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kotlinlang

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. 

Then yea you're on the right track, just make sure not to consume the events when you want to ignore them. 

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. 

This isn't a compose thing, pointer events work this way in views too the api is just different. 

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! :slightly_smiling_face: