Korner

Smooth rounded corners and squircles for Compose Multiplatform.

Korner provides beautiful iOS-style smooth corner shapes and superellipses for Compose Multiplatform with fully customizable radius and smoothing values per corner.

Supports:

• Android
• iOS
• Desktop
• WASM/Web

Based on the original smooth corner implementation by racra: https://github.com/racra/smooth-corner-rect-android-compose

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Features

• Smooth iOS-style corners
• Superellipse / squircle rendering
• Per-corner radius customization
• Per-corner smoothing customization
• Type-safe smoothing API
• Compose Multiplatform support
• Works with any Compose UI component
• Lightweight and allocation-friendly

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Why Korner?

Traditional rounded rectangles use simple circular arcs.

Korner generates smooth superellipse-style curves with more natural transitions and better visual balance — similar to modern design systems used in iOS and contemporary UI frameworks.

Compared to standard rounded corners, smooth corners:

• feel more organic
• reduce visual sharpness
• improve large-radius aesthetics
• create cleaner modern UI surfaces

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Installation

Gradle

repositories {
    mavenCentral()
}

dependencies {
    implementation("io.github.dev778g-me:korner:2.0.0")
}

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Basic Usage

Box(
    modifier = Modifier
        .size(200.dp)
        .background(
            color = Color(0xFFF6EABE),
            shape = AbsoluteSmoothCornerShape(
                cornerRadius = 32.dp,
                cornerSmoothing = CornerSmoothing.Continuous
            )
        )
)

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Per-Corner Configuration

Box(
    modifier = Modifier
        .size(200.dp)
        .background(
            color = Color(0xFFF6EABE),
            shape = AbsoluteSmoothCornerShape(
                topLeftRadius = 40.dp,
                topLeftCornerSmoothing = CornerSmoothing.Continuous,

                topRightRadius = 12.dp,
                topRightCornerSmoothing = CornerSmoothing.Balanced,

                bottomRightRadius = 40.dp,
                bottomRightCornerSmoothing = CornerSmoothing.Smooth,

                bottomLeftRadius = 12.dp,
                bottomLeftCornerSmoothing = CornerSmoothing.Subtle
            )
        )
)

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Corner Smoothing

Korner uses a type-safe CornerSmoothing API:

@JvmInline
value class CornerSmoothing(val percent: Int) {
    init {
        require(percent in 0..100) {
            "Corner smoothing must be between 0 and 100"
        }
    }

    companion object {
        val Subtle = CornerSmoothing(25)
        val Balanced = CornerSmoothing(50)
        val Smooth = CornerSmoothing(75)
        val Continuous = CornerSmoothing(100)
    }
}

Presets

Preset	Value
Subtle	25
Balanced	50
Smooth	75
Continuous	100

Custom values are also supported:

CornerSmoothing(65)

Valid range: 0..100

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Attribution

Korner is adapted from: https://github.com/racra/smooth-corner-rect-android-compose

Original work copyright © racra.

Licensed under the MIT License.