Merge branch 'custom_color'

examples/colors.rs

@@ -0,0 +1,45 @@
+extern crate cursive;
+
+use cursive::{Cursive, Printer};
+use cursive::theme::{ColorStyle, Color};
+use cursive::view::Boxable;
+use cursive::views::Canvas;
+
+fn main() {
+    let mut siv = Cursive::new();
+
+    siv.add_layer(Canvas::new(()).with_draw(draw).fixed_size((20, 10)));
+
+    siv.add_global_callback('q', |s| s.quit());
+
+    siv.run();
+}
+
+fn front_color(x: u8, y: u8, x_max: u8, y_max: u8) -> Color {
+    Color::Rgb(x * (255 / x_max),
+               y * (255 / y_max),
+               (x + 2 * y) * (255 / (x_max + 2 * y_max)))
+}
+
+fn back_color(x: u8, y: u8, x_max: u8, y_max: u8) -> Color {
+
+    Color::Rgb(128 + (2 * y_max + x - 2 * y) * (128 / (x_max + 2 * y_max)),
+               255 - y * (255 / y_max),
+               255 - x * (255 / x_max))
+}
+
+fn draw(p: &Printer, _: &()) {
+    let x_max = p.size.x as u8;
+    let y_max = p.size.y as u8;
+
+    for x in 0..x_max {
+        for y in 0..y_max {
+            let style = ColorStyle::Custom {
+                front: front_color(x, y, x_max, y_max),
+                back: back_color(x, y, x_max, y_max),
+            };
+
+            p.with_color(style, |printer| { printer.print((x, y), "+"); });
+        }
+    }
+}

examples/theme_manual.rs

@@ -1,26 +1,33 @@
 extern crate cursive;
 
 use cursive::Cursive;
-use cursive::views::Dialog;
+use cursive::theme::{ColorStyle, BaseColor, Color, BorderStyle};
-use cursive::theme::BorderStyle;
+use cursive::views::{EditView, LinearLayout, Dialog, TextView};
 
 fn main() {
     let mut siv = Cursive::new();
 
-    siv.add_layer(Dialog::text("This is a dynamic theme example!")
+    let layout = LinearLayout::vertical()
-        .button("Change", |s| {
+        .child(TextView::new("This is a dynamic theme example!"))
-            let mut theme = s.current_theme().clone();
+        .child(EditView::new().content("Woo! colors!").style(ColorStyle::Custom {
+                                         front: Color::Rgb(200, 150, 150),
+                                         back: Color::Dark(BaseColor::Blue),
+                                     }));
 
-            theme.shadow = !theme.shadow;
+    siv.add_layer(Dialog::around(layout)
-            theme.borders = match theme.borders {
+                      .button("Change", |s| {
-                Some(BorderStyle::Simple) => Some(BorderStyle::Outset),
+        let mut theme = s.current_theme().clone();
-                Some(BorderStyle::Outset) => None,
-                None => Some(BorderStyle::Simple),
-            };
 
-            s.set_theme(theme);
+        theme.shadow = !theme.shadow;
-        })
+        theme.borders = match theme.borders {
-        .button("Quit", Cursive::quit));
+            BorderStyle::Simple => BorderStyle::Outset,
+            BorderStyle::Outset => BorderStyle::None,
+            BorderStyle::None => BorderStyle::Simple,
+        };
+
+        s.set_theme(theme);
+    })
+                      .button("Quit", Cursive::quit));
 
     siv.run();
 }

src/backend/blt.rs

@@ -6,7 +6,7 @@ use self::bear_lib_terminal::terminal::{self, Event as BltEvent, KeyCode};
 use backend;
 use event::{Event, Key};
 use std::collections::BTreeMap;
-use theme::{BaseColor, Color, ColorStyle, Effect};
+use theme::{BaseColor, Color, ColorPair, Effect};
 
 pub struct Concrete {
     colours: BTreeMap<i16, (BltColor, BltColor)>,
@@ -24,15 +24,9 @@ impl backend::Backend for Concrete {
         terminal::close();
     }
 
-    fn init_color_style(&mut self, style: ColorStyle, foreground: &Color,
+    fn with_color<F: FnOnce()>(&self, color: ColorPair, f: F) {
-                        background: &Color) {
+        let fg = colour_to_blt_colour(color.front);
-        self.colours.insert(style.id(),
+        let bg = colour_to_blt_colour(color.back);
-                            (colour_to_blt_colour(foreground),
-                             colour_to_blt_colour(background)));
-    }
-
-    fn with_color<F: FnOnce()>(&self, color: ColorStyle, f: F) {
-        let (fg, bg) = self.colours[&color.id()];
         terminal::with_colors(fg, bg, f);
     }
 
@@ -60,7 +54,8 @@ impl backend::Backend for Concrete {
         (width as usize, height as usize)
     }
 
-    fn clear(&self) {
+    fn clear(&self, color: Color) {
+        terminal::set_background(colour_to_blt_colour(color));
         terminal::clear(None);
     }
 
