---
title: "Change: stamp"
description: An element comes down like a rubber stamp, squashes on impact and puffs dust when a value changes.
---

Stamp brings the element down from slightly larger than its size, as if it were pressed onto the page. It lands with a squash, settles with one small rebound and puffs dust out at its base. Use it for a verdict: approved, rejected, verified, sold.

## Usage

The sample stamps an "Approved" label when a report's status changes.

```kotlin
import androidx.compose.foundation.border
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.BasicText
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.rotate
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.unit.dp
import com.jantursky.kapow.ChangeEffect
import com.jantursky.kapow.changeEffect

@Composable
fun StatusStamp(status: String) {
    val coral = Color(0xFFFF6B5A)
    BasicText(
        text = status.uppercase(),
        style = TextStyle(color = coral),
        modifier = Modifier
            .changeEffect(status, ChangeEffect.stamp(scale = 1.4f))
            .rotate(-8f)
            .border(2.dp, coral, RoundedCornerShape(6.dp))
            .padding(horizontal = 10.dp, vertical = 4.dp),
    )
}
```

## Parameters

| Parameter | Default | Description |
| --- | --- | --- |
| `scale` | `1.3f` | How much larger the element starts. Must be at least 1. |
| `dustColor` | `Color(0xFFB0B0B0)` | Color of the dust puffs at the base. |
| `duration` | `560.milliseconds` | How long the stamp takes from the start of the drop to the end of the rebound. A quarter of it is the drop. Must be positive. |
| `squash` | `0.1f` | How flat the impact squashes the element, as a fraction of its size, from 0 to 0.5. |
| `rebound` | `1f` | How much the element springs back after the squash, from 0 (settles at once) to 1. |
| `dustCount` | `5` | How many puffs of dust fly out to each side. 0 leaves out the dust. |
| `dustSize` | `8.dp` | The size of a puff of dust. Must be positive. |
| `dustSpread` | `1f` | How far the dust flies, as a factor on the standard. |
| `tilt` | `0f` | How many degrees the element is turned as it starts to drop. It levels out as it lands. |
| `origin` | `TransformOrigin.Center` | The point the element drops around, as fractions of its width and height. |
| `seed` | `0` | The first seed. Each landing takes the next ones, so the same seed gives the same dust. |

## Reduced motion

The element does not move or scale and no dust is puffed. It brightens briefly. With `reducedMotion(ReducedMotionMode.EndState)` nothing shows at all, since the effect ends at rest.

## Notes

- The drop takes 0.14 s and speeds up as it comes down, starting faint and turning fully opaque as it lands. The squash and the settle take another 0.42 s.
- The squash flattens the element by up to 10 % and widens it by 7 %, with its base kept on the ground. There is one small rebound and no shake.
- The dust runs out sideways from both bottom corners. It draws through a [particle layer](/guides/particle-layer) when there is one above the element.
- Scaling happens in the element's own graphics layer, so the layout around it does not move.
- There is no cooldown. A change during a stamp starts it again from the top.

## Live example

<iframe class="live-example" src="https://kapow-demo.vercel.app/#change-stamp" title="Live example: change-stamp" loading="lazy" allow="autoplay"></iframe>