Add initial TextArea

Cargo.toml

@@ -2,16 +2,17 @@
 authors = ["Alexandre Bury <alexandre.bury@gmail.com>"]
 description = "A TUI library based on ncurses-rs."
 documentation = "https://gyscos.github.io/Cursive/cursive/index.html"
+exclude = ["doc", "assets"]
 keywords = ["ncurses", "TUI"]
 license = "MIT"
 name = "cursive"
 readme = "Readme.md"
 repository = "https://github.com/gyscos/Cursive"
 version = "0.1.1"
-exclude = ["doc", "assets"]
 
 [dependencies]
 ncurses = "5.80.0"
+odds = "0.2.14"
 toml = "0.1"
 unicode-segmentation = "0.1.2"
 unicode-width = "0.1.3"

examples/hello_world.rs

@@ -5,10 +5,11 @@ use cursive::prelude::*;
 fn main() {
     let mut siv = Cursive::new();
 
-    // We can quit by pressing q
-    siv.add_global_callback('q', |s| s.quit());
+    // We can quit by pressing `q`
+    siv.add_global_callback('q', Cursive::quit);
 
-    siv.add_layer(TextView::new("Hello World!\nPress q to quit the application."));
+    siv.add_layer(TextView::new("Hello World!\n\
+                                Press q to quit the application."));
 
     siv.run();
 }

examples/text_area.rs

@@ -0,0 +1,16 @@
+extern crate cursive;
+
+use cursive::prelude::*;
+
+fn main() {
+    let mut siv = Cursive::new();
+
+    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")))
+        .button("Ok", Cursive::quit));
+
+    siv.run();
+}

src/lib.rs

@@ -51,6 +51,7 @@ extern crate ncurses;
 extern crate toml;
 extern crate unicode_segmentation;
 extern crate unicode_width;
+extern crate odds;
 
 macro_rules! println_stderr(
     ($($arg:tt)*) => { {

src/prelude.rs

@@ -11,6 +11,6 @@ pub use event::{Event, Key};
 pub use view::{Identifiable, Selector, View};
 pub use views::{BoxView, Button, Checkbox, Dialog, EditView, FullView,
                 IdView, KeyEventView, LinearLayout, ListView, Panel,
-                ProgressBar, SelectView, TextView};
+                ProgressBar, SelectView, TextArea, TextView};
 pub use vec::Vec2;
 pub use menu::MenuTree;

src/theme.rs

@@ -126,6 +126,7 @@ use toml;
 use B;
 
 /// Text effect
+#[derive(Clone, Copy, Debug)]
 pub enum Effect {
     /// No effect
     Simple,

src/utils/lines_iterator.rs

@@ -8,9 +8,16 @@ use utils::prefix_length;
 /// Given a long text and a width constraint, it iterates over
 /// substrings of the text, each within the constraint.
 pub struct LinesIterator<'a> {
+    /// Content to iterate on.
     content: &'a str,
-    start: usize,
+    /// Current offset in the content.
+    offset: usize,
+    /// Available width. Don't output lines wider than that.
     width: usize,
+
+    /// If `true`, keep a blank cell at the end of lines
+    /// when a whitespace or newline should be.
+    show_spaces: bool,
 }
 
 impl<'a> LinesIterator<'a> {
@@ -21,59 +28,96 @@ impl<'a> LinesIterator<'a> {
         LinesIterator {
             content: content,
             width: width,
-            start: 0,
+            offset: 0,
+            show_spaces: false,
         }
     }
+
+    /// Leave a blank cell at the end of lines.
+    ///
+    /// Unless a word had to be truncated, in which case
+    /// it takes the entire width.
+    pub fn show_spaces(mut self) -> Self {
+        self.show_spaces = true;
+        self
+    }
 }
 
 /// Represents a row of text within a `String`.
 ///
-/// A row is made of an offset into a parent `String` and a length.
+/// A row is made of offsets into a parent `String`.
 /// The corresponding substring should take `width` cells when printed.
+#[derive(Debug, Clone, Copy)]
 pub struct Row {
     /// Beginning of the row in the parent `String`.
     pub start: usize,
-    /// Length of the row, in bytes.
+    /// End of the row (excluded)
     pub end: usize,
     /// Width of the row, in cells.
     pub width: usize,
 }
 
