Refactor BoxView

Add `Boxable` trait.

examples/key_codes.rs

@@ -6,7 +6,7 @@ use cursive::event::EventResult;
 fn main() {
     let mut siv = Cursive::new();
 
-    siv.add_layer(BoxView::fixed_size((30, 10), KeyCodeView::new(10)));
+    siv.add_layer(KeyCodeView::new(10).fixed_size((30, 10)));
 
     siv.run();
 }

examples/linear.rs

@@ -16,10 +16,10 @@ fn main() {
             .child(TextView::new("Title").h_align(HAlign::Center))
             // Box the textview, so it doesn't get too wide.
             // A 0 height value means it will be unconstrained.
-            .child(BoxView::fixed_width(30, TextView::new(text).scrollable(false)))
-            .child(BoxView::fixed_width(30, TextView::new(text)))
-            .child(BoxView::fixed_width(30, TextView::new(text)))
-            .child(BoxView::fixed_width(30, TextView::new(text))))
+            .child(TextView::new(text).scrollable(false).fixed_width(30))
+            .child(TextView::new(text).fixed_width(30))
+            .child(TextView::new(text).fixed_width(30))
+            .child(TextView::new(text).fixed_width(30)))
         .button("Quit", |s| s.quit())
         .h_align(HAlign::Center));
 

examples/select.rs

@@ -17,8 +17,8 @@ fn main() {
     let mut siv = Cursive::new();
 
     // Let's add a BoxView to keep the list at a reasonable size - it can scroll anyway.
-    siv.add_layer(Dialog::new(BoxView::fixed_size((20, 10), select))
-                      .title("Where are you from?"));
+    siv.add_layer(Dialog::new(select.fixed_size((20, 10)))
+        .title("Where are you from?"));
 
     siv.run();
 }
@@ -26,6 +26,7 @@ fn main() {
 // Let's put the callback in a separate function to keep it clean, but it's not required.
 fn show_next_window(siv: &mut Cursive, city: &String) {
     siv.pop_layer();
-    siv.add_layer(Dialog::new(TextView::new(format!("{} is a great city!", city)))
-                      .button("Quit", |s| s.quit()));
+    let text = format!("{} is a great city!", city);
+    siv.add_layer(Dialog::new(TextView::new(text))
+        .button("Quit", |s| s.quit()));
 }

examples/text_area.rs

@@ -7,9 +7,10 @@ fn main() {
 
     siv.add_layer(Dialog::empty()
         .title("Describe your issue")
-        .padding((1,1,1,0))
-        .content(BoxView::fixed_size((30, 5),
-                                     TextArea::new().with_id("text")))
+        .padding((1, 1, 1, 0))
+        .content(TextArea::new()
+            .with_id("text")
+            .fixed_size((30, 5)))
         .button("Ok", Cursive::quit));
 
     siv.run();

src/prelude.rs

@@ -8,7 +8,7 @@
 
 pub use {Cursive, Printer, With};
 pub use event::{Event, Key};
-pub use view::{Identifiable, Selector, View};
+pub use view::{Boxable, Identifiable, Selector, View};
 pub use views::{BoxView, Button, Checkbox, Dialog, EditView, FullView,
                 IdView, KeyEventView, LinearLayout, ListView, Panel,
                 ProgressBar, SelectView, TextArea, TextView};

