calculateCentroid

fun PointerEvent.calculateCentroid(useCurrent: Boolean = true): Offset

Returns the centroid of all pointers that are down and were previously down. If no pointers are down, Offset.Unspecified is returned. If useCurrent is true, the centroid of the PointerInputChange.position is returned and if false, the centroid of the PointerInputChange.previousPosition is returned. Only pointers that are down in both the previous and current state are used to calculate the centroid.

Example Usage:

Code Examples

CalculateCentroidSize

@Composable
fun CalculateCentroidSize() {
    var centroidSize by remember { mutableStateOf(0f) }
    var position by remember { mutableStateOf(Offset.Zero) }
    Box(
        Modifier.drawBehind {
                // Draw a circle where the gesture is
                drawCircle(Color.Blue, centroidSize, center = position)
            }
            .pointerInput(Unit) {
                awaitEachGesture {
                    awaitFirstDown().also { position = it.position }
                    do {
                        val event = awaitPointerEvent()
                        val size = event.calculateCentroidSize()
                        if (size != 0f) {
                            centroidSize = event.calculateCentroidSize()
                        }
                        val centroid = event.calculateCentroid()
                        if (centroid != Offset.Unspecified) {
                            position = centroid
                        }
                    } while (event.changes.any { it.pressed })
                }
            }
            .fillMaxSize()
    )
}