A region is a fraction of the output plus an offset and the shader resolves it against the window every frame, so a resize already moves the whole drawing without the CPU. Wiping the tree and drawing it again was throwing that away. `Painter::output_size` and `px_size` now record that a widget read pixels, the way reading a child's size records a dependency on it, and a resize marks only those. In the `text` example that is the two wrapping paragraphs out of forty-odd widgets; everything else keeps its drawing and the window uniform puts it in the right place. Two defects the change surfaced, both of which made a resize land somewhere a cold start would not: `redraw` climbed to the highest reader of the changed widget and drew from there, trusting that draw to reach back down. It does not: an intermediate whose own box has not changed is reused as it stands and the draw stops there. Everything between the two is now marked as well, which is the only thing that stops the reuse. Not resize-specific -- `a_change_two_levels_under_its_reader_still_reaches_it` fails on the mutation path too. `mov` cannot stretch a drawing out of a box with no relative extent. `UiScalar::within` puts a part into such a box as a plain offset from its start, and `lerp_inv`'s divide-by-zero fallback then returns a rel of 0 rather than saying it cannot invert, so the remap silently leaves the drawing its old size. `OnResize::Scale` now only reuses across a length change when the old box had a relative extent. The underlying loss belongs to the position chain, which separates the drawn box from the offered one; until then this is the honest predicate. Checked: fmt, clippy and 33 tests. `tabs` (with the image replay), `view`, `minimal` still byte-identical to `upstream/main`, and `text` unchanged at 1920x1200 and 900x1200. Driven live under the GPU as well: started at 1920x1200, resized to 900x1200 and back through sway, and each screenshot matches a cold start at that size byte for byte.
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