Complex Map Workbench

Live: https://alarion239.github.io/complex-map-workbench/

The guided tour will be reworked in the next major version (v17): clearer captions, highlights that show the part of the screen each step changes, and an auto-advance that works while you keep moving. The plan for the next versions, with the usability audit behind it, is in ROADMAP.md.

New in v16.5 (27 October 2026):

• Snapping and railing of points: points snap to points and handles, zeros and poles, crossings, curves (the unit circle and the axes included) and the grid. A point placed on a curve rides it when dragged; pull it hard to free it (Alt places freely on a laptop).
• Two points on one circle are no longer refused as "needs distinct points": picks are compared by where they are.
• Phone: Undo in every sheet and in the deformation bar, and Android Back closes the open sheet instead of leaving the app.
• ⌘K finds everything: commands, tools, examples and help, by everyday words ("dark", "png", "help", "zero").
• The first-run invitation to the tour is one line in the tour's strip, not a card over the planes.
• Messages cover nothing: legends and one-time notes sit in the plane's title row, and messages never land on controls.

An interactive workbench for complex analysis. Draw regions and curves in the z-plane, chain complex functions, and see what they do:

• X → Y: your shapes on the left (plane or Riemann sphere), their exact images on the right. Images are computed per pixel by running the chain backwards through every branch (z^i of the upper half-plane is the exact annulus e^−π < |w| < 1; log of the half-plane reaches the window edges at any zoom), with a sphere-mesh fallback for maps that cannot be inverted.
• Phase and Landscape: full-width phase portraits and 3D landscapes of the chain. Landscape walls stay closed wherever |F| is continuous, however steep, and break only at real discontinuities (cuts and sheet seams); All sheets tints each sheet so you can tell them apart.
• Phase colours (the colour disc in the bar): the workbench's hue wheel, or one of the color functions of Fredrik Johansson's Arb (Arb, gold and blue, the blend, chrome, warm, cold, tomato). One setting for every view, its keys and the figure export.
• The function chain: each step is a card with a picture that follows the open view; the Inspector edits the selected step (with large Add zero / Add pole buttons for a zeros-and-poles step), and the F tile holds the formula of F, its guarantees and its domain. Right-click a shape, a zero or a pole (or hold it on a phone) for its menu; a right-click while drawing cancels the drawing, and a double-click centres the view.
• Shared numbers: type Re z = a and a slider for a appears; every field can use it, and the formulas keep its name (F(z) = z + c, not z + 0.25), so a slider moves the picture and leaves the formula as it is. Copy link and scene files hand the whole figure on.
• Typed formulas (LaTeX or plain) are recognized as the catalog steps they are made of, so \sin(z^2+1) runs as fast as the catalog and is offered as its steps (z ↦ z² ↦ z²+1 ↦ sin(z²+1)) in one click; in the search, sin z is the Sine step.
• Deformation: a toggle that morphs every view along natural homotopies from z to F(z) (analytic at every moment, on F's own branches), one step after another or all at once, with live paths t ↦ H_t(z) that can be switched off. A bracket over the chain cards chooses which steps deform: the steps before it act first and the steps after it act last, so you can watch f(z) become f(√z) (a pullback) or push an image you already have forward.
• Zeros and poles: a step a·∏(z − z_k)/∏(z − p_j) whose zeros (dots) and poles (crosses) you drag in the plane.
• Constructions: circles through 3 points, lines through 2, intersections, midpoints, bisectors, circles perpendicular to a line or circle (hyperbolic lines in the disk and half-plane; "Inside" keeps only the arc inside the circle) and touching circles and tangents, built from any point on the page (points, shape corners, zeros and poles, crossings of curves); they follow what they are built on.
• Equation curves (Re z = 0, |z − 1| = 2, …), targets and their preimages, integrals along closed curves, and guarantees (analytic, injective, …) that are only lit when they are proven.
• Figure export (⌘E): article-grade PDF, SVG and PNG for every view, with presets for articles (one or two columns) and homework, black-and-white versions, LaTeX snippets for Overleaf, images for Docs, deformation filmstrips for every view, and MP4/WebM videos of the deformation.
• Sound: small struck, plucked and blown interface and event cues (on by default after the first click), and an optional "hear the function": a phase harp plucks a note each time arg F under the pointer crosses one of five phase lines (a rising scale round a zero, a falling one round a pole; the low Ds count the winding number), also while the deformation plays; a closed curve sings its winding number as one note. The example "In the Hall of the Mountain King" plays Grieg's theme (public domain) along one spiral under z^(−2+24i).
• Guided tour from the Help button, suggested once on first opening: a docked strip that never covers the planes, lights the exact control each step needs and moves on by itself about 3 s after you do the task. A chapter plays the Grieg example and explains how a curve becomes a melody.
• Russian and Italian: the interface follows the browser's language (or the globe button), with Russian notation (tg, sh, ch, …) and Russian or Italian figure captions (decimal comma in both).

Build

The app is a single HTML file built from src/:

python3 build.py

build.py joins the files of src/ in a fixed order into one <script>. app.js and gl.js are kept as ordered parts: src/app/ and src/gl/ hold a wrap.js (the closure's first and last lines) and the parts NN-subject.js, which take the place of its // @parts line in file name order (tools/src_parts.py; test/src_text.js joins them the same way for the tests).

This writes dist/complex-map-workbench.html (the published page, test hooks stripped) and dist/test.html (with test hooks). The live page is published by GitHub Pages from CI (.github/workflows/pages.yml): pushing a release tag (git tag v16.6 && git push origin v16.6) builds it and deploys it; Actions > Pages > Run workflow does the same by hand. The build reads and writes UTF-8 with LF line endings on every platform (Windows included). The Italian table is tools/it_table.json; after editing it, run python3 tools/make_it_table.py (it writes src/i18n_it.js and reports strings the Russian table has and it lacks).

Tests

• Unit tests (Node): node test/t_inverse.js (and the other test/t_*.js).
• GPU and app checks run in headless Chrome through test/cdp_kit (see its README); on Windows they use ANGLE's Direct3D 11 back end (what Chrome uses there), as do both regression suites.
• Regression suites in test/regress/ (see its README): image quality against exact mathematical ground truth, and a paired performance gate against a reference build.
• CI (ci/README.md): the whole gate runs on GitHub Actions for every pull request and push to main, on Linux, Windows and macOS, split into short jobs; the real-GPU part runs on our own Windows laptop and Mac (ci/RUNNERS.md).

Design notes

notes/ holds the specifications and reviews the app was built from: the renderer (notes/sphere-design/SPEC.md), the UI (notes/ui-design/), the curve engine (notes/curves-design.md) and the backlog (notes/UI_BACKLOG.md).