Basic linear layout implementation

Not tested yet

src/lib.rs

@@ -39,8 +39,8 @@ use std::collections::HashMap;
 use std::path::Path;
 
 use vec::Vec2;
-use view::View;
 use printer::Printer;
+use view::View;
 use view::{StackView,Selector};
 
 use event::{Event,ToEvent,Key,EventResult,Callback};

src/vec.rs

@@ -1,10 +1,10 @@
 //! Points on the 2D character grid.
 
 use std::ops::{Add, Sub, Mul, Div};
-use std::cmp::{min,max};
+use std::cmp::{min,max,Ordering};
 
 /// Simple 2D size, in characters.
-#[derive(Clone,Copy)]
+#[derive(Clone,Copy,PartialEq)]
 pub struct Vec2 {
     /// X coordinate (column), from left to right.
     pub x: usize,
@@ -12,6 +12,15 @@ pub struct Vec2 {
     pub y: usize,
 }
 
+impl PartialOrd for Vec2 {
+    fn partial_cmp(&self, other: &Vec2) -> Option<Ordering> {
+        if self == other { Some(Ordering::Equal) }
+        else if self.x < other.x && self.y < other.y { Some(Ordering::Less) }
+        else if self.x > other.x && self.y > other.y { Some(Ordering::Greater) }
+        else { None }
+    }
+}
+
 impl Vec2 {
     /// Creates a new Vec2 from coordinates.
     pub fn new(x: usize, y: usize) -> Self {
@@ -45,6 +54,16 @@ impl Vec2 {
     pub fn zero() -> Self {
         Vec2::new(0,0)
     }
+
+    /// Returns (max(self.x,other.x), self.y+other.y)
+    pub fn stack_vertical(&self, other: &Vec2) -> Vec2 {
+        Vec2::new(max(self.x, other.x), self.y + other.y)
+    }
+
+    /// Returns (self.x+other.x, max(self.y,other.y))
+    pub fn stack_horizontal(&self, other: &Vec2) -> Vec2 {
+        Vec2::new(self.x + other.x, max(self.y, other.y))
+    }
 }
 
 /// A generic trait for converting a value into a 2D vector.

src/view/box_view.rs

@@ -2,13 +2,12 @@ use vec::{Vec2,ToVec2};
 use super::{View,ViewWrapper,SizeRequest};
 
 /// BoxView is a wrapper around an other view, with a given minimum size.
-pub struct BoxView {
+pub struct BoxView<T: View> {
     size: Vec2,
-
-    content: Box<View>,
+    view: T,
 }
 
-impl BoxView {
+impl <T: View> BoxView<T> {
     /// Creates a new BoxView with the given minimum size and content
     ///
     /// # Example
@@ -18,17 +17,17 @@ impl BoxView {
     /// // Creates a 20x4 BoxView with a TextView content.
     /// let view = BoxView::new((20,4), TextView::new("Hello!"));
     /// ```
-    pub fn new<S: ToVec2, V: View + 'static>(size: S, view: V) -> Self {
+    pub fn new<S: ToVec2>(size: S, view: T) -> Self {
         BoxView {
             size: size.to_vec2(),
-            content: Box::new(view),
+            view: view,
         }
     }
 }
 
-impl ViewWrapper for BoxView {
+impl <T: View> ViewWrapper for BoxView<T> {
 
-    wrap_impl!(self.content);
+    wrap_impl!(&self.view);
 
