Cache layout in TextView

Calling either get_min_size or layout will cache the results, so the
next call with the same constraints will not re-compute everything.

src/lib.rs

@@ -25,6 +25,15 @@ extern crate toml;
 extern crate unicode_segmentation;
 extern crate unicode_width;
 
+macro_rules! println_stderr(
+    ($($arg:tt)*) => { {
+        use ::std::io::Write;
+        let r = writeln!(&mut ::std::io::stderr(), $($arg)*);
+        r.expect("failed printing to stderr");
+    } }
+);
+
+
 pub mod event;
 pub mod view;
 pub mod printer;

src/view/box_view.rs

@@ -30,7 +30,7 @@ impl<T: View> BoxView<T> {
 impl<T: View> ViewWrapper for BoxView<T> {
     wrap_impl!(&self.view);
 
-    fn wrap_get_min_size(&self, mut req: Vec2) -> Vec2 {
+    fn wrap_get_min_size(&mut self, mut req: Vec2) -> Vec2 {
         if self.size.x > 0 {
             req.x = cmp::min(self.size.x, req.x);
         }

src/view/button.rs

@@ -43,7 +43,7 @@ impl View for Button {
         });
     }
 
-    fn get_min_size(&self, _: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, _: Vec2) -> Vec2 {
         // Meh. Fixed size we are.
         Vec2::new(2 + self.label.width(), 1)
     }

src/view/dialog.rs

@@ -159,7 +159,7 @@ impl View for Dialog {
 
     }
 
-    fn get_min_size(&self, req: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, req: Vec2) -> Vec2 {
         // Padding and borders are not available for kids.
         let content_req = req - (self.padding.combined() + self.borders.combined());
         let content_size = self.content.get_min_size(content_req);
@@ -168,7 +168,7 @@ impl View for Dialog {
         if !self.buttons.is_empty() {
             buttons_size.x += self.buttons.len() - 1;
         }
-        for button in &self.buttons {
+        for button in &mut self.buttons {
             let s = button.view.get_min_size(req);
             buttons_size.x += s.x;
             buttons_size.y = max(buttons_size.y, s.y + 1);

src/view/edit_view.rs

@@ -139,7 +139,7 @@ impl View for EditView {
         self.last_length = size.x;
     }
 
-    fn get_min_size(&self, _: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, _: Vec2) -> Vec2 {
         Vec2::new(self.min_length, 1)
     }
 

src/view/full_view.rs

@@ -16,7 +16,7 @@ impl<T: View> FullView<T> {
 impl<T: View> ViewWrapper for FullView<T> {
     wrap_impl!(&self.view);
 
-    fn wrap_get_min_size(&self, req: Vec2) -> Vec2 {
+    fn wrap_get_min_size(&mut self, req: Vec2) -> Vec2 {
         req
     }
 }

src/view/linear_layout.rs

@@ -127,7 +127,7 @@ impl View for LinearLayout {
         // Look how mean we are: we offer the whole size to every child.
         // As if they could get it all.
         let min_sizes: Vec<Vec2> = self.children
-                                       .iter()
+                                       .iter_mut()
                                        .map(|child| Vec2::min(size, child.view.get_min_size(size)))
                                        .collect();
         let min_size = self.orientation.stack(min_sizes.iter());
@@ -160,10 +160,10 @@ impl View for LinearLayout {
         }
     }
 
-    fn get_min_size(&self, req: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, req: Vec2) -> Vec2 {
         // First, make a naive scenario: everything will work fine.
         let sizes: Vec<Vec2> = self.children
-                                   .iter()
+                                   .iter_mut()
                                    .map(|view| view.view.get_min_size(req))
                                    .collect();
         self.orientation.stack(sizes.iter())

src/view/menu_popup.rs

@@ -160,7 +160,7 @@ impl View for MenuPopup {
         });
     }
 
-    fn get_min_size(&self, req: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, req: Vec2) -> Vec2 {
         // We can't really shrink our items here, so it's not flexible.
         let w = 4 +
                 self.menu

src/view/mod.rs

@@ -65,7 +65,7 @@ pub trait View {
     }
 
     /// Returns the minimum size the view requires under the given restrictions.
-    fn get_min_size(&self, Vec2) -> Vec2 {
+    fn get_min_size(&mut self, Vec2) -> Vec2 {
         Vec2::new(1, 1)
     }
 

src/view/select_view.rs

@@ -145,7 +145,7 @@ impl<T: 'static> View for SelectView<T> {
         });
     }
 
-    fn get_min_size(&self, req: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, req: Vec2) -> Vec2 {
         // Items here are not compressible.
         // So no matter what the horizontal requirements are,
         // we'll still return our longest item.

src/view/shadow_view.rs

@@ -41,7 +41,7 @@ impl<T: View> ShadowView<T> {
 impl<T: View> ViewWrapper for ShadowView<T> {
     wrap_impl!(&self.view);
 
