Cloudy

Kotlin Multiplatform blur and liquid glass effect library for Compose, with GPU-accelerated rendering and CPU fallback for older devices. See documentation for more details.

The `blur` modifier supports only Android 12 and higher, and `RenderScript` APIs are deprecated starting in Android 12. Cloudy is the backport of the blur effect for Jetpack Compose with cross-platform support.

Supported Platforms (Blur Effect)

Platform	Implementation	Performance	State Type
Android 31+	RenderEffect (GPU)	GPU-accelerated	Success.Applied
Android 30-	Native C++ (CPU)	NEON/SIMD optimized	Success.Captured
iOS	Skia BlurEffect (Metal GPU)	GPU-accelerated	Success.Applied
macOS	Skia BlurEffect (Metal GPU)	GPU-accelerated	Success.Applied
Desktop (JVM)	Skia BlurEffect (GPU)	GPU-accelerated	Success.Applied
WASM (Browser)	Skia BlurEffect (WebGL)	GPU-accelerated	Success.Applied

See Liquid Glass Effect for liquid glass platform support.

Download

Version Catalog

If you're using Version Catalog, you can configure the dependency by adding it to your libs.versions.toml file as follows:

[versions]
#...
cloudy = "0.6.1"

[libraries]
#...
compose-cloudy = { module = "com.github.skydoves:cloudy", version.ref = "cloudy" }

Gradle

Add the dependency below to your module's build.gradle.kts file:

dependencies {
    implementation("com.github.skydoves:cloudy:0.6.1")
    
    // if you're using Version Catalog
    implementation(libs.compose.cloudy)
}

For Kotlin Multiplatform, add the dependency below to your module's build.gradle.kts file:

sourceSets {
    commonMain.dependencies {
        implementation("com.github.skydoves:cloudy:$version")
    }
}

Usage

Cloudy offers two blur modes: Modifier.cloudy(radius = …) blurs a composable's own content (covered below), while Background Blur blurs the content behind a composable for glassmorphism surfaces.

You can implement blur effect with Modifier.cloudy() composable function as seen below:

Text(
  modifier = Modifier.cloudy(),
  text = "This text is blurred"
)

You can change the degree of the blur effect by changing the radius parameter of Modifier.cloudy() composable function.

Column(
  modifier = Modifier.cloudy(radius = 15)
) {
  Image(..)

  Text(
    modifier = Modifier
      .fillMaxWidth()
      .padding(8.dp),
    text = posterModel.name,
    fontSize = 40.sp,
    color = MaterialTheme.colors.onBackground,
    textAlign = TextAlign.Center
  )

  Text(
    modifier = Modifier
      .fillMaxWidth()
      .padding(8.dp),
    text = posterModel.description,
    color = MaterialTheme.colors.onBackground,
    textAlign = TextAlign.Center
  )
}

Observing Blurring Status

You can monitor the status of the blurring effect by using the onStateChanged parameter, which provides CloudyState. This allows you to observe and respond to changes in the blurring effect's state effectively.

GlideImage(
  modifier = Modifier
    .size(400.dp)
    .cloudy(
      radius = 25,
      onStateChanged = { state ->
        when (state) {
          is CloudyState.Success.Applied -> {
            // GPU blur applied (iOS, Android 31+)
            // No bitmap available - blur rendered directly
          }
          is CloudyState.Success.Captured -> {
            // CPU blur completed (Android 30-)
            // Blurred bitmap available: state.bitmap
            val blurredBitmap = state.bitmap
          }
          is CloudyState.Loading -> {
            // Blur processing in progress
          }
          is CloudyState.Error -> {
            // Handle error: state.throwable
          }
          CloudyState.Nothing -> {
            // Initial state
          }
        }
      }
    ),
  ..
)

CloudyState Types

State	Description	Bitmap Available
Success.Applied	GPU blur applied in rendering pipeline	No
Success.Captured	CPU blur completed with bitmap	Yes (state.bitmap)
Success.Scrim	Scrim overlay shown instead of blur (background blur on Android 30-)	No
Loading	Blur processing in progress	No
Error	Blur operation failed	No
Nothing	Initial state	No

Maintaining Blurring Effect on Responsive Composable

The Modifier.cloudy captures the bitmap of the composable node under the hood.

LazyVerticalGrid(
  state = rememberLazyGridState(),
  columns = GridCells.Fixed(2)
) {
  itemsIndexed(key = { index, item -> item.id }, items = posters) { index, item ->
    HomePoster(poster = item)
  }
}

@Composable
private fun HomePoster(poster: Poster) {
    ConstraintLayout {
      val (image, title, content) = createRefs()
      GlideImage(
        modifier = Modifier
          .cloudy(radius = 15)
          .aspectRatio(0.8f)
          .constrainAs(image) {
            centerHorizontallyTo(parent)
            top.linkTo(parent.top)
          }
          ..

