Add `emath::OrderedFloat` (moved from `epaint::util::OrderedFloat`) (#4389)

It makes much more sense in `emath`

Cargo.lock

@@ -1242,6 +1242,7 @@ dependencies = [
  "ahash",
  "backtrace",
  "document-features",
+ "emath",
  "epaint",
  "log",
  "nohash-hasher",

crates/ecolor/src/rgba.rs

@@ -26,6 +26,7 @@ impl std::ops::IndexMut<usize> for Rgba {
     }
 }
 
+/// Deterministically hash an `f32`, treating all NANs as equal, and ignoring the sign of zero.
 #[inline]
 pub(crate) fn f32_hash<H: std::hash::Hasher>(state: &mut H, f: f32) {
     if f == 0.0 {

crates/egui/Cargo.toml

@@ -81,6 +81,7 @@ unity = ["epaint/unity"]
 
 
 [dependencies]
+emath = { workspace = true, default-features = false }
 epaint = { workspace = true, default-features = false }
 
 ahash.workspace = true

crates/egui/src/load.rs

@@ -55,23 +55,21 @@
 mod bytes_loader;
 mod texture_loader;
 
-use std::borrow::Cow;
-use std::fmt::Debug;
-use std::ops::Deref;
-use std::{fmt::Display, sync::Arc};
+use std::{
+    borrow::Cow,
+    fmt::{Debug, Display},
+    ops::Deref,
+    sync::Arc,
+};
 
 use ahash::HashMap;
 
-use epaint::mutex::Mutex;
-use epaint::util::FloatOrd;
-use epaint::util::OrderedFloat;
-use epaint::TextureHandle;
-use epaint::{textures::TextureOptions, ColorImage, TextureId, Vec2};
+use emath::{Float, OrderedFloat};
+use epaint::{mutex::Mutex, textures::TextureOptions, ColorImage, TextureHandle, TextureId, Vec2};
 
 use crate::Context;
 
-pub use self::bytes_loader::DefaultBytesLoader;
-pub use self::texture_loader::DefaultTextureLoader;
+pub use self::{bytes_loader::DefaultBytesLoader, texture_loader::DefaultTextureLoader};
 
 /// Represents a failed attempt at loading an image.
 #[derive(Clone, Debug)]

crates/egui/src/widgets/image.rs

@@ -1,12 +1,12 @@
 use std::borrow::Cow;
 
-use crate::load::TextureLoadResult;
+use emath::{Float as _, Rot2};
+use epaint::RectShape;
+
 use crate::{
-    load::{Bytes, SizeHint, SizedTexture, TexturePoll},
+    load::{Bytes, SizeHint, SizedTexture, TextureLoadResult, TexturePoll},
     *,
 };
-use emath::Rot2;
-use epaint::{util::FloatOrd, RectShape};
 
 /// A widget which displays an image.
 ///

crates/egui_plot/src/items/mod.rs

@@ -3,7 +3,7 @@
 
 use std::ops::RangeInclusive;
 
-use epaint::{emath::Rot2, util::FloatOrd, Mesh};
+use epaint::{emath::Rot2, Mesh};
 
 use crate::*;
 

crates/egui_plot/src/lib.rs

@@ -17,7 +17,8 @@ use std::{cmp::Ordering, ops::RangeInclusive, sync::Arc};
 
 use egui::ahash::HashMap;
 use egui::*;
-use epaint::{util::FloatOrd, Hsva};
+use emath::Float as _;
+use epaint::Hsva;
 
 pub use crate::{
     axis::{Axis, AxisHints, HPlacement, Placement, VPlacement},

crates/emath/src/lib.rs

@@ -30,6 +30,7 @@ use std::ops::{Add, Div, Mul, RangeInclusive, Sub};
 pub mod align;
 mod history;
 mod numeric;
+mod ordered_float;
 mod pos2;
 mod range;
 mod rect;
@@ -40,10 +41,11 @@ mod ts_transform;
 mod vec2;
 mod vec2b;
 
