Better wide char support

assets/cities.txt

@@ -28,6 +28,7 @@ Bangui
 Banjul
 Basseterre
 Beijing
+北京
 Beirut
 Belgrade
 Belmopan
@@ -227,6 +228,7 @@ Thimphu
 Tirana
 Tiraspol
 Tokyo
+東京
 Tórshavn
 Tripoli
 Tskhinvali
@@ -234,7 +236,7 @@ Tunis
 Ulaanbaatar
 Vaduz
 Valletta
-Valparaíso­so
+Valparaíso
 Vatican City
 Victoria
 Vienna

src/menubar.rs

@@ -8,6 +8,8 @@ use event::*;
 
 use std::rc::Rc;
 
+use unicode_width::UnicodeWidthStr;
+
 /// Current state of the menubar
 #[derive(PartialEq, Debug)]
 enum State {
@@ -78,7 +80,7 @@ impl Menubar {
                            (i == self.focus);
             printer.with_selection(selected, |printer| {
                 printer.print((offset, 0), &format!(" {} ", title));
-                offset += title.len() + 2;
+                offset += title.width() + 2;
             });
         }
     }
@@ -108,7 +110,7 @@ impl Menubar {
                 self.state = State::Submenu;
                 let offset = (self.menus[..self.focus]
                                   .iter()
-                                  .map(|&(ref title, _)| title.len() + 2)
+                                  .map(|&(ref title, _)| title.width() + 2)
                                   .fold(0, |a, b| a + b),
                               if self.autohide {
                     1

src/view/button.rs

@@ -6,6 +6,7 @@ use vec::Vec2;
 use view::{View};
 use event::*;
 use printer::Printer;
+use unicode_width::UnicodeWidthStr;
 
 /// Simple text label with a callback when ENTER is pressed.
 /// A button shows its content in a single line and has a fixed size.
@@ -44,7 +45,7 @@ impl View for Button {
 
     fn get_min_size(&self, _: Vec2) -> Vec2 {
         // Meh. Fixed size we are.
-        Vec2::new(2 + self.label.chars().count(), 1)
+        Vec2::new(2 + self.label.width(), 1)
     }
 
     fn on_event(&mut self, event: Event) -> EventResult {

src/view/dialog.rs

@@ -10,6 +10,8 @@ use view::{Button, SizedView};
 use vec::{ToVec4, Vec2, Vec4};
 use printer::Printer;
 
+use unicode_width::UnicodeWidthStr;
+
 #[derive(PartialEq)]
 enum Focus {
     Content,
@@ -147,7 +149,7 @@ impl View for Dialog {
         printer.print_box(Vec2::new(0, 0), printer.size);
 
         if !self.title.is_empty() {
-            let len = self.title.chars().count();
+            let len = self.title.width();
             let x = (printer.size.x - len) / 2;
             printer.print((x - 2, 0), "┤ ");
             printer.print((x + len, 0), " ├");
@@ -181,7 +183,7 @@ impl View for Dialog {
 
         if !self.title.is_empty() {
             // If we have a title, we have to fit it too!
-            inner_size.x = max(inner_size.x, self.title.chars().count() + 6);
+            inner_size.x = max(inner_size.x, self.title.width() + 6);
         }
 
         inner_size

src/view/edit_view.rs

@@ -1,4 +1,5 @@
 use unicode_segmentation::UnicodeSegmentation;
+use unicode_width::UnicodeWidthStr;
 
 use std::cmp::min;
 
@@ -8,16 +9,19 @@ use view::{IdView, View};
 use event::*;
 use printer::Printer;
 
+
 /// Input box where the user can enter and edit text.
 pub struct EditView {
-    /// Current content
+    /// Current content.
     content: String,
-    /// Cursor position in the content
+    /// Cursor position in the content, in bytes.
     cursor: usize,
-    /// Minimum layout length asked to the parent
+    /// Minimum layout length asked to the parent.
     min_length: usize,
 
-    /// When the content is too long for the display, offset it
+    /// Number of bytes to skip at the beginning of the content.
+    ///
+    /// (When the content is too long for the display, we hide part of it)
     offset: usize,
     /// Last display length, to know the possible offset range
     last_length: usize, /* scrollable: bool,
@@ -73,48 +77,62 @@ impl EditView {
     }
 }
 