Background Blur (Backdrop Blur)

Background blur — also called backdrop blur — blurs the content that sits behind a composable, producing a glassmorphism / frosted-glass surface such as a translucent app bar, bottom navigation, or card. Unlike Modifier.cloudy(radius = …), which blurs a composable's own content, the backdrop API samples a shared snapshot of the background and renders it blurred underneath your overlay.

It is built from three pieces:

API	Role
rememberSky()	Creates a Sky — the shared state holder for the captured background.
Modifier.sky(sky)	Marks the source container whose content is captured for blur.
Modifier.cloudy(sky = sky, …)	The overlay that draws the captured background, blurred and clipped to its bounds.

https://github.com/user-attachments/assets/c22cb656-4415-471e-a30a-521d39344447

https://github.com/user-attachments/assets/faf67c77-cb1e-4b20-994b-bb8afe340087

Basic Usage

Put Modifier.sky(sky) on the background you want to blur, then overlay a composable with Modifier.cloudy(sky = sky, …):

val sky = rememberSky()

Box(modifier = Modifier.fillMaxSize()) {
  // 1) Source — the content captured for blur
  LazyVerticalGrid(
    columns = GridCells.Fixed(2),
    modifier = Modifier.sky(sky),
  ) {
    items(posters) { poster -> GridPosterItem(poster) }
  }

  // 2) Overlay — a frosted glass app bar that blurs the grid behind it
  Box(
    modifier = Modifier
      .fillMaxWidth()
      .height(56.dp)
      .cloudy(
        sky = sky,
        radius = 20,
        tint = MaterialTheme.colorScheme.surface.copy(alpha = 0.3f),
      )
  ) {
    Text("Frosted Glass App Bar")
  }
}

Clipping to a Shape

By default the blurred backdrop is clipped to a rectangle. Pass a shape so the blur follows rounded corners instead of leaving a hard rectangular box inside a rounded glass surface:

val barShape = RoundedCornerShape(36.dp)

Row(
  modifier = Modifier
    .clip(barShape)
    .cloudy(sky = sky, radius = 24, shape = barShape)
    .background(Color.White.copy(alpha = 0.15f)),
) {
  // tabs
}

Progressive (Gradient) Blur

Use the progressive parameter to fade the blur across the surface — ideal for scroll-edge fades or vignettes:

// Blur is strongest at the top and fades to clear toward the bottom
Modifier.cloudy(
  sky = sky,
  radius = 25,
  progressive = CloudyProgressive.TopToBottom(),
)

Mode	Effect
CloudyProgressive.None	Uniform blur (default)
CloudyProgressive.TopToBottom(start, end, easing)	Blur fades from top → bottom
CloudyProgressive.BottomToTop(start, end, easing)	Blur fades from bottom → top
CloudyProgressive.Edges(fadeDistance, easing)	Blur at the edges, clear in the center (vignette)

Progressive blur uses an AGSL shader on Android 33+ and Skia shaders on iOS/macOS/Desktop/WASM. On Android 32 and below it falls back to uniform blur.

Refreshing the Blur

The backdrop refreshes automatically while the background scrolls or animates, and parks at zero frames once it settles. When the background changes outside of a scroll/animation (for example, an image finishes loading or you swap content), call Sky.invalidate() to re-capture:

AsyncImage(
  model = imageUrl,
  modifier = Modifier.sky(sky),
  onSuccess = { sky.invalidate() },
)

For an animated change that lasts a known duration (e.g. a tab cross-fade), pass the duration so the blur tracks the whole transition instead of freezing once the short settle tail elapses:

LaunchedEffect(selectedTab) {
  sky.invalidate(durationMillis = 240) // matches the cross-fade duration
}

Parameters (Modifier.cloudy(sky = …))

Parameter	Default	Description
sky	–	The Sky holding the captured background (required).
radius	20 (CloudyDefaults.BACKGROUND_RADIUS)	Blur radius in pixels. Must be non-negative.
progressive	CloudyProgressive.None	Gradient blur configuration.
tint	Color.Transparent	Optional color blended over the blurred backdrop.
enabled	true	When false, the effect is disabled (renders nothing).
cpuBlurEnabled	false (CloudyDefaults.CPP_BLUR_ENABLED)	Enable CPU blur on Android 30-; otherwise a scrim is shown.
shape	RectangleShape	Shape the blurred backdrop is clipped to.
onStateChanged	{}	Callback for CloudyState changes.

