Break out line drawing style into a trait

Author: milliams

examples/function_svg.rs

@@ -1,5 +1,7 @@
 extern crate plotlib;
 
+use plotlib::style::Line;
+
 fn main() {
     let f1 = plotlib::function::Function::new(|x| x * 5., 0., 10.)
         .style(plotlib::function::Style::new().colour("burlywood"));

src/function.rs

@@ -20,6 +20,7 @@ use svg;
 use axis;
 use representation::Representation;
 use svg_render;
+use style;
 
 #[derive(Debug, Default)]
 pub struct Style {
@@ -31,22 +32,24 @@ impl Style {
         Style { colour: None }
     }
 
-    pub fn overlay(&mut self, other: Self) {
+    pub fn overlay(&mut self, other: &Self) {
         match other.colour {
-            Some(v) => self.colour = Some(v),
+            Some(ref v) => self.colour = Some(v.clone()),
             None => {}
         }
     }
+}
 
-    pub fn colour<T>(mut self, value: T) -> Self
+impl style::Line for Style {
+    fn colour<T>(&mut self, value: T) -> &mut Self
     where
         T: Into<String>,
     {
         self.colour = Some(value.into());
         self
     }
 
-    pub fn get_colour(&self) -> String {
+    fn get_colour(&self) -> String {
         match self.colour.clone() {
             Some(v) => v,
             None => "".into(),
@@ -75,8 +78,8 @@ impl Function {
         }
     }
 
-    pub fn style(mut self, style: Style) -> Self {
-        self.style.overlay(style);
+    pub fn style(mut self, style: &Style) -> Self {
+        self.style.overlay(&style);
         self
     }
 

src/lib.rs

@@ -74,6 +74,7 @@ pub mod page;
 pub mod histogram;
 pub mod scatter;
 pub mod function;
+pub mod style;
 mod axis;
 mod utils;
 mod text_render;

src/style.rs

@@ -0,0 +1,13 @@
+/*!
+
+Manage how elements should be drawn
+
+*/
+
+pub trait Line {
+    fn colour<T>(&mut self, value: T) -> &mut Self
+    where
+        T: Into<String>;
+
+    fn get_colour(&self) -> String;
+}

src/svg_render.rs

@@ -5,6 +5,7 @@ use histogram;
 use scatter;
 use function;
 use axis;
+use style;
 use utils::PairWise;
 
 fn value_to_face_offset(value: f64, axis: &axis::Axis, face_size: f64) -> f64 {
@@ -191,14 +192,17 @@ pub fn draw_face_bars(
     group
 }
 
-pub fn draw_face_line(
+pub fn draw_face_line<S>(
     s: &function::Function,
     x_axis: &axis::Axis,
     y_axis: &axis::Axis,
     face_width: f64,
     face_height: f64,
-    style: &function::Style,
-) -> node::element::Group {
+    style: &S,
+) -> node::element::Group
+where
+    S: style::Line,
+{
     let mut group = node::element::Group::new();
 
     let mut d: Vec<node::element::path::Command> = vec![];