src/view/boxable.rs

@@ -0,0 +1,76 @@
+use view::{SizeConstraint, View};
+use views::BoxView;
+use vec::Vec2;
+
+/// Makes a view wrappable in a [`BoxView`].
+///
+/// [`BoxView`]: ../views/struct.BoxView.html
+pub trait Boxable: View + Sized {
+
+    /// Wraps `self` in a `BoxView` with the given size constraints.
+    fn boxed(self, width: SizeConstraint, height: SizeConstraint) -> BoxView<Self> {
+        BoxView::new(width, height, self)
+    }
+
+    /// Wraps `self` into a fixed-size `BoxView`.
+    fn fixed_size<S: Into<Vec2>>(self, size: S) -> BoxView<Self> {
+        BoxView::with_fixed_size(size, self)
+    }
+
+    /// Wraps `self` into a fixed-width `BoxView`.
+    fn fixed_width(self, width: usize) -> BoxView<Self> {
+        BoxView::with_fixed_width(width, self)
+    }
+
+    /// Wraps `self` into a fixed-width `BoxView`.
+    fn fixed_height(self, height: usize) -> BoxView<Self> {
+        BoxView::with_fixed_height(height, self)
+    }
+
+    /// Wraps `self` into a full-screen `BoxView`.
+    fn full_screen(self) -> BoxView<Self> {
+        BoxView::with_full_screen(self)
+    }
+
+    /// Wraps `self` into a full-width `BoxView`.
+    fn full_width(self) -> BoxView<Self> {
+        BoxView::with_full_width(self)
+    }
+
+    /// Wraps `self` into a full-height `BoxView`.
+    fn full_height(self) -> BoxView<Self> {
+        BoxView::with_full_height(self)
+    }
+
+    /// Wraps `self` into a limited-size `BoxView`.
+    fn max_size<S: Into<Vec2>>(self, size: S) -> BoxView<Self> {
+        BoxView::with_max_size(size, self)
+    }
+
+    /// Wraps `self` into a limited-width `BoxView`.
+    fn max_width(self, max_width: usize) -> BoxView<Self> {
+        BoxView::with_max_width(max_width, self)
+    }
+
+    /// Wraps `self` into a limited-height `BoxView`.
+    fn max_height(self, max_height: usize) -> BoxView<Self> {
+        BoxView::with_max_height(max_height, self)
+    }
+
+    /// Wraps `self` into a `BoxView` at least sized `size`.
+    fn min_size<S: Into<Vec2>>(self, size: S) -> BoxView<Self> {
+        BoxView::with_min_size(size, self)
+    }
+
+    /// Wraps `self` in a `BoxView` at least `min_width` wide.
+    fn min_width(self, min_width: usize) -> BoxView<Self> {
+        BoxView::with_min_width(min_width, self)
+    }
+
+    /// Wraps `self` in a `BoxView` at least `min_height` tall.
+    fn min_height(self, min_height: usize) -> BoxView<Self> {
+        BoxView::with_min_height(min_height, self)
+    }
+}
+
+impl<T: View> Boxable for T {}

src/view/identifiable.rs

@@ -0,0 +1,14 @@
+use views::IdView;
+use view::View;
+
+/// Makes a view wrappable in an [`IdView`].
+///
+/// [`IdView`]: ../views/struct.IdView.html
+pub trait Identifiable: View + Sized {
+    /// Wraps this view into an IdView with the given id.
+    fn with_id(self, id: &str) -> IdView<Self> {
+        IdView::new(id, self)
+    }
+}
+
+impl<T: View> Identifiable for T {}

src/view/mod.rs

@@ -40,17 +40,18 @@ mod view_wrapper;
 
 // Essentials components
 mod position;
+mod size_cache;
+mod size_constraint;
 mod view_path;
 
 // Helper bases
 mod scroll;
-
-// Views
+mod identifiable;
+mod boxable;
 
 
 use std::any::Any;
 
-use XY;
 use direction::Direction;
 use event::{Event, EventResult};
 use vec::Vec2;
@@ -60,8 +61,12 @@ pub use self::position::{Offset, Position};
 
 pub use self::scroll::ScrollBase;
 
+pub use self::size_cache::SizeCache;
+pub use self::size_constraint::SizeConstraint;
 pub use self::view_path::ViewPath;
 pub use self::view_wrapper::ViewWrapper;
+pub use self::identifiable::Identifiable;
+pub use self::boxable::Boxable;
 
 
 /// Main trait defining a view behaviour.
@@ -121,61 +126,6 @@ pub trait View {
     }
 }
 
