[jasozh]

Summary:

Fixes the issue described in #48727, where adding inline views and images into Text when line height is specified results in the image clipping and overflowing the parent container.

Root Cause

On Android, CustomLineHeightSpan uses the line's merged font metrics fm to set the line's ascent/descent so text clamps to lineHeight. However, the calculation assumes fm only describes text whereas in reality, it also includes the height of inline views/images. As a result, taller images are also clamped to lineHeight and overflow.

Additionally, because StaticLayout seeds each line with the previous line's adjusted font metrics when a text run wraps, the lines after the inline view also inherit its height and get misplaced baselines. The result is that wrapped text following an inline image appear unusually squashed.

On iOS, lineHeight sets both minimumLineHeight and maximumLineHeight so TextKit clamps every line to the same height, even for lines with a taller inline view/image.

Additionally, RCTApplyBaselineOffset lifts the text with NSBaselineOffset to center it in the line, but for inline views, this is computed from the unlifted baseline, causing images to sit below the text baseline.

This PR

For Android, modify CustomLineHeightSpan so that if the text includes an inline view, we use TextPaint to re-derive fm via measureTextRun() for every line. This means fm only describes text during the chooseHeight() calculation, and each line is unaffected by wrapping issues. Then, raise the line's ascent/top to fit the inline view.

For iOS, set RCTTextLayoutManager as a NSLayoutManagerDelegate if an inline view exists so the layout manager calls layoutManagerShouldSetLineFragmentRect() which grows the line to match the height of the inline view. Separately, modify the baseline shift so that attachments match the text baseline.

All changes are gated behind the fixTextInlineViewLineHeight flag.

Changelog: [General][Fixed] - Inline views in Text with lineHeight no longer overflow the text

Differential Revision: D126795867

[meta-codesync]

@jasozh has exported this pull request. If you are a Meta employee, you can view the originating Diff in D126795867.

[github-actions]

Visual regression

1 visual difference(s) at 10de712f212b. Visual differences need maintainer approval. Review the report, then apply visual-change-approved.

ios switch/custom-colors/toggled: Changed, 11804 px (0.474%)

Expected and Captured

Expected	Captured