Add &Backend to Printer struct

Makes `::B` public but undocumented.
Backend is currently an immutable ref, may need to become
mutable to be more useful (will need to change the View trait)

src/lib.rs

@@ -132,6 +132,8 @@ pub struct Cursive {
 
     running: bool,
 
+    backend: B,
+
     cb_source: mpsc::Receiver<Box<Fn(&mut Cursive) + Send>>,
     cb_sink: mpsc::Sender<Box<Fn(&mut Cursive) + Send>>,
 }
@@ -140,7 +142,8 @@ new_default!(Cursive);
 
 // Use the Ncurses backend.
 // TODO: make this feature-driven
-type B = NcursesBackend;
+#[doc(hidden)]
+pub type B = NcursesBackend;
 
 impl Cursive {
     /// Creates a new Cursive root, and initialize ncurses.
@@ -163,6 +166,7 @@ impl Cursive {
             running: true,
             cb_source: rx,
             cb_sink: tx,
+            backend: NcursesBackend,
         };
 
         res.screens.push(views::StackView::new());
@@ -441,7 +445,7 @@ impl Cursive {
     fn draw(&mut self) {
         // TODO: don't clone the theme
         // Reference it or something
-        let printer = Printer::new(self.screen_size(), self.theme.clone());
+        let printer = Printer::new(self.screen_size(), self.theme.clone(), &mut self.backend);
 
         // Draw the currently active screen
         // If the menubar is active, nothing else can be.
@@ -462,7 +466,8 @@ impl Cursive {
 
         let printer =
             printer.sub_printer(Vec2::new(0, offset), printer.size, !selected);
-        self.screen_mut().draw(&printer);
+        let id = self.active_screen;
+        self.screens.get_mut(id).unwrap().draw(&printer);
 
         B::refresh();
     }

src/printer.rs

@@ -12,8 +12,7 @@ use theme::{BorderStyle, ColorStyle, Effect, Theme};
 use vec::Vec2;
 
 /// Convenient interface to draw on a subset of the screen.
-#[derive(Clone)]
-pub struct Printer {
+pub struct Printer<'a> {
     /// Offset into the window this printer should start drawing at.
     pub offset: Vec2,
     /// Size of the area we are allowed to draw on.
@@ -22,16 +21,22 @@ pub struct Printer {
     pub focused: bool,
     /// Currently used theme
     pub theme: Theme,
+
+    backend: &'a B,
 }
 
-impl Printer {
+impl <'a> Printer<'a> {
     /// Creates a new printer on the given window.
-    pub fn new<T: Into<Vec2>>(size: T, theme: Theme) -> Self {
+    ///
+    /// But nobody needs to know that.
+    #[doc(hidden)]
+    pub fn new<T: Into<Vec2>>(size: T, theme: Theme, backend: &'a B) -> Self {
         Printer {
             offset: Vec2::zero(),
             size: size.into(),
             focused: true,
             theme: theme,
+            backend: backend,
         }
     }
 
@@ -90,7 +95,9 @@ impl Printer {
     /// ```no_run
     /// # use cursive::Printer;
     /// # use cursive::theme;
-    /// # let printer = Printer::new((6,4), theme::load_default());
+    /// # use cursive::B;
+    /// # let b = B{};
+    /// # let printer = Printer::new((6,4), theme::load_default(), &b);
     /// printer.with_color(theme::ColorStyle::Highlight, |printer| {
     ///     printer.print((0,0), "This text is highlighted!");
     /// });
@@ -121,7 +128,9 @@ impl Printer {
     /// ```no_run
     /// # use cursive::Printer;
     /// # use cursive::theme;
-    /// # let printer = Printer::new((6,4), theme::load_default());
+    /// # use cursive::B;
+    /// # let b = B{};
+    /// # let printer = Printer::new((6,4), theme::load_default(), &b);
     /// printer.print_box((0,0), (6,4), false);
     /// ```
     pub fn print_box<T: Into<Vec2>, S: Into<Vec2>>(&self, start: T, size: S,
@@ -213,9 +222,9 @@ impl Printer {
     }
 
     /// Returns a printer on a subset of this one's area.
-    pub fn sub_printer<S: Into<Vec2>, T: Into<Vec2>>(&self, offset: S,
+    pub fn sub_printer<S: Into<Vec2>, T: Into<Vec2>>(&'a self, offset: S,
                                                      size: T, focused: bool)
-                                                     -> Printer {
+                                                     -> Printer<'a> {
         let size = size.into();
         let offset = offset.into().or_min(self.size);
         Printer {
@@ -224,6 +233,7 @@ impl Printer {
             size: Vec2::min(self.size - offset, size),
             focused: self.focused && focused,
             theme: self.theme.clone(),
+            backend: self.backend,
         }
     }
 

src/view/scroll.rs

@@ -134,8 +134,10 @@ impl ScrollBase {
     /// # use cursive::view::ScrollBase;
     /// # use cursive::Printer;
     /// # use cursive::theme;
+    /// # use cursive::B;
     /// # let scrollbase = ScrollBase::new();
-    /// # let printer = Printer::new((5,1), theme::load_default());
+    /// # let b = B{};
+    /// # let printer = Printer::new((5,1), theme::load_default(), &b);
     /// # let printer = &printer;
     /// let lines = ["Line 1", "Line number 2"];
     /// scrollbase.draw(printer, |printer, i| {