iris
f192f75b25
`desired_width`/`desired_height`, `WidgetAxisFns`, `SizeCtx` and the size cache are gone. A widget states what it used with `Painter::set_size` while it draws, and `Painter::widget` hands back a `DrawResult` whose `size()` both reads the child and records that this widget's size depends on it. Reading nothing keeps the parent independent of what the child came to. `Span` is what the change is for. It takes each child's `size_hint` where there is one, draws only the children that cannot answer, allocates the flexible space, then places everything -- which deletes `desired_ortho`, whose own comment said it "literally copies draw ... which makes this slow and not cool". Invalidation follows the dependency edges the draw recorded: a widget that needs redrawing hands off to the highest ancestor that read its size, instead of re-running a measurement to find out whether anything changed. `Widget::size_dependence(axis)` says how much of its box a widget's drawing depends on -- none of it, its own extent, or the whole box -- so the retained path can keep a drawing and write a new box into it. Asked per axis, because wrapped text depends on the width it is offered and not on the height. `Internal` does not yet buy more than `External`: keeping a drawing when only the room around it changed is a translation, which waits for the move chain. `tests/retained.rs` covers the second frame rather than the first, which is where the bugs were: a placed child that was not recorded as one got pruned as departed on the next draw. `examples/text.rs` is new, since wrapping was the one thing here with no way to see it on its own.
iris
My experimental attempt at a rust ui library (also my first ui library).
It's currently designed around using retained data structures (widgets), rather than diffing generated trees from data like xilem or iced. This is an experiment and I'm not sure if it's a good idea or not.
Examples are in examples, eg. cargo run --example tabs.
Goals, in general order:
- does what I want it to (text, images, video, animations)
- very easy to use ignoring ergonomic ref counting
- reasonably fast / efficient (a lot faster than electron, save battery life, try to beat iced and xilem)
dev details
not targeting web rn cause wanna use actual nice gpu features & entire point of this is to make desktop apps / not need a web browser
general ideas trynna use rn / experiment with:
- retained mode
- specifically designed around wgpu so there's no translation
- postfix functions for most things to prevent unreadable indentation (going very well)
- events can be done directly where you draw the widgets
- almost no macros in user code & actual LSP typechecking (variadic generics if you can hear me please save us)
- relative anchor + absolute offset coord system (+ "rest" / leftover during widget layout)
- single threaded ui & pass context around to make non async usage straightforward (pretty unsure about this)
- widgets store outside of the actual rendering so they can be moved around and swapped easily (unsure about this but seems to work good for now)
under heavy initial development so not gonna try to explain status, maybe check TODO for that; sizable chance it gets a rewrite once I know everything I need and what seems to work best
it's called iris because it's the structure around what you actually want to display and colorful