@@ -103,8 +98,8 @@ impl backend::Backend for Concrete {
     }
 }
 
-fn colour_to_blt_colour(clr: &Color) -> BltColor {
+fn colour_to_blt_colour(clr: Color) -> BltColor {
-    let (r, g, b) = match *clr {
+    let (r, g, b) = match clr {
         // Colours taken from
         // https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
         Color::Dark(BaseColor::Black) => (0, 0, 0),
@@ -140,11 +135,11 @@ fn blt_keycode_to_ev(kc: KeyCode, shift: bool, ctrl: bool) -> Event {
         KeyCode::F1 | KeyCode::F2 | KeyCode::F3 | KeyCode::F4 |
         KeyCode::F5 | KeyCode::F6 | KeyCode::F7 | KeyCode::F8 |
         KeyCode::F9 | KeyCode::F10 | KeyCode::F11 | KeyCode::F12 |
-        KeyCode::Enter | KeyCode::Escape | KeyCode::Backspace |
+        KeyCode::NumEnter | KeyCode::Enter | KeyCode::Escape |
-        KeyCode::Tab | KeyCode::Pause | KeyCode::Insert | KeyCode::Home |
+        KeyCode::Backspace | KeyCode::Tab | KeyCode::Pause |
-        KeyCode::PageUp | KeyCode::Delete | KeyCode::End |
+        KeyCode::Insert | KeyCode::Home | KeyCode::PageUp |
-        KeyCode::PageDown | KeyCode::Right | KeyCode::Left |
+        KeyCode::Delete | KeyCode::End | KeyCode::PageDown |
-        KeyCode::Down | KeyCode::Up => {
+        KeyCode::Right | KeyCode::Left | KeyCode::Down | KeyCode::Up => {
             match (shift, ctrl) {
                 (true, true) => Event::CtrlShift(blt_keycode_to_key(kc)),
                 (true, false) => Event::Shift(blt_keycode_to_key(kc)),
@@ -168,10 +163,9 @@ fn blt_keycode_to_ev(kc: KeyCode, shift: bool, ctrl: bool) -> Event {
         KeyCode::Apostrophe | KeyCode::Comma | KeyCode::Period |
         KeyCode::Slash | KeyCode::Space | KeyCode::NumDivide |
         KeyCode::NumMultiply | KeyCode::NumMinus | KeyCode::NumPlus |
-        KeyCode::NumEnter | KeyCode::NumPeriod | KeyCode::Num1 |
+        KeyCode::NumPeriod | KeyCode::Num1 | KeyCode::Num2 |
-        KeyCode::Num2 | KeyCode::Num3 | KeyCode::Num4 | KeyCode::Num5 |
+        KeyCode::Num3 | KeyCode::Num4 | KeyCode::Num5 | KeyCode::Num6 |
-        KeyCode::Num6 | KeyCode::Num7 | KeyCode::Num8 | KeyCode::Num9 |
+        KeyCode::Num7 | KeyCode::Num8 | KeyCode::Num9 | KeyCode::Num0 => {
-        KeyCode::Num0 => {
             if ctrl {
                 Event::CtrlChar(blt_keycode_to_char(kc, shift))
             } else {
@@ -246,7 +240,10 @@ fn blt_keycode_to_char(kc: KeyCode, shift: bool) -> char {
         KeyCode::Num8 => '8',
         KeyCode::Num9 => '9',
         KeyCode::Num0 => '0',
-        _ => unreachable!(),
+        _ => {
+            println_stderr!("Found unknown input: {:?}", kc);
+            unreachable!()
+        }
     }
 }
 
@@ -264,7 +261,7 @@ fn blt_keycode_to_key(kc: KeyCode) -> Key {
         KeyCode::F10 => Key::F10,
         KeyCode::F11 => Key::F11,
         KeyCode::F12 => Key::F12,
-        KeyCode::Enter => Key::Enter,
+        KeyCode::NumEnter | KeyCode::Enter => Key::Enter,
         KeyCode::Escape => Key::Esc,
         KeyCode::Backspace => Key::Backspace,
         KeyCode::Tab => Key::Tab,

src/backend/curses/mod.rs

@@ -11,7 +11,7 @@ mod pan;
 pub use self::pan::*;
 
 
-fn find_closest(color: &Color) -> u8 {
+fn find_closest(color: &Color) -> i16 {
     match *color {
         Color::Dark(BaseColor::Black) => 0,
         Color::Dark(BaseColor::Red) => 1,
@@ -33,8 +33,8 @@ fn find_closest(color: &Color) -> u8 {
             let r = 6 * r as u16 / 256;
             let g = 6 * g as u16 / 256;
             let b = 6 * b as u16 / 256;
-            (16 + 36 * r + 6 * g + b) as u8
+            (16 + 36 * r + 6 * g + b) as i16
         }
-        Color::RgbLowRes(r, g, b) => (16 + 36 * r + 6 * g + b) as u8,
+        Color::RgbLowRes(r, g, b) => (16 + 36 * r + 6 * g + b) as i16,
     }
 }

src/backend/curses/n.rs

@@ -1,13 +1,65 @@
 extern crate ncurses;
 
-
 use self::super::find_closest;
 use backend;
 use event::{Event, Key};
-use theme::{Color, ColorStyle, Effect};
+use std::cell::{RefCell, Cell};
+use std::collections::HashMap;
+use theme::{Color, ColorPair, Effect};
 use utf8;
 
-pub struct Concrete;
+pub struct Concrete {
+    current_style: Cell<ColorPair>,
+    pairs: RefCell<HashMap<ColorPair, i16>>,
+}
+
+impl Concrete {
+    /// Save a new color pair.
+    fn insert_color(&self, pairs: &mut HashMap<ColorPair, i16>,
+                    pair: ColorPair)
+                    -> i16 {
+
+        let n = 1 + pairs.len() as i16;
+        let target = if ncurses::COLOR_PAIRS() > n as i32 {
+            // We still have plenty of space for everyone.
+            n
+        } else {
+            // The world is too small for both of us.
+            let target = n - 1;
+            // Remove the mapping to n-1
+            pairs.retain(|_, &mut v| v != target);
+            target
+        };
+        pairs.insert(pair, target);
+        ncurses::init_pair(target,
+                           find_closest(&pair.front),
+                           find_closest(&pair.back));
+        target
+    }
+
+    /// Checks the pair in the cache, or re-define a color if needed.
+    fn get_or_create(&self, pair: ColorPair) -> i16 {
+
+        let mut pairs = self.pairs.borrow_mut();
+
+        // Find if we have this color in stock
+        if pairs.contains_key(&pair) {
+            // We got it!
+            pairs[&pair]
+        } else {
+            self.insert_color(&mut *pairs, pair)
+        }
+    }
+
+    fn set_colors(&self, pair: ColorPair) {
+
+        let i = self.get_or_create(pair);
+
+        self.current_style.set(pair);
+        let style = ncurses::COLOR_PAIR(i);
+        ncurses::attron(style);
+    }
+}
 
 impl backend::Backend for Concrete {
     fn init() -> Self {
@@ -22,10 +74,11 @@ impl backend::Backend for Concrete {
         ncurses::cbreak();
         ncurses::start_color();
         ncurses::curs_set(ncurses::CURSOR_VISIBILITY::CURSOR_INVISIBLE);
-        ncurses::wbkgd(ncurses::stdscr(),
-                       ncurses::COLOR_PAIR(ColorStyle::Background.id()));
 