-
-/// Cache around a one-dimensional layout result.
-///
-/// This is not a View, but something to help you if you create your own Views.
-#[derive(PartialEq, Debug, Clone, Copy)]
-pub struct SizeCache {
-    /// Cached value
-    pub value: usize,
-    /// `true` if the last size was constrained.
-    ///
-    /// If unconstrained, any request larger than this value
-    /// would return the same size.
-    pub constrained: bool,
-}
-
-impl SizeCache {
-    /// Creates a new sized cache
-    pub fn new(value: usize, constrained: bool) -> Self {
-        SizeCache {
-            value: value,
-            constrained: constrained,
-        }
-    }
-
-    /// Returns `true` if `self` is still valid for the given `request`.
-    pub fn accept(self, request: usize) -> bool {
-        if request < self.value {
-            false
-        } else if request == self.value {
-            true
-        } else {
-            !self.constrained
-        }
-    }
-
-    /// Creates a new bi-dimensional cache.
-    ///
-    /// It will stay valid for the same request, and compatible ones.
-    ///
-    /// A compatible request is one where, for each axis, either:
-    ///
-    /// * the request is equal to the cached size, or
-    /// * the request is larger than the cached size and the cache is unconstrained
-    ///
-    /// Notes:
-    ///
-    /// * `size` must fit inside `req`.
-    /// * for each dimension, `constrained = (size == req)`
-    pub fn build(size: Vec2, req: Vec2) -> XY<Self> {
-        XY::new(SizeCache::new(size.x, size.x >= req.x),
-                SizeCache::new(size.y, size.y >= req.y))
-    }
-}
-
-
 /// Selects a single view (if any) in the tree.
 pub enum Selector<'a> {
     /// Selects a view from its ID.
@@ -183,13 +133,3 @@ pub enum Selector<'a> {
     /// Selects a view from its path.
     Path(&'a ViewPath),
 }
-
-/// Makes a view wrappable in an `IdView`.
-pub trait Identifiable: View + Sized {
-    /// Wraps this view into an IdView with the given id.
-    fn with_id(self, id: &str) -> ::views::IdView<Self> {
-        ::views::IdView::new(id, self)
-    }
-}
-
-impl<T: View> Identifiable for T {}

src/view/size_cache.rs

@@ -0,0 +1,55 @@
+use XY;
+use vec::Vec2;
+
+/// Cache around a one-dimensional layout result.
+///
+/// This is not a View, but something to help you if you create your own Views.
+#[derive(PartialEq, Debug, Clone, Copy)]
+pub struct SizeCache {
+    /// Cached value
+    pub value: usize,
+    /// `true` if the last size was constrained.
+    ///
+    /// If unconstrained, any request larger than this value
+    /// would return the same size.
+    pub constrained: bool,
+}
+
+impl SizeCache {
+    /// Creates a new sized cache
+    pub fn new(value: usize, constrained: bool) -> Self {
+        SizeCache {
+            value: value,
+            constrained: constrained,
+        }
+    }
+
+    /// Returns `true` if `self` is still valid for the given `request`.
+    pub fn accept(self, request: usize) -> bool {
+        if request < self.value {
+            false
+        } else if request == self.value {
+            true
+        } else {
+            !self.constrained
+        }
+    }
+
+    /// Creates a new bi-dimensional cache.
+    ///
+    /// It will stay valid for the same request, and compatible ones.
+    ///
+    /// A compatible request is one where, for each axis, either:
+    ///
+    /// * the request is equal to the cached size, or
+    /// * the request is larger than the cached size and the cache is unconstrained
+    ///
+    /// Notes:
+    ///
+    /// * `size` must fit inside `req`.
+    /// * for each dimension, `constrained = (size == req)`
+    pub fn build(size: Vec2, req: Vec2) -> XY<Self> {
+        XY::new(SizeCache::new(size.x, size.x >= req.x),
+                SizeCache::new(size.y, size.y >= req.y))
+    }
+}

src/view/size_constraint.rs

@@ -0,0 +1,50 @@
+use std::cmp::min;
+
+/// Single-dimensional constraint on a view size.
+///
+/// This describes a possible behaviour for a [`BoxView`].
+///
+/// [`BoxView`]: ../views/struct.BoxView.html
+#[derive(Debug, Clone, Copy)]
+pub enum SizeConstraint {
+    /// No constraint imposed, the child view's response is used.
+    Free,
+    /// Tries to take all available space, no matter what the child needs.
+    Full,
+    /// Always return the included size, no matter what the child needs.
+    Fixed(usize),
+    /// Returns the minimum of the included value and the child view's size.
+    AtMost(usize),
+    /// Returns the maximum of the included value and the child view's size.
+    AtLeast(usize),
+}
+
+impl SizeConstraint {
+
+    /// Returns the size to be given to the child.
+    ///
+    /// When `available` is offered to the `BoxView`.
+    pub fn available(self, available: usize) -> usize {
+        match self {
+            SizeConstraint::Free |
+            SizeConstraint::Full |
+            SizeConstraint::AtLeast(_) => available,
+            // If the available space is too small, always give in.
+            SizeConstraint::Fixed(value) |
+            SizeConstraint::AtMost(value) => min(value, available),
+        }
+    }
+
+    /// Returns the size the child view should actually use.
+    ///
+    /// When it said it wanted `result`.
+    pub fn result(self, (result, available): (usize, usize)) -> usize {
+        match self {
+            SizeConstraint::AtLeast(value) if result < value => value,
+            SizeConstraint::AtMost(value) if result > value => value,
+            SizeConstraint::Fixed(value) => value,
+            SizeConstraint::Full => available,
+            _ => result,
+        }
+    }
+}

src/views/box_view.rs

@@ -1,64 +1,150 @@
-use std::cmp;
-
 use XY;
 use vec::Vec2;
-use view::{View, ViewWrapper};
+use view::{SizeConstraint, View, ViewWrapper};
 
