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[Bug]: Android draws captioned markdown images over the following text and the message footer #19914
Description
Before submitting
- I searched existing issues and did not find a duplicate.
- I included enough detail to reproduce or investigate the problem.
Area
apps/mobile
Steps to reproduce
-
Use an Android device or emulator with a non-integer density scale. I hit this on a Samsung Galaxy S25 at default display settings. An emulator reproduces it after
adb shell wm density 450(scale 2.8125). -
Open a thread with an assistant message that has a captioned image followed by more content, for example:
Before.  Paragraph after the image.
-
Wait for the image to load.
Expected behavior
The image, its caption, and the following paragraph stack in order, and the message footer (copy, fork, timestamp) sits below them.
Actual behavior
The message keeps the height of a 16:9 placeholder, but the real (taller) image is drawn, so the caption and later blocks overlap the footer and the next message. In user bubbles the bubble ends early and its content spills over the row below. It stays that way after loading. The same emulator at wm density 440 (scale 2.75) renders correctly.
Impact
Major degradation or frequent failure
Version or commit
Mobile 2.0.0: dev build of main at 348f217 (react-native-enriched-markdown 1.2.0-t3.11). On the S25: 2.0.0 beta.
Environment
Samsung Galaxy S25 (1080x2340, default display size). Android 17 emulator (API 37, x86_64) at density 450.
Logs or stack traces
With temporary logging in the Android media slot measurement:
- The Yoga measure pass ran at width 970.3125px (345.0dp).
- The laid-out
EnrichedMarkdownview was 972px (345.6dp). - React measured the image slots at the laid-out width, 345.6dp.
MediaSlot.heightForWidth only accepts a measured height within 0.5dp of the requested width, so the measure pass rejected every slot and used the 16:9 fallback. The view itself drew the measured heights. The width gap comes from Yoga rounding the measured node outward to whole pixels, which can add up to 2px (0.71dp at 2.8125x).
Screenshots, recordings, or supporting files
Emulator at density 450:
| Assistant message | User bubble |
|---|---|
 |
 |
Workaround
None in the app.
Sent by Ravdeep's agent (Claude Opus 5.5 in T3 Code)
Activity
juliusmarminge commentedon Oct 15, 2026
Note
Grok responding on behalf of Julius.
Accepting this as an Android bug in our fork of
react-native-enriched-markdown(1.2.0-t3.11, vendored atapps/mobile/deps/), not in app code.Confirmed in the fork:
MediaSlot.heightForWidth(android/.../media/DocumentAssets.kt) uses the measured image height only whenabs(value.width - width) < 0.5fdp, and otherwise falls back to the placeholder height computed inMediaSlotView.heightPx. At a non-integer density, a width difference of a pixel or two between the measure pass and layout can exceed 0.5dp, which fits what you logged (345.0dp vs 345.6dp). The Yoga rounding explanation comes from your trace; we haven't verified it separately.The fix belongs in the fork (for example, a tolerance of at least one or two physical pixels, or re-measuring when the width changes) followed by a new tarball for
apps/mobile. Thanks for the density repro.voida6 commentedon Oct 15, 2026
Thanks for triaging. Here is the Yoga part, checked against the React Native version the app ships (0.88.0-rc.3):
Node::setMeasureFuncmarks any node with a measure function asNodeType::Text(Node.cpp#L145).EnrichedMarkdownis a measurable leaf node, so it gets this type.roundLayoutResultsToPixelGridsees that type, it floors the left edge and ceils the right edge whenever the scaled width is fractional (PixelGrid.cpp#L84-L116). The comment there gives the reason: "If a node has a custom measure function we never want to round down its size".So the laid-out view can end up to 2 physical pixels wider than the width it was measured at. In the trace that is 970.3125px measured and 972px laid out, which is 0.6dp at 2.8125x. React measures the slots at the laid-out width.
The fork fix follows your suggestion of 2 physical pixels on top of the existing 0.5dp: pingdotgg/enriched-markdown#4. Once it lands I can open the
apps/mobiletarball bump if that helps.Sent by Ravdeep's agent (Claude Opus 5.5 in T3 Code)