Skip to main content

AsyncPicTransition

Sealed class controlling the reveal animation when an image finishes loading.

sealed class AsyncPicTransition {
    object Standard : AsyncPicTransition()
    data class ShaderReveal(
        val type: RevealType = RevealType.DISSOLVE,
        val durationMillis: Int = 1000
    ) : AsyncPicTransition()
}

AsyncPicTransition.Standard​

Default behavior — uses Coil's built-in crossfade. Works on all API levels.

transition = AsyncPicTransition.Standard

AsyncPicTransition.ShaderReveal​

GPU-accelerated AGSL shader transition. Requires Android 13 (API 33). Silently ignored on older versions.

transition = AsyncPicTransition.ShaderReveal(
    type = RevealType.DISSOLVE,
    durationMillis = 1000
)
FieldTypeDefaultDescription
typeRevealTypeDISSOLVEWhich shader effect to use
durationMillisInt1000Duration of the animation in ms

RevealType​

enum class RevealType {
    DISSOLVE,   // Noise-based particle dissolve
    PIXELATE,   // Block pixels that resolve to full image
    WIPE        // Left-to-right wipe
}

DISSOLVE​

Uses a fract(sin(...)) noise function to reveal the image one random pixel group at a time. The most organic-looking transition.

PIXELATE​

Starts at blockSize = 50px and shrinks to 0 as progress increases. Creates a retro pixel-art style reveal.

WIPE​

Linear left-to-right reveal: pixels left of progress * resolution.x are shown, pixels right are transparent.

AGSL Shader Source​

The three shaders are defined in AsyncPicShaders:

object AsyncPicShaders {
    const val DISSOLVE_SHADER: String
    const val PIXELATE_SHADER: String
    const val WIPE_SHADER: String
}

Each shader receives a progress uniform (0.0 → 1.0) driven by animateFloatAsState. PIXELATE and WIPE additionally receive a resolution uniform (width, height in pixels).