/pull/296)).
36- Remove `include/boost/gil/version.hpp` file as unused ([PR #403](https://github.com/boostorg/gil/pull/403)).
37
38### Fixed
39- Undetermined value of default-initialized channel and pixel objects ([PR #273](https://github.com/boostorg/gil/pull/273)).
40- Undefined behaviour due to `std::is_trivially_default_constructible` specializations ([PR #284](https://github.com/boostorg/gil/pull/284)).
41- Crash when reading PNG files with an invalid header ([PR #385](https://github.com/boostorg/gil/pull/385)).
42- Applied the [Rule of Three](https://en.wikipedia.org/wiki/Rule_of_three_(C%2B%2B_programming)) for numerous types.
43- Removed uses of deprecated implicit definition of defaulted copy assignment operator or copy constructor.
44
45## [1.68.0] - 2018-08-09
46
47### Added
48- The library now requires a C++11-compliant compiler.
49- Added Toolbox extension following the [review and acceptance into Boost](https://lists.boost.org/boost-announce/2011/01/0281.php).
50
51### Changed
52- The I/O extensions have been entirely rewritten as I/O v2, [reviewed and accepted into Boost](https://lists.boost.org/boost-announce/2011/01/0281.php).
53- Documentation has been reformatted and updated.
54
55### Removed
56- The existing I/O v1 extension has been replaced with I/O v2.
57
58## [1.53.0] - 2013-02-04
59
60### Fixed
61- Fixed self-assignment warnings (Trac [#4919](https://svn.boost.org/trac10/ticket/4919)).
62
63## [1.35.0] - 2008-03-29
64
65### Added
66- First Boost release of Generic Image Library developed by Lubomir Bourdev and Hailin Jin following the [review and acceptance into Boost](https://lists.boost.org/Archives/boost/2006/11/112896.php).
67
68---------------------------------------------------------------------
69
70## Pre-Boost History of the Generic Image Library (GIL) by Adobe
71
72The log of changes prior the first release of GIL as part of Boost
73was collected from https://stlab.adobe.com/gil/news.html site and
74linked PDF documents with detailed changes.
75
76---------------------------------------------------------------------
77
78## [2.1.1] - 2007-09-15
79
80### Changed
81- Swapped template arguments for `color_element_type`, `color_element_reference_type` and `color_element_const_reference_type` to take `ColorBase` first for consistency with the other similar metafunctions.
82
83### Fixed
84- Minor bugs fixed.
85
86## [2.1.0] - 2007-06-17
87
88### Added
89- Added support for accessing raw memory from image views by getting raw pointer to the beginning of the memory
90  associated with a homogeneous image view using new functions `interleaved_view_get_raw_data` or `planar_view_get_raw_data`.
91- Support for non-byte-aligned images (e.g. 6-bit RGB222, or 1-bit grayscale).
92  To support bit distance, we are using the same classes that were providing byte distance (`byte_addressible_step_iterator`, `byte_addressible_2d_locator`, etc.)
93  except that now they operate on memory units instead of bytes.
94  A memory unit can currently be either a byte or a bit.
95- New `byte_to_memunit` function required by the `MemoryBasedIteratorConcept`, which specifies the number of bits per memory unit (either 1 or 8).
96- New classes for references and iterators over bit-aligned pixels: `bit_aligned_pixel_reference`, `bit_aligned_pixel_iterator`.
97  The memory unit of bit aligned pixel iterators is a bit, i.e. `byte_to_unit<bit_aligned_pixel_iterator<T> >::value == 8`.
98- The `value_type` of a bit-aligned image is a `packed_pixel` (new name, see below).
99  A packed pixel is a pixel that is byte-aligned but whose channels may not be byte aligned.
100  There is a strong analogy with the way interleaved and planar images are implemented, with `packed_pixel` corresponding
101  to `pixel`, `bit_aligned_pixel_reference` corresponding to `planar_pixel_reference`
102  and `bit_aligned_pixel_iterator` corresponding to `planar_pixel_iterator`.
103- New metafunction `bit_aligned_image_type` for constructing bit-aligned images.
104  A bit-aligned image is an image whose pixels may not be byte-aligned (such as an RGB222 image).
105- New metafunction `pixel_value_type` for constructing homogenous pixel value from elements.
106- New metafunction `packed_pixel_type` for constructing homogenous packed pixel from elements.
107- New metafunction `packed_image_type` for constructing packed images with packed pixel as its `value_type`.
108
109### Changed
110- Renamed `heterogeneous_packed_pixel` to `packed_pixel`.
