Curvature View & Auto Smooth / Harmonization Tool

Honor

I would like to suggest two features that would significantly enhance VectorStyler for logotype and lettering workflows:

Curvature View (Live Curvature Visualization)
A real-time curvature overlay for Bézier curves to detect curvature spikes, G2 discontinuities, and flow inconsistencies.
Auto Smooth / Harmonization Tool
An intelligent smoothing function that redistributes curvature across selected nodes or segments, improving G2 continuity and preserving overall curve flow during local edits. For reference, tools like Glyphs (SpeedPunk curvature visualization) demonstrate how real-time curvature feedback can significantly improve precision in curve refinement workflows.

These features would make VectorStyler a much stronger precision tool for logo and typographic shape construction.

VectorStyler

@Honor I will add this to the backlog for 1.4, some clarifications might be needed later

VectorStyler

@Honor Hi, I would need more info on both point(1) and (2).

how would this look? is this an indicator? some visual examples would help. (G2 continuity at nodes can be easily added, but I sense that this is more).

2)would this be a separate tool?

Honor

Thanks for the follow up.

How would this look?

It would not be a single indicator but a lightweight overlay directly on the curve.

The idea is a combination of:

A color-based curvature heatmap along the path (low - high curvature)
Optional curvature comb lines, mainly emphasized around problem areas
Small visual highlights where curvature changes abruptly (spikes / G2 breaks)

So instead of showing full technical data everywhere, it highlights where attention is needed.

Would this be a separate tool?

No, I think it should work as a toggleable overlay, not a separate tool.

For example:
View --- Curvature Overlay (on/off)

This allows users to enable it during editing without interrupting the workflow.

Auto Smooth / Harmonization would be a separate action:

Applied to selected nodes or segments
Redistributes curvature more evenly
Preserves the overall shape while improving flow

The goal is to make curvature issues immediately visible and easy to correct during normal editing.

For reference, here is a quick example of how curvature visualization works in practice (around 2:50)

https://www.youtube.com/watch?v=LtyQ3r_S740

From what I found, a similar feature was requested in Affinity Designer a few years ago

https://forum.affinity.serif.com/index.php?/topic/55085-show-curvature-combs-on-bezier-paths/

G2 at nodes makes connections look smooth, but it doesn’t show how the curve behaves in between.

With a visual overlay like this, you can actually see where the curve tightens or breaks flow, and adjust it until the whole curve feels balanced.

What I had in mind is a way to visualize how the curve “flows” where curvature increases, tightens, or changes abruptly.

As a first step, even adding G2 continuity at nodes would already be very helpful.
But in the longer termm a visual curvature feedback system like this could make curve editing much more precise and intuitive.

In Glyphs, this kind of functionality exists as a plugin rather than a built-in feature.

Thank you for taking the time.