Fletcher (noun) a maker of arrows

A Typst package for drawing diagrams with arrows, built on top of CeTZ.

#import "@preview/fletcher:0.4.0" as fletcher: node, edge


#fletcher.diagram(cell-size: 15mm, $
	G edge(f, ->) edge("d", pi, ->>) & im(f) \
	G slash ker(f) edge("ur", tilde(f), "hook-->")
$)


#fletcher.diagram(
	node-fill: rgb("aafa"),
	node-outset: 2pt,
	axes: (ltr, btt),

	node((0,0), `typst`),
	node((1,0), "A"),
	node((2.5,0), "B", stroke: c + 2pt),
	node((2,1), "C", extrude: (+1, -1)),

	for i in range(3) {
		edge((0,0), (1,0), bend: (i - 1)*25deg)
	},
	edge((1,0), (2,1), "..}>", corner: right),
	edge((1,0), (2.5,0), "-||-|>", bend: -0deg),
),

Todo

• [x] Mathematical arrow styles
• [x] Also allow &-delimited equations for specifying nodes
• [ ] Support CeTZ arrowheads
• [ ] Support arbitrary node shapes drawn with CeTZ
• [ ] Allow referring to node coordinates by their content?
• [ ] Support loops connecting a node to itself
• [x] More ergonomic syntax to avoid repeating coordinates?

Change log

0.4.0

• Add ability to specify diagrams in math-mode, using & to separate nodes.
• Allow implicit and relative edge coordinates, e.g., edge("d") becomes edge(prev-node, (0, 1)).
• Add ability to place marks anywhere along an edge. Shorthands now accept an optional middle mark, for example |->-| and hook-/->>.
• Add “hanging tail” correction to marks on curved edges. Marks now rotate a bit to fit more comfortably along tightly curving arcs.
• Add more arrowheads for the sake of it: }>, <{, /, \, x, X, * (solid dot), @ (solid circle).
• Add axes option to diagram() to control the direction of each axis in the diagram’s coordinate system.
• Add width, height and radius options to node() for explicit control over size.
• Add corner-radius option to node().
• Add stroke option to edge() replacing thickness and paint options.
• Add edge-stroke option to diagram() replacing edge-thickness.

0.3.0

• Make round-style arrow heads better approximate the default math font.
• Add solid arrow heads with shorthand <|-, -|> and double-bar ||-, -||.
• Add an extrude option to node() which duplicates and extrudes the node’s stroke, enabling double stroke effects.

0.2.0

• Experimental support for customising arrowheads.
• Add right-angled edges with edge(..., corner: left/right).