E440-Scale
E440-Scale
This code is deprecated. It’s functionality has been integrated in Scale Generator
SVG scale artwork and web generator for E440-style round-dial analog panel meters. Scales are typeset in Alte DIN 1451 Mittelschrift.
Repository layout
E440-Scale_template.svg Inkscape working file (case body, tick marks, labels)
E440-Scale_paths.svg Paths-only export — text converted to outlines
E440-Scale_text.svg Live-text export — embedded font, editable labels
fonts/ TTF fonts (required for Docker build)
web/ Flask web generator
k8s/ Kubernetes manifests
Dockerfile Container build
SVG files
The canvas is 93.824249 × 57.215687 mm. The coordinate origin is
offset: layer 1 carries transform="translate(-60.717741,-107.14126)", so
absolute SVG coordinates begin around x=61, y=107.
The dial’s case geometry — body outline, mounting ears, pivot point
(local 107.42845, 162.62819), rim radius (43.842751 mm), and angular
sweep (±45.667° from vertical) — is fixed across every generated scale.
Only the tick marks, numeric labels, unit label, and corner text vary.
| File | Purpose |
|---|---|
E440-Scale_template.svg | Master Inkscape file. Edit this one. |
E440-Scale_paths.svg | All text converted to outlines. Use for cutting plotters, laser engravers, or any workflow where fonts must not be embedded as live text. |
E440-Scale_text.svg | Live <text> nodes with the font embedded as base64. Smaller file; requires an SVG viewer that supports embedded fonts. |
Open files in Inkscape (developed with v1.4.3). There is no build step — edit the SVG directly or use the web generator.
Web generator
A Flask app that generates arc-dial scale SVGs from a form. Supports two output modes switchable in the UI:
- Paths — glyphs rendered as outlines via fontTools; opens cleanly in Inkscape, Illustrator, and cutting software
- Text — live
<text>elements with the selected font embedded as base64
Run locally
source .venv/bin/activate
cd web && python app.py # http://localhost:5000
Fonts are loaded at startup from the fonts/ directory in the repo root.
Form parameters
| Field | Description |
|---|---|
| Unit | Symbol shown centered above the arc (e.g. uA, V, %). Supports inline markup — see below |
| «««< Updated upstream | |
| Left label / Right label | Up to 2 lines each, placed in the bottom-left/bottom-right corners of the dial. Support the same math markup as the unit label |
| Mapping | Linear, √ (square root), Log, or 1/x (reciprocal). Major ticks are always evenly spaced angularly; the mapping controls their values and how minor ticks are placed within each interval. |
| Min / Max | Numeric range of the scale. For reciprocal scales Max may be ∞ (tick the “Max is ∞” box) |
======= | Left label / Right label | Up to 2 lines each, placed in the bottom-left/bottom-right corners of the dial. Support the same inline markup as the unit label | | Mapping | Linear, √ (square root), Log, or 1/x (reciprocal). Major ticks are always evenly spaced angularly; the mapping controls their values and how minor ticks are placed within each interval. | | Min / Max | Numeric range of the scale. Max may be set to ∞ (infinite) for the 1/x mapping |
Stashed changes | Major intervals | Number of major tick intervals | | Minor per interval | Minor ticks between each pair of major ticks. When odd, the exact midpoint subdivision is drawn as a taller “medium” tick, matching the reference dial’s 3-tier tick scheme | | Labels | Number of numeric labels; Labels − 1 should divide evenly into Major intervals | | Custom labels | Optional comma-separated labels that override the calculated numbers | | Label size (mm) | Font size of the numeric labels, in millimetres (default
5.1126) | | Font | Font used for all text, chosen from every.ttfinfonts/(default Alte DIN 1451 Mittelschrift) | | Tick size | Collapsible section — overrides the length and thickness of major, medium, and small ticks (defaults match the hand-drawn files) |
Fonts — numeric labels, the unit label, and the left/right corner labels each have their own font dropdown (default Alte DIN 1451 Mittelschrift). Unit and corner label sizes are independently adjustable; the unit label auto-sizes to fit above the arc unless you set an explicit size.
Ticks — the length and stroke width of each of the three tick tiers (major, medium, small) are configurable in millimetres.
Colour segments — draw one or more concentric coloured arc bands from
value a to value b (e.g. red/green/yellow zone markings). Each segment
can carry its own colour and stroke width; a global thickness and radial
offset set the defaults. Colours must be hex values such as #ff0000.
Scale mappings
| Mapping | Major tick values | Minor tick placement | Constraints |
|---|---|---|---|
| Linear | Evenly spaced | Uniform | None |
| √ | Quadratic (0, 1, 4, 9 … × max) — compresses low values | Crowded toward the high end of each interval | Min ≥ 0 |
| Log | Geometric (min × r⁰, r¹, r² …) — each interval spans the same ratio | Crowded toward the high end of each interval | Min and Max > 0 |
| 1/x | Harmonic (values decrease left → right, e.g. ∞, 10, 5, 2, 1) — compresses high values | Uniform (in angle space, i.e. proportional to 1/v) | Min and Max > 0; Max may be ∞ |
Inline text markup
«««< Updated upstream The Unit, left-label, and right-label fields accept a lightweight shorthand (no LaTeX engine — everything is drawn as glyph paths and auto-sized to fit above the arc):
The Unit and corner-label fields accept a lightweight shorthand (no LaTeX engine — everything is drawn as glyph paths; the unit label auto-sizes to fit above the arc):
Stashed changes
| Markup | Result |
|---|---|
cm^2 | superscript (^{...} for multiple characters) |
H_2O | subscript (_{...} for multiple characters) |
{1/2} | stacked fraction with a horizontal rule; a bare / stays inline |
| «««< Updated upstream | |
[ac] [dc] [acdc] | drawn AC waveform, DC dashed line, or combined symbol |
Constructs nest: {m/s^2} is a fraction with a superscript in the
denominator, x^{1/2} a superscripted fraction, [ac]V an AC voltage
symbol.
Missing glyphs fall back across the bundled fonts (e.g. ∞ and Ω). Deeply
nested markup is rejected as an error.
Testing
The app ships an unittest suite; run it from the web/ directory with the
repo-root venv active:
source .venv/bin/activate
cd web && python -m unittest discover -s tests -v
=======
| [AC], [DC], [ACDC] | vector symbols for AC, DC, and combined AC/DC (case-insensitive) |
Constructs nest: {m/s^2} is a fraction with a superscript in the
denominator, x^{1/2} a superscripted fraction. The same markup applies to
the left/right corner labels, which are rendered as glyph paths.
Stashed changes
Container
docker build -t e440-scale:latest .
docker run -p 5000:5000 e440-scale:latest
Fonts are loaded from fonts/ in the repo root; they are bundled into the
image at build time.
The production image is at git.baumann.gr/adebaumann/e440-generator.
Kubernetes
Manifests in k8s/ deploy to the works namespace with a Traefik v2
IngressRoute at works.baumann.gr/E440-generator.
# Managed by ArgoCD — push to git to deploy
git push
Resources: namespace, deployment (1 replica, gunicorn), ClusterIP service, Traefik IngressRoute + stripPrefix middleware.
License
GPL-3.0 — see LICENSE.