Platform Behavior (Background Blur)

Platform	API Level	Implementation	Progressive Blur
Android	33+	AGSL RuntimeShader	Supported
Android	31–32	RenderEffect	Uniform only
Android	30-	Bitmap + CPU (if cpuBlurEnabled) or scrim	Uniform only
iOS / macOS / Desktop / WASM	–	Skia BlurEffect	Supported

On Android 30 and below, CPU blur is disabled by default and a semi-transparent scrim (CloudyState.Success.Scrim) is shown instead, following a performance-first approach. Set cpuBlurEnabled = true to force CPU blur on those devices.

Blur Effect with Network Images

You can easily implement blur effect with Landscapist, which is a Jetpack Compose image loading library that fetches and displays network images with Glide, Coil, and Fresco. For more information, see the Transformation section.

Liquid Glass Effect

Cloudy provides a Modifier.liquidGlass() that creates a realistic glass lens effect with SDF-based crisp edges, normal-based refraction, and chromatic dispersion.

Note: For blur effects, use Modifier.cloudy() separately. The two modifiers are designed to work independently, giving you full control over each effect.

Platform Support (Liquid Glass)

Platform	Implementation	Features
Android 33+	RuntimeShader (AGSL)	Full effect
Android 32-	Fallback	Tint + edge + shape (no lens refraction)
iOS	Skia RuntimeEffect	Full effect
macOS	Skia RuntimeEffect	Full effect
Desktop (JVM)	Skia RuntimeEffect	Full effect
WASM	Skia RuntimeEffect	Full effect

Basic Usage

var lensCenter by remember { mutableStateOf(Offset(100f, 100f)) }

Box(
  modifier = Modifier
    .fillMaxSize()
    .pointerInput(Unit) {
      detectDragGestures { change, _ ->
        lensCenter = change.position
      }
    }
    .cloudy(radius = 15) // Use Cloudy for blur (independent)
    .liquidGlass(lensCenter = lensCenter) // Lens distortion effect
) {
  Image(
    painter = painterResource(R.drawable.photo),
    contentDescription = null,
    modifier = Modifier.fillMaxSize()
  )
}

Combining with Cloudy Blur

The liquidGlass() and cloudy() modifiers are independent and composable:

// Blur only
.cloudy(radius = 20)

// Lens effect only
.liquidGlass(lensCenter = lensCenter)

// Both effects combined
.cloudy(radius = 15)
.liquidGlass(lensCenter = lensCenter)

This separation gives you full access to Cloudy's blur API (radius, onStateChanged, CloudyState) while using the liquid glass lens effect.

Customization

You can customize the liquid glass effect with various parameters:

.liquidGlass(
  lensCenter = lensCenter,
  lensSize = Size(350f, 350f),  // Size of the glass lens
  cornerRadius = 50f,           // Rounded corners
  refraction = 0.25f,           // Distortion amount
  curve = 0.25f,                // Lens curvature strength
  dispersion = 0.0f,            // Chromatic dispersion (RGB separation)
  saturation = 1.0f,            // Color saturation
  contrast = 1.0f,              // Light/dark contrast
  tint = Color.Transparent,     // Optional color tint
  edge = 0.2f,                  // Edge lighting width
)

Parameters

Parameter	Default	Description	Fallback (Android 32-)
lensCenter	-	Center position of the glass lens (required)	Yes
lensSize	350x350	Size of the lens in pixels	Yes
cornerRadius	50f	Corner radius for rounded rectangle shape	Yes
refraction	0.25f	Controls how much background distorts through lens	No (requires API 33+)
curve	0.25f	Controls how strongly lens curves at center vs edges	No (requires API 33+)
dispersion	0.0f	Chromatic dispersion/aberration intensity	No (requires API 33+)
saturation	1.0f	Color saturation (1.0 = normal)	Approximation
contrast	1.0f	Light/dark contrast (1.0 = normal)	Approximation
tint	Transparent	Optional color tint overlay	Yes
edge	0.2f	Edge lighting width (0 = none)	Yes (as stroke)
enabled	true	Enable/disable the effect	Yes

Note: On Android 32 and below, the lens refraction effect is not available since it requires RuntimeShader (API 33+). The fallback draws a visible lens shape with tint, edge lighting, and color adjustments. For blur effects, use Modifier.cloudy() separately.

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Acknowledgements

The liquid glass shader implementation was inspired by FletchMcKee/liquid.

License

Designed and developed by 2022 skydoves (Jaewoong Eum)

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.