Add DragValue::new and Slider::new

emath/src/lib.rs

@@ -67,6 +67,7 @@ use std::ops::{Add, Div, Mul, RangeInclusive, Sub};
 // ----------------------------------------------------------------------------
 
 pub mod align;
+mod numeric;
 mod pos2;
 mod rect;
 mod rect_transform;
@@ -76,6 +77,7 @@ mod vec2;
 
 pub use {
     align::{Align, Align2},
+    numeric::*,
     pos2::*,
     rect::*,
     rect_transform::*,

emath/src/numeric.rs

@@ -0,0 +1,60 @@
+/// Implemented for all builtin numeric types
+pub trait Numeric: Clone + Copy + PartialEq + PartialOrd + 'static {
+    /// Is this an integer type?
+    const INTEGRAL: bool;
+
+    /// Smallest finite value
+    const MIN: Self;
+
+    /// Largest finite value
+    const MAX: Self;
+
+    fn to_f64(self) -> f64;
+
+    fn from_f64(num: f64) -> Self;
+}
+
+macro_rules! impl_numeric_float {
+    ($t:ident) => {
+        impl Numeric for $t {
+            const INTEGRAL: bool = false;
+            const MIN: Self = std::$t::MIN;
+            const MAX: Self = std::$t::MAX;
+            fn to_f64(self) -> f64 {
+                self as f64
+            }
+            fn from_f64(num: f64) -> Self {
+                num as Self
+            }
+        }
+    };
+}
+
+macro_rules! impl_numeric_integer {
+    ($t:ident) => {
+        impl Numeric for $t {
+            const INTEGRAL: bool = true;
+            const MIN: Self = std::$t::MIN;
+            const MAX: Self = std::$t::MAX;
+            fn to_f64(self) -> f64 {
+                self as f64
+            }
+            fn from_f64(num: f64) -> Self {
+                num as Self
+            }
+        }
+    };
+}
+
+impl_numeric_float!(f32);
+impl_numeric_float!(f64);
+impl_numeric_integer!(i8);
+impl_numeric_integer!(u8);
+impl_numeric_integer!(i16);
+impl_numeric_integer!(u16);
+impl_numeric_integer!(i32);
+impl_numeric_integer!(u32);
+impl_numeric_integer!(i64);
+impl_numeric_integer!(u64);
+impl_numeric_integer!(isize);
+impl_numeric_integer!(usize);