Sagitta

Sagitta

A keyboard-driven tikz-cd editor.

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v0.7.1 · GPLv3 · forked from quiver

A commutative diagram of the snake lemma: two exact rows joined by three vertical maps, their kernels and cokernels in sequence, and a connecting morphism snaking through the centre.
The snake lemma, drawn in Sagitta.

Sagitta is a keyboard-driven tikz-cd editor that produces LaTeX-ready diagrams at speed. The syntax of tikz-cd is elegant, but it is not always the fastest to write, the easiest for complex diagrams, or the easiest to tweak afterwards. A hand-drawn diagram is quick and accurate, but it is not reproducible and is nearly impossible to edit after creation. Sagitta aspires to combine the benefits of both.

Type it, get tikz-cd

The keys pressed and the file Sagitta saves.

A pair of morphisms

  1. SPC Create a vertex.
  2. → SPC Move right and create a second vertex, with an arrow to it.
  3. ↓ SPC Move down and create a third, with an arrow to it.
  4. TAB A TAB f TAB B TAB g TAB C TAB cycles through the unlabelled vertices and arrows; type a label for each.
A Sagitta screenshot of A mapping by f to B, and B mapping down by g to C.
A composable pair of morphisms, labelled.
%#q=WzAsMyxbMCwwLCJBIl0sWzEsMCwiQiJdLFsxLDEsIkMiXSxbMCwxLCJmIl0sWzEsMiwiZyJdXQ==
\[\begin{tikzcd}
	A & B \\
	& C
	\arrow["f", from=1-1, to=1-2]
	\arrow["g", from=1-2, to=2-2]
\end{tikzcd}\]
The saved .tikzcd, ready for LaTeX to \input.

Crossing over

  1. SPC → → SPC ESC Create two vertices two cells apart, with an arrow between them, then clear the selection.
  2. ↑ ← SPC ↓ ↓ SPC Create two more above and below the gap, with an arrow down across the first.
  3. / A S RET Select the first arrow by its code, AS.
  4. x Let it cross over the other.
A Sagitta screenshot of four bullets in a cross: a horizontal arrow cuts over a vertical arrow.
One arrow crossing over another.
%#q=WzAsNCxbMCwxLCJcXGJ1bGxldCJdLFsyLDEsIlxcYnVsbGV0Il0sWzEsMCwiXFxidWxsZXQiXSxbMSwyLCJcXGJ1bGxldCJdLFswLDEsIiIsMCx7ImNyb3NzaW5nX292ZXIiOjF9XSxbMiwzXV0=
\[\begin{tikzcd}
	& \bullet \\
	\bullet && \bullet \\
	& \bullet
	\arrow[from=1-2, to=3-2]
	\arrow[crossing over, from=2-1, to=2-3]
\end{tikzcd}\]
The saved .tikzcd, ready for LaTeX to \input.

Smiley face

  1. SPC → SPC Create two vertices, with an arrow between them.
  2. / A S RET Select the arrow by its code, AS.
  3. ← ↓ k Add the cell below the source to the arrow’s route as a checkpoint.
  4. → k Add the cell below the target.
  5. b 8 RET Set the curve radius to maximum.
A Sagitta screenshot of two bullets side by side, the arrow between them routed down below them in a U and back up.
An arrow routed down and back up.
%#q=WzAsMixbMCwwLCJcXGJ1bGxldCJdLFsxLDAsIlxcYnVsbGV0Il0sWzAsMSwiIiwwLHsicm91dGUiOltbMCwxXSxbMSwxXV0sInJvdW5kaW5nIjo4fV1d
\[\begin{tikzcd}[execute at empty cell={\node[name=\tikzmatrixname-\the\pgfmatrixcurrentrow-\the\pgfmatrixcurrentcolumn, inner sep=0pt]{};}]
	\bullet & \bullet \\
	&
	\arrow[to path={[rounded corners=16pt] -- (\tikzcdmatrixname-2-1.center) -- (\tikzcdmatrixname-2-2.center) \tikztonodes -- (\tikztotarget) [sharp corners]}, from=1-1, to=1-2]
\end{tikzcd}\]
The saved .tikzcd, ready for LaTeX to \input.

Full walkthrough: the snake lemma →

Two modes

Sagitta supports the alternative spreadsheet mode. By default, with spreadsheet mode off, bare keys execute the commands associated with them, and ; opens the command menu. Label editing requires first pressing RET.

In spreadsheet mode, typing most keys drops directly into label editing. Pressing ; enables commands and shows the command menu after a short delay. If the first character you want is otherwise bound, such as ;, you must still first press RET.

The command line : and search / function the same in both modes.

Get it

Platform Package Notes
Linux AppImage I use this one!
Windows Installer or portable .exe Tested by my friends.
Browser Webpage No install, friendly for macOS.

In the browser, Sagitta needs HTTPS to open and save files and folders. Chromium opens and saves a file in place; Firefox reads a copy and saves by downloading one. Settings and the keybindings live in the browser’s storage. Keys the browser reserves are unavailable, so a new diagram is :new rather than C-n.

Notes

Expect major changes until v1.0.0.

Sagitta is a fork of varkor’s quiver and opens quiver #q= links. The #q= links Sagitta produces are mostly compatible with quiver, save for some constructions like checkpoint arrows and crossings. Many thanks to varkor for giving the world quiver.

For the story of how Sagitta came to be, check out my blog!