-fn remove_char(s: &mut String, cursor: usize) {
-    let i = match s.char_indices().nth(cursor) {
-        Some((i, _)) => i,
-        None => return,
-    };
-    s.remove(i);
-}
-
 impl View for EditView {
     fn draw(&mut self, printer: &Printer) {
         // let style = if focused { color::HIGHLIGHT } else { color::HIGHLIGHT_INACTIVE };
-        let len = self.content.chars().count();
+        assert!(printer.size.x == self.last_length);
+
+        let width = self.content.width();
         printer.with_color(ColorStyle::Secondary, |printer| {
             printer.with_effect(Effect::Reverse, |printer| {
-                if len < self.last_length {
+                if width < self.last_length {
+                    // No problem, everything fits.
                     printer.print((0, 0), &self.content);
-                    printer.print_hline((len, 0), printer.size.x - len, "_");
+                    printer.print_hline((width, 0),
+                                        printer.size.x - width,
+                                        "_");
                 } else {
-                    let visible_end = min(self.content.len(), self.offset + self.last_length);
+                    let content = &self.content[self.offset..];
+                    let display_bytes = content.graphemes(true)
+                                               .scan(0, |w, g| {
+                                                   *w += g.width();
+                                                   if *w > self.last_length {
+                                                       None
+                                                   } else {
+                                                       Some(g)
+                                                   }
+                                               })
+                                               .map(|g| g.len())
+                                               .fold(0, |a, b| a + b);
+
+                    let content = &content[..display_bytes];
 
-                    let content = &self.content[self.offset..visible_end];
                     printer.print((0, 0), content);
-                    if visible_end - self.offset < printer.size.x {
+                    let width = content.width();
-                        printer.print((printer.size.x - 1, 0), "_");
+
+                    if width < self.last_length {
+                        printer.print_hline((width, 0),
+                                            self.last_length - width,
+                                            "_");
                     }
                 }
             });
 
             // Now print cursor
             if printer.focused {
-                let c = if self.cursor == len {
+                let c = if self.cursor == self.content.len() {
                     "_"
                 } else {
                     // Get the char from the string... Is it so hard?
-                    self.content
+                    self.content[self.cursor..]
                         .graphemes(true)
-                        .nth(self.cursor)
+                        .next()
                         .expect(&format!("Found no char at cursor {} in {}",
                                          self.cursor,
                                          self.content))
                 };
-                printer.print_hline((self.cursor - self.offset, 0), 1, c);
+                let offset = self.content[self.offset..self.cursor].width();
+                printer.print((offset, 0), c);
             }
         });
     }
@@ -137,25 +155,41 @@ impl View for EditView {
             Event::Char(ch) => {
                 // Find the byte index of the char at self.cursor
 
-                match self.content.char_indices().nth(self.cursor) {
+                self.content.insert(self.cursor, ch);
-                    None => self.content.push(ch),
-                    Some((i, _)) => self.content.insert(i, ch),
-                }
                 // TODO: handle wide (CJK) chars
-                self.cursor += 1;
+                self.cursor += ch.len_utf8();
             }
             Event::Key(key) => {
                 match key {
                     Key::Home => self.cursor = 0,
-                    Key::End => self.cursor = self.content.chars().count(),
+                    Key::End => self.cursor = self.content.len(),
-                    Key::Left if self.cursor > 0 => self.cursor -= 1,
+                    Key::Left if self.cursor > 0 => {
-                    Key::Right if self.cursor < self.content.chars().count() => self.cursor += 1,
+                        let len = self.content[..self.cursor]
-                    Key::Backspace if self.cursor > 0 => {
+                                      .graphemes(true)
-                        self.cursor -= 1;
+                                      .last()
-                        remove_char(&mut self.content, self.cursor);
+                                      .unwrap()
+                                      .len();
+                        self.cursor -= len;
                     }
-                    Key::Del if self.cursor < self.content.chars().count() => {
+                    Key::Right if self.cursor < self.content.len() => {
-                        remove_char(&mut self.content, self.cursor);
+                        let len = self.content[self.cursor..]
+                                      .graphemes(true)
+                                      .next()
+                                      .unwrap()
+                                      .len();
+                        self.cursor += len;
+                    }
+                    Key::Backspace if self.cursor > 0 => {
+                        let len = self.content[..self.cursor]
+                                      .graphemes(true)
+                                      .last()
+                                      .unwrap()
+                                      .len();
+                        self.cursor -= len;
+                        self.content.remove(self.cursor);
+                    }
+                    Key::Del if self.cursor < self.content.len() => {
+                        self.content.remove(self.cursor);
                     }
                     _ => return EventResult::Ignored,
                 }
@@ -165,20 +199,51 @@ impl View for EditView {
         // Keep cursor in [offset, offset+last_length] by changing offset
         // So keep offset in [last_length-cursor,cursor]
         // Also call this on resize, but right now it is an event like any other
-        if self.cursor >= self.offset + self.last_length {
+        if self.cursor < self.offset {
-            self.offset = self.cursor - self.last_length + 1;
-        } else if self.cursor < self.offset {
             self.offset = self.cursor;
-        }
-        if self.offset + self.last_length > self.content.len() + 1 {
-
-            self.offset = if self.content.len() > self.last_length {
-                self.content.len() - self.last_length + 1
         } else {
-                0
+            // So we're against the right wall.
-            };
+            // Let's find how much space will be taken by the selection (either a char, or _)
+            let c_len = self.content[self.cursor..]
+                            .graphemes(true)
+                            .map(|g| g.width())
+                            .next()
+                            .unwrap_or(1);
+            // Now, we have to fit self.content[..self.cursor] into self.last_length - c_len.
+            let available = self.last_length - c_len;
+            // Look at the content before the cursor (we will print its tail).
+            // From the end, count the length until we reach `available`.
+            // Then sum the byte lengths.
+            let tail_bytes =
+                tail_bytes(&self.content[self.offset..self.cursor], available);
+            self.offset = self.cursor - tail_bytes;
+            assert!(self.cursor >= self.offset);
+
+        }
+
+        // If we have too much space
+        if self.content[self.offset..].width() < self.last_length {
+            let tail_bytes = tail_bytes(&self.content, self.last_length - 1);
+            self.offset = self.content.len() - tail_bytes;
         }
 