-        Concrete
+        Concrete {
+            current_style: Cell::new(ColorPair::from_256colors(0, 0)),
+            pairs: RefCell::new(HashMap::new()),
+        }
     }
 
     fn screen_size(&self) -> (usize, usize) {
@@ -44,25 +97,17 @@ impl backend::Backend for Concrete {
     }
 
 
-    fn init_color_style(&mut self, style: ColorStyle, foreground: &Color,
+    fn with_color<F: FnOnce()>(&self, colors: ColorPair, f: F) {
-                        background: &Color) {
+        let current = self.current_style.get();
-        // TODO: build the color on the spot
+        if current != colors {
+            self.set_colors(colors);
+        }
 
-        ncurses::init_pair(style.id(),
-                           find_closest(foreground) as i16,
-                           find_closest(background) as i16);
-    }
-
-    fn with_color<F: FnOnce()>(&self, color: ColorStyle, f: F) {
-        let mut current_style: ncurses::attr_t = 0;
-        let mut current_color: i16 = 0;
-        ncurses::attr_get(&mut current_style, &mut current_color);
-
-        let style = ncurses::COLOR_PAIR(color.id());
-        ncurses::attron(style);
         f();
-        // ncurses::attroff(style);
+
-        ncurses::attron(current_style);
+        if current != colors {
+            self.set_colors(current);
+        }
     }
 
     fn with_effect<F: FnOnce()>(&self, effect: Effect, f: F) {
@@ -75,7 +120,13 @@ impl backend::Backend for Concrete {
         ncurses::attroff(style);
     }
 
-    fn clear(&self) {
+    fn clear(&self, color: Color) {
+        let id = self.get_or_create(ColorPair {
+                                        front: color,
+                                        back: color,
+                                    });
+        ncurses::wbkgd(ncurses::stdscr(), ncurses::COLOR_PAIR(id));
+
         ncurses::clear();
     }
 

src/backend/curses/pan.rs

@@ -1,17 +1,69 @@
 extern crate pancurses;
 
-
-
 use self::super::find_closest;
 use backend;
 use event::{Event, Key};
-use theme::{Color, ColorStyle, Effect};
+use std::cell::{RefCell, Cell};
+use std::collections::HashMap;
+use theme::{Color, ColorPair, Effect};
 use utf8;
 
 pub struct Concrete {
+    current_style: Cell<ColorPair>,
+    pairs: RefCell<HashMap<ColorPair, i32>>,
     window: pancurses::Window,
 }
 
+impl Concrete {
+    /// Save a new color pair.
+    fn insert_color(&self, pairs: &mut HashMap<ColorPair, i32>,
+                    pair: ColorPair)
+                    -> i32 {
+
+        let n = 1 + pairs.len() as i32;
+
+        // TODO: when COLORS_PAIRS is available...
+        let target = if 16 > n {
+            // We still have plenty of space for everyone.
+            n
+        } else {
+            // The world is too small for both of us.
+            let target = n - 1;
+            // Remove the mapping to n-1
+            pairs.retain(|_, &mut v| v != target);
+            target
+        };
+        pairs.insert(pair, target);
+        pancurses::init_pair(target as i16,
+                             find_closest(&pair.front),
+                             find_closest(&pair.back));
+        target
+    }
+
+    /// Checks the pair in the cache, or re-define a color if needed.
+    fn get_or_create(&self, pair: ColorPair) -> i32 {
+
+        let mut pairs = self.pairs.borrow_mut();
+
+        // Find if we have this color in stock
+        if pairs.contains_key(&pair) {
+            // We got it!
+            pairs[&pair]
+        } else {
+            self.insert_color(&mut *pairs, pair)
+        }
+    }
+
+    fn set_colors(&self, pair: ColorPair) {
+
+        let i = self.get_or_create(pair);
+
+        self.current_style.set(pair);
+        let style = pancurses::COLOR_PAIR(i as pancurses::chtype);
+        self.window.attron(style);
+    }
+}
+
 impl backend::Backend for Concrete {
     fn init() -> Self {
         let window = pancurses::initscr();
@@ -21,9 +73,12 @@ impl backend::Backend for Concrete {
         pancurses::cbreak();
         pancurses::start_color();
         pancurses::curs_set(0);
-        window.bkgd(pancurses::ColorPair(ColorStyle::Background.id() as u8));
 
-        Concrete { window: window }
+        Concrete {
+            current_style: Cell::new(ColorPair::from_256colors(0, 0)),
+            pairs: RefCell::new(HashMap::new()),
+            window: window,
+        }
     }
 
     fn screen_size(&self) -> (usize, usize) {
@@ -39,20 +94,18 @@ impl backend::Backend for Concrete {
         pancurses::endwin();
     }
 
-    fn init_color_style(&mut self, style: ColorStyle, foreground: &Color,
+    fn with_color<F: FnOnce()>(&self, colors: ColorPair, f: F) {
-                        background: &Color) {
+        let current = self.current_style.get();
-        pancurses::init_pair(style.id(),
-                             find_closest(foreground) as i16,
-                             find_closest(background) as i16);
-    }
 
-    fn with_color<F: FnOnce()>(&self, color: ColorStyle, f: F) {
+        if current != colors {
-        let (_, current_color_pair) = self.window.attrget();
+            self.set_colors(colors);
-        let color_attribute = pancurses::ColorPair(color.id() as u8);
+        }
 
