VectorFox 3.1: straight lines stay straight, and a cleaner trace from small images

VectorFox 3.1 is out. I spent a few days tracing the same dozen test images over and over, looking hard at where the results fell short, and this release fixes the four things that bothered me most. The one I kept coming back to was buildings.

Straight things stay straight

Trace a city skyline with Balanced in 3.0 and the windows came back as soft, slightly melted lozenges. You could fix it by going up to Detailed, but that doubles the file size for something that should have been right in the first place.

The tracer smooths every outline before it fits curves. That's what you want for a wobbly hand-drawn edge. It is wrong for a window. So 3.1 looks for the straight stretches of an outline first, draws each one as a real line, and puts the corner back exactly where the two sides meet. Curves are left alone: a side has to end in a genuine corner to count, so circles and rounded shapes trace as they did.

On my skyline test image, Balanced in 3.1 is now as accurate as Detailed was in 3.0, at less than half the size. Pixel art benefits too. A character sprite that used to come out as rounded blobs keeps its square steps.

Enhance

Small images are hard to trace well. There just aren't enough pixels along each edge. Upscale helps by doubling the image first, and 3.1 adds Enhance right beside it, which does that job with a small model that cleans the image up as it enlarges it. Soft edges come back crisp, JPEG fuzz goes away, and thin outlines that a plain upscale loses are kept.

It runs on your Mac in a fraction of a second. Nothing is uploaded. On flat illustration, logos and AI-generated art it gives a cleaner result with 30 to 60% fewer paths at the Detailed preset, which also means a smaller file.

But it isn't for everything, so it's off by default. It makes pixel art worse, and it does nothing useful for a photograph. It works on images up to 1024 px, when Upscale is doubling the image.

No more grey fringes

This one was a bug I'm glad to be rid of. The soft, anti-aliased edge of a flat shape looks like a tiny color ramp, and the tracer was faithfully fitting a gradient to it. The result was a faint grey halo around logos and mascots, and a much bigger file than the artwork deserved.

Gradients are now fitted on the inside of each region only. My skyline went from 244 gradients to 37 and came out 30% smaller. Flat artwork loses the halo completely.

Also in 3.1

• Thin lines survive. Twigs, whiskers and fine strokes that were part of a larger piece used to get worn away into dashes. They're kept whole now.
• Balanced keeps close tones apart. Two similar greens or two similar skin tones no longer merge into one. Files are about 8% larger on average, and I think that's the right trade.
• Detailed is smaller and faster. About 17% fewer bytes and 15% less time across my test set, with better accuracy.
• Upscale reads Off, Auto, 2×. "1×" was a confusing label for doing nothing.

VectorFox 3.1 is a free update for every license, and the 14-day trial has all of it. If you already have VectorFox it will offer the update itself. Otherwise get it from the VectorFox page or with Homebrew: brew install --cask skulkworks/tap/vectorfox. Everything, down to the fixes, is in the changelog.

Enjoy!