Split Printer::sub_printer into sub-methods

src/cursive.rs

@@ -537,7 +537,7 @@ impl Cursive {
             1
         };
         let id = self.active_screen;
-        let sv_printer = printer.offset((0, offset), !selected);
+        let sv_printer = printer.offset((0, offset)).focused(!selected);
 
         self.screens[id].draw_bg(&sv_printer);
 
@@ -545,11 +545,7 @@ impl Cursive {
         // If the menubar is active, nothing else can be.
         // Draw the menubar?
         if self.menubar.visible() {
-            let printer = printer.sub_printer(
-                Vec2::zero(),
-                printer.size,
-                self.menubar.receive_events(),
-            );
+            let printer = printer.focused(self.menubar.receive_events());
             self.menubar.draw(&printer);
         }
 

src/printer.rs

@@ -9,6 +9,7 @@ use theme::{BorderStyle, ColorStyle, Effect, PaletteColor, Style, Theme};
 use unicode_segmentation::UnicodeSegmentation;
 use utils::lines::simple::prefix;
 use vec::Vec2;
+use with::With;
 
 /// Convenient interface to draw on a subset of the screen.
 pub struct Printer<'a> {
@@ -36,6 +37,20 @@ pub struct Printer<'a> {
     backend: &'a backend::Concrete,
 }
 
+impl<'a> Clone for Printer<'a> {
+    fn clone(&self) -> Self {
+        Printer {
+            offset: self.offset,
+            content_offset: self.content_offset,
+            size: self.size,
+            focused: self.focused,
+            theme: self.theme,
+            backend: self.backend,
+            new: Rc::clone(&self.new),
+        }
+    }
+}
+
 impl<'a> Printer<'a> {
     /// Creates a new printer on the given window.
     ///
@@ -308,37 +323,73 @@ impl<'a> Printer<'a> {
     }
 
     /// Prints a horizontal delimiter with side border `├` and `┤`.
-    pub fn print_hdelim<T: Into<Vec2>>(&self, start: T, len: usize) {
+    pub fn print_hdelim<T>(&self, start: T, len: usize)
+    where
+        T: Into<Vec2>,
+    {
         let start = start.into();
         self.print(start, "├");
         self.print_hline(start + (1, 0), len.saturating_sub(2), "─");
         self.print(start + (len.saturating_sub(1), 0), "┤");
     }
 
-    /// Returns a printer on a subset of this one's area.
-    pub fn sub_printer<S: Into<Vec2>, T: Into<Vec2>>(
-        &'a self, offset: S, size: T, focused: bool
-    ) -> Printer<'a> {
-        let size = size.into();
-        let offset = offset.into().or_min(self.size);
-        let available = if !offset.fits_in(self.size) {
-            Vec2::zero()
-        } else {
-            Vec2::min(self.size - offset, size)
-        };
-        Printer {
-            offset: self.offset + offset,
-            // We can't be larger than what remains
-            size: available,
-            focused: self.focused && focused,
-            theme: self.theme,
-            backend: self.backend,
-            new: Rc::clone(&self.new),
-        }
+    /// Returns a sub-printer with the given offset.
+    pub fn offset<S>(&self, offset: S) -> Printer
+    where
+        S: Into<Vec2>,
+    {
+        let offset = offset.into();
+        self.clone().with(|s| {
+            let consumed = Vec2::min(s.content_offset, offset);
+
+            s.content_offset = s.content_offset - consumed;
+            s.offset = s.offset + offset - consumed;
+            s.size = s.size.saturating_sub(offset);
+        })
     }
 