-        self.window.attron(color_attribute);
         f();
-        self.window.attron(pancurses::ColorPair(current_color_pair as u8));
+
+        if current != colors {
+            self.set_colors(current);
+        }
     }
 
     fn with_effect<F: FnOnce()>(&self, effect: Effect, f: F) {
@@ -65,7 +118,12 @@ impl backend::Backend for Concrete {
         self.window.attroff(style);
     }
 
-    fn clear(&self) {
+    fn clear(&self, color: Color) {
+        let id = self.get_or_create(ColorPair {
+                                        front: color,
+                                        back: color,
+                                    });
+        self.window.bkgd(pancurses::ColorPair(id as u8));
         self.window.clear();
     }
 
@@ -94,12 +152,14 @@ impl backend::Backend for Concrete {
                 pancurses::Input::Character(c) if 32 <= (c as u32) &&
                                                   (c as u32) <= 255 => {
                     Event::Char(utf8::read_char(c as u8, || {
-                        self.window.getch().and_then(|i| match i {
+                        self.window
-                                pancurses::Input::Character(c) => {
+                            .getch()
-                                    Some(c as u8)
+                            .and_then(|i| match i {
-                                }
+                                          pancurses::Input::Character(c) => {
-                                _ => None,
+                                              Some(c as u8)
-                            })
+                                          }
+                                          _ => None,
+                                      })
                     })
                                         .unwrap())
                 }

src/backend/mod.rs

@@ -18,23 +18,23 @@ pub use self::termion::*;
 pub trait Backend {
     fn init() -> Self;
     // TODO: take `self` by value?
+    // Or implement Drop?
     fn finish(&mut self);
 
-    fn clear(&self);
     fn refresh(&mut self);
 
     fn has_colors(&self) -> bool;
-
-    fn init_color_style(&mut self, style: theme::ColorStyle,
-                        foreground: &theme::Color, background: &theme::Color);
-
-    fn print_at(&self, (usize, usize), &str);
-
-    fn poll_event(&self) -> event::Event;
-    fn set_refresh_rate(&mut self, fps: u32);
     fn screen_size(&self) -> (usize, usize);
 
+    /// Main input method
+    fn poll_event(&self) -> event::Event;
+
+    /// Main method used for printing
+    fn print_at(&self, (usize, usize), &str);
+    fn clear(&self, color: theme::Color);
+
+    fn set_refresh_rate(&mut self, fps: u32);
     // TODO: unify those into a single method?
-    fn with_color<F: FnOnce()>(&self, color: theme::ColorStyle, f: F);
+    fn with_color<F: FnOnce()>(&self, colors: theme::ColorPair, f: F);
     fn with_effect<F: FnOnce()>(&self, effect: theme::Effect, f: F);
 }

src/backend/termion.rs

@@ -13,8 +13,6 @@ use backend;
 use chan;
 use event::{Event, Key};
 use std::cell::Cell;
-use std::collections::BTreeMap;
-use std::fmt;
 use std::io::Write;
 use std::thread;
 
@@ -22,9 +20,7 @@ use theme;
 
 pub struct Concrete {
     terminal: AlternateScreen<termion::raw::RawTerminal<::std::io::Stdout>>,
-    current_style: Cell<theme::ColorStyle>,
+    current_style: Cell<theme::ColorPair>,
-    colors: BTreeMap<i16, (Box<tcolor::Color>, Box<tcolor::Color>)>,
-
     input: chan::Receiver<Event>,
     resize: chan::Receiver<chan_signal::Signal>,
     timeout: Option<u32>,
@@ -35,20 +31,6 @@ trait Effectable {
     fn off(&self);
 }
 
-struct ColorRef<'a>(&'a tcolor::Color);
-
-impl<'a> tcolor::Color for ColorRef<'a> {
-    #[inline]
-    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        self.0.write_fg(f)
-    }
-
-    #[inline]
-    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        self.0.write_bg(f)
-    }
-}
-
 impl Effectable for theme::Effect {
     fn on(&self) {
         match *self {
@@ -65,14 +47,10 @@ impl Effectable for theme::Effect {
     }
 }
 
-fn apply_colors(fg: &tcolor::Color, bg: &tcolor::Color) {
-    print!("{}{}", tcolor::Fg(ColorRef(fg)), tcolor::Bg(ColorRef(bg)));
-}
-
 impl Concrete {
-    fn apply_colorstyle(&self, color_style: theme::ColorStyle) {
+    fn apply_colors(&self, colors: theme::ColorPair) {
-        let (ref fg, ref bg) = self.colors[&color_style.id()];
+        with_color(&colors.front, |c| print!("{}", tcolor::Fg(c)));
-        apply_colors(&**fg, &**bg);
+        with_color(&colors.back, |c| print!("{}", tcolor::Bg(c)));
     }
 }
 
@@ -82,7 +60,9 @@ impl backend::Backend for Concrete {
 
         let resize = chan_signal::notify(&[chan_signal::Signal::WINCH]);
 
-        let terminal = AlternateScreen::from(::std::io::stdout().into_raw_mode().unwrap());
+        let terminal = AlternateScreen::from(::std::io::stdout()
+                                                 .into_raw_mode()
+                                                 .unwrap());
         let (sender, receiver) = chan::async();
 
         thread::spawn(move || for key in ::std::io::stdin().events() {
@@ -93,8 +73,7 @@ impl backend::Backend for Concrete {
 
         let backend = Concrete {
             terminal: terminal,
-            current_style: Cell::new(theme::ColorStyle::Background),
+            current_style: Cell::new(theme::ColorPair::from_256colors(0, 0)),
-            colors: BTreeMap::new(),
             input: receiver,
             resize: resize,
             timeout: None,
@@ -111,24 +90,20 @@ impl backend::Backend for Concrete {
                termion::clear::All);
     }
 