111- Renamed `ByteAdvancableIteratorConcept` to `MemoryBasedIteratorConcept`.
112- Renamed `byte_addressable_{step_iterator,2d_locator}` to `memory_based_{step_iterator,2d_locator}`.
113- Renamed `byte_{advance,advanced,distance,step}` to `memunit_{advance,advanced,distance,step}`,
114- Renamed `locator::row_bytes()` to `locator::row_size()` and `locator::pix_bytestep()` to `locator::pixel_size()`.
115- Simplified `packed_channel_reference` and `packed_dynamic_channel_reference` by removing the `BitField` parameter (it is now computed automatically).
116- Improved `channel_convert` - it is faster by switching to floating-point math only if necessary.
117
118### Fixed
119- Fixed a roundoff bug in the conversion (related to floating-point math switching).
120- Fixed histogram regression tests.
121
122## [2.0.x] - 2007-03-27
123
124### Changed
125- Minor bug fixes.
126- Regression test improvements.
127
128### Removed
129- Removed any external dependencies from the regression tests.
130
131## [2.0.0] - 2007-03-08
132
133### Added
134- Further Boost integration:
135  - Directories follow the Boost convention.
136  - Different models are usually now split in separate files.
137  - Renamed some files for better consistency.
138  - Renamed classes, functions and template arguments with longer but clearer and more consistent names.
139- New `deprecated.hpp` - a file that maps many of the deprecated names to current ones.
140  Including it will help porting your code to GIL 2.0. After porting to GIL 2.0, however,
141  make sure that your code works when this file is not included.
142- New `swap` function required for reference proxies, since the `std::swap` default does not do the right thing.
143- Metafunctions `iterator_type_from_pixel` and `view_type_from_pixel` to allow creating standard iterators and views associated with a pixel type.
144- New `scoped_channel_value`, a channel adaptor that changes the operational range of a channel. `bits32f` is defined as a `float` with range `0.0` to `1.0`.
145- New `packed_channel_value`, `packed_channel_reference` and `packed_dynamic_channel_reference` which model channels operating on bit ranges.
146- New `heterogeneous_packed_pixel`, a model of a pixel whose channels are bit ranges (e.g. 16-bit RGB pixel in the 565 format).
147- Metafunctions to get the k-th element of a color base (or its reference): `kth_semantic_element_type`, `kth_semantic_element_reference_type`, `kth_semantic_element_const_reference_type`.
148- Metafunctions to operate on pixel iterator: `const_iterator_type`, `iterator_is_mutable`, `is_iterator_adaptor`.
149- New image view algorithms `uninitialized_fill_pixels`, `uninitialized_copy_pixels` and method `is_1d_traversable`.
150- Added support for creating images with a new value to fill.
151
152### Changed
153- Updated the design guide and tutorial, updated syntax of concepts to the latest concepts proposal.
154- In `image`, `image_view`, `any_image`, `any_image_view`:
155  There are no longer global functions `get_width()`, `get_height()`, `get_dimensions()`, `num_channels()`.
156  Use  methods `width()`, `height()`, `dimensions()` instead.
157- In models of pixel, pixel iterator, pixel locator, image view and image:
158  There used to be different ways of getting to a pixel, channel, color space, etc. of an image view,
159  pixel, locator, iterator and image (e.g. traits, member typedefs).
160  Now all pixel-based GIL constructs (pixels, pixel iterators, locators, image views and images) model
161  `PixelBasedConcept`, which means they provide the following metafunctions: `color_space_type`, `channel_mapping_type`, `is_planar`, `num_channels`
162  and for homogeneous constructs we also have: `channel_type`.
163  To get the pixel type or pixel reference/const reference type of an image, image view, locator
164  and pixel, use member typedefs `value_type`, `reference` and `const_reference`.
165- In `locator`, `image`, `image_view`, `any_image` and `any_image_view`:
166  Removed `dynamic_x_step_t`, `dynamic_y_step_t`, `dynamic_xy_step_t` and `dynamic_xy_step_transposed_t`
167  as member typedefs of locators and image views.
168  Instead, there are separate concepts `HasDynamicXStepTypeConcept`, `HasDynamicYStepTypeConcept`,
169  `HasTransposedTypeConcept` which all GIL-provided locators, views and images model.
170  Those concepts require a metafunction to get the corresponding type.
171  Analogously, all GIL pixel iterators model `HasDynamicXStepTypeConcept`.
172- In channel, the min and max value is now part of the channel traits.
173  For all built-in types the channel range equals the physical range (as determined by `std::numeric_traits<T>::max()`).
