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Fletcher (noun) a maker of arrows

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

#import "@preview/fletcher:0.4.1" 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-->")
$)

// https://xkcd.com/1195/
#import fletcher.shapes: diamond
#set text(font: "Comic Neue", weight: 600)

#fletcher.diagram( 
  edge-stroke: 1pt,
  node((0,0), [Start], corner-radius: 2pt, extrude: (0, 3)),
  edge("-|>"),
  node((0,1), align(center)[
    Hey, wait,\ this flowchart\ is a trap!
  ], shape: diamond),
  edge("d,r,u,l", "-|>", [Yes], label-pos: 0.1)
)

#fletcher.diagram(
  node-stroke: .1em,
  node-fill: gradient.radial(blue.lighten(80%), blue, center: (30%, 20%), radius: 80%),
  spacing: 4em,
  edge((-1,0), "r", "-|>", `open(path)`, label-pos: 0, label-side: center),
  node((0,0), `reading`, radius: 2em),
  edge(`read()`, "-|>"),
  node((1,0), `eof`, radius: 2em),
  edge(`close()`, "-|>"),
  node((2,0), `closed`, radius: 2em, extrude: (-2.5, 0)),
  edge((0,0), (0,0), `read()`, "--|>", bend: 130deg),
  edge((0,0), (2,0), `close()`, "-|>", bend: -40deg),
)

Todo/wishlist

  • [x] Mathematical arrow styles
  • [x] Also allow &-delimited equations for specifying nodes
  • [ ] Support CeTZ arrowheads
  • [x] 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?
  • [x] Poly-edges with multiple segments
  • [ ] Add way to adjust edge connection points while still having them snap to node edges
  • [ ] Zig-zags and waves

Change log

0.4.1

  • Support custom node shapes! Edges connect to node outlines automatically.
    • New shapes submodule, containing diamond, pill, parallelogram, hexagon, and other node shapes.
  • Allow edges to have multiple segments.
    • Add vertices an corner-radius options to edge().
    • Relative coordinate shorthands may be comma separated to signify multiple segments, e.g., "r,u,ll".
  • Add dodge option to edge() to adjust end points.
  • Support cetz:0.2.0.

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).