feat(illustrated-message) - new size and orientation API

[miwha-adobe]

Description

Adds size and orientation as additive properties to swc-illustrated-message as part of the Spectrum 2 migration. Includes:

• ILLUSTRATED_MESSAGE_VALID_SIZES and ILLUSTRATED_MESSAGE_VALID_ORIENTATIONS constants and derived types in IllustratedMessage.types.ts
• size ('s' | 'm' | 'l', default 'm') and orientation ('vertical' | 'horizontal', default 'vertical') reflected properties on IllustratedMessageBase
• Structural CSS placeholder selectors for both attributes (full S2 token-based styles tracked in SWC-1838)

Motivation and context

Spectrum 2 introduces t-shirt sizing and a horizontal layout variant for illustrated message. Full token-based styling will follow in SWC-1838.

Related issue(s)

• SWC-1835
• SWC-1836
• SWC-1837

Screenshots (if appropriate)

N/A — visual tokens not yet implemented (SWC-1838).

Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

Manual review test cases

Note: Storybook is not fully configured. Those changes will be covered in: https://jira.corp.adobe.com/browse/SWC-1841

• size attribute reflects correctly

  1. Open illustrated message Storybook story
  2. Expect the attribute to be visible

• orientation attribute reflects correctly

  1. Open illustrated message Storybook story
  2. Expect the attribute to be visible

Accessibility testing checklist

• Keyboard — No interactive elements added; no keyboard behavior changes. Tab moves through any slotted actions in DOM order, which is unchanged by orientation (CSS-only layout shift).

• Screen reader — No ARIA changes. orientation affects only visual layout, not DOM order, so reading order is unaffected.

[github-actions]

📚 Branch Preview Links

• Documentation Site (first-gen)
• Storybook (first-gen)
• Storybook (second-gen)

🔍 First Generation Visual Regression Test Results

When a visual regression test fails (or has previously failed while working on this branch), its results can be found in the following URLs:

• Spectrum | Light | Medium | LTR
• Spectrum | Dark | Large | RTL
• Express | Light | Medium | LTR
• Express | Dark | Large | RTL
• Spectrum-two | Light | Medium | LTR
• Spectrum-two | Dark | Large | RTL
• High Contrast Mode | Medium | LTR

Deployed to Azure Blob Storage: pr-6155

If the changes are expected, update the current_golden_images_cache hash in the circleci config to accept the new images. Instructions are included in that file.
If the changes are unexpected, you can investigate the cause of the differences and update the code accordingly.

[Rajdeepc]

Looking good. If you can tests for attribute <-> property checks for size and orientation for optionally invalid values with warnings that would be great.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 3a935a8

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