Use strum for SVGUnit

dyesub-tool/Cargo.toml

@@ -6,3 +6,5 @@ edition = "2021"
 [dependencies]
 askama = "0.12.0"
 derive_more = "0.99.17"
+strum = "0.25.0"
+strum_macros = "0.25.2"

dyesub-tool/src/svg/unit.rs

@@ -1,19 +1,26 @@
-use std::fmt::{self, Display};
+use strum_macros::{Display, EnumString, IntoStaticStr};
 
 /// https://oreillymedia.github.io/Using_SVG/guide/units.html
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[derive(Display, EnumString, IntoStaticStr)]
 pub enum SVGUnit {
     /// Pixel units, directly equivalent to SVG user units.
+    #[strum(serialize = "px")]
     Pixel,
     /// Inches.
+    #[strum(serialize = "in")]
     Inch,
     /// Centimeters.
+    #[strum(serialize = "cm")]
     Centimeter,
     /// Millimeters.
+    #[strum(serialize = "mm")]
     Millimeter,
     /// Points.
+    #[strum(serialize = "pt")]
     Point,
     // Picas.
+    #[strum(serialize = "pc")]
     Pica,
 }
 
@@ -29,22 +36,4 @@ impl SVGUnit {
             Pica => 16.0,
         }
     }
-}
-
-impl Display for SVGUnit {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use SVGUnit::*;
-        write!(
-            f,
-            "{}",
-            match &self {
-                Pixel => "px",
-                Inch => "in",
-                Centimeter => "cm",
-                Millimeter => "mm",
-                Point => "pt",
-                Pica => "pc",
-            }
-        )
-    }
-}
+}