what is the difference between

modifier.clip(RoundedCornerShape(20.dp).background(Color.White)

and

modifier.background(color = Color.White, shape = RoundedCornerShape(20.dp))

Drawing a shape will always be cheaper than clipping a shape

but is this the same effect?

Clipping is more expensive and can produce some aliasing artifacts on older API levels. If you just want to draw a shape it would be better to draw it outright

then if i add padding after background with shape i think then that is better than clipping, am i right

Yes padding just changes the drawing bounds and does not clip. Compose does not clip UI components by default as opposed to the Android View system which always clips to bounds

but if i want to make the children take the shape of its parent then clipping is what i should use

Strictly speaking clipRect is much cheaper than clipPath but if you can avoid clipping that would be best

thanks very much that was helpful

Interesting convo and just following along. I don't know how much more expensive one technique is over the other, but I could see myself doing this in the future. Is a lint check or something like that possible here?

Not sure if this is possible with a lint check because it is valid to use a clip with a shape and for various use cases it is the only solution. Prefer drawing a shape if you can and if you need to clip, clipping to a rectangle via clipRect is fairly cheap however clipPath is more expensive and can have visual artifacts on older API levels.

could i ask how to clip using clipRect, from what i see clip takes only shape

That will happen if either you use

Modifier.clipToBounds

or

Modifier.clip(RectangleShape)

using

Modifier.clipToBounds

will not work with the shape in the

modifier.background

write? and does

RoundedCornerShape

have the same effect as

RectangleShape

Yes

Modifier.clipToBounds

will not achieve the effect you are looking for as you are using rounded corners.

thanks a lot.