     fn wrap_get_min_size(&self, _: SizeRequest) -> Vec2 {
         self.size

src/view/linear_layout.rs

@@ -0,0 +1,183 @@
+use view::{View,SizeRequest,DimensionRequest};
+use vec::Vec2;
+use printer::Printer;
+
+struct Child {
+    view: Box<View>,
+    size: Vec2,
+    weight: usize,
+}
+
+pub struct LinearLayout {
+    children: Vec<Child>,
+    orientation: Orientation,
+}
+
+pub enum Orientation {
+    Horizontal,
+    Vertical,
+}
+
+impl Orientation {
+    fn get(&self, v: &Vec2) -> usize {
+        match *self {
+            Orientation::Horizontal => v.x,
+            Orientation::Vertical => v.y,
+        }
+    }
+
+    fn swap(&self) -> Self {
+        match *self {
+            Orientation::Horizontal => Orientation::Vertical,
+            Orientation::Vertical => Orientation::Horizontal,
+        }
+    }
+
+    fn get_ref<'a,'b>(&'a self, v: &'b mut Vec2) -> &'b mut usize {
+        match *self {
+            Orientation::Horizontal => &mut v.x,
+            Orientation::Vertical => &mut v.y,
+        }
+    }
+
+    fn stack<'a,T: Iterator<Item=&'a Vec2>>(&self, iter: T) -> Vec2 {
+        match *self {
+            Orientation::Horizontal => iter.fold(Vec2::zero(), |a,b| a.stack_horizontal(&b)),
+            Orientation::Vertical => iter.fold(Vec2::zero(), |a,b| a.stack_vertical(&b)),
+        }
+    }
+}
+
+impl LinearLayout {
+    pub fn new(orientation: Orientation) -> Self {
+        LinearLayout {
+            children: Vec::new(),
+            orientation: orientation,
+        }
+    }
+
+    pub fn weight(mut self, weight: usize) -> Self {
+        self.children.last_mut().unwrap().weight = weight;
+
+        self
+    }
+
+    pub fn child<V: View + 'static>(mut self, view: V) -> Self {
+        self.children.push(Child {
+            view: Box::new(view),
+            size: Vec2::zero(),
+            weight: 0,
+        });
+
+        self
+    }
+
+    pub fn vertical() -> Self {
+        LinearLayout::new(Orientation::Vertical)
+    }
+    pub fn horizontal() -> Self {
+        LinearLayout::new(Orientation::Horizontal)
+    }
+}
+
+fn find_max(list: &Vec<usize>) -> usize {
+    let mut max_value = 0;
+    let mut max = 0;
+    for (i,&x) in list.iter().enumerate() {
+        if x > max_value {
+            max_value = x;
+            max = i;
+        }
+    }
+    max
+}
+
+fn share(total: usize, weights: Vec<usize>) -> Vec<usize> {
+    if weights.len() == 0 { return Vec::new(); }
+
+    let sum_weight = weights.iter().fold(0,|a,b| a+b);
+    if sum_weight == 0 {
+        return (0..weights.len()).map(|_| 0).collect();
+    }
+
+    let mut base = Vec::with_capacity(weights.len());
+    let mut rest = Vec::with_capacity(weights.len());
+    let mut extra = total;
+
+    for weight in weights.iter() {
+        let b = total * weight / sum_weight;
+        extra -= b;
+        base.push(b);
+        rest.push(total * weight - b*sum_weight);
+    }
+
+    // TODO: better to sort (base,rest) as one array and pick the extra first.
+    for _ in 0..extra {
+        let i = find_max(&rest);
+        rest[i] = 0;
+        base[i] += 1;
+    }
+
+    base
+}
+
+impl View for LinearLayout {
+    fn draw(&mut self, printer: &Printer) {
+        // Use pre-computed sizes
+        let mut offset = Vec2::zero();
+        for child in self.children.iter_mut() {
+            child.view.draw(&printer.sub_printer(offset, child.size, true));
+
+            *self.orientation.get_ref(&mut offset) += self.orientation.get(&child.size);
+        }
+    }
+
+    fn layout(&mut self, size: Vec2) {
+        // Compute the very minimal required size
+        let req = SizeRequest{
+            w: DimensionRequest::AtMost(size.x),
+            h: DimensionRequest::AtMost(size.y),
+        };
+        let min_sizes: Vec<Vec2> = self.children.iter().map(|child| child.view.get_min_size(req)).collect();
+        let min_size = self.orientation.stack(min_sizes.iter());
+
+        // Emulate 'non-strict inequality' on integers
+        // (default comparison on Vec2 is strict)
+        if !(min_size < size+(1,1)) {
+            // Error! Not enough space! Emergency procedures!
+            return
+        }
+
+        // Now share this extra space among everyone
+
+        let extras = {
+            let extra = size - min_size;
+            let space = self.orientation.get(&extra);
+            share(space, self.children.iter().map(|child| child.weight).collect())
+        };
+
+        for (child,(child_size,extra)) in self.children.iter_mut().zip(min_sizes.iter().zip(extras.iter())) {
+            let mut child_size = *child_size;
+            *self.orientation.get_ref(&mut child_size) += *extra;
+            *self.orientation.swap().get_ref(&mut child_size) = self.orientation.swap().get(&size);
+            child.size = child_size;
+            child.view.layout(child_size);
+        }
+    }
+
+    fn get_min_size(&self, req: SizeRequest) -> Vec2 {
+        // First, make a naive scenario: everything will work fine.
+        let sizes: Vec<Vec2> = self.children.iter().map(|view| view.view.get_min_size(req)).collect();
+        self.orientation.stack(sizes.iter())
+
+
+        // Did it work? Champagne!
+
+
+        // Ok, so maybe it didn't.
+        // Last chance: did someone lie about his needs?
+        // Could we squash him a little?
+
+        // Find out who's fluid, if any.
+    }
+}

