[gavr (gavr123456789)]

Fixes CMP-8371 Text cursor shrinks after typing begins when a TextField
There are 2 problems fixed.

1. cursor height is different between empty string and non-empty string

Screen.Recording.2026-09-09.at.22.36.40.mov

2. new symbol on the second line changes the baseline when font size is larger than line height

Screen.Recording.2026-09-09.at.22.38.07.mov

(fix by SkikoParagraphBuilder.nonAndroid.kt file)

To reproduce:

 Row(
            modifier = Modifier.fillMaxWidth(),
            horizontalArrangement = Arrangement.SpaceEvenly
        ) {

            var text by remember { mutableStateOf("") }
            val textFieldStyle = LocalTextStyle.current.copy(fontSize = 64.sp)
            TextField(
                value = text,
                onValueChange = {
                    println(
                        "[TextFieldDebug] text=${it} " +
                            "length=${it.length} style=$textFieldStyle"
                    )
                    text = it
                },
                modifier = Modifier.onFocusChanged {
                    println(
                        "[TextFieldDebug] focus=" +
                            "isFocused=${it.isFocused} isCaptured=${it.isCaptured}"
                    )
                },
                textStyle = textFieldStyle,
            )

            Column(modifier = Modifier.width(340.dp)) {
                var multilineText by remember { mutableStateOf("") }
                TextField(
                    value = multilineText,
                    onValueChange = { multilineText = it },
                    label = { Text("Multiline: 48sp font / 28sp lineH") },
                    textStyle = LocalTextStyle.current.copy(fontSize = 48.sp, lineHeight = 28.sp),
                    maxLines = 4,
                    modifier = Modifier.fillMaxWidth().height(150.dp),
                )

                var monospaceText by remember { mutableStateOf("") }
                TextField(
                    value = monospaceText,
                    onValueChange = { monospaceText = it },
                    label = { Text("Monospace: 32sp font / 48sp lineH") },
                    textStyle = LocalTextStyle.current.copy(
                        fontSize = 32.sp,
                        fontFamily = FontFamily.Monospace,
                        lineHeight = 48.sp,
                    ),
                    modifier = Modifier.fillMaxWidth(),
                )

                var smallText by remember { mutableStateOf("") }
                TextField(
                    value = smallText,
                    onValueChange = { smallText = it },
                    label = { Text("Small: 14sp font / 20sp lineH") },
                    textStyle = LocalTextStyle.current.copy(fontSize = 14.sp, lineHeight = 20.sp),
                    modifier = Modifier.fillMaxWidth(),
                )
            }
        }

Testing

Screen.Recording.2026-09-09.at.22.48.18.mov

Release Notes

Fixes - Multiple Platforms

• Fixed the cursor metrics difference between empty and non-empty string

[gavr (gavr123456789)]

test getBoundingBox_lineHeight is broken after my second fix.
https://youtrack.jetbrains.com/issue/CMP-7963

Expected Behavior
Hello and There should overlap each other

Now I see that this isn’t a bug: when the user chooses a font size > lineH, overlap is expected. Will unroll second fix.

[Ivan Matkov (MatkovIvan)]

Please resolve merge conflicts (rebase)

[Ivan Matkov (MatkovIvan)]

Why cannot we reuse receiveLineMetrics() here and need a separate resolve? Shouldn't we fix that variant instead (if it's wrong for some reason) and keep a single source of truth?

[gavr (gavr123456789)]

receiveLineMetrics() chooses its source based on whether the whole text is empty,
for an empty paragraph it returns the same empty-line metrics, but for non-empty text it returns paragraph.lineMetrics, that's where the difference in cursor height comes from.
The cursor intentionally uses empty-line metrics so its height does not change after a new char typed on the empty/newline line

I can extract the empty-line metrics construction and trimming into a helper used by both receiveLineMetrics() and the cursor.
receiveLineMetrics() shouldn't return empty-line metrics for non-empty text, since paragraph.lineMetrics are also used for line geometry, while the empty-line metrics are only needed for the cursor.

[Vladimir Mazunin (mazunin-v-jb)]

+1. receiveLineMetrics() is fine; the issue is emptyLineMetrics using fontSize instead of the font's intrinsic height. Fixing that removes the need for a second source (see my other comment).

[Copilot]

🟡 Changes recommended

Cursor sizing discards styled-font metrics, and the claimed baseline-layout fix is absent.

2 open issues

• Preserve styled-font metrics for cursor height normalization · New
• Implement second-line baseline fix or remove unsupported claims · New

What changed in this PR

Adjusts Skiko cursor sizing to reduce height changes when typing into empty text fields.

Changes:

• Reuses cached empty-line metrics for cursors with explicit line heights.
• Adds an empty-versus-nonempty cursor-height regression test.
• Adds a StrutStyle import without changing paragraph layout.

File	Description
compose/​ui/​ui-skiko/​src/​nonAndroidTest/​kotlin/​androidx/​compose/​ui/​text/​SkikoParagraphTest.kt	Tests consistent cursor height.
compose/​ui/​ui-skiko/​src/​nonAndroidMain/​kotlin/​androidx/​compose/​ui/​text/​SkikoParagraph.nonAndroid.kt	Changes cursor metric selection and caching.
compose/​ui/​ui-skiko/​src/​nonAndroidMain/​kotlin/​androidx/​compose/​ui/​text/​platform/​SkikoParagraphBuilder.nonAndroid.kt	Adds an unused import.

_{Review effort: Balanced}

[Vladimir Mazunin (mazunin-v-jb)]

Thanks for digging into this!
However, I think the fix lands in the wrong place, though: the caret is fine, but the empty-line metrics it is compared against are wrong.

emptyLineMetrics uses fontSize where Skia uses the font's intrinsic height (see the inline comments).

Could you please try aligning emptyLineMetrics with Skia's computeEmptyMetrics and reverting the getCursorRect changes?
That should fix the empty-field caret and keep the non-empty ones matching the line height.

[Vladimir Mazunin (mazunin-v-jb)]

+1. receiveLineMetrics() is fine; the issue is emptyLineMetrics using fontSize instead of the font's intrinsic height. Fixing that removes the need for a second source (see my other comment).

[Vladimir Mazunin (mazunin-v-jb)]

lgtm now, thank you!