-    fn init_color_style(&mut self, style: theme::ColorStyle,
+    fn with_color<F: FnOnce()>(&self, color: theme::ColorPair, f: F) {
-                        foreground: &theme::Color, background: &theme::Color) {
-        // Step 1: convert foreground and background into proper termion Color
-        self.colors.insert(style.id(),
-                           (colour_to_termion_colour(foreground),
-                            colour_to_termion_colour(background)));
-    }
-
-    fn with_color<F: FnOnce()>(&self, color: theme::ColorStyle, f: F) {
         let current_style = self.current_style.get();
 
-        self.apply_colorstyle(color);
+        if current_style != color {
+            self.apply_colors(color);
+            self.current_style.set(color);
+        }
 
-        self.current_style.set(color);
         f();
-        self.current_style.set(current_style);
 
-        self.apply_colorstyle(current_style);
+        if current_style != color {
+            self.current_style.set(current_style);
+            self.apply_colors(current_style);
+        }
     }
 
     fn with_effect<F: FnOnce()>(&self, effect: theme::Effect, f: F) {
@@ -147,8 +122,11 @@ impl backend::Backend for Concrete {
         (x as usize, y as usize)
     }
 
-    fn clear(&self) {
+    fn clear(&self, color: theme::Color) {
-        self.apply_colorstyle(theme::ColorStyle::Background);
+        self.apply_colors(theme::ColorPair {
+            front: color,
+            back: color,
+        });
         print!("{}", termion::clear::All);
     }
 
@@ -214,49 +192,43 @@ fn map_key(event: TEvent) -> Event {
 
 }
 
-fn colour_to_termion_colour(clr: &theme::Color) -> Box<tcolor::Color> {
+fn with_color<F, R>(clr: &theme::Color, f: F) -> R
+    where F: FnOnce(&tcolor::Color) -> R
+{
+
     match *clr {
-        theme::Color::Dark(theme::BaseColor::Black) => Box::new(tcolor::Black),
+          theme::Color::Dark(theme::BaseColor::Black) => f(&tcolor::Black),
-        theme::Color::Dark(theme::BaseColor::Red) => Box::new(tcolor::Red),
+          theme::Color::Dark(theme::BaseColor::Red) => f(&tcolor::Red),
-        theme::Color::Dark(theme::BaseColor::Green) => Box::new(tcolor::Green),
+          theme::Color::Dark(theme::BaseColor::Green) => f(&tcolor::Green),
-        theme::Color::Dark(theme::BaseColor::Yellow) => {
+          theme::Color::Dark(theme::BaseColor::Yellow) => f(&tcolor::Yellow),
-            Box::new(tcolor::Yellow)
+          theme::Color::Dark(theme::BaseColor::Blue) => f(&tcolor::Blue),
-        }
+          theme::Color::Dark(theme::BaseColor::Magenta) => f(&tcolor::Magenta),
-        theme::Color::Dark(theme::BaseColor::Blue) => Box::new(tcolor::Blue),
+          theme::Color::Dark(theme::BaseColor::Cyan) => f(&tcolor::Cyan),
-        theme::Color::Dark(theme::BaseColor::Magenta) => {
+          theme::Color::Dark(theme::BaseColor::White) => f(&tcolor::White),
-            Box::new(tcolor::Magenta)
-        }
-        theme::Color::Dark(theme::BaseColor::Cyan) => Box::new(tcolor::Cyan),
-        theme::Color::Dark(theme::BaseColor::White) => Box::new(tcolor::White),
 
-        theme::Color::Light(theme::BaseColor::Black) => {
+          theme::Color::Light(theme::BaseColor::Black) => {
-            Box::new(tcolor::LightBlack)
+              f(&tcolor::LightBlack)
-        }
+          }
-        theme::Color::Light(theme::BaseColor::Red) => {
+          theme::Color::Light(theme::BaseColor::Red) => f(&tcolor::LightRed),
-            Box::new(tcolor::LightRed)
+          theme::Color::Light(theme::BaseColor::Green) => {
-        }
+              f(&tcolor::LightGreen)
-        theme::Color::Light(theme::BaseColor::Green) => {
+          }
-            Box::new(tcolor::LightGreen)
+          theme::Color::Light(theme::BaseColor::Yellow) => {
-        }
+              f(&tcolor::LightYellow)
-        theme::Color::Light(theme::BaseColor::Yellow) => {
+          }
-            Box::new(tcolor::LightYellow)
+          theme::Color::Light(theme::BaseColor::Blue) => f(&tcolor::LightBlue),
-        }
+          theme::Color::Light(theme::BaseColor::Magenta) => {
-        theme::Color::Light(theme::BaseColor::Blue) => {
+              f(&tcolor::LightMagenta)
-            Box::new(tcolor::LightBlue)
+          }
-        }
+          theme::Color::Light(theme::BaseColor::Cyan) => f(&tcolor::LightCyan),
-        theme::Color::Light(theme::BaseColor::Magenta) => {
+          theme::Color::Light(theme::BaseColor::White) => {
-            Box::new(tcolor::LightMagenta)
+              f(&tcolor::LightWhite)
-        }
+          }
-        theme::Color::Light(theme::BaseColor::Cyan) => {
-            Box::new(tcolor::LightCyan)
-        }
-        theme::Color::Light(theme::BaseColor::White) => {
-            Box::new(tcolor::LightWhite)
-        }
 