src/view/mod.rs

@@ -1,43 +1,50 @@
 //! Defines various views to use when creating the layout.
 
 #[macro_use] mod view_wrapper;
+
 mod box_view;
-mod stack_view;
-mod text_view;
-mod key_event_view;
-mod view_path;
-mod dialog;
 mod button;
-mod sized_view;
+mod dialog;
+mod edit_view;
 mod full_view;
 mod id_view;
+mod key_event_view;
+mod linear_layout;
+mod request;
 mod shadow_view;
-mod edit_view;
-mod select_view;
-
 mod scroll;
+mod select_view;
+mod sized_view;
+mod stack_view;
+mod text_view;
+mod view_path;
+
 
 use std::any::Any;
 
-pub use self::view_path::ViewPath;
-pub use self::key_event_view::KeyEventView;
-pub use self::box_view::BoxView;
-pub use self::stack_view::StackView;
-pub use self::text_view::TextView;
-pub use self::dialog::Dialog;
-pub use self::button::Button;
-pub use self::sized_view::SizedView;
-pub use self::view_wrapper::ViewWrapper;
-pub use self::full_view::FullView;
-pub use self::id_view::IdView;
-pub use self::shadow_view::ShadowView;
-pub use self::edit_view::EditView;
-pub use self::select_view::SelectView;
+use event::{Event,EventResult};
+use vec::Vec2;
+use printer::Printer;
+
+pub use self::request::{DimensionRequest,SizeRequest};
 pub use self::scroll::ScrollBase;
 
-use event::{Event,EventResult};
-use vec::{Vec2,ToVec2};
-use printer::Printer;
+pub use self::box_view::BoxView;
+pub use self::button::Button;
+pub use self::dialog::Dialog;
+pub use self::edit_view::EditView;
+pub use self::full_view::FullView;
+pub use self::id_view::IdView;
+pub use self::key_event_view::KeyEventView;
+pub use self::linear_layout::LinearLayout;
+pub use self::view_path::ViewPath;
+pub use self::select_view::SelectView;
+pub use self::shadow_view::ShadowView;
+pub use self::stack_view::StackView;
+pub use self::text_view::TextView;
+pub use self::sized_view::SizedView;
+pub use self::view_wrapper::ViewWrapper;
+
 
 /// Main trait defining a view behaviour.
 pub trait View {
@@ -68,54 +75,3 @@ pub enum Selector<'a> {
     Path(&'a ViewPath),
 }
 
