File size colours on a scale

This adds an option (always on at the moment) to use a colour scale of green to yellow to orange for the file size field instead of always green. See #65.

src/options/view.rs

@@ -34,12 +34,13 @@ impl View {
             }
             else {
                 let term_colours = try!(TerminalColours::deduce(matches));
+                let scale        = true;
                 let colours = match term_colours {
-                    TerminalColours::Always    => Colours::colourful(),
+                    TerminalColours::Always    => Colours::colourful(scale),
                     TerminalColours::Never     => Colours::plain(),
                     TerminalColours::Automatic => {
                         if dimensions().is_some() {
-                            Colours::colourful()
+                            Colours::colourful(scale)
                         }
                         else {
                             Colours::plain()
@@ -84,12 +85,13 @@ impl View {
         let other_options_scan = || {
             let term_colours = try!(TerminalColours::deduce(matches));
             let term_width   = try!(TerminalWidth::deduce());
+            let scale        = true;
 
             if let Some(&width) = term_width.as_ref() {
                 let colours = match term_colours {
-                    TerminalColours::Always    => Colours::colourful(),
+                    TerminalColours::Always    => Colours::colourful(scale),
                     TerminalColours::Never     => Colours::plain(),
-                    TerminalColours::Automatic => Colours::colourful(),
+                    TerminalColours::Automatic => Colours::colourful(scale),
                 };
 
                 if matches.opt_present("oneline") {
@@ -132,7 +134,7 @@ impl View {
                 // fallback to the lines view.
 
                 let colours = match term_colours {
-                    TerminalColours::Always    => Colours::colourful(),
+                    TerminalColours::Always    => Colours::colourful(scale),
                     TerminalColours::Never     => Colours::plain(),
                     TerminalColours::Automatic => Colours::plain(),
                 };

src/output/colours.rs

@@ -4,6 +4,8 @@ use ansi_term::Colour::{Red, Green, Yellow, Blue, Cyan, Purple, Fixed};
 
 #[derive(Clone, Copy, Debug, Default, PartialEq)]
 pub struct Colours {
+    pub scale: bool,
+
     pub filetypes:  FileTypes,
     pub perms:      Permissions,
     pub size:       Size,
@@ -96,8 +98,10 @@ impl Colours {
         Colours::default()
     }
 
-    pub fn colourful() -> Colours {
+    pub fn colourful(scale: bool) -> Colours {
         Colours {
+            scale: scale,
+
             filetypes: FileTypes {
                 normal:      Style::default(),
                 directory:   Blue.bold(),
@@ -170,7 +174,26 @@ impl Colours {
         }
     }
 
-    pub fn file_size(&self, _size: u64) -> Style {
-        self.size.numbers
+    pub fn file_size(&self, size: u64) -> Style {
+        if self.scale {
+            if size < 1024 {
+                Fixed(118).normal()
+            }
+            else if size < 1024 * 1024 {
+                Fixed(190).normal()
+            }
+            else if size < 1024 * 1024 * 1024 {
+                Fixed(226).normal()
+            }
+            else if size < 1024 * 1024 * 1024 * 1024 {
+                Fixed(220).normal()
+            }
+            else {
+                Fixed(214).normal()
+            }
+        }
+        else {
+            self.size.numbers
+        }
     }
 }