linebender / linebender/vello

BezPath 0-length stroke

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Dominant language
Rust
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Merged PRs (30d)
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Description

Hello! I want to make a scribble / writing app and am using the new vello sparse strip thing with the fast_stroke kurbo branch patched in.
Now, I want to present a "dot" when the user started writing even without moving, so I create a BezPath with [MoveTo(p), LineTo(p)] but that doesn't show anything. Even with LineTo(p + f64::EPSILON) it doesn't work, only with + 0.001 which makes it seem ugly when I don't go to the bottom right with the stroke but for example the top left, as the start is now wrong for a short bit.
Can we please get an option to allow 0-length paths?

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  3. Fork the repository and make your change on a branch.
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Research direction

Start by reproducing the report's MoveTo(p), LineTo(p) and near-zero-length cases with the vello sparse strip path and patched fast_stroke kurbo branch. Inspect how zero-length paths are handled and define the smallest renderer-facing option that preserves the requested dot position. Done means a zero-length writing gesture renders a dot without an arbitrary epsilon, with regression coverage for the reported cases.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
computer-graphics
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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