Tracer

Vectorizes logos, icons and flat-color illustrations: a bitmap image in, a clean SVG out — few nodes, true circles, true straight lines, gradients preserved.

Native macOS app (SwiftUI), no external dependencies. The interface is in French.

What it does

• Color layers — the image is split into colors (k-means in Lab space). Bands of the same gradient are detected and merged, so you can ask for more colors than needed without breaking a gradient apart.
• Sub-pixel outlines — every edge is placed from the pixel's actual coverage (its blended color, or its alpha), not snapped to the pixel grid.
• Pared-down curves — straight lines are detected, circles come out exact (4 Béziers), sharp corners are rebuilt, and the rest is fitted with Schneider's algorithm within a tolerance you set.
• Gradients — each layer gets a flat fill or a linear gradient fitted to its pixels.
• Stacked layers — a shape runs under whatever sits on top of it: no hairline gap between two colors, no needless hole (a disc stays a disc under its letter).
• Checking — four views, Original, Vecteur (vector), Contours (paths and anchor points over the original) and Écart (error map), with the mean error as a number.
• Exports — SVG, PNG from 1024 to 4096 px, and a complete favicon set (favicon.ico 16/32/48, PNGs, apple-touch-icon, 192/512 and maskable icons, site.webmanifest).

Install

Download

Get Tracer-x.y.z.zip from the Releases, unzip it and drag Tracer.app into Applications. macOS 14 or later, Apple Silicon or Intel.

The app is not notarized by Apple, so macOS blocks it on first launch. Open System Settings › Privacy & Security and click Open Anyway (or, in Terminal: xattr -dr com.apple.quarantine /Applications/Tracer.app).

Build

You need Xcode (or the Command Line Tools with Swift 6) and macOS 14 or later.

./scripts/build-app.sh            # builds and installs ~/Applications/Tracer.app
./scripts/build-app.sh /Applications
UNIVERSAL=1 ./scripts/build-app.sh  # Apple Silicon + Intel binary

The build folder lives in ~/Library/Caches/TracerBuild: when the Desktop or Documents folder is synced with iCloud, codesign rejects the attributes iCloud adds to files.

Use

1. Drop an image into the window (or ⌘O, or "Open With…" in the Finder).
2. Adjust Couleurs (colors) and Précision (precision): the result updates live.
3. Hide a layer with the eye button (typically the white background) — the choice is kept when you change the settings.
4. Export: ⌘E for the SVG, ⇧⌘E for the favicons, or the Exporter menu.

Known limitations

Tracer is built for flat colors and linear gradients. It does not model complex shading (folds, drop shadows, textures): these are approximated with a linear gradient. Very small details (under 3 px) are absorbed by the neighboring color.

Command line

swift run --scratch-path ~/Library/Caches/TracerBuild -c release tracer-cli logo.png -o logo.svg --colors 8 --precision 1

Layout

Folder	Contents
Sources/TracerCore	the engine: segmentation, contour tracing, curve fitting, gradients, rendering, exports
Sources/Tracer	the SwiftUI app
Sources/tracer-cli	the same from the command line
Tests/TracerCoreTests	tests (Swift Testing): swift test --scratch-path ~/Library/Caches/TracerBuild

License

MIT — see LICENSE.