Re-recording the demo

The README opens on a recording of the loop: ank context, ank graph, a claim, the code change, and ank done. It is a function of three scripts in assets/demo/, so a retake is a re-run and not a performance, and it goes stale whenever the output it shows changes.

assets/demo/setup.sh    builds the demo repository the recording is made in
assets/demo/play.sh     what the recording plays, command by command
assets/demo/render.sh   renders the cast to the two images the README shows
assets/demo/demo.cast   the last recording, as asciicast v2

What the scripts expect

They were written for one machine and say so in their first lines, rather than taking arguments:

• the repository checked out at ~/ank, and built with cargo build --release, because both setup.sh and play.sh run ~/ank/target/release/ank;
• ~/demo free: setup.sh deletes and rebuilds it, and writes a throwaway SSH signing key to ~/demo-sign so the ratification in the recording is signed;
• agg on the PATH or in ~/.cargo/bin, and JetBrains Mono in ~/fonts or in the directory ANK_DEMO_FONT_DIR names. render.sh refuses at exit 9 and prints the install command when either is missing, rather than falling back to another font without saying so.

Retaking it

cargo build --release
bash assets/demo/setup.sh
asciinema rec --cols 100 --rows 34 -c "bash assets/demo/play.sh" assets/demo/demo.cast
bash assets/demo/render.sh assets/demo/demo.cast assets

setup.sh ends by printing ank graph and ank context on the fresh demo repository; read them before recording, because they are the state the recording starts from. The cast is recorded at 100 by 34, the size the current one declares. render.sh writes assets/demo.gif in Catppuccin Latte and assets/demo-dark.gif in Mocha, which the README picks between with prefers-color-scheme.

GIF and not SVG, and that was measured. An SVG rendering of a cast animates when the SVG is inlined into a page and not when it is loaded through an <img>, which is the only way a README can embed it, so it showed an empty terminal. play.sh keeps to the eight ANSI colours for the same kind of reason: a 256-colour escape would come out of the terminal’s palette instead of the theme render.sh hands agg.

Commit the cast and both images together, and update the image’s alt text in the README if what the recording shows changed.