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nih-plug/src/formatters.rs
2022-03-08 18:45:18 +01:00

39 lines
1.6 KiB
Rust

//! Convenience functions for formatting and parsing parameter values in common formats.
use std::sync::Arc;
/// Round an `f32` value to always have a specific number of decimal digits.
pub fn f32_rounded(digits: usize) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
Arc::new(move |x| format!("{:.digits$}", x))
}
/// Format a `[0, 1]` number as a percentage. Does not include the percent sign, you should specify
/// this as the parameter's unit.
pub fn f32_percentage(digits: usize) -> Arc<dyn Fn(f32) -> String + Send + Sync> {
Arc::new(move |value| format!("{:.digits$}", value * 100.0))
}
/// Parse a `[0, 100]` percentage to a `[0, 1]` number. Handles the percentage unit for you. Used in
/// conjunction with [`f32_percentage`].
pub fn from_f32_percentage() -> Arc<dyn Fn(&str) -> Option<f32> + Send + Sync> {
Arc::new(|string| {
string
.trim_end_matches(&[' ', '%'])
.parse()
.ok()
.map(|x: f32| x / 100.0)
})
}
/// Format an order/power of two. Useful in conjunction with [`from_power_of_two()`] to limit
/// integer parameter ranges to be only powers of two.
pub fn i32_power_of_two() -> Arc<dyn Fn(i32) -> String + Send + Sync> {
Arc::new(|value| format!("{}", 1 << value))
}
/// Parse a parameter input string to a power of two. Useful in conjunction with [`power_of_two()`]
/// to limit integer parameter ranges to be only powers of two.
pub fn from_i32_power_of_two() -> Arc<dyn Fn(&str) -> Option<i32> + Send + Sync> {
Arc::new(|string| string.parse().ok().map(|n: i32| (n as f32).log2() as i32))
}