- * 'java -cp jexer.jar jexer.demos.Demo6' . This demonstrates two
- applications performing I/O across three screens: an xterm screen
- and Swing screen, monitored from a third Swing screen.
-
-
-
-More Screenshots
-----------------
-
-![Several Windows Open Including A Terminal](/screenshots/screenshot1.png?raw=true "Several Windows Open Including A Terminal")
-
-![Yo Dawg...](/screenshots/yodawg.png?raw=true "Yo Dawg, I heard you like text windowing systems, so I ran a text windowing system inside your text windowing system so you can have a terminal in your terminal.")
-
-![Sixel Pictures Of Cliffs Of Moher And Buoy](/screenshots/sixel_images.png?raw=true "Sixel Pictures Of Cliffs Of Moher And Buoy")
-
-![Sixel Color Wheel](/screenshots/sixel_color_wheel.png?raw=true "Sixel Color Wheel")
-
-
-Terminal Support
-----------------
-
-The table below lists terminals tested against Jexer's ECMA48/Xterm
-backend.
-
-| Terminal | Environment | Mouse Click | Mouse Cursor | Images |
-| -------------- | ------------------ | ----------- | ------------ | ------ |
-| xterm | X11 | yes | yes | yes |
-| lcxterm(3) | CLI, Linux console | yes | yes | no |
-| rxvt-unicode | X11 | yes | yes | no |
-| alacritty(3) | X11 | yes | yes | no |
-| gnome-terminal | X11 | yes | yes | no |
-| xfce4-terminal | X11 | yes | yes | no |
-| aminal(3) | X11 | yes | no | no |
-| konsole | X11 | yes | no | no |
-| yakuake | X11 | yes | no | no |
-| screen | CLI | no(1) | no | no(2) |
-| tmux | CLI | no(1) | no | no |
-| putty | X11, Windows | yes | no | no(2) |
-| Linux | Linux console | no | no | no(2) |
-| qodem(3) | CLI, Linux console | yes | yes(4) | no |
-| qodem-x11(3) | X11 | yes | no | no |
-
-1 - Passes mouse to its host console, so will support mouse if the
-host console does.
-
-2 - Also fails to filter out sixel data, leaving garbage on screen.
-
-3 - Latest in repository.
-
-4 - Requires TERM=xterm-1003 before starting.
-
-
-
-System Properties
------------------
-
-The following properties control features of Jexer:
-
- jexer.Swing
- -----------
-
- Used only by jexer.demos.Demo1 and jexer.demos.Demo4. If true, use
- the Swing interface for the demo application. Default: true on
- Windows (os.name starts with "Windows") and Mac (os.name starts with
- "Mac"), false on non-Windows and non-Mac platforms.
-
- jexer.Swing.cursorStyle
- -----------------------
-
- Used by jexer.backend.SwingTerminal. Selects the cursor style to
- draw. Valid values are: underline, block, outline. Default:
- underline.
-
- jexer.Swing.tripleBuffer
- ------------------------
-
- Used by jexer.backend.SwingTerminal. If true, use triple-buffering
- which reduces screen tearing but may also be slower to draw on
- slower systems. If false, use naive Swing thread drawing, which may
- be faster on slower systems but also more likely to have screen
- tearing. Default: true.
-
- jexer.TTerminal.ptypipe
- -----------------------
-
- Used by jexer.TTerminalWindow. If true, spawn shell using the
- 'ptypipe' utility rather than 'script'. This permits terminals to
- resize with the window. ptypipe is a separate C language utility,
- available at https://gitlab.com/klamonte/ptypipe. Default: false.
-
- jexer.TTerminal.closeOnExit
- ---------------------------
-
- Used by jexer.TTerminalWindow. If true, close the window when the
- spawned shell exits. Default: false.
-
- jexer.ECMA48.rgbColor
- ---------------------
-
- Used by jexer.backend.ECMA48Terminal. If true, emit T.416-style RGB
- colors for normal system colors. This is expensive in bandwidth,
- and potentially terrible looking for non-xterms. Default: false.
-
- jexer.ECMA48.sixel
- ------------------
-
- Used by jexer.backend.ECMA48Terminal. If true, emit image data
- using sixel, otherwise show blank cells where images could be. This
- is expensive in bandwidth, very expensive in CPU (especially for
- large images), and will leave artifacts on the screen if the
- terminal does not support sixel. Default: true.
-
-
-
-Known Issues / Arbitrary Decisions
-----------------------------------
-
-Some arbitrary design decisions had to be made when either the
-obviously expected behavior did not happen or when a specification was
-ambiguous. This section describes such issues.
-
- - See jexer.tterminal.ECMA48 for more specifics of terminal
- emulation limitations.
-
- - TTerminalWindow uses cmd.exe on Windows. Output will not be seen
- until enter is pressed, due to cmd.exe's use of line-oriented
- input (see the ENABLE_LINE_INPUT flag for GetConsoleMode() and
- SetConsoleMode()).
