Improve documentation and manpage. Fix buffer overflow

• Updated documentaion,
• Improved built-in manpage.
• Fixed buffer overflow #115 / CVE-2023-40968

No functional change

tmux-in-Kitty support, integrated manpage, -f/-F filelist

tmux

High resolution image support in tmux (#95). On the Kitty terminal with tmux (>= version 3.3) it is now possible to show images in the terminal multiplexer (works on Kitty 0.28.1, but avoid 0.29.0 due to a bug).

Buldin Manpage

timg --help is now an integrated manpage. This will allow AppImage users to see the documentation without the installed manpage. If you have not looked at the manual page yet, now is a good time to discover it :)

Filelist changes

The file list allows to read image filenames from a file. This is very useful if you want to give timg more filenames on the command line than the shell allows you :). This feature has been around for a while, but it now comes in two flavors that determine how relative paths are treated in these files. A relative path is one that is not originating from the root of the filesytems, e.g. img/foo.jpg. There are two options -f and -F that influence that behavior.

• -f filenames are resolved relative to your current directory. So just like if you invoked timg img/foo.jpg
• -F filenames are resolved relative to the directory the file list is in. So so if you have a file list in some directory and it contains filenames of the form img/foo.jpg, these files will be resolved relative to that directory, not wherever your current shell currently is.

Note, this changed from before: There was no -F option, and -f was behaving like -F is now. But since -F is confusing unless explicitly chosen, this backward incompatible change had to be introduced.

AppImage

And finally: there is an timg AppImage now in the release section to quickly test out new versions (#103). AppImage is a package format that allows to use an application on almost all Linux distributions out-of-the-box.

The AppImage is meant to be small and has not everything compiled in, e.g. it does not contain full video decoding or all image imports that ImageMagick does support (Otherwise, the binary would be more than 100MiB large). But even with that, most common tasks work well (*.png, *.jpg, animated gifs, *.qoi,...) and is a good starting point to decide if you want to install it with your regular distribution package manager; some of them packagae timg regularly.

Sixel support; faster compressed graphical image transfers.

This release adds sixel support, it can be selected with --pixelation=sixel or, short -ps.
The sixel support has been tested with xterm (invoke with option -ti vt340), mlterm, xfce4-terminal (compiled with latest vte that allows for sixels) and alacritty-sixel.

Typically, you'd need to provide the -ps option if you want to test sixel output as auto-detection is currently only supported for xterm and mlterm.

Other than that, some few refinements here and there, faster compression for --pixelation=kitty and --pixelation=iterm2.

QOI image format, better SVG transprency handling

In this maintenance release, the QOI image format has been added.
Also a few bug fixes, such as handling SVG transparency properly.

Fix compilation with latest ffmpeg

No functional updates, just improving compilation with latest ffmpeg.

Title variables; allow stb

• Provide compile-time alternative stb image loading library useful in environments with reduced dependencies.
• Provide place-holder formatting options for title print: %f-filename, %b-basename, %w-image width, %h-image height #67
• Fix compilation issue on OpenBSD #63
• Various small fixes and improvements.

Finer gained cmake selections

No code changes, just more fine-grained cmake choices.

Allow older cmake versions (Maintenance release)

No code changes since 1.4.0, just updates to cmake files (being able to work with older cmake versions) and documentation.

Add OpenSlide support

Thanks to @lromor , we now have OpenSlide support showing the overview of multi-resolution images. This will help biologists and astronomers alike to quickly scan through their imagery.

Usability fix: if multiple files given, only loop animations once

This is mostly fixing a regression that used to work but broke due to a typo.