         EventResult::Consumed(None)
     }
 }
+
+// Return the number of bytes, from the end of text,
+// which constitute the longest tail that fits in the given width.
+fn tail_bytes(text: &str, width: usize) -> usize {
+    text.graphemes(true)
+        .rev()
+        .scan(0, |w, g| {
+            *w += g.width();
+            if *w > width {
+                None
+            } else {
+                Some(g)
+            }
+        })
+        .map(|g| g.len())
+        .fold(0, |a, b| a + b)
+}

src/view/select_view.rs

@@ -9,6 +9,8 @@ use event::{Event, EventResult, Key};
 use vec::Vec2;
 use printer::Printer;
 
+use unicode_width::UnicodeWidthStr;
+
 struct Item<T> {
     label: String,
     value: Rc<T>,
@@ -134,7 +136,7 @@ impl<T: 'static> View for SelectView<T> {
 
         self.scrollbase.draw(printer, |printer, i| {
             printer.with_selection(i == self.focus, |printer| {
-                let l = self.items[i].label.chars().count();
+                let l = self.items[i].label.width();
                 let x = self.align.h.get_offset(l, printer.size.x);
                 printer.print_hline((0, 0), x, " ");
                 printer.print((x, 0), &self.items[i].label);
@@ -149,7 +151,7 @@ impl<T: 'static> View for SelectView<T> {
         // we'll still return our longest item.
         let w = self.items
                     .iter()
-                    .map(|item| item.label.len())
+                    .map(|item| item.label.width())
                     .max()
                     .unwrap_or(1);
         let h = self.items.len();

src/view/text_view.rs

@@ -7,6 +7,8 @@ use align::*;
 use event::*;
 use super::scroll::ScrollBase;
 
+use unicode_width::UnicodeWidthStr;
+
 /// A simple view showing a fixed text
 pub struct TextView {
     content: String,
@@ -40,7 +42,7 @@ fn get_line_span(line: &str, max_width: usize) -> usize {
     // (Or use a common function? Better!)
     let mut lines = 1;
     let mut length = 0;
-    for l in line.split(' ').map(|word| word.chars().count()) {
+    for l in line.split(' ').map(|word| word.width()) {
         length += l;
         if length > max_width {
             length = l;
@@ -111,7 +113,7 @@ impl TextView {
 
         for line in self.content.split('\n') {
             height += 1;
-            max_width = max(max_width, line.chars().count());
+            max_width = max(max_width, line.width());
         }
 
         Vec2::new(max_width, height)
@@ -150,7 +152,7 @@ impl<'a> Iterator for LinesIterator<'a> {
         let content = &self.content[self.start..];
 
         if let Some(next) = content.find('\n') {
-            if content[..next].chars().count() <= self.width {
+            if content[..next].width() <= self.width {
                 // We found a newline before the allowed limit.
                 // Break early.
                 self.start += next + 1;
@@ -161,7 +163,7 @@ impl<'a> Iterator for LinesIterator<'a> {
             }
         }
 
-        let content_len = content.chars().count();
+        let content_len = content.width();
         if content_len <= self.width {
             // I thought it would be longer! -- that's what she said :(
             self.start += content.len();
@@ -209,7 +211,7 @@ impl View for TextView {
         self.scrollbase.draw(printer, |printer, i| {
             let row = &self.rows[i];
             let text = &self.content[row.start..row.end];
-            let l = text.chars().count();
+            let l = text.width();
             let x = self.align.h.get_offset(l, printer.size.x);
             printer.print((x, 0), text);
         });