-/// Describe constraints on a view layout in one dimension.
-#[derive(PartialEq,Clone,Copy)]
-pub enum DimensionRequest {
-    /// The view must use exactly the attached size.
-    Fixed(usize),
-    /// The view is free to choose its size if it stays under the limit.
-    AtMost(usize),
-    /// No clear restriction apply.
-    Unknown,
-}
-
-impl DimensionRequest {
-    /// Returns a new request, reduced from the original by the given offset.
-    pub fn reduced(self, offset: usize) -> Self {
-        match self {
-            DimensionRequest::Fixed(w) => DimensionRequest::Fixed(w - offset),
-            DimensionRequest::AtMost(w) => DimensionRequest::AtMost(w - offset),
-            DimensionRequest::Unknown => DimensionRequest::Unknown,
-        }
-    }
-}
-
-/// Describes constraints on a view layout.
-#[derive(PartialEq,Clone,Copy)]
-pub struct SizeRequest {
-    /// Restriction on the view width
-    pub w: DimensionRequest,
-    /// Restriction on the view height
-    pub h: DimensionRequest,
-}
-
-impl SizeRequest {
-    /// Returns a new SizeRequest, reduced from the original by the given offset.
-    pub fn reduced<T: ToVec2>(self, offset: T) -> Self {
-        let ov = offset.to_vec2();
-        SizeRequest {
-            w: self.w.reduced(ov.x),
-            h: self.h.reduced(ov.y),
-        }
-    }
-
-    /// Creates a new dummy request, with no restriction.
-    pub fn dummy() -> Self {
-        SizeRequest {
-            w: DimensionRequest::Unknown,
-            h: DimensionRequest::Unknown,
-        }
-    }
-}
-
-

src/view/request.rs

@@ -0,0 +1,53 @@
+use vec::ToVec2;
+
+/// Describe constraints on a view layout in one dimension.
+#[derive(PartialEq,Clone,Copy)]
+pub enum DimensionRequest {
+    /// The view must use exactly the attached size.
+    Fixed(usize),
+    /// The view is free to choose its size if it stays under the limit.
+    AtMost(usize),
+    /// No clear restriction apply.
+    Unknown,
+}
+
+impl DimensionRequest {
+    /// Returns a new request, reduced from the original by the given offset.
+    pub fn reduced(self, offset: usize) -> Self {
+        match self {
+            DimensionRequest::Fixed(w) => DimensionRequest::Fixed(w - offset),
+            DimensionRequest::AtMost(w) => DimensionRequest::AtMost(w - offset),
+            DimensionRequest::Unknown => DimensionRequest::Unknown,
+        }
+    }
+}
+
+/// Describes constraints on a view layout.
+#[derive(PartialEq,Clone,Copy)]
+pub struct SizeRequest {
+    /// Restriction on the view width
+    pub w: DimensionRequest,
+    /// Restriction on the view height
+    pub h: DimensionRequest,
+}
+
+impl SizeRequest {
+    /// Returns a new SizeRequest, reduced from the original by the given offset.
+    pub fn reduced<T: ToVec2>(self, offset: T) -> Self {
+        let ov = offset.to_vec2();
+        SizeRequest {
+            w: self.w.reduced(ov.x),
+            h: self.h.reduced(ov.y),
+        }
+    }
+
+    /// Creates a new dummy request, with no restriction.
+    pub fn dummy() -> Self {
+        SizeRequest {
+            w: DimensionRequest::Unknown,
+            h: DimensionRequest::Unknown,
+        }
+    }
+}
+
+

src/view/view_wrapper.rs

@@ -77,7 +77,7 @@ impl <T: ViewWrapper> View for T {
 ///
 /// If the wrapped view is in a box, just name it in the macro:
 ///
-/// ```rust
+/// ```no_run
 /// # #[macro_use] extern crate cursive;
 /// # use cursive::view::{View,ViewWrapper};
 /// struct BoxFooView {
@@ -87,13 +87,12 @@ impl <T: ViewWrapper> View for T {
 /// impl ViewWrapper for BoxFooView {
 ///     wrap_impl!(self.content);
 /// }
-///
 /// # fn main() { }
 /// ```
 ///
 /// If the content is directly a view, reference it:
 ///
-/// ```
+/// ```no_run
 /// # #[macro_use] extern crate cursive;
 /// # use cursive::view::{View,ViewWrapper};
 /// struct FooView<T: View> {