Is there a reason why `DirectionalAlignment` is a private class? Being able to create an alignment ...

# compose

[bruno.aybar]

Is there a reason why DirectionalAlignment is a private class? Being able to create an alignment with custom vertical and horizontal bias could be really useful. In my case I need to move a component around, and this seemed like the easiest way:

@Composable
fun Sample {

    val offset = animatedFloat(initVal = ...)
    onActive { offset.animateTo(...) }

    Stack {
        SomethingThatMoves(Modifier.align(DirectionalAlignment(offset.value,offset.value)))
    }
}

Given that it's private, I just copy & pasted the class, and worked perfectly. Is there another easy way to accomplish that?

[Nader Jawad]

We do provide the Alignment interface and DirectionalAlignment implements that. We also provide some default alignment implementations for center, bottom right, top left, etc.

[bruno.aybar]

Yes, and those implementations look like

@Stable
        val TopStart: Alignment = DirectionalAlignment(-1f, -1f)
        @Stable
        val TopCenter: Alignment = DirectionalAlignment(-1f, 0f)
        @Stable
        val TopEnd: Alignment = DirectionalAlignment(-1f, 1f)
        @Stable
        val CenterStart: Alignment = DirectionalAlignment(0f, -1f)
        @Stable
        val Center: Alignment = DirectionalAlignment(0f, 0f)

But let's say that I want some element not quite at the top center, but almost there (verticalBias = -0.75f instead of -1f).

Why not provide the ability to create new instances of that DirectionalAlignment implementation?

As you say, yes it's an interface so custom implementations can be easily created, that's really good. Just wondering if there's any reason why that specific implementation is private instead of public.

[Mihai Popa]

Could you please file a bug to make this public? Thanks 🙂

[Nader Jawad]

Looks like AbsoluteAlignment is exposed and supports the use case you are looking for although it does not expose rtl support

[Mihai Popa]

AbsoluteAlignment 's constructor is also internal

[Mihai Popa]

We want to provide a few factories for `Alignment`s. You should not need to copy paste DirectionalAlignment to create custom Alignments by percentage

[bruno.aybar]

@Nader Jawad I was not aware of AbsoluteAlignment ! That's actually what I was looking for, as I don't need rtl support

[bruno.aybar]

@Mihai Popa done! Here's the bug: https://issuetracker.google.com/issues/169406772