I have a

Box

and I want to use

pointerInput

to detect drag gestures inside this box, but I want to ignore cases when drag starts in the smaller child in center of that box. For example box is 400x400.dp and I want to ignore drags coming from within 100x100.dp of its centered child. How can I achieve this? Use

onGlobalLayout

to capture the position and size of the child and then in

onDrag

check if

change: PointerInputChange

comes from a child area and do not do what I usually do there in this case?

You can observe the

interactionSource

of the child, and do nothing in case it was being dragged:

val interactionSource = remember { MutableInteractionSource() }
val isChildDragged by interactionSource.collectIsDraggedAsState()
Box(
   modifier = Modifier.pointerInput{
   // check if isChildDragged or not
}
) {
    Child(
modifier = Modifier.draggable(
    interactionSource = interactionSource,
    ...
)
)
}

You don't need

onGloballyPositioned

for this case,

onPlaced

is sufficient and much cheaper since you're only using it to grab the LayoutCoordinates and then read it later.

Thanks for suggestions! By "not consuming" you mean simply not doing the usual action, or do I have to somehow explicitly state that I do not consume a certain event? I'm not very familiar with gesture APIs yet...

When you are processing the events for a drag, you need to explicitly consume them (by calling the consume* methods on the event), so the views underneath you don't process them again.

right, in the View api I was returning true/false from onTouchEvent. In compose I plan to use

pointerInput

+

detectDragGestures

. I see that

change

parameter of the latter has the

consume

method, so I will play with this! 🙂