1 files changed, 144 insertions, 0 deletions
diff --git a/src/engine/size.rs b/src/engine/size.rs
new file mode 100644
index 00000000..a6624c57
--- /dev/null
+++ b/src/engine/size.rs
@@ -0,0 +1,144 @@
+use std::cmp::Ordering;
+use std::fmt::{self, Display, Debug, Formatter};
+use std::iter::Sum;
+use std::ops::*;
+
+
+/// A general distance type that can convert between units.
+#[derive(Copy, Clone, PartialEq)]
+pub struct Size {
+    /// The size in typographic points (1/72 inches).
+    points: f32,
+}
+
+impl Size {
+    /// Create an zeroed size.
+    #[inline]
+    pub fn zero() -> Size { Size { points: 0.0 } }
+
+    /// Create a size from a number of points.
+    #[inline]
+    pub fn from_points(points: f32) -> Size { Size { points } }
+
+    /// Create a size from a number of inches.
+    #[inline]
+    pub fn from_inches(inches: f32) -> Size { Size { points: 72.0 * inches } }
+
+    /// Create a size from a number of millimeters.
+    #[inline]
+    pub fn from_mm(mm: f32) -> Size { Size { points: 2.83465 * mm  } }
+
+    /// Create a size from a number of centimeters.
+    #[inline]
+    pub fn from_cm(cm: f32) -> Size { Size { points: 28.3465 * cm } }
+
+    /// Create a size from a number of points.
+    #[inline]
+    pub fn to_points(&self) -> f32 { self.points }
+
+    /// Create a size from a number of inches.
+    #[inline]
+    pub fn to_inches(&self) -> f32 { self.points * 0.0138889 }
+
+    /// Create a size from a number of millimeters.
+    #[inline]
+    pub fn to_mm(&self) -> f32 { self.points * 0.352778 }
+
+    /// Create a size from a number of centimeters.
+    #[inline]
+    pub fn to_cm(&self) -> f32 { self.points * 0.0352778 }
+}
+
+impl Display for Size {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        write!(f, "{}pt", self.points)
+    }
+}
+
+impl Debug for Size {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        Display::fmt(self, f)
+    }
+}
+
+impl PartialOrd for Size {
+    fn partial_cmp(&self, other: &Size) -> Option<Ordering> {
+        self.points.partial_cmp(&other.points)
+    }
+}
+
+impl Neg for Size {
+    type Output = Size;
+
+    fn neg(self) -> Size {
+        Size { points: -self.points }
+    }
+}
+
+impl Sum for Size {
+    fn sum<I>(iter: I) -> Size where I: Iterator<Item=Size> {
+        iter.fold(Size::zero(), Add::add)
+    }
+}
+
+macro_rules! impl_reflexive {
+    ($trait:ident, $func:ident, $assign_trait:ident, $assign_func:ident) => {
+        impl $trait for Size {
+            type Output = Size;
+
+            #[inline]
+            fn $func(self, other: Size) -> Size {
+                Size { points: $trait::$func(self.points, other.points) }
+            }
+        }
+
+        impl $assign_trait for Size {
+            #[inline]
+            fn $assign_func(&mut self, other: Size) {
+                $assign_trait::$assign_func(&mut self.points, other.points);
+            }
+        }
+    };
+}
+
+macro_rules! impl_num_back {
+    ($trait:ident, $func:ident, $assign_trait:ident, $assign_func:ident, $ty:ty) => {
+        impl $trait<$ty> for Size {
+            type Output = Size;
+
+            #[inline]
+            fn $func(self, other: $ty) -> Size {
+                Size { points: $trait::$func(self.points, other as f32) }
+            }
+        }
+
+        impl $assign_trait<$ty> for Size {
+            #[inline]
+            fn $assign_func(&mut self, other: $ty) {
+                $assign_trait::$assign_func(&mut self.points, other as f32);
+            }
+        }
+    };
+}
+
+macro_rules! impl_num_both {
+    ($trait:ident, $func:ident, $assign_trait:ident, $assign_func:ident, $ty:ty) => {
+        impl_num_back!($trait, $func, $assign_trait, $assign_func, $ty);
+
+        impl $trait<Size> for $ty {
+            type Output = Size;
+
+            #[inline]
+            fn $func(self, other: Size) -> Size {
+                Size { points: $trait::$func(self as f32, other.points) }
+            }
+        }
+    };
+}
+
+impl_reflexive!(Add, add, AddAssign, add_assign);
+impl_reflexive!(Sub, sub, SubAssign, sub_assign);
+impl_num_both!(Mul, mul, MulAssign, mul_assign, f32);
+impl_num_both!(Mul, mul, MulAssign, mul_assign, i32);
+impl_num_back!(Div, div, DivAssign, div_assign, f32);
+impl_num_back!(Div, div, DivAssign, div_assign, i32);