-pub use {
+pub use self::{
     align::{Align, Align2},
     history::History,
     numeric::*,
+    ordered_float::*,
     pos2::*,
     range::Rangef,
     rect::*,

crates/emath/src/ordered_float.rs

@@ -7,9 +7,12 @@ use std::hash::{Hash, Hasher};
 /// Wraps a floating-point value to add total order and hash.
 /// Possible types for `T` are `f32` and `f64`.
 ///
-/// See also [`FloatOrd`].
+/// All NaNs are considered equal to each other.
+/// The size of zero is ignored.
+///
+/// See also [`Float`].
 #[derive(Clone, Copy)]
-pub struct OrderedFloat<T>(T);
+pub struct OrderedFloat<T>(pub T);
 
 impl<T: Float + Copy> OrderedFloat<T> {
     #[inline]
@@ -68,44 +71,34 @@ impl<T> From<T> for OrderedFloat<T> {
 ///
 /// Example with `f64`:
 /// ```
-/// use epaint::util::FloatOrd;
+/// use emath::Float as _;
 ///
 /// let array = [1.0, 2.5, 2.0];
 /// let max = array.iter().max_by_key(|val| val.ord());
 ///
 /// assert_eq!(max, Some(&2.5));
 /// ```
-pub trait FloatOrd {
+pub trait Float: PartialOrd + PartialEq + private::FloatImpl {
     /// Type to provide total order, useful as key in sorted contexts.
     fn ord(self) -> OrderedFloat<Self>
     where
         Self: Sized;
 }
 
-impl FloatOrd for f32 {
+impl Float for f32 {
     #[inline]
     fn ord(self) -> OrderedFloat<Self> {
         OrderedFloat(self)
     }
 }
 
-impl FloatOrd for f64 {
+impl Float for f64 {
     #[inline]
     fn ord(self) -> OrderedFloat<Self> {
         OrderedFloat(self)
     }
 }
 
-// ----------------------------------------------------------------------------
-
-/// Internal abstraction over floating point types
-#[doc(hidden)]
-pub trait Float: PartialOrd + PartialEq + private::FloatImpl {}
-
-impl Float for f32 {}
-
-impl Float for f64 {}
-
 // Keep this trait in private module, to avoid exposing its methods as extensions in user code
 mod private {
     use super::*;
@@ -124,7 +117,13 @@ mod private {
 
         #[inline]
         fn hash<H: Hasher>(&self, state: &mut H) {
-            crate::f32_hash(state, *self);
+            if *self == 0.0 {
+                state.write_u8(0);
+            } else if self.is_nan() {
+                state.write_u8(1);
+            } else {
+                self.to_bits().hash(state);
+            }
         }
     }
 
@@ -136,7 +135,13 @@ mod private {
 
         #[inline]
         fn hash<H: Hasher>(&self, state: &mut H) {
-            crate::f64_hash(state, *self);
+            if *self == 0.0 {
+                state.write_u8(0);
+            } else if self.is_nan() {
+                state.write_u8(1);
+            } else {
+                self.to_bits().hash(state);
+            }
         }
     }
 }

crates/epaint/src/lib.rs

@@ -152,32 +152,6 @@ macro_rules! epaint_assert {
     }
 }
 
-// ----------------------------------------------------------------------------
-
-#[inline(always)]
-pub(crate) fn f32_hash<H: std::hash::Hasher>(state: &mut H, f: f32) {
-    if f == 0.0 {
-        state.write_u8(0);
-    } else if f.is_nan() {
-        state.write_u8(1);
-    } else {
-        use std::hash::Hash;
-        f.to_bits().hash(state);
-    }
-}
-
-#[inline(always)]
-pub(crate) fn f64_hash<H: std::hash::Hasher>(state: &mut H, f: f64) {
-    if f == 0.0 {
-        state.write_u8(0);
-    } else if f.is_nan() {
-        state.write_u8(1);
-    } else {
-        use std::hash::Hash;
-        f.to_bits().hash(state);
-    }
-}
-
 // ---------------------------------------------------------------------------
 
 /// Was epaint compiled with the `rayon` feature?

