Chartsanimated

Crosshair area

An area chart with a tracking crosshair and a floating value tag at the focus point.

82%

Installation

caveui components are copy-paste Jetpack Compose built entirely on Material 3 — there's no caveui dependency to add. Make sure Material 3 is on your classpath (it ships with the Compose BOM), then copy the Usage snippet below into your project.

kotlin

// build.gradle.kts (module)
dependencies {
    implementation(platform("androidx.compose:compose-bom:2025.06.00"))
    implementation("androidx.compose.material3:material3")
}

Usage

kotlin

@Composable
fun CrosshairArea(
    values: List<Float> = listOf(0.4f, 0.55f, 0.5f, 0.7f, 0.62f, 0.82f, 0.74f),
    focus: Int = 5,
    accent: Color = Color(0xFF3B82F6),
    modifier: Modifier = Modifier,
) {
    val reveal by animateFloatAsState(1f, tween(1000, easing = EaseOutCubic), label = "r")
    val guide = MaterialTheme.colorScheme.outlineVariant
    Canvas(modifier.fillMaxWidth().height(124.dp)) {
        val step = size.width / (values.size - 1)
        val line = Path()
        values.forEachIndexed { i, v ->
            val x = i * step
            val y = size.height * (1f - v)
            if (i == 0) line.moveTo(x, y) else line.lineTo(x, y)
        }
        val area = Path().apply { addPath(line); lineTo(size.width, size.height); lineTo(0f, size.height); close() }
        clipRect(right = size.width * reveal) {
            drawPath(area, Brush.verticalGradient(listOf(accent.copy(alpha = 0.3f), Color.Transparent)))
            drawPath(line, accent, style = Stroke(3.dp.toPx(), cap = StrokeCap.Round))
        }
        val fx = focus * step
        val fy = size.height * (1f - values[focus])
        drawLine(guide, Offset(fx, 0f), Offset(fx, size.height), 1.dp.toPx(), pathEffect = PathEffect.dashPathEffect(floatArrayOf(6f, 6f)))
        drawCircle(accent, 5.dp.toPx(), Offset(fx, fy))
        drawCircle(Color.White, 2.dp.toPx(), Offset(fx, fy))
    }
}