Make Data panel scalars selectable inline, denoise float display, and standardize breadcrumb string truncation (#4470)

* Make Data panel scalars selectable inline, denoise float display, and move breadcrumb truncation to Rust

* Code review fixes

* Remove denoising from f32

node-graph/libraries/core-types/src/math/float_noise.rs

@@ -0,0 +1,71 @@
+use std::fmt::Write;
+
+/// Recovers the intended number from floating point imprecision noise when that can be done reliably, e.g. 0.30000000000000004 -> 0.3.
+/// Rounding to each significant digit count from 1 to 12, the first candidate within a relative 1e-13 of the original is accepted.
+/// Actual high-precision values (like 0.3333333333333333) never pass the tolerance and are returned unchanged.
+/// f64 only, as f32 lacks precision to reliably distinguish between intentional digits and noise.
+pub fn round_away_float_noise(value: f64) -> f64 {
+	if value == 0. || !value.is_finite() {
+		return if value == 0. { 0. } else { value };
+	}
+
+	// Candidates come from decimal formatting rather than scaling by a power of ten, which is inexact enough to invent
+	// noise of its own: it turns 1e300 into 9.999999999999999e299 and 999999.9999999 into 999999.9999999999.
+	// One buffer serves every candidate, since the digit counts are tried in turn.
+	let mut buffer = String::with_capacity(32);
+	for significant_digits in 1..=12 {
+		buffer.clear();
+		let _ = write!(buffer, "{value:.*e}", significant_digits - 1);
+
+		let Ok(rounded) = buffer.parse::<f64>() else { continue };
+		if ((rounded - value) / value).abs() < 1e-13 {
+			return rounded;
+		}
+	}
+
+	value
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn round_away_float_noise_snaps_noisy_values() {
+		assert_eq!(round_away_float_noise(0.1 + 0.2), 0.3);
+		assert_eq!(round_away_float_noise(0.3000000000000012), 0.3);
+		assert_eq!(round_away_float_noise(2.99999999999993), 3.);
+		assert_eq!(round_away_float_noise(45.00000000000001), 45.);
+	}
+
+	#[test]
+	fn round_away_float_noise_keeps_honest_values() {
+		assert_eq!(round_away_float_noise(1. / 3.), 1. / 3.);
+		assert_eq!(round_away_float_noise(0.2394023940209349), 0.2394023940209349);
+		assert_eq!(round_away_float_noise(0.25), 0.25);
+		assert_eq!(round_away_float_noise(-17.5), -17.5);
+	}
+
+	#[test]
+	fn round_away_float_noise_keeps_deliberate_values_with_zero_runs() {
+		assert_eq!(round_away_float_noise(0.30000005), 0.30000005);
+		assert_eq!(round_away_float_noise(0.3000000000001), 0.3000000000001);
+		assert_eq!(round_away_float_noise(1.00000001), 1.00000001);
+		assert_eq!(round_away_float_noise(2.9999993), 2.9999993);
+	}
+
+	#[test]
+	fn round_away_float_noise_normalizes_zero() {
+		let result = round_away_float_noise(-0.);
+		assert_eq!(result, 0.);
+		assert!(result.is_sign_positive());
+	}
+
+	#[test]
+	fn round_away_float_noise_keeps_extreme_magnitudes_exact() {
+		assert_eq!(round_away_float_noise(1e300), 1e300);
+		assert_eq!(round_away_float_noise(1.5e300), 1.5e300);
+		assert_eq!(round_away_float_noise(1e-300), 1e-300);
+		assert_eq!(round_away_float_noise(f64::MIN_POSITIVE), f64::MIN_POSITIVE);
+	}
+}

node-graph/libraries/core-types/src/math/mod.rs

@@ -1,4 +1,5 @@
 pub mod bbox;
+pub mod float_noise;
 pub mod polynomial;
 pub mod quad;
 pub mod rect;

node-graph/libraries/core-types/src/ops.rs

@@ -1,6 +1,7 @@
 use crate::Node;
+use crate::math::float_noise::round_away_float_noise;
 use crate::transform::Footprint;
-use glam::DVec2;
+use glam::{DAffine2, DVec2};
 use std::future::Future;
 use std::marker::PhantomData;
 
@@ -45,11 +46,26 @@ pub trait Convert<T, C>: Sized {
 	fn convert(self, footprint: Footprint, converter: C) -> impl Future<Output = T> + Send;
 }
 
-impl<T: ToString + Send> Convert<String, ()> for T {
-	/// Converts this type into a `String` using its `ToString` implementation.
+/// Implements the [`Convert`] trait for formatting a type into a `String` via [`ToString`].
+macro_rules! impl_convert_to_string {
+	($($from:ty),* $(,)?) => {
+		$(
+			impl Convert<String, ()> for $from {
+				#[inline]
+				async fn convert(self, _: Footprint, _converter: ()) -> String {
+					self.to_string()
+				}
+			}
+		)*
+	};
+}
+impl_convert_to_string!(f32, u32, u64, i32, i64, bool, DVec2, DAffine2);
+
+// Denoised so 0.1 + 0.2 reaches the string as "0.3" rather than "0.30000000000000004"
+impl Convert<String, ()> for f64 {
 	#[inline]
 	async fn convert(self, _: Footprint, _converter: ()) -> String {
-		self.to_string()
+		round_away_float_noise(self).to_string()
 	}
 }