fltk/README.bundled-libs.txt

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README.bundled-libs.txt - Developer information for bundled libraries
---------------------------------------------------------------------
This file is mainly intended for FLTK developers and contains information
about the current versions of all bundled libraries and about how to
upgrade these bundled libraries.
Starting with FLTK 1.4.0 the bundled libraries jpeg, png, and zlib use
"symbol prefixing" with the prefix 'fltk_' for all external symbols to
distinguish the bundled libraries from existing system libraries and
to avoid runtime errors.
User code compiled correctly with the header files provided by the
bundled image libraries need not be changed.
The nanosvg library is not affected.
Current versions of bundled libraries (as of Sep 13, 2021):
Library Version Release date FLTK Version
--------------------------------------------------------------------------
jpeg jpeg-9d 2020-01-12 1.4.0
nanosvg 06a9113e29 [1] 2022-07-09 1.4.0
png libpng-1.6.37 2019-04-14 1.4.0
zlib zlib-1.2.11 2017-01-15 1.4.0
--------------------------------------------------------------------------
Previous versions of bundled libraries (FLTK 1.3.x):
Library Version Release date FLTK Version
------------------------------------------------------------------
jpeg jpeg-9d 2020-01-12 1.3.6 - 1.3.8
png libpng-1.6.37 2019-04-14 1.3.6 - 1.3.8
zlib zlib-1.2.11 2017-01-15 1.3.6 - 1.3.8
--------------------------------------------------------------------------
[1] Git commit in branch 'fltk' of https://github.com/fltk/nanosvg
See also git tag 'fltk_yyyy-mm-dd' where yyyy-mm-dd == "Release date"
and file nanosvg/README.txt.
General information:
FLTK does not include the entire library distributions. We only provide the
source files necessary to build the FLTK library and some README and/or
CHANGELOG files. There are no test programs or other contributed files.
We use our own build files, hence a few files MUST NOT be upgraded when
the library source files are upgraded. We strive to keep changes to the
library source files as small as possible. Patching library code to
work with FLTK should be a rare exception. Symbol prefixing with prefix
'fltk_' is one such exception to the rule.
If patches are necessary all changes in the library files should be
marked with "FLTK" in a comment so a developer who upgrades the library
later is aware of changes in the source code for FLTK. Look for 'FLTK'
and/or 'fltk_' to find the differences.
Additional comments should be added to show the rationale, i.e. why
a particular change was necessary. If applicable, add a reference to
a Software Trouble Report, GitHub Issue or Pull Request (PR) like
"STR 3456", "Issue #123", or "PR #234".
How to update the bundled libraries:
It is generally advisable to use a graphical merge program. I'm using
'meld' under Linux, but YMMV.
Do not add any source files unless they are required to build the library.
Some config header files may be pre-generated in the FLTK sources. These
header files should be left untouched, but it may be necessary to update
these files if new items were added to the new library version. In this
case the new header should be pre-generated on a Linux system with default
options unless otherwise mentioned below for a specific library.
Currently there are no known exceptions.
Merging source files:
Please check if some source and header files contain "FLTK" comments
and/or 'fltk_' symbol prefixing to be aware of necessary merges.
It is also good to download the distribution tar ball or Git source
files of the previous version and to run a (graphical) diff or merge
tool on the previous version and the bundled version of FLTK to see
the "previous" differences.
Files that were not patched in previous versions should be copied to
the new version w/o changes. Files that had FLTK specific patches must
be merged manually. FLTK patches should be verified (if still necessary)
and should be kept in the new source files.
Source and header files that have been added in the new library version
should be added in FLTK as well if they are necessary to build the
library. A simple "trial and error" should be sufficient to find files
that need to be added. Added files must be added to FLTK's build files
as well, usually to both `Makefile' and `CMakeLists.txt' to be used in
configure/make and in CMake based builds, respectively.
Upgrade order:
There is only one dependency between all bundled libraries: libpng
depends on zlib. Hence zlib should be upgraded first, then all other
libs can be upgraded in arbitrary order.
Tests after merge:
Tests should be done on as many platforms as possible, both with
autotools (configure/make) and CMake. Windows (Visual Studio) and
macOS (Xcode) builds need CMake to generate the IDE files.
Upgrade notes for specific libraries:
The following chapters contain informations about specific files and
how they are upgraded. Since the changes in all bundled libraries are
not known in advance this information may change in the future. Please
verify that no other changes are necessary.
zlib:
Website: https://zlib.net/
Download: See website and follow links.
Repository: git clone https://github.com/madler/zlib.git
zlib should be upgraded first because libpng depends on zlib.
Download the latest zlib sources, `cd' to /path-to/zlib and run
$ ./configure --zprefix
This creates the header file 'zconf.h' with definitions to enable
the standard 'z_' symbol prefix.
Unfortunately zlib requires patching some source and header files to
convert this 'z_' prefix to 'fltk_z_' to be more specific. As of this
writing (Nov. 2021) three files need symbol prefix patches:
- gzread.c
- zconf.h
- zlib.h
You may want to compare these files and/or the previous version to
find out which changes are required. The general rule is to change
all occurrences of 'z_' to 'fltk_z_' but there *are* exceptions.
The following files need special handling:
CMakeLists.txt: Keep FLTK version, update manually if necessary.
Makefile: Same as CMakeLists.txt.
gzread.c: Merge changes (see above, manual merge recommended).
zconf.h: Merge changes (see above, manual merge recommended).
zlib.h: Merge changes (see above, manual merge recommended).
makedepend: Keep this file.
