Is it possible to merge `Preview` annotations? Fo...

# compose

[eygraber]

Is it possible to merge Preview annotations?

For example, if I have a annotation class FontScalePreviews annotated with a bunch of different @Preview with fontScale set, and a annotation class DensityScalePreviews with a bunch of different @Preview with device set, can I create another annotation that merges those?

[mattinger]

I tried this, and it seems like when it encounters that, it renders multiple previews. The Preview annotation is allowed to be specified multiple times, so that you can see a variety of different preview configurations of a single function. I'm not convinced there's a way to have it merge the attributes together. So while you can create a composite annotation, there's no way to mix and match. Each Preview annotation gets rendered on it's own

[Alex Vanyo]

Yeah, the current behavior is that each underlying @Preview annotation will be rendered, and they won’t “cross-multiply” to apply combinations. That would be cool for `@Preview`s that have orthogonal parameters specified, but I’m not sure how you’d handle cases where multiply `@Preview`s specify the same conflicting parameter.

You would probably just have to make a new multi-preview annotation with the manual merging.

[eygraber]

I was imagining some way of specifying which parameters to merge.

I was able to achieve this by just exploding the Preview annotations for every combination of font scale and density that I wanted, but there's a lot 😬