Make use of colors preset by terminals

src/backend/blt.rs

@@ -2,12 +2,17 @@ extern crate bear_lib_terminal;
 
 use self::bear_lib_terminal::Color as BltColor;
 use self::bear_lib_terminal::geometry::Size;
-use self::bear_lib_terminal::terminal::{self, Event as BltEvent, KeyCode};
+use self::bear_lib_terminal::terminal::{self, state, Event as BltEvent, KeyCode};
 use backend;
 use event::{Event, Key};
 use std::collections::BTreeMap;
 use theme::{BaseColor, Color, ColorPair, Effect};
 
+enum ColorRole {
+    Foreground,
+    Background,
+}
+
 pub struct Concrete {
     colours: BTreeMap<i16, (BltColor, BltColor)>,
 }
@@ -25,8 +30,8 @@ impl backend::Backend for Concrete {
     }
 
     fn with_color<F: FnOnce()>(&self, color: ColorPair, f: F) {
-        let fg = colour_to_blt_colour(color.front);
-        let bg = colour_to_blt_colour(color.back);
+        let fg = colour_to_blt_colour(color.front, ColorRole::Foreground);
+        let bg = colour_to_blt_colour(color.back, ColorRole::Background);
         terminal::with_colors(fg, bg, f);
     }
 
@@ -55,7 +60,7 @@ impl backend::Backend for Concrete {
     }
 
     fn clear(&self, color: Color) {
-        terminal::set_background(colour_to_blt_colour(color));
+        terminal::set_background(colour_to_blt_colour(color, ColorRole::Background));
         terminal::clear(None);
     }
 
@@ -98,8 +103,17 @@ impl backend::Backend for Concrete {
     }
 }
 
-fn colour_to_blt_colour(clr: Color) -> BltColor {
+fn colour_to_blt_colour(clr: Color, role: ColorRole) -> BltColor {
     let (r, g, b) = match clr {
+        Color::Default => {
+            let clr = match role {
+                ColorRole::Foreground => state::foreground(),
+                ColorRole::Background => state::background(),
+            };
+
+            return clr;
+        },
+
         // Colours taken from
         // https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
         Color::Dark(BaseColor::Black) => (0, 0, 0),

src/backend/curses/mod.rs

@@ -13,6 +13,7 @@ pub use self::pan::*;
 
 fn find_closest(color: &Color) -> i16 {
     match *color {
+        Color::Default => -1,
         Color::Dark(BaseColor::Black) => 0,
         Color::Dark(BaseColor::Red) => 1,
         Color::Dark(BaseColor::Green) => 2,

src/backend/termion.rs

@@ -197,6 +197,7 @@ fn with_color<F, R>(clr: &theme::Color, f: F) -> R
 {
 
     match *clr {
+          theme::Color::Default => f(&tcolor::Reset),
           theme::Color::Dark(theme::BaseColor::Black) => f(&tcolor::Black),
           theme::Color::Dark(theme::BaseColor::Red) => f(&tcolor::Red),
           theme::Color::Dark(theme::BaseColor::Green) => f(&tcolor::Green),

src/theme.rs

@@ -167,6 +167,8 @@ impl ColorPair {
 /// The current theme will assign each role a foreground and background color.
 #[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
 pub enum ColorStyle {
+    /// Style set by terminal before entering a Cursive program.
+    Default,
     /// Application background, where no view is present.
     Background,
     /// Color used by view shadows. Only background matters.
@@ -201,6 +203,7 @@ impl ColorStyle {
     pub fn resolve(&self, theme: &Theme) -> ColorPair {
         let c = &theme.colors;
         let (front, back) = match *self {
+            ColorStyle::Default => (Color::Default, Color::Default),
             ColorStyle::Background => (c.view, c.background),
             ColorStyle::Shadow => (c.shadow, c.shadow),
             ColorStyle::Primary => (c.primary, c.view),
@@ -411,6 +414,8 @@ impl From<u8> for BaseColor {
 /// Represents a color used by the theme.
 #[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
 pub enum Color {
+    /// Represents a color, preset by terminal.
+    Default,
     /// One of the 8 base colors.
     Dark(BaseColor),
     /// Lighter version of a base color.