Run `make depend' in the zlib folder on a Linux system after
the upgrade to update this file.
png:
Website: http://libpng.org/pub/png/libpng.html
Download: See website and follow links.
Repository: git clone https://git.code.sf.net/p/libpng/code libpng
libpng should be upgraded after zlib because it depends on zlib.
Download the latest libpng sources, `cd' to /path-to/libpng and run
$ ./configure --with-libpng-prefix=fltk_
This creates the header files 'pnglibconf.h' and 'pngprefix.h'
with the 'fltk_' symbol prefix.
The following files need special handling:
CMakeLists.txt: Keep FLTK version, update manually if necessary.
Makefile: Same as CMakeLists.txt.
pnglibconf.h: Generate on a Linux system and merge (see above).
pngprefix.h: Generate on a Linux system and merge (see above).
makedepend: Keep this file.
Run `make depend' in the png folder on a Linux system after
the upgrade to update this file.
jpeg:
Website: https://ijg.org/
Download: See website and follow links.
Repository: <unknown>
Download the latest jpeg-xy sources on a Linux (or Unix) system,
`cd' to /path-to/jpeg-xy and run
$ ./configure
$ make [-jN]
This builds the library and should create the static library file
'.libs/libjpeg.a'.
Execute the following command to extract the libjpeg symbol names
used to build the 'prefixed' libfltk_jpeg library:
$ nm --extern-only --defined-only .libs/libjpeg.a | awk '{print $3}' \
| sed '/^$/d' | sort -u | awk '{print "#define "$1" fltk_"$1}' \
> fltk_jpeg_prefix.h
This creates the header file 'fltk_jpeg_prefix.h' with the
'#define' statements using the 'fltk_' symbol prefix.
The following files need special handling:
CMakeLists.txt: Keep FLTK version, update manually if necessary.
Makefile: Same as CMakeLists.txt.
fltk_jpeg_prefix.h: Generate on a Linux system and merge (see above).
Note: more to come...
makedepend: Keep this file.
Run `make depend' in the jpeg folder on a Linux system after
the upgrade to update this file.
nanosvg:
Website: https://github.com/memononen/nanosvg
Download: See website and follow links.
Repository: git clone https://github.com/memononen/nanosvg.git
FLTK Fork: git clone https://github.com/fltk/nanosvg.git
FLTK has its own GitHub fork of the original repository (see above).
The intention is to update this fork from time to time so the FLTK
specific patches are up-to-date with the original library. Hopefully
the FLTK patches will be accepted upstream at some time in the future
so we no longer need our own patches.
AlbrechtS, 04 Feb 2018.
Update (Feb 22, 2021): The upstream library is officially no longer
maintained (see README.md) although updates appear from time to time.
Use this fork (branch 'fltk') to get the nanosvg library with FLTK
specific patches:
$ git clone https://github.com/fltk/nanosvg.git nanosvg-fltk
$ cd nanosvg-fltk
$ git checkout fltk
$ cd src
$ cp nanosvg.h nanosvgrast.h /path/to/fltk-1.4/nanosvg/
This library does not have its own build files since it is a header-only
library. The headers are included in FLTK where necessary.
The following files need special handling:
nanosvg.h: Merge or download from FLTK's fork (see above).
nanosvgrast.h: Merge or download from FLTK's fork (see above).
Maintaining branch 'fltk' in FLTK's fork of nanosvg (fltk/nanosvg):
Only maintainers with write access on fltk/nanosvg can do this.
Others can fork our fltk/nanosvg fork in their own GitHub account
and either open a PR on fltk/nanosvg or tell us about their
changes in fltk.development.
Use something similar to the following commands to update FLTK's
fork of nanosvg to the latest version. Commands are only examples,
you may need to change more or less, depending on the outstanding
updates.
Step 1: clone the fltk/nanosvg fork, set the remote 'upstream',
and update the 'master' branch:
$ cd /to/your/dev/dir
$ git clone https://github.com/fltk/nanosvg.git nanosvg-fltk
$ cd nanosvg-fltk
$ git remote add upstream https://github.com/memononen/nanosvg
$ git checkout master
$ git pull upstream master
Note: the 'master' branch must never be changed, i.e. it must
always be the same as 'upstream/master'. Never commit your own
(FLTK specific) changes to branch 'master'.
Step 2: rebase branch 'fltk' on the new master (upstream/master),
fix potential conflicts, and tag the new branch.
It is important to keep the individual FLTK specific patches intact
(one commit per patch) because this will preserve the history and
the committer and make it easier to skip single patches when they
are accepted upstream.
$ git checkout fltk
$ git rebase upstream/master
At this point you may need to fix conflicts! Do whatever is
necessary to update the branch 'fltk'.
Now `git tag' the 'fltk' branch for later reference.
Hint: use `git show <any-older-tag-name>' to see its contents.
I like to write a summary of commits in the tag comment.
$ git tag -a fltk_yyyy-mm-dd fltk
Replace 'yyyy-mm-dd' with the current date and add a comment
when asked for it (your editor will open an empty file).
Step 3: at this point it is recommended to copy the changed
header files to your working copy of the FLTK library and test
the changes. If anything is wrong, go back, fix the bugs
and change the git tag (delete and create a new one).
Step 4: push the new branch 'fltk' and the tag to the fltk/nanosvg
repository:
$ git push -f origin fltk
$ git push origin fltk_yyyy-mm-dd
Step 5: copy the changed files to your working copy of the FLTK
repository (if not done already), update this file accordingly,
and commit/push the update to the fltk/fltk repository.