-    fn wrap_get_min_size(&self, req: Vec2) -> Vec2 {
+    fn wrap_get_min_size(&mut self, req: Vec2) -> Vec2 {
         let offset = self.padding();
         self.view.get_min_size(req - offset) + offset
     }

src/view/stack_view.rs

@@ -100,11 +100,11 @@ impl View for StackView {
         }
     }
 
-    fn get_min_size(&self, size: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, size: Vec2) -> Vec2 {
         // The min size is the max of all children's
 
         self.layers
-            .iter()
+            .iter_mut()
             .map(|layer| layer.view.get_min_size(size))
             .fold(Vec2::new(1, 1), Vec2::max)
     }

src/view/text_view.rs

@@ -19,12 +19,15 @@ pub struct TextView {
 
     // ScrollBase make many scrolling-related things easier
     scrollbase: ScrollBase,
+    last_size: Option<Vec2>,
+    width: Option<usize>,
 }
 
 // Subset of the main content representing a row on the display.
 struct Row {
     start: usize,
     end: usize,
+    width: usize,
 }
 
 // If the last character is a newline, strip it.
@@ -63,6 +66,8 @@ impl TextView {
             rows: Vec::new(),
             scrollbase: ScrollBase::new(),
             align: Align::top_left(),
+            last_size: None,
+            width: None,
         }
     }
 
@@ -119,6 +124,35 @@ impl TextView {
 
         Vec2::new(max_width, height)
     }
+
+    fn is_cache_valid(&self, size: Vec2) -> bool {
+        match self.last_size {
+            None => false,
+            Some(last) => if last.x != size.x {
+                false
+            } else {
+                (last.y < self.rows.len()) == (size.y < self.rows.len())
+            },
+        }
+    }
+
+    fn compute_rows(&mut self, size: Vec2) {
+        if !self.is_cache_valid(size) {
+            // Recompute
+            self.rows = LinesIterator::new(&self.content, size.x).collect();
+            let mut scrollbar = 0;
+            if self.rows.len() > size.y {
+                scrollbar = 2;
+                // If we're too high, include a scrollbar
+                self.rows = LinesIterator::new(&self.content, size.x - scrollbar)
+                    .collect();
+            }
+
+            self.width = self.rows.iter().map(|row| row.width).max().map(|w| w + scrollbar);
+
+            self.last_size = Some(size);
+        }
+    }
 }
 
 // Given a multiline string, and a given maximum width,
@@ -152,16 +186,19 @@ impl<'a> Iterator for LinesIterator<'a> {
         let start = self.start;
         let content = &self.content[self.start..];
 
-        if let Some(next) = content.find('\n') {
-            if content[..next].width() <= self.width {
-                // We found a newline before the allowed limit.
-                // Break early.
-                self.start += next + 1;
-                return Some(Row {
-                    start: start,
-                    end: next + start,
-                });
-            }
+        let next = content.find('\n').unwrap_or(content.len());
+        let content = &content[..next];
+
+        let line_width = content.width();
+        if line_width <= self.width {
+            // We found a newline before the allowed limit.
+            // Break early.
+            self.start += next + 1;
+            return Some(Row {
+                start: start,
+                end: next + start,
+                width: line_width,
+            });
         }
 
         // Keep adding indivisible tokens
@@ -175,6 +212,7 @@ impl<'a> Iterator for LinesIterator<'a> {
         Some(Row {
             start: start,
             end: start + head_bytes,
+            width: self.width,
         })
     }
 }
@@ -220,20 +258,13 @@ impl View for TextView {
         EventResult::Consumed(None)
     }
 
-    fn get_min_size(&self, size: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, size: Vec2) -> Vec2 {
         // If we have no directive, ask for a single big line.
         // TODO: what if the text has newlines??
         // Don't _force_ the max width, but take it if we have to.
-        let ideal = self.get_ideal_size();
 
-        if size.x >= ideal.x {
-            ideal
-        } else {
-            // Ok, se we have less width than we'd like.
-            // Take everything we can, and plan our height accordingly.
-            let h = self.get_num_lines(size.x);
-            Vec2::new(size.x, h)
-        }
+        self.compute_rows(size);
+        Vec2::new(self.width.unwrap_or(0), self.rows.len())
     }
 
     fn take_focus(&mut self) -> bool {
@@ -242,11 +273,7 @@ impl View for TextView {
 
     fn layout(&mut self, size: Vec2) {
         // Compute the text rows.
-        self.rows = LinesIterator::new(&self.content, size.x).collect();
-        if self.rows.len() > size.y {
-            self.rows = LinesIterator::new(&self.content, size.x - 2)
-                            .collect();
-        }
+        self.compute_rows(size);
         self.scrollbase.set_heights(size.y, self.rows.len());
     }
 }

src/view/view_wrapper.rs

@@ -21,8 +21,8 @@ pub trait ViewWrapper {
     }
 
     /// Wraps the get_min_size method.
-    fn wrap_get_min_size(&self, req: Vec2) -> Vec2 {
-        self.get_view().get_min_size(req)
+    fn wrap_get_min_size(&mut self, req: Vec2) -> Vec2 {
+        self.get_view_mut().get_min_size(req)
     }
 
     /// Wraps the on_event method.
@@ -50,7 +50,7 @@ impl<T: ViewWrapper> View for T {
         self.wrap_draw(printer);
     }
 
-    fn get_min_size(&self, req: Vec2) -> Vec2 {
+    fn get_min_size(&mut self, req: Vec2) -> Vec2 {
         self.wrap_get_min_size(req)
     }