-    /// Returns a sub-printer with the given offset.
-    pub fn offset<S: Into<Vec2>>(&self, offset: S, focused: bool) -> Printer {
-        self.sub_printer(offset, self.size, focused)
+    /// Returns a new sub-printer inheriting the given focus.
+    ///
+    /// If `self` is focused and `focused == true`, the child will be focused.
+    ///
+    /// Otherwise, he will be unfocused.
+    pub fn focused(&self, focused: bool) -> Self {
+        self.clone().with(|s| {
+            s.focused &= focused;
+        })
+    }
+
+    /// Returns a new sub-printer with a cropped area.
+    ///
+    /// The new printer size will be the minimum of `size` and its current size.
+    ///
+    /// Any size reduction happens at the bottom-right.
+    pub fn cropped<S>(&self, size: S) -> Self
+    where
+        S: Into<Vec2>,
+    {
+        self.clone().with(|s| {
+            s.size = Vec2::min(s.size, size);
+        })
+    }
+
+    /// Returns a new sub-printer with a shrinked area.
+    ///
+    /// The printer size will be reduced by the given border from the bottom-right.
+    pub fn shrinked<S>(&self, borders: S) -> Self
+    where
+        S: Into<Vec2>,
+    {
+        self.cropped(self.size.saturating_sub(borders))
+    }
+
+    /// Returns a new sub-printer with a content offset.
+    pub fn content_offset<S>(&self, offset: S) -> Self
+    where
+        S: Into<Vec2>,
+    {
+        self.clone().with(|s| {
+            s.content_offset = s.content_offset + offset;
+        })
     }
 }

src/view/scroll.rs

@@ -269,7 +269,7 @@ impl ScrollBase {
             // Y is the actual coordinate of the line.
             // The item ID is then Y + self.start_line
             line_drawer(
-                &printer.sub_printer(Vec2::new(0, y), Vec2::new(w, 1), true),
+                &printer.offset((0, y)).cropped((w, 1)),
                 y + self.start_line,
             );
         }

src/views/dialog.rs

@@ -371,11 +371,10 @@ impl Dialog {
             // Add some special effect to the focused button
             let position = Vec2::new(offset, y);
             button.offset.set(position);
-            button.button.draw(&printer.sub_printer(
-                position,
-                size,
-                self.focus == DialogFocus::Button(i),
-            ));
+            button.button.draw(&printer
+                .offset(position)
+                .cropped(size)
+                .focused(self.focus == DialogFocus::Button(i)));
             // Keep 1 blank between two buttons
             offset += size.x + 1;
             // Also keep 1 blank above the buttons
@@ -395,11 +394,10 @@ impl Dialog {
             None => return,
         };
 
-        self.content.draw(&printer.sub_printer(
-            self.borders.top_left() + self.padding.top_left(),
-            inner_size,
-            self.focus == DialogFocus::Content,
-        ));
+        self.content.draw(&printer
+            .offset(self.borders.top_left() + self.padding.top_left())
+            .cropped(inner_size)
+            .focused(self.focus == DialogFocus::Content));
     }
 
     fn draw_title(&self, printer: &Printer) {

src/views/linear_layout.rs

@@ -327,11 +327,10 @@ impl View for LinearLayout {
             // eprintln!("Printer size: {:?}", printer.size);
             // eprintln!("Child size: {:?}", item.child.size);
             // eprintln!("Offset: {:?}", item.offset);
-            let printer = &printer.sub_printer(
-                self.orientation.make_vec(item.offset, 0),
-                item.child.size,
-                i == self.focus,
-            );
+            let printer = &printer
+                .offset(self.orientation.make_vec(item.offset, 0))
+                .cropped(item.child.size)
+                .focused(i == self.focus);
             item.child.view.draw(printer);
         }
     }

src/views/list_view.rs

@@ -279,7 +279,9 @@ impl View for ListView {
             .draw(printer, |printer, i| match self.children[i] {
                 ListChild::Row(ref label, ref view) => {
                     printer.print((0, 0), label);
-                    view.draw(&printer.offset((offset, 0), i == self.focus));
+                    view.draw(&printer
+                        .offset((offset, 0))
+                        .focused(i == self.focus));
                 }
                 ListChild::Delimiter => (),
             });

src/views/menu_popup.rs

@@ -211,7 +211,7 @@ impl View for MenuPopup {
         let h = self.menu.len();
         // If we're too high, add a vertical offset
         let offset = self.align.v.get_offset(h, printer.size.y);
-        let printer = &printer.offset((0, offset), true);
+        let printer = &printer.offset((0, offset));
 
