Repository navigation
Conversation
Summary: On Android 15 and 16.0, `Layout.computeDrawingBoundingBox()` reuses a single `RectF` for every line and `TextLine.metrics()` does not reset it. A line whose paragraph direction is LTR, laid out after an RTL line, inherits the RTL line's bounds in RTL-relative (negative) coordinates. With `setShiftDrawingOffsetForStartOverhang(true)`, `Layout.draw()` then translates the whole text right by about one line width, so the text disappears or only a few glyphs stay visible at the right edge. Common RTL content hits this: a blank line between Arabic or Hebrew paragraphs has no strong character and is laid out LTR. The platform fixed it in a later Android 16 release by resetting the rect per line. When an exactly sized layout has mixed paragraph directions, rebuild it without the start-overhang drawing shift. Bounds-based line breaking is kept, so the measured line breaks are unchanged. Single-direction text keeps the existing start-overhang behavior. Changelog: [Android][Fixed] - Fix multi-paragraph RTL `Text` with blank or LTR lines being drawn off-screen on Android 15+ Differential Revision: D125908523
meta-cla
Bot
added
the
CLA Signed
|
@fkgozali has exported this pull request. If you are a Meta employee, you can view the originating Diff in D125908523. |
This branch has not been deployed
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary:
On Android 15 and 16.0,
Layout.computeDrawingBoundingBox()reuses a singleRectFfor every line andTextLine.metrics()does not reset it. A line whose paragraph direction is LTR, laid out after an RTL line, inherits the RTL line's bounds in RTL-relative (negative) coordinates. WithsetShiftDrawingOffsetForStartOverhang(true),Layout.draw()then translates the whole text right by about one line width, so the text disappears or only a few glyphs stay visible at the right edge.Common RTL content hits this: a blank line between Arabic or Hebrew paragraphs has no strong character and is laid out LTR. The platform fixed it in a later Android 16 release by resetting the rect per line.
When an exactly sized layout has mixed paragraph directions, rebuild it without the start-overhang drawing shift. Bounds-based line breaking is kept, so the measured line breaks are unchanged. Single-direction text keeps the existing start-overhang behavior.
Changelog:
[Android][Fixed] - Fix multi-paragraph RTL
Textwith blank or LTR lines being drawn off-screen on Android 15+Differential Revision: D125908523