Add ratio method to Size

[tigerros]

A new aspect_ratio function to create a Responsive with a given ratio. More info in the doc and examples.

A simple aspect_ratio function for Size<f32> which returns a new Size that satisfies the given aspect ratio within the bounds of the current Size while being as large as possible.

[airstrike]

For the record—and I understand this is subjective—I'm not a huge fan of the double closures API as it "feels out of place" (again subjective) relative to how other widgets work.

My current half-baked view is that the ideal implementation would be one that modifies Responsive to include additional fields such that it allows for configuration of its sizing strategy between:

1. the current "Fill parent in both axes" approach
2. Fill only the width axis
3. Fill only the height axis
4. fill by using an aspect ratio

I haven't explored a draft implementation yet but that's my current thinking in terms of what I've seen people need, what I'd like to have myself, and what I think would feel idiomatic for iced.

[tigerros]

double closures API as it "feels out of place" (again subjective) relative to how other widgets work

Could this be because there's not a lot of helpers/widgets that work with Responsive? If you wanted to create other Responsive helpers, you might encounter this pattern again. One closure to generate the Element, then another closure to (optionally) wrap the modified Element from the first one, because wrapping the whole Responsive outside of the helper doesn't produce the same behavior.

[edwloef]

Could this maybe also be a helper function in the layout module, similar to layout::atomic but with a fixed aspect ratio?

[tigerros]

Changed it to just a simple Size function because forcing it to be a Responsive had issues. Now it's simpler, easier to use and more flexible.

[hecrj]

Thanks!