         // Start with a box
         printer.print_box(Vec2::new(0, 0), printer.size, false);
@@ -219,8 +219,7 @@ impl View for MenuPopup {
         // We're giving it a reduced size because of borders.
         // But we're keeping the full width,
         // to integrate horizontal delimiters in the frame.
-        let size = printer.size - (0, 2);
-        let printer = printer.sub_printer((0, 1), size, true);
+        let printer = printer.offset((0, 1)).shrinked((0, 1));
 
         self.scrollbase.draw(&printer, |printer, i| {
             printer.with_selection(i == self.focus, |printer| {

src/views/panel.rs

@@ -35,8 +35,7 @@ impl<V: View> ViewWrapper for Panel<V> {
 
     fn wrap_draw(&self, printer: &Printer) {
         printer.print_box((0, 0), printer.size, true);
-        let size = printer.size.saturating_sub((2, 2));
-        let printer = printer.sub_printer((1, 1), size, true);
+        let printer = printer.offset((1, 1)).shrinked((1, 1));
         self.view.draw(&printer);
     }
 

src/views/progress_bar.rs

@@ -215,7 +215,7 @@ impl View for ProgressBar {
             printer.with_effect(Effect::Reverse, |printer| {
                 printer.print((offset, 0), &label);
             });
-            let printer = &printer.sub_printer((0, 0), (length, 1), true);
+            let printer = &printer.cropped((length, 1));
             printer.print_hline((0, 0), length, " ");
             printer.print((offset, 0), &label);
         });

src/views/scroll_view.rs

@@ -6,12 +6,17 @@ use vec::Vec2;
 pub struct ScrollView<V> {
     inner: V,
     offset: Vec2,
+
+    // Togglable horizontal/vertical scrolling?
 }
 
 impl <V> View for ScrollView<V> where V: View {
 
     fn draw(&self, printer: &Printer) {
-        self.printer.offset
-        self.inner.draw(printer);
+        // Draw content
+        let printer = printer.content_offset(self.offset);
+        self.inner.draw(&printer);
+
+        // Draw scrollbar?
     }
 }

src/views/select_view.rs

@@ -703,8 +703,7 @@ impl<T: 'static> View for SelectView<T> {
         } else {
             let h = self.items.len();
             let offset = self.align.v.get_offset(h, printer.size.y);
-            let printer =
-                &printer.sub_printer(Vec2::new(0, offset), printer.size, true);
+            let printer = &printer.offset((0, offset));
 
             self.scrollbase.draw(printer, |printer, i| {
                 printer.with_selection(i == self.focus(), |printer| {

src/views/shadow_view.rs

@@ -86,7 +86,7 @@ impl<T: View> ViewWrapper for ShadowView<T> {
             self.left_padding as usize,
             self.top_padding as usize,
         );
-        let printer = &printer.offset(offset, true);
+        let printer = &printer.offset(offset);
         if printer.theme.shadow {
             let h = printer.size.y;
             let w = printer.size.x;
@@ -102,11 +102,7 @@ impl<T: View> ViewWrapper for ShadowView<T> {
         }
 
         // Draw the view background
-        let printer = printer.sub_printer(
-            Vec2::zero(),
-            printer.size.saturating_sub((1, 1)),
-            true,
-        );
+        let printer = printer.shrinked((1,1));
         self.view.draw(&printer);
     }
 }

src/views/stack_view.rs

@@ -420,11 +420,10 @@ impl StackView {
                 StackPositionIterator::new(self.layers.iter(), printer.size)
                     .enumerate()
             {
-                v.view.draw(&printer.sub_printer(
-                    offset,
-                    v.size,
-                    i + 1 == last,
-                ));
+                v.view.draw(&printer
+                    .offset(offset)
+                    .cropped(v.size)
+                    .focused(i + 1 == last));
             }
         });
     }

src/views/text_view.rs

@@ -455,7 +455,7 @@ impl View for TextView {
         let h = self.rows.len();
         // If the content is smaller than the view, align it somewhere.
         let offset = self.align.v.get_offset(h, printer.size.y);
-        let printer = &printer.offset((0, offset), true);
+        let printer = &printer.offset((0, offset));
 
         let content = self.content.lock().unwrap();