-/// Wrapper around another view, with a fixed size.
+/// Wrapper around another view, with a controlled size.
 ///
-/// Each axis can be enabled independantly.
+/// Each axis can independently be set to:
 ///
-/// * If both axis are fixed, the view always asks for this size.
-/// * If both axis are left free, the wrapper has no effect and the underlying
-///   view is directly queried.
-/// * If only one axis is fixed, it will override the size request when
-///   querying the wrapped view.
+/// * Keep a **fixed** size
+/// * Use **all** available size
+/// * Use **at most** a given size
+/// * Use **at least** a given size
+/// * Let the wrapped view decide.
 ///
 /// # Examples
 ///
 /// ```
 /// # use cursive::views::{BoxView,TextView};
 /// // Creates a 20x4 BoxView with a TextView content.
-/// let view = BoxView::fixed_size((20,4), TextView::new("Hello!"));
+/// let view = BoxView::with_fixed_size((20,4), TextView::new("Hello!"));
 /// ```
 pub struct BoxView<T: View> {
-    size: XY<Option<usize>>,
+    /// Constraint on each axis
+    size: XY<SizeConstraint>,
+
+    /// `true` if the view can be squished.
+    ///
+    /// This means if the required size is less than the computed size,
+    /// consider returning a smaller size.
+    /// For instance, try to return the child's desires size.
+    squishable: bool,
+
+    /// The actual view we're wrapping.
     view: T,
 }
 
 impl<T: View> BoxView<T> {
-    /// Wraps `view` in a new `BoxView` with the given size.
-    pub fn fixed_size<S: Into<Vec2>>(size: S, view: T) -> Self {
-        let size = size.into();
-
-        BoxView::new(Some(size.x), Some(size.y), view)
-    }
-
     /// Creates a new `BoxView` with the given width and height requirements.
     ///
     /// `None` values will use the wrapped view's preferences.
-    pub fn new(width: Option<usize>, height: Option<usize>, view: T) -> Self {
+    pub fn new(width: SizeConstraint, height: SizeConstraint, view: T) -> Self {
         BoxView {
             size: (width, height).into(),
+            squishable: false,
             view: view,
         }
     }
 
+    /// Sets `self` to be squishable.
+    ///
+    /// A squishable `BoxView` will take a smaller size than it should when
+    /// the available space is too small. In that case, it will allow the
+    /// child view to contract, if it can.
+    ///
+    /// More specifically, if the available space is less than the size we
+    /// would normally ask for, return the child size.
+    pub fn squishable(mut self) -> Self {
+        self.squishable = true;
+        self
+    }
+
+    /// Wraps `view` in a new `BoxView` with the given size.
+    pub fn with_fixed_size<S: Into<Vec2>>(size: S, view: T) -> Self {
+        let size = size.into();
+
+        BoxView::new(SizeConstraint::Fixed(size.x),
+                     SizeConstraint::Fixed(size.y),
+                     view)
+    }
+
     /// Wraps `view` in a new `BoxView` with fixed width.
-    pub fn fixed_width(width: usize, view: T) -> Self {
-        BoxView::new(Some(width), None, view)
+    pub fn with_fixed_width(width: usize, view: T) -> Self {
+        BoxView::new(SizeConstraint::Fixed(width), SizeConstraint::Free, view)
     }
 
     /// Wraps `view` in a new `BoxView` with fixed height.
-    pub fn fixed_height(height: usize, view: T) -> Self {
-        BoxView::new(None, Some(height), view)
+    pub fn with_fixed_height(height: usize, view: T) -> Self {
+        BoxView::new(SizeConstraint::Free, SizeConstraint::Fixed(height), view)
     }
-}
 