-
- - TTerminalWindow by default launches 'script -fqe /dev/null' or
- 'script -q -F /dev/null' on non-Windows platforms. This is a
- workaround for the C library behavior of checking for a tty:
- script launches $SHELL in a pseudo-tty. This works on Linux and
- Mac but might not on other Posix-y platforms.
-
- - Closing a TTerminalWindow without exiting the process inside it
- may result in a zombie 'script' process.
-
- - When using the Swing backend, and not using 'ptypipe', closing a
- TTerminalWindow without exiting the process inside it may result
- in a SIGTERM to the JVM causing it to crash. The root cause is
- currently unknown, but is potentially a bug in more recent
- releases of the 'script' utility from the util-linux package.
-
- - TTerminalWindow can only notify the child process of changes in
- window size if using the 'ptypipe' utility, due to Java's lack of
- support for forkpty() and similar. ptypipe is available at
- https://gitlab.com/klamonte/ptypipe.
-
- - Java's InputStreamReader as used by the ECMA48 backend requires a
- valid UTF-8 stream. The default X10 encoding for mouse
- coordinates outside (160,94) can corrupt that stream, at best
- putting garbage keyboard events in the input queue but at worst
- causing the backend reader thread to throw an Exception and exit
- and make the entire UI unusable. Mouse support therefore requires
- a terminal that can deliver either UTF-8 coordinates (1005 mode)
- or SGR coordinates (1006 mode). Most modern terminals can do
- this.
-
- - jexer.session.TTYSession calls 'stty size' once every second to
- check the current window size, performing the same function as
- ioctl(TIOCGWINSZ) but without requiring a native library.
-
- - jexer.backend.ECMA48Terminal calls 'stty' to perform the
- equivalent of cfmakeraw() when using System.in/out. System.out is
- also (blindly!) put in 'stty sane cooked' mode when exiting.
-
- - jexer.backend.ECMA48Terminal uses a single palette containing
- MAX_COLOR_REGISTERS colors for all sixel images. These colors are
- generated in the SixelPalette.makePalette() method with bits for
- hue, saturation, and luminance, and the two extremes set to pure
- black and pure white. This provides a reasonable general-purpose
- palette light on CPU, but at a cost that individual images do not
- look as good as the terminal is actually capable of.
-
-
-
-See Also
---------
-
-[Tranquil Java IDE](https://tjide.sourceforge.io) is a TUI-based
-integrated development environment for the Java language that was
-built using a very lightly modified GPL version of Jexer. TJ provided
-a real-world use case to shake out numerous bugs and limitations of
-Jexer.
-
-
-
-Maintainers Wanted
-------------------
-
-Both Jexer and TJIDE are seeking additional maintainers. I am not in
-a position in life to take on significant off-hours programming work,
-and am willing to hand these projects over to one or more persons with
-time and interest.
-
-My personal code design philosophy for TJIDE/Jexer is outlined at
-https://gitlab.com/klamonte/tjide/blob/master/java/docs/code_design.txt
-. I realize that some of the features listed below may require
-deviations from this philosophy, but this is what I have built so far.
-
-Some of the areas that will likely require significant efforts are:
-
- * Editor improvements. The editor is currently very minimalistic,
- much closer to MS-DOS edit.com than a real programmer's editor.
- Users will probably desire many more features: drag-and-drop, real
- syntax or at least regexp highlighting (not just keywords), paren
- matching, paragraph/comment reflow, and dozens more. The
- underlying Document/Line/Word model is not going to be sufficient
- to meet these features.
-
- * Better Windows and OSX support. It would be nice to ship a
- jlink'ed JVM on these platforms with the JRE, JDK, and JPDA
- modules all together. For Windows, it might be preferable to
- consider doing any of the following: ship a third-party terminal,
- use PowerShell, or use the newer ConPTY for TTerminalWindow.
-
- * Bug fixes. The Jexer codebase is quite large despite my best
- efforts. Bugs are typically very small to fix, but can take some
- time to find: a simple NPE or AssertionError can sometimes take
- 4-8 hours to squash. Fortunately, fixing issues in one place has
- not often led to breakages elsewhere.
-
- * New Jexer applications. So far as I know, Jexer is the only
- mouse-supporting full TUI windowing framework with sixel image
- support in existence. I cannot predict what kinds of applications
- could be built out of it, and how those needs will push back to
- the framework.
-
-These are what I can clearly see right now. Obviously users are
-capable of finding many more.
-
-I intend to continue poking on Jexer and TJIDE, and will maintain a
-branch to be "the fastest and simplest Java language IDE available",
-which will deliberately remain small.
-
-I hope that other languages choose to transliterate Jexer to provide
-TUIs to their own platforms. I will be happy to help them understand
-the code to support those efforts.