-        theme::Color::Rgb(r, g, b) => Box::new(tcolor::Rgb(r, g, b)),
+          theme::Color::Rgb(r, g, b) => f(&tcolor::Rgb(r, g, b)),
-        theme::Color::RgbLowRes(r, g, b) => {
+          theme::Color::RgbLowRes(r, g, b) => {
-            Box::new(tcolor::AnsiValue::rgb(r, g, b))
+              f(&tcolor::AnsiValue::rgb(r, g, b))
-        }
+          }
-    }
+
+      }
 }

src/lib.rs

@@ -170,10 +170,10 @@ new_default!(Cursive);
 impl Cursive {
     /// Creates a new Cursive root, and initialize the back-end.
     pub fn new() -> Self {
-        let mut backend = backend::Concrete::init();
+        let backend = backend::Concrete::init();
 
         let theme = theme::load_default();
-        theme.activate(&mut backend);
+        // theme.activate(&mut backend);
         // let theme = theme::load_theme("assets/style.toml").unwrap();
 
         let (tx, rx) = mpsc::channel();
@@ -287,15 +287,15 @@ impl Cursive {
     /// Sets the current theme.
     pub fn set_theme(&mut self, theme: theme::Theme) {
         self.theme = theme;
-        self.theme.activate(&mut self.backend);
+        // self.theme.activate(&mut self.backend);
-        self.backend.clear();
+        self.clear();
     }
 
     /// Clears the screen.
     ///
     /// Users rarely have to call this directly.
     pub fn clear(&self) {
-        self.backend.clear();
+        self.backend.clear(self.theme.colors.background);
     }
 
     /// Loads a theme from the given file.
@@ -534,9 +534,6 @@ impl Cursive {
     }
 
     fn draw(&mut self) {
-        // TODO: don't clone the theme
-        // Reference it or something
-
         let sizes = self.screen().layer_sizes();
         if self.last_sizes != sizes {
             self.clear();
@@ -544,7 +541,7 @@ impl Cursive {
         }
 
         let printer = Printer::new(self.screen_size(),
-                                   self.theme.clone(),
+                                   &self.theme,
                                    &self.backend);
 
         // Draw the currently active screen
@@ -625,7 +622,7 @@ impl Cursive {
         }
 
         if event == Event::WindowResize {
-            self.backend.clear();
+            self.clear();
         }
 
         // Event dispatch order:

src/printer.rs

@@ -21,7 +21,7 @@ pub struct Printer<'a> {
     /// Whether the view to draw is currently focused or not.
     pub focused: bool,
     /// Currently used theme
-    pub theme: Theme,
+    pub theme: &'a Theme,
 
     /// `true` if nothing has been drawn yet.
     new: Rc<Cell<bool>>,
@@ -34,7 +34,7 @@ impl<'a> Printer<'a> {
     ///
     /// But nobody needs to know that.
     #[doc(hidden)]
-    pub fn new<T: Into<Vec2>>(size: T, theme: Theme,
+    pub fn new<T: Into<Vec2>>(size: T, theme: &'a Theme,
                               backend: &'a backend::Concrete)
                               -> Self {
         Printer {
@@ -53,7 +53,7 @@ impl<'a> Printer<'a> {
     ///
     /// Users rarely need to call this directly.
     pub fn clear(&self) {
-        self.backend.clear();
+        self.backend.clear(self.theme.colors.background);
     }
 
     /// Returns `true` if nothing has been printed yet.
@@ -123,7 +123,8 @@ impl<'a> Printer<'a> {
     /// # use cursive::theme;
     /// # use cursive::backend::{self, Backend};
     /// # let b = backend::Concrete::init();
-    /// # let printer = Printer::new((6,4), theme::load_default(), &b);
+    /// # let t = theme::load_default();
+    /// # let printer = Printer::new((6,4), &t, &b);
     /// printer.with_color(theme::ColorStyle::Highlight, |printer| {
     ///     printer.print((0,0), "This text is highlighted!");
     /// });
@@ -131,7 +132,7 @@ impl<'a> Printer<'a> {
     pub fn with_color<F>(&self, c: ColorStyle, f: F)
         where F: FnOnce(&Printer)
     {
-        self.backend.with_color(c, || f(self));
+        self.backend.with_color(c.resolve(self.theme), || f(self));
     }
 
     /// Same as `with_color`, but apply a ncurses style instead,
@@ -156,7 +157,8 @@ impl<'a> Printer<'a> {
     /// # use cursive::theme;
     /// # use cursive::backend::{self, Backend};
     /// # let b = backend::Concrete::init();
-    /// # let printer = Printer::new((6,4), theme::load_default(), &b);
+    /// # let t = theme::load_default();
+    /// # let printer = Printer::new((6,4), &t, &b);
     /// printer.print_box((0,0), (6,4), false);
     /// ```
     pub fn print_box<T: Into<Vec2>, S: Into<Vec2>>(&self, start: T, size: S,
@@ -195,8 +197,8 @@ impl<'a> Printer<'a> {
         where F: FnOnce(&Printer)
     {
         let color = match self.theme.borders {
-            None => return,
+            BorderStyle::None => return,
-            Some(BorderStyle::Outset) if !invert => ColorStyle::Tertiary,
+            BorderStyle::Outset if !invert => ColorStyle::Tertiary,
             _ => ColorStyle::Primary,
         };
 
@@ -213,8 +215,8 @@ impl<'a> Printer<'a> {
         where F: FnOnce(&Printer)
     {
         let color = match self.theme.borders {
-            None => return,
+            BorderStyle::None => return,
-            Some(BorderStyle::Outset) if invert => ColorStyle::Tertiary,
+            BorderStyle::Outset if invert => ColorStyle::Tertiary,
             _ => ColorStyle::Primary,
         };
 
@@ -260,7 +262,7 @@ impl<'a> Printer<'a> {
             // We can't be larger than what remains
             size: Vec2::min(self.size - offset, size),
             focused: self.focused && focused,
-            theme: self.theme.clone(),
+            theme: self.theme,
             backend: self.backend,
             new: self.new.clone(),
         }

src/theme.rs

@@ -114,8 +114,6 @@
 //! 	highlight_inactive = "#5555FF"
 //! ```
 
-
-use backend::{self, Backend};
 use std::fs::File;
 use std::io;
 use std::io::Read;
@@ -133,12 +131,41 @@ pub enum Effect {
     // TODO: bold, italic, underline
 }
 
