feat(avatar): line, rectangle, gradient, noise and shade drawing tools (0.8.0)

[DoodleBears]

Summary

This adds the drawing algorithms behind the Custom Part editor's richer tools (BotHarness/DeepSeekBot#1216) and releases them as @botharness/pixel-avatar 0.8.0.

• partLinePoints(from, to, snap): pixel-perfect Bresenham lines. With snap (Shift), the end snaps to 0°, 45° or 90°.
• partRectPoints(from, to, square): a rectangle outline with each cell once. With square, the far corner makes a square.
• gradientPartLayer(slot, layer, from, to, color, fromTone, toTone, {dither, mirror}): fills the 4-connected region of the start cell. Each cell's position along from→to steps through the tones in between, with 4×4 or 2×2 Bayer dithering (ditherThreshold) between neighboring tones. No RGB is blended.
• noisePartLayer(slot, layer, amount, seed, mirror): a seeded ±1 tone texture. The same seed gives the same result, and empty cells stay empty.
• shadePartLayer(slot, layer, points, delta, mirror): moves each colored cell on a stroke one tone, once per stroke, clamped to −2..2.

Every tool mirrors across the centerline. Gradient dithering and noise rolls are taken from the source side, so the mirrored half is an exact copy. Every tool produces ordinary cells, so a part's content and customPartId never depend on the tool or the seed. Rendering is unchanged and the golden fixtures are untouched.

Verification

• pnpm verify passed: format, lint, typecheck, and 93 tests.
• The new drawing-tools.test.ts covers:
  • line steps and snapping
  • rectangle and square outlines
  • the Bayer matrices
  • gradient tone stepping, region bounds, 2×2 dithering and mirror symmetry
  • noise determinism and mirror symmetry
  • shade once-per-stroke and clamping

Refs: BotHarness/DeepSeekBot#1216

🤖 Generated with Claude Code

https://claude.ai/code/session_01MozvQ2eMvqX1MzSqm9G2o8

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Generated by Claude Code

Summary by CodeRabbit

• New Features
  • Added drawing tools for custom avatar parts, including lines, rectangles, gradients, seeded noise, and one-tone shading.
  • Gradient, noise, and shading tools support mirrored painting; line and rectangle tools offer direction and shape options.

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⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 758430a2-eabe-4dc3-b28d-fd259059faaa

📥 Commits

Reviewing files that changed from the base of the PR and between 97fc5a2 and 6e1e5a9.

📒 Files selected for processing (2)

• packages/avatar/src/part.ts
• packages/avatar/test/drawing-tools.test.ts

📝 Walkthrough

Walkthrough

The avatar package adds line and rectangle point generation and gradient, seeded-noise, and shading operations for custom-part layers. It exports the new APIs and updates package documentation and version information.

Changes

Custom-part drawing tools

Layer / File(s)	Summary
Line and rectangle point generation packages/avatar/src/part.ts, packages/avatar/test/drawing-tools.test.ts	Adds Bresenham line points with optional snapping and rectangle outlines with optional square dimensions. Tests cover generated coordinates and duplicate handling.
Gradient, noise, and shading packages/avatar/src/part.ts, packages/avatar/test/drawing-tools.test.ts	Adds ordered-dither thresholds, gradient painting across matching 4-connected cells, deterministic seeded tone noise, and point-based shading. Tests cover tone ranges, empty cells, and mirrored output.
Public exports and package release packages/avatar/src/index.ts, packages/avatar/package.json, packages/avatar/README.md, CHANGELOG.md	Exports the new drawing APIs and updates the package version to 0.8.0. The README and changelog describe the tools and their output.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Merge Risk: 🔵 Low · up to 97fc5

The mirrored gradient tool can produce an asymmetric result when the starting region crosses the centerline, which conflicts with the stated centerline mirroring. The rest of the change looks low risk, so it is mergeable with this as a follow-up fix.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: new line, rectangle, gradient, noise, and shading drawing tools for the avatar package, with the 0.8.0 release.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files. (3 skipped: 3 …
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
Review comments at @packages/avatar/src/part.ts:
- Around line 358-367: Update gradientPartLayer’s mirror-mode painting so cells
on the opposite side of the centerline receive the tone of their mirrored
source-side cell, including when the initial region spans both sides; do not let
the first paint pass prevent the mirror pass from updating those cells.

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ℹ️ Review info

⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 5deb4225-5f92-4751-9d8e-40d2c8e2bb54

📥 Commits

Reviewing files that changed from the base of the PR and between 300a857 and 97fc5a2.

📒 Files selected for processing (6)

• CHANGELOG.md
• packages/avatar/README.md
• packages/avatar/package.json
• packages/avatar/src/index.ts
• packages/avatar/src/part.ts
• packages/avatar/test/drawing-tools.test.ts

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