-fn min<T: Ord>(a: T, b: Option<T>) -> T {
-    match b {
-        Some(b) => cmp::min(a, b),
-        None => a,
+    /// Wraps `view` in a `BoxView` which will take all available space.
+    pub fn with_full_screen(view: T) -> Self {
+        BoxView::new(SizeConstraint::Full, SizeConstraint::Full, view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will take all available width.
+    pub fn with_full_width(view: T) -> Self {
+        BoxView::new(SizeConstraint::Full, SizeConstraint::Free, view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will take all available height.
+    pub fn with_full_height(view: T) -> Self {
+        BoxView::new(SizeConstraint::Free, SizeConstraint::Full, view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will never be bigger than `size`.
+    pub fn with_max_size<S: Into<Vec2>>(size: S, view: T) -> Self {
+        let size = size.into();
+
+        BoxView::new(SizeConstraint::AtMost(size.x),
+                     SizeConstraint::AtMost(size.y),
+                     view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will enforce a maximum width.
+    ///
+    /// The resulting width will never be more than `max_width`.
+    pub fn with_max_width(max_width: usize, view: T) -> Self {
+        BoxView::new(SizeConstraint::AtMost(max_width),
+                     SizeConstraint::Free,
+                     view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will enforce a maximum height.
+    ///
+    /// The resulting height will never be more than `max_height`.
+    pub fn with_max_height(max_height: usize, view: T) -> Self {
+        BoxView::new(SizeConstraint::Free,
+                     SizeConstraint::AtMost(max_height),
+                     view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will never be smaller than `size`.
+    pub fn with_min_size<S: Into<Vec2>>(size: S, view: T) -> Self {
+        let size = size.into();
+
+        BoxView::new(SizeConstraint::AtLeast(size.x),
+                     SizeConstraint::AtLeast(size.y),
+                     view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will enforce a minimum width.
+    ///
+    /// The resulting width will never be less than `min_width`.
+    pub fn with_min_width(min_width: usize, view: T) -> Self {
+        BoxView::new(SizeConstraint::AtLeast(min_width),
+                     SizeConstraint::Free,
+                     view)
+    }
+
+    /// Wraps `view` in a `BoxView` which will enforce a minimum height.
+    ///
+    /// The resulting height will never be less than `min_height`.
+    pub fn with_min_height(min_height: usize, view: T) -> Self {
+        BoxView::new(SizeConstraint::Free,
+                     SizeConstraint::AtLeast(min_height),
+                     view)
     }
 }
 
@@ -67,24 +153,24 @@ impl<T: View> ViewWrapper for BoxView<T> {
 
     fn wrap_get_min_size(&mut self, req: Vec2) -> Vec2 {
 
-        if let (Some(w), Some(h)) = self.size.pair() {
-            // If we know everything already, no need to ask
-            Vec2::new(w, h)
+        let req = self.size.zip_map(req, SizeConstraint::available);
+        let child_size = self.view.get_min_size(req);
+        let result = self.size
+            .zip_map(child_size.zip(req), SizeConstraint::result);
+
+        if self.squishable {
+            // We respect the request if we're less or equal.
+            let respect_req = result.zip_map(req, |res, req| res <= req);
+            result.zip_map(respect_req.zip(child_size),
+                           |res, (respect, child)| if respect {
+                               // If we respect the request, keep the result
+                               res
+                           } else {
+                               // Otherwise, take the child as squish attempt.
+                               child
+                           })
         } else {
-            // If req < self.size in any axis, we're screwed.
-            // TODO: handle insufficient space
-            // (should probably show an error message or a blank canvas)
-
-            // From now on, we assume req >= self.size.
-
-            // Override the request on the restricted axis
-            let req = req.zip_map(self.size, min);
-
-            // Back in my time, we didn't ask kids for their opinions!
-            let child_size = self.view.get_min_size(req);
-
-            // This calls unwrap_or on each axis
-            self.size.unwrap_or(child_size)
+            result
         }
     }
 }

src/xy.rs

@@ -45,6 +45,11 @@ impl<T> XY<T> {
         }
     }
 
+    /// Returns a new `XY` of tuples made by zipping `self` and `other`.
+    pub fn zip<U>(self, other: XY<U>) -> XY<(T, U)> {
+        XY::new((self.x, other.x), (self.y, other.y))
+    }
+
     /// Returns a new `XY` by calling `f` on `self` and `other` for each axis.
     pub fn zip_map<U, V, F: Fn(T, U) -> V>(self, other: XY<U>, f: F) -> XY<V> {
         XY::new(f(self.x, other.x), f(self.y, other.y))