174- Provide `channel_convert` support to convert between any of the GIL-provided channel types.
175  The operation is also consistent - conversion is done as a linear mapping that maps the min/max to the min/max.
176- In pixel, major redesign of pixel-level constructs.
177  Renamed `color_base` to `homogeneous_color_base` and defined it once, not for each color space.
178  The color base is a first-class concept and allows to model any bundle of color elements.
179  Work needed to define a new color space has been simplified a lot.
180  All former pixel-level algorithms and accessors now operate on color bases.
181  The elements of a color base can be accessed by physical or semantic index or by name (channel names
182  can no longer be accessed as members of the pixel e.g. `my_pixel.gray = 0`), use `get_color` instead).
183- In color base, algorithms now can take heterogeneous pixels (i.e. pixels each channel of which may have a different type).
184  The `color_convert` can operate on heterogeneous pixels with the exception of to/from RGBA.
185- In image, the class `image` is no longer templated over the image view. It is now templated over pixel value.
186- In dynamic image, instead of removed `cross_vector_image_types` and `cross_vector_image_view_types`, create MPL vector to enumerate types.
187- Renamed algorithms `{copy,equal,fill,for_each,generate,max,min,transform}_channels` to `static_{copy,equal,fill,for_each,generate,max,min,transform}`.
188- Rename metafunctions `channel` to `at_c`, `semantic_channel` to `semantic_at_c`, `get_nth_channel` to `dynamic_at_c`.
189- Renamed `planar_{ptr,ref}` to `planar_pixel_{iterator,reference}`.
190- Renamed `PixelConcept` to `HomogeneousPixelConcept`.
191- Renamed `HeterogeneousPixelConcept` to `PixelConcept`.
192- Renamed `pixel_image_iterator` to `iterator_from_2d`.
193- Renamed `is_contiguous` to `is_1d_traversable`.
194- Renamed `membased_2d_locator` to `byte_addressable_2d_locator`.
195- Renamed `resize_clobber_image` to `image::recreate`.
196
197### Fixed
198- Now compiles with GCC 4.1.1.
199- Fixed some bugs in defining reference proxies.
200
201### Removed
202- Flattened the `core` directory as part of Boost integration.
203- Got rid of channel accessors from pixel types.
204- Got rid of `pixel_traits`. Use nested typedefs `value_type`, `reference` and `const_reference` or metafunctions implementing `PixelBasedConcept`.
205- Got rid of `pixel_iterator_traits`. Use `std::iterator_traits`, `PixelBasedConcept` metafunctions or the new metafunctions for pixel iterators.
206- Got rid of the ability to directly access pixels through image, only through views. The image no longer models STL's random access container concept.
207- No more LAB and HSB color space, because there is no color conversion support implemented for these. New color spaces can be added with just a few lines of code.
208
209## [1.x] - 2007-01-03
210
211### Added
212- Restored back the ability to assign a channel to a grayscale pixel.
213
214### Changed
215- Fixed some minor issues with color converted views of dynamic images.
216
217## [1.x] - 2006-11-07
218
219GIL accepted to Boost.
220
221GIL's Boost review was successful and GIL will be part of the Boost libraries.
222It will most likely first appear in the 1.35 version of Boost.
223In the future our web page will continue to provide you with the latest
224improvements to GIL, as we have the flexibility to release more frequently than Boost.
225
226## [1.x] - 2006-10-20
227
228### Added
229- New regression tests.
230- Source code of usage examples is available to download from the website.
231
232### Changed
233- Minor changes to GIL core.
234
235## [1.x] - 2006-10-02
236
237### Added
238- First version of the Numeric extension.
239  The extension provides some basic image processing algorithms, such as convolution and resampling.
240- Introduction of pixel traits.
241
242### Changed
243- Improved consistent use of MPL predicates and standardized template parameter names.
244
245## [1.x] - 2006-09-20
246
247### Added
248- GIL now allows users to overload the default color conversion with one of their own.
249- Section in the design guide describes how to overload default color conversion.
250
251### Changed
252- Color conversion improvements.
253
254## [1.0] - 2006-08-29
255
256### Added
257- Pixel dereference adaptors are introduced.
258- Locator concepts/models are made more generic.
259- Example of creating the Mandelbrot set is described in the tutorial.
260
261### Changed
262- It is now easier to construct virtual image views.
263
264## [] - 2006-06-27
265
266### Added
267- A GIL Flash presentation is posted (aka video lecture).
268
269## [] - 2006-06-14
270
271### Added
272- GIL homepage goes live
273