Implement FromStr for SVGMeasure

dyesub-tool/Cargo.toml

@@ -6,5 +6,7 @@ edition = "2021"
 [dependencies]
 askama = "0.12.0"
 derive_more = "0.99.17"
+lazy_static = "1.4.0"
+regex = "1.9.3"
 strum = "0.25.0"
 strum_macros = "0.25.2"

dyesub-tool/src/svg/measure.rs

@@ -1,10 +1,16 @@
 use super::SVGUnit;
 use std::cmp::Ordering;
 use std::fmt;
+use std::num::ParseFloatError;
+use std::str::FromStr;
 use std::{
     fmt::Display,
     ops::{Add, Div, Mul, Sub},
 };
+use lazy_static::lazy_static;
+use regex::Regex;
+use derive_more::From;
+use strum::ParseError;
 
 #[derive(Debug, Clone, Copy)]
 pub struct SVGMeasure {
@@ -29,6 +35,32 @@ impl SVGMeasure {
     }
 }
 
+#[derive(From, Debug)]
+pub enum SVGUnitParseError {
+    ParseMeasure(ParseFloatError),
+    ParseUnit(ParseError),
+    Invalid,
+}
+
+impl FromStr for SVGMeasure {
+    type Err = SVGUnitParseError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s == "0" {
+            return Ok(SVGMeasure::new(0.0, SVGUnit::Pixel));
+        }
+        lazy_static! {
+            static ref RE: Regex = Regex::new(r"^([\d.]+)([a-zA-Z]+)$").unwrap();
+        }
+        if let Some(captures) = RE.captures(s) {
+            let measure = captures[1].parse::<f64>()?;
+            let unit = captures[2].parse::<SVGUnit>()?;
+            Ok(SVGMeasure::new(measure, unit))
+        } else {
+            Err(SVGUnitParseError::Invalid)
+        }
+    }
+}
+
 const EQ_TOLERANCE: f64 = 0.00001;
 
 impl PartialEq for SVGMeasure {

dyesub-tool/src/svg/tests.rs

@@ -1,3 +1,5 @@
+use std::str::FromStr;
+
 use crate::svg::{SVGMeasure, SVGUnit};
 
 #[test]
@@ -52,3 +54,13 @@ fn cmp() {
     assert!(m_10cm > m_5mm);
     assert!(m_5mm < m_10cm);
 }
+
+#[test]
+fn from_str() {
+    let m_10cm = SVGMeasure::new(10.0, SVGUnit::Centimeter);
+    let m_5mm = SVGMeasure::new(5.0, SVGUnit::Millimeter);
+    let m_0 = SVGMeasure::new(0.0, SVGUnit::Pixel);
+    assert_eq!(m_10cm, SVGMeasure::from_str("10cm").unwrap());
+    assert_eq!(m_5mm, SVGMeasure::from_str("5mm").unwrap());
+    assert_eq!(m_0, SVGMeasure::from_str("0").unwrap());
+}