+/// Combines a front and back color.
+#[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
+pub struct ColorPair {
+    /// Color used for the foreground.
+    pub front: Color,
+    /// Color used for the background.
+    pub back: Color,
+}
+
+impl ColorPair {
+    /// Return an inverted color pair.
+    ///
+    /// With swapped front abd back color.
+    pub fn invert(&self) -> Self {
+        ColorPair {
+            front: self.back,
+            back: self.front,
+        }
+    }
+
+    /// Creates a new color pair from color IDs.
+    pub fn from_256colors(front: u8, back: u8) -> Self {
+        Self {
+            front: Color::from_256colors(front),
+            back: Color::from_256colors(back),
+        }
+    }
+}
+
 /// Possible color style for a cell.
 ///
 /// Represents a color pair role to use when printing something.
 ///
 /// The current theme will assign each role a foreground and background color.
-#[derive(Clone,Copy)]
+#[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
 pub enum ColorStyle {
     /// Application background, where no view is present.
     Background,
@@ -158,22 +185,34 @@ pub enum ColorStyle {
     Highlight,
     /// Highlight color for inactive views (not in focus).
     HighlightInactive,
+    /// Directly specifies colors, independently of the theme.
+    Custom {
+        /// Foreground color
+        front: Color,
+        /// Background color
+        back: Color,
+    },
 }
 
 impl ColorStyle {
-    /// Returns the ncurses pair ID associated with this color pair.
+    /// Return the color pair that this style represents.
-    pub fn id(self) -> i16 {
+    ///
-        match self {
+    /// Returns `(front, back)`.
-            ColorStyle::Background => 1,
+    pub fn resolve(&self, theme: &Theme) -> ColorPair {
-            ColorStyle::Shadow => 2,
+        let c = &theme.colors;
-            ColorStyle::Primary => 3,
+        let (front, back) = match *self {
-            ColorStyle::Secondary => 4,
+            ColorStyle::Background => (c.view, c.background),
-            ColorStyle::Tertiary => 5,
+            ColorStyle::Shadow => (c.shadow, c.shadow),
-            ColorStyle::TitlePrimary => 6,
+            ColorStyle::Primary => (c.primary, c.view),
-            ColorStyle::TitleSecondary => 7,
+            ColorStyle::Secondary => (c.secondary, c.view),
-            ColorStyle::Highlight => 8,
+            ColorStyle::Tertiary => (c.tertiary, c.view),
-            ColorStyle::HighlightInactive => 9,
+            ColorStyle::TitlePrimary => (c.title_primary, c.view),
-        }
+            ColorStyle::TitleSecondary => (c.title_secondary, c.view),
+            ColorStyle::Highlight => (c.view, c.highlight),
+            ColorStyle::HighlightInactive => (c.view, c.highlight_inactive),
+            ColorStyle::Custom { front, back } => (front, back),
+        };
+        ColorPair { front, back }
     }
 }
 
@@ -183,7 +222,7 @@ pub struct Theme {
     /// Whether views in a StackView should have shadows.
     pub shadow: bool,
     /// How view borders should be drawn.
-    pub borders: Option<BorderStyle>,
+    pub borders: BorderStyle,
     /// What colors should be used through the application?
     pub colors: Palette,
 }
@@ -192,7 +231,7 @@ impl Default for Theme {
     fn default() -> Self {
         Theme {
             shadow: true,
-            borders: Some(BorderStyle::Simple),
+            borders: BorderStyle::Simple,
             colors: Palette {
                 background: Color::Dark(BaseColor::Blue),
                 shadow: Color::Dark(BaseColor::Black),
@@ -223,64 +262,29 @@ impl Theme {
             self.colors.load(table);
         }
     }
-
-    /// Sets a theme as active.
-    ///
-    /// **Don't use this directly.** Uses [`Cursive::set_theme`] instead.
-    ///
-    /// [`Cursive::set_theme`]: ../struct.Cursive.html#method.set_theme
-    pub fn activate(&self, backend: &mut backend::Concrete) {
-        // Initialize each color with the backend
-        backend.init_color_style(ColorStyle::Background,
-                                 &self.colors.view,
-                                 &self.colors.background);
-        backend.init_color_style(ColorStyle::Shadow,
-                                 &self.colors.shadow,
-                                 &self.colors.shadow);
-        backend.init_color_style(ColorStyle::Primary,
-                                 &self.colors.primary,
-                                 &self.colors.view);
-        backend.init_color_style(ColorStyle::Secondary,
-                                 &self.colors.secondary,
-                                 &self.colors.view);
-        backend.init_color_style(ColorStyle::Tertiary,
-                                 &self.colors.tertiary,
-                                 &self.colors.view);
-        backend.init_color_style(ColorStyle::TitlePrimary,
-                                 &self.colors.title_primary,
-                                 &self.colors.view);
-        backend.init_color_style(ColorStyle::TitleSecondary,
-                                 &self.colors.title_secondary,
-                                 &self.colors.view);
-        backend.init_color_style(ColorStyle::Highlight,
-                                 &self.colors.view,
-                                 &self.colors.highlight);
-        backend.init_color_style(ColorStyle::HighlightInactive,
-                                 &self.colors.view,
-                                 &self.colors.highlight_inactive);
-        backend.clear();
-    }
 }
 
