ctx terminal

A UTF-8 vector graphics and audio capable terminal, with support for the ctx vector protocol, itself implemented with ctx, thus able to run in many places using SDL2, on KMS/DRM (linux and openbsd verified), fbdev and other ctx backends. It contains an on-screen keyboard useful on single or multi-touch displays. Fullscreen use is optimized for two 80 column wide terminals side by side on a laptop - the UI is not yet tailored for portrait mode.

The clock in the above screenshot is a shellscript.

The ctx terminal and the core parsers in ctx (and rasterization as driven by it) has been fuzz tested with afl+ for many cycles, and even earlier crude vt specific fuzzing for the terminal uncovered problems also in screen, mlterm, zutty and other terminals.

Exhaustive list of supported escape sequences acts as a refererence for further development and a shorthand cheat-sheet for writing code for the terminal.

VT4xx, ECMA-48
Almost full vt100 and vt220 escape sequence handling, scrollback, like xterm/*, dterm window manipulation (among tabs/clients),*/ bracketed paste, 256 and 24bit colors are supported - and a growing subset of vt420 and other relevant terminal escape sequences.
The 16 ANSI colors are tuned for optimizing color contrast, even with color vision deficiencies.
ctx vector graphics
Using the ctx protocol, by first entering ctx mode with \e[?7020h which creates a new or accesses an existing vector drawing context for the current line.
atty
audio recording and playback (only raw pcm for now, opus codec NYI)
sixels
DEC compatible raster encoding, with 6row high 1bit raster lines * colors used.
kitty graphics
max 4 images per line, no z-ordering - using stb_image for PNG decoding.
iterm2 inline images
iterm2 inline image image protocol in one bulk base64 transfer, using stb_image for image decoding.
mouse xterm
xterm mouse reporting modes - somewhat incomplete
dterm
Most of dterms window management integration.
UTF-8
The terminal uses 7bit control codes, and reserves bytes>127 for use in character data.
vt102 escapes
>100 points on the vttest score card
ECMA-48 colors
The standard defining the 16 colors
ECMA-48 justification
Only implementing wordwrap for now, can be extended with more.
pixel mouse
escape sequence to get pixel coordinates for mouse events
ECMA-48 proportional
Limited predictable proportional rather than monospaced text, for best results render proportional text in a finall pass, starting with left most column.
multiplexed streams
A bi-directional APC interface, used in fullscreen ctx contexts, streams are torn down on session close. Streams are identified by eid and a numberic client assigned id, for file upload eids are announced as streams - and download initied by the terminal on demand. Plans are underway to let this create additional or overlay ctx contexts, as well as audio for mic and speaker, perhaps optionally with mp3 or opus, as well as video.

Missing bits:

hyperlink escape sequence
Drag to select in vim
The final result of the interaction is correct, but intermediate frames are perhaps not queued for draw?
Cursor setting
alt-screen issue
only code 1049 works fully specs compliant, the others leave the cursor in the wrong spot.
vt52 cursor keys
not passing vttest in vt52 mode
audio
should be using opus rather than 8khz 8bit ulaw, and reimplemented on top of new stream transports.
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Historic predecessors for vector or graphics capable terminals include: ReGIS, The MGR Window System and ripscript have provided more graphics rich terminal experiences in the past.