mirror of
https://github.com/a-b-street/abstreet.git
synced 2024-11-28 20:29:04 +03:00
111 lines
4.2 KiB
Markdown
111 lines
4.2 KiB
Markdown
# widgetry notes
|
|
|
|
Rustwarts School of Glitchcraft and Widgetry.
|
|
|
|
This is a GUI + 2D drawing + data viz library I've built up for A/B Street. I'm
|
|
considering cleaning up the API surface and making it a proper standalone crate.
|
|
|
|
## Running the demo
|
|
|
|
Because of wasm-pack issues, normal Rust example binaries don't work. The
|
|
example code is instead in the
|
|
[widgetry_demo crate](../widgetry_demo/src/lib.rs).
|
|
|
|
```
|
|
git clone https://github.com/a-b-street/abstreet.git
|
|
cd abstreet/widgetry_demo
|
|
cargo run
|
|
|
|
# Or for web
|
|
cd abstreet/widgetry_demo
|
|
./run_web.sh
|
|
```
|
|
|
|
|
|
|
|
If you want a more thorough idea of what this crate can do, see
|
|
[A/B Street](https://abstreet.org).
|
|
|
|
## Features
|
|
|
|
### Runs in lots of places
|
|
|
|
Runs on Linux, Mac, Windows via [glow](https://github.com/grovesNL/glow/). Also
|
|
works in the browser using WebAssembly, but text support still coming in
|
|
[a few months](https://github.com/RazrFalcon/resvg/issues/229).
|
|
|
|
Why OpenGL? My requirements are super simple; I don't need the power of Vulkan
|
|
or other new stuff. I want something simple that runs everywhere. If you want to
|
|
make this work with WGPU or something else, it should be easy. The backends are
|
|
a few hundred lines -- [Glow](src/backend_glow.rs) running either
|
|
[on native](src/backend_glow_native.rs) or [on wasm](src/backend_glow_wasm.rs).
|
|
|
|
### 2D drawing
|
|
|
|
Everything is a colored polygon. Upload stuff once, redraw many times with a
|
|
simple camera transform. Panning and smooth zooming. One extremely simple
|
|
shader.
|
|
|
|
Thanks to [usvg](https://github.com/RazrFalcon/resvg) and
|
|
[lyon](https://github.com/nical/lyon/), SVGs and text are transformed into
|
|
colored polygons. Programatically swap colors, rotate, scale stuff. Find bounds
|
|
for precise mouseover.
|
|
|
|
### GUI
|
|
|
|
Widgets like buttons (with keybindings), checkboxes, sliders, pop-up menus, text
|
|
entry, and some data viz things. You can combine these in `Panel`s to dispatch
|
|
event handling and drawing. Styling (background colors, outline, padding) and
|
|
Flexbox-ish layouting via [stretch](https://vislyhq.github.io/stretch/).
|
|
|
|
The API / programming style is kind of funny; see the
|
|
[demo](../widgetry_demo/src/lib.rs) to get a sense of it. No callbacks. You
|
|
manually feed events into your `Panel`s of widgets and ask about what happened.
|
|
There's no smart diffing of widget trees; most of the time it's fine to
|
|
completely recreate a `Panel` from scratch when something changes, or replace a
|
|
single widget in an existing `Panel`.
|
|
|
|
(This is not a performance critical library. The perf bottlenecks in A/B Street
|
|
are not in the GUI, and I probably won't invest much time speeding things up
|
|
here until they are. (Or if somebody else winds up using this library and hits a
|
|
problem.))
|
|
|
|
### Data visualization
|
|
|
|
Not exactly sure how this wound up in here too, but at some point I needed
|
|
histograms and line plots that update live over time and show some info when you
|
|
mouseover points, so here it is.
|
|
|
|
## Big problems to solve before release
|
|
|
|
When you ask a `Panel` what action happened (what button was clicked), it hands
|
|
you back `Option<String>`. Not so typesafe. How boilerplatey is it to associate
|
|
buttons with a user-provided enum?
|
|
|
|
There are hardcoded colors / padding in lots of places. Need to make style
|
|
easily configurable, with good defaults.
|
|
|
|
The error handling is pretty bad; lots of unwraps and panics to clean up.
|
|
|
|
When returning a `Transition::Replace`, ideally we can consume `self` instead of
|
|
just having `&mut self`, so we can avoid cloning stuff from one `State`.
|
|
|
|
## Why another Rust GUI library?
|
|
|
|
When I started, nothing did what I needed, or it required awkward callbacks.
|
|
Today, [iced](https://github.com/hecrj/iced) looks awesome, but wgpu doesn't
|
|
work on my laptop. This is a dealbreaker -- I want to build stuff that runs
|
|
~anywhere. I looked into adding an OpenGL backend, but the current structure of
|
|
iced has a
|
|
[huge](https://github.com/hecrj/iced/blob/master/native/src/renderer/null.rs)
|
|
API surface to implement for a new backend.
|
|
|
|
For the moment, I don't have enough time to get something else on-par with this
|
|
library and port A/B Street over, so I'll continue to invest in this library. If
|
|
there's lots of interest in other people using this library, I'll invest much
|
|
more and make it a real contender.
|
|
|
|
## Future work
|
|
|
|
- Draggable panels
|