 /// Specifies how some borders should be drawn.
 ///
 /// Borders are used around Dialogs, select popups, and panels.
-#[derive(Clone,Copy,Debug)]
+#[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
 pub enum BorderStyle {
     /// Simple borders.
     Simple,
     /// Outset borders with a simple 3d effect.
     Outset,
+    /// No borders.
+    None,
 }
 
 impl BorderStyle {
-    fn from(s: &str) -> Option<Self> {
+    fn from(s: &str) -> Self {
         if s == "simple" {
-            Some(BorderStyle::Simple)
+            BorderStyle::Simple
         } else if s == "outset" {
-            Some(BorderStyle::Outset)
+            BorderStyle::Outset
         } else {
-            None
+            BorderStyle::None
         }
     }
 }
@@ -288,7 +292,7 @@ impl BorderStyle {
 /// Color configuration for the application.
 ///
 /// Assign each color role an actual color.
-#[derive(Clone,Debug)]
+#[derive(Copy,Clone,Debug)]
 pub struct Palette {
     /// Color used for the application background.
     pub background: Color,
@@ -352,7 +356,7 @@ fn load_color(target: &mut Color, value: Option<&toml::Value>) -> bool {
 }
 
 /// One of the 8 base colors.
-#[derive(Clone,Copy,Debug)]
+#[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
 pub enum BaseColor {
     /// Black color
     ///
@@ -388,8 +392,24 @@ pub enum BaseColor {
     White,
 }
 
+impl From<u8> for BaseColor {
+    fn from(n: u8) -> Self {
+        match n % 8 {
+            0 => BaseColor::Black,
+            1 => BaseColor::Red,
+            2 => BaseColor::Green,
+            3 => BaseColor::Yellow,
+            4 => BaseColor::Blue,
+            5 => BaseColor::Magenta,
+            6 => BaseColor::Cyan,
+            7 => BaseColor::White,
+            _ => unreachable!(),
+        }
+    }
+}
+
 /// Represents a color used by the theme.
-#[derive(Clone,Copy,Debug)]
+#[derive(Clone,Copy,Debug,PartialEq,Eq,Hash)]
 pub enum Color {
     /// One of the 8 base colors.
     Dark(BaseColor),
@@ -405,8 +425,6 @@ pub enum Color {
     RgbLowRes(u8, u8, u8),
 }
 
-impl Color {}
-
 /// Possible error returned when loading a theme.
 #[derive(Debug)]
 pub enum Error {
@@ -429,26 +447,47 @@ impl From<toml::de::Error> for Error {
 }
 
 impl Color {
+    /// Creates a color from its ID in the 256 colors list.
+    ///
+    /// * Colors 0-7 are base dark colors.
+    /// * Colors 8-15 are base light colors.
+    /// * Colors 16-255 are rgb colors with 6 values per channel.
+    pub fn from_256colors(n: u8) -> Self {
+        if n < 8 {
+            Color::Dark(BaseColor::from(n))
+        } else if n < 16 {
+            Color::Light(BaseColor::from(n))
+        } else {
+            let n = n - 16;
+
+            let r = n / 36;
+            let g = (n % 36) / 6;
+            let b = n % 6;
+
+            Color::RgbLowRes(r, g, b)
+        }
+    }
+
     fn parse(value: &str) -> Option<Self> {
         Some(match value {
-            "black" => Color::Dark(BaseColor::Black),
+                 "black" => Color::Dark(BaseColor::Black),
-            "red" => Color::Dark(BaseColor::Red),
+                 "red" => Color::Dark(BaseColor::Red),
-            "green" => Color::Dark(BaseColor::Green),
+                 "green" => Color::Dark(BaseColor::Green),
-            "yellow" => Color::Dark(BaseColor::Yellow),
+                 "yellow" => Color::Dark(BaseColor::Yellow),
-            "blue" => Color::Dark(BaseColor::Blue),
+                 "blue" => Color::Dark(BaseColor::Blue),
-            "magenta" => Color::Dark(BaseColor::Magenta),
+                 "magenta" => Color::Dark(BaseColor::Magenta),
-            "cyan" => Color::Dark(BaseColor::Cyan),
+                 "cyan" => Color::Dark(BaseColor::Cyan),
-            "white" => Color::Dark(BaseColor::White),
+                 "white" => Color::Dark(BaseColor::White),
-            "light black" => Color::Light(BaseColor::Black),
+                 "light black" => Color::Light(BaseColor::Black),
-            "light red" => Color::Light(BaseColor::Red),
+                 "light red" => Color::Light(BaseColor::Red),
-            "light green" => Color::Light(BaseColor::Green),
+                 "light green" => Color::Light(BaseColor::Green),
-            "light yellow" => Color::Light(BaseColor::Yellow),
+                 "light yellow" => Color::Light(BaseColor::Yellow),
-            "light blue" => Color::Light(BaseColor::Blue),
+                 "light blue" => Color::Light(BaseColor::Blue),
-            "light magenta" => Color::Light(BaseColor::Magenta),
+                 "light magenta" => Color::Light(BaseColor::Magenta),
-            "light cyan" => Color::Light(BaseColor::Cyan),
+                 "light cyan" => Color::Light(BaseColor::Cyan),
-            "light white" => Color::Light(BaseColor::White),
+                 "light white" => Color::Light(BaseColor::White),
-            value => return Color::parse_special(value),
+                 value => return Color::parse_special(value),
-        })
+             })
     }
 
     fn parse_special(value: &str) -> Option<Color> {

src/vec.rs

@@ -114,6 +114,11 @@ impl From<(u32, u32)> for XY<usize> {
     }
 }
 
+impl From<(u8, u8)> for XY<usize> {
+    fn from((x, y): (u8, u8)) -> Self {
+        (x as usize, y as usize).into()
+    }
+}
 
 impl<T: Add<Output = T>, O: Into<XY<T>>> Add<O> for XY<T> {
     type Output = Self;

src/view/scroll.rs

@@ -159,7 +159,8 @@ impl ScrollBase {
     /// # use cursive::backend::{self, Backend};
     /// # let scrollbase = ScrollBase::new();
     /// # let b = backend::Concrete::init();
-    /// # let printer = Printer::new((5,1), theme::load_default(), &b);
+    /// # let t = theme::load_default();
+    /// # let printer = Printer::new((5,1), &t, &b);
     /// # let printer = &printer;
     /// let lines = ["Line 1", "Line number 2"];
     /// scrollbase.draw(printer, |printer, i| {