crates/epaint/src/stroke.rs

@@ -48,7 +48,7 @@ impl std::hash::Hash for Stroke {
     #[inline(always)]
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         let Self { width, color } = *self;
-        crate::f32_hash(state, width);
+        emath::OrderedFloat(width).hash(state);
         color.hash(state);
     }
 }

crates/epaint/src/text/fonts.rs

@@ -8,7 +8,7 @@ use crate::{
     },
     TextureAtlas,
 };
-use emath::NumExt as _;
+use emath::{NumExt as _, OrderedFloat};
 
 // ----------------------------------------------------------------------------
 
@@ -56,7 +56,7 @@ impl std::hash::Hash for FontId {
     #[inline(always)]
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         let Self { size, family } = self;
-        crate::f32_hash(state, *size);
+        emath::OrderedFloat(*size).hash(state);
         family.hash(state);
     }
 }
@@ -567,21 +567,6 @@ impl FontsAndCache {
 
 // ----------------------------------------------------------------------------
 
-#[derive(Clone, Copy, Debug, PartialEq)]
-struct HashableF32(f32);
-
-#[allow(clippy::derived_hash_with_manual_eq)]
-impl std::hash::Hash for HashableF32 {
-    #[inline(always)]
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-        crate::f32_hash(state, self.0);
-    }
-}
-
-impl Eq for HashableF32 {}
-
-// ----------------------------------------------------------------------------
-
 /// The collection of fonts used by `epaint`.
 ///
 /// Required in order to paint text.
@@ -591,7 +576,7 @@ pub struct FontsImpl {
     definitions: FontDefinitions,
     atlas: Arc<Mutex<TextureAtlas>>,
     font_impl_cache: FontImplCache,
-    sized_family: ahash::HashMap<(HashableF32, FontFamily), Font>,
+    sized_family: ahash::HashMap<(OrderedFloat<f32>, FontFamily), Font>,
 }
 
 impl FontsImpl {
@@ -641,7 +626,7 @@ impl FontsImpl {
         let FontId { size, family } = font_id;
 
         self.sized_family
-            .entry((HashableF32(*size), family.clone()))
+            .entry((OrderedFloat(*size), family.clone()))
             .or_insert_with(|| {
                 let fonts = &self.definitions.families.get(family);
                 let fonts = fonts

crates/epaint/src/text/text_layout_types.rs

@@ -185,7 +185,7 @@ impl std::hash::Hash for LayoutJob {
         text.hash(state);
         sections.hash(state);
         wrap.hash(state);
-        crate::f32_hash(state, *first_row_min_height);
+        emath::OrderedFloat(*first_row_min_height).hash(state);
         break_on_newline.hash(state);
         halign.hash(state);
         justify.hash(state);
@@ -214,7 +214,7 @@ impl std::hash::Hash for LayoutSection {
             byte_range,
             format,
         } = self;
-        crate::f32_hash(state, *leading_space);
+        OrderedFloat(*leading_space).hash(state);
         byte_range.hash(state);
         format.hash(state);
     }
@@ -293,9 +293,9 @@ impl std::hash::Hash for TextFormat {
             valign,
         } = self;
         font_id.hash(state);
-        crate::f32_hash(state, *extra_letter_spacing);
+        emath::OrderedFloat(*extra_letter_spacing).hash(state);
         if let Some(line_height) = *line_height {
-            crate::f32_hash(state, line_height);
+            emath::OrderedFloat(line_height).hash(state);
         }
         color.hash(state);
         background.hash(state);
@@ -375,7 +375,7 @@ impl std::hash::Hash for TextWrapping {
             break_anywhere,
             overflow_character,
         } = self;
-        crate::f32_hash(state, *max_width);
+        emath::OrderedFloat(*max_width).hash(state);
         max_rows.hash(state);
         break_anywhere.hash(state);
         overflow_character.hash(state);

crates/epaint/src/util/mod.rs

@@ -1,6 +1,5 @@
-mod ordered_float;
-
-pub use ordered_float::*;
+#[deprecated = "Use emath::OrderedFloat instead"]
+pub use emath::OrderedFloat;
 
 /// Hash the given value with a predictable hasher.
 #[inline]