Bevy-UI String Parser Utilities

This rust crate provides a set of parsing functions that can be used to convert strings into various bevy-ui types like Color, Val or UiRect. The syntax matches CSS, but it doesn't try to replicate it perfectly.

It depends on the nom library for parsing.

Parsers

Color

Parses Color values, such as #f0f or yellow.

use bevy::render::color::Color;
use bevy_ui_string_parser::color_string_parser;
let color: Option<Color> = color_string_parser("#f00");
assert_eq!(color, Some(Color::RED));

Supported syntax

• red, blue -> css color names (see https://drafts.csswg.org/css-color/#named-colors)
• #f0f, #ff00ff -> hex color (3 or 6 digits)
• #ff00ff00 -> hex color with alpha (8 digits)
• rgb(1.0, 0.0, 0.0) -> rgb color (0.0-1.0)
• rgba(1.0, 0.0, 0.0, 1.0) -> rgb color with alpha (0.0-1.0)
• hsl(0.0, 1.0, 0.5) -> hsl color (0.0-1.0)
• hsla(0.0, 1.0, 0.5, 1.0) -> hsl color with alpha (0.0-1.0)

Val

Parses Val values, such as 1px or 50%.

use bevy::ui::Val;
use bevy_ui_string_parser::val_string_parser;
let value: Option<Val> = val_string_parser("45%");
assert_eq!(value, Some(Val::Percent(45.0)));

Supported syntax

• auto -> Val::Auto
• 12px -> Val::Px(12.0)
• 12% -> Val::Percent(12.0)
• 12vw -> Val::Vw(12.0)
• 12vh -> Val::Vh(12.0)
• 12vmin -> Val::VMin(12.0)
• 12vmax -> Val::VMax(12.0)

Rect

Parses UiRect values, such as 25px 50px.

This uses the same ordering as CSS properties like padding or margin, see mdn for more information.

use bevy::ui::{UiRect, Val};
use bevy_ui_string_parser::rect_string_parser;
let rect: Option<UiRect> = rect_string_parser("50px 100px");
assert_eq!(rect, Some(UiRect::new(
    Val::Px(100.0), Val::Px(100.0), Val::Px(50.0), Val::Px(50.0))));

Supported syntax

• 10px 20px 30px 40px -> top | right | bottom | left
• 10px 20px 10px -> top | left and right | bottom
• 10px 20px -> top and bottom | left and right
• 10px -> top, right, bottom and left

Angle

Parses angles into float values, such as 180deg, returns radians.

use bevy_ui_string_parser::angle_string_parser;
let angle: Option<f32> = angle_string_parser("180deg");
assert_eq!(angle, Some(180.0_f32.to_radians()));

Supported syntax

• 180deg -> 3.14159265359
• 1.3rad -> 1.3
• 1.3 -> 1.3

Serde

Each parser also provides a serde deserializer *_serde_parser, for example:

use serde::Deserialize;
use std::f32::consts::PI;

#[derive(Deserialize)]
pub struct Foo {
    #[serde(deserialize_with = "bevy_ui_string_parser::angle_serde_parser")]
    pub angle: f32,
}

let foo: Foo = serde_json::from_str(r#"{"angle": "180deg"}"#).unwrap();
assert_eq!(foo.angle, PI);

It requires the optional serde feature.

Changelog

• v0.1.2 made serde feature optional
• v0.1.1 readme added
• v0.1.0 initial release