Multitouch: Panning, zooming, rotating

To detect multitouch gestures used for panning, zooming and rotating, you can use the transformable modifier. This modifier does not transform elements by itself, it only detects the gestures.

@Composable
privatefunTransformableSample(){
// set up all transformation states
varscalebyremember{mutableFloatStateOf(1f)}
varrotationbyremember{mutableFloatStateOf(0f)}
varoffsetbyremember{mutableStateOf(Offset.Zero)}
valstate=rememberTransformableState{zoomChange,offsetChange,rotationChange->
scale*=zoomChange
rotation+=rotationChange
offset+=offsetChange
}
Box(
Modifier
// apply other transformations like rotation and zoom
// on the pizza slice emoji
.graphicsLayer(
scaleX=scale,
scaleY=scale,
rotationZ=rotation,
translationX=offset.x,
translationY=offset.y
)
// add transformable to listen to multitouch transformation events
// after offset
.transformable(state=state)
.background(Color.Blue)
.fillMaxSize()
)
}
GesturesSnippets.kt 

A UI element responding to multitouch gestures—panning, zooming, and rotating

If you need to combine zooming, panning and rotation with other gestures, you can use the PointerInputScope.detectTransformGestures detector.

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