Add visual regression tests to visual-testing branch

[khuntvidisha13]

Summary

The visual-testing branch has a testing framework but several areas
lack test coverage. I'd like to add visual regression tests for:

• Primitive shapes (rect, ellipse, triangle, arc, line, point)
• Blend modes (OVERLAY, HARD_LIGHT, SOFT_LIGHT)
• Stroke styles (weight, cap, join)
• Transform operations (translate, rotate, scale)

Approach

Each area would be a separate focused PR.

Related

PR #1460 (to be broken into smaller PRs)

[khuntvidisha13]

Thank you @dpoppe7 for the feedback! I've opened Issue #1465 to discuss the approach. I'll break this into smaller focused PRs. Should I close this PR and reopen separate ones for each area?

[dpoppe7]

Maintainer guidance is best here, as they can better let you about how/when they want to take this on. Also friendly reminder since it says in the guidelines, before working on PRs, a maintainer should assign you to the issue. It looks like there has been previous discussion or issues about this #1207. It's always good to search the open issues beforehand.

[khuntvidisha13]

Thank you @dpoppe7 for the guidance! I wasn't aware of the assignment requirement — I'll keep that in mind going forward. I've reviewed #1207 and understand the existing discussion. Could a maintainer please assign me to work on extending the visual tests in the visual-testing branch? I'm happy to follow the established architecture and break my work into smaller focused PRs.

[khuntvidisha13]

Hi! I have completed the edge case and stroke tests for rect() and ellipse() — all 12 tests pass locally on Windows with baselines created. Could a maintainer please assign me to this issue so I can open a focused PR on the visual-testing branch? Thank you!