Map Drawer Part 2

MapDrawer.kt

@Composable
fun MapDrawer(onDrawingEnd : (List<Point>) -> Unit) {
    var state by remember { mutableStateOf(MapPolygonState()) }
    val brush = remember { SolidColor(Color.Black) }
    val path = remember { Path() }
    Canvas(
        modifier = Modifier
            .fillMaxSize()
            .pointerInput(Unit) {
                awaitEachGesture {
                    val screenPoints = mutableListOf<Point>()
                    awaitPointerEvent().changes
                        .first()
                        .also { changes ->
                            val position = changes.position
                            screenPoints.add(position.toPoint())
                            state = state.copy(
                                currentPosition = position,
                                event = DrawerMotionEvent.down
                            )
                        }
                    do {
                        val event: PointerEvent = awaitPointerEvent()
                        event.changes.forEach { changes ->
                            val position = changes.position
                            screenPoints.add(position.toPoint())
                            state = state.copy(
                                currentPosition = position,
                                event = DrawerMotionEvent.move
                            )
                        }
                    } while (event.changes.any { it.pressed })
                    
                    currentEvent.changes
                        .first()
                        .also { change ->
                            state = state.copy(
                                currentPosition = change.position,
                                event = DrawerMotionEvent.up
                            )
                            screenPoints.add(change.position.toPoint())
                        }
                    onDrawingEnd.invoke(screenPoints)
                }
            },
        onDraw = {
            when (state.event) {
                DrawerMotionEvent.idle -> Unit
                DrawerMotionEvent.up, DrawerMotionEvent.move -> path.lineTo(
                    state.currentPosition.x,
                    state.currentPosition.y
                )

                DrawerMotionEvent.down -> path.moveTo(
                    state.currentPosition.x,
                    state.currentPosition.y
                )
            }
            drawPath(
                path = path,
                brush = brush,
                style = Stroke(width = 5f)
            )
        }
    )
}