+impl Row {
+    /// Shift a row start and end by `offset`.
+    pub fn shift(mut self, offset: usize) -> Self {
+        self.start += offset;
+        self.end += offset;
+        self
+    }
+}
+
 impl<'a> Iterator for LinesIterator<'a> {
     type Item = Row;
 
     fn next(&mut self) -> Option<Row> {
-        if self.start >= self.content.len() {
+        if self.offset >= self.content.len() {
             // This is the end.
             return None;
         }
 
-        let start = self.start;
-        let content = &self.content[self.start..];
+        // We start at the current offset.
+        let start = self.offset;
+        let content = &self.content[start..];
 
+        // Find the ideal line, in an infinitely wide world.
+        // We'll make a line larger than that.
         let next = content.find('\n').unwrap_or(content.len());
         let content = &content[..next];
 
+        let allowed_width = if self.show_spaces {
+            self.width - 1
+        } else {
+            self.width
+        };
+
         let line_width = content.width();
-        if line_width <= self.width {
+        if line_width <= allowed_width {
             // We found a newline before the allowed limit.
             // Break early.
-            self.start += next + 1;
+            // Advance the cursor to after the newline.
+            self.offset += next + 1;
             return Some(Row {
                 start: start,
-                end: next + start,
+                end: start + next,
                 width: line_width,
             });
         }
 
-        // Keep adding indivisible tokens
+        // First attempt: only break on spaces.
         let prefix_length =
-            match prefix_length(content.split(' '), self.width, " ") {
+            match prefix_length(content.split(' '), allowed_width, " ") {
+                // If this fail, fallback: only break on graphemes.
+                // There's no whitespace to skip there.
+                // And don't reserve the white space anymore.
                 0 => prefix_length(content.graphemes(true), self.width, ""),
                 other => {
-                    self.start += 1;
+                    // If it works, advance the cursor by 1
+                    // to jump the whitespace.
+                    // We don't want to add 1 to `prefix_length` though, it
+                    // would include the whitespace in the row.
+                    self.offset += 1;
                     other
-                }
+                },
             };
 
         if prefix_length == 0 {
@@ -82,7 +126,8 @@ impl<'a> Iterator for LinesIterator<'a> {
             return None;
         }
 
-        self.start += prefix_length;
+        // Advance the offset to the end of the line.
+        self.offset += prefix_length;
 
         Some(Row {
             start: start,
@@ -91,3 +136,11 @@ impl<'a> Iterator for LinesIterator<'a> {
         })
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    #[test]
+    fn test_layout() {
+    }
+}

src/views/edit_view.rs

@@ -200,6 +200,7 @@ impl EditView {
         // It means it'll just return a ref if no one else has a ref,
         // and it will clone it into `self.content` otherwise.
         Rc::make_mut(&mut self.content).insert(self.cursor, ch);
+        self.cursor += ch.len_utf8();
     }
 
     /// Remove the character at the current cursor position.
@@ -317,7 +318,6 @@ impl View for EditView {
                 // Find the byte index of the char at self.cursor
 
                 self.insert(ch);
-                self.cursor += ch.len_utf8();
             }
             // TODO: handle ctrl-key?
             Event::Key(Key::Home) => self.cursor = 0,

src/views/mod.rs

@@ -15,10 +15,11 @@ mod menubar;
 mod menu_popup;
 mod panel;
 mod progress_bar;
-mod shadow_view;
 mod select_view;
+mod shadow_view;
 mod sized_view;
 mod stack_view;
+mod text_area;
 mod text_view;
 mod tracked_view;
 
@@ -41,5 +42,6 @@ pub use self::select_view::SelectView;
 pub use self::shadow_view::ShadowView;
 pub use self::sized_view::SizedView;
 pub use self::stack_view::StackView;
+pub use self::text_area::TextArea;
 pub use self::text_view::TextView;
 pub use self::tracked_view::TrackedView;

src/views/text_area.rs

@@ -0,0 +1,325 @@
+use unicode_segmentation::UnicodeSegmentation;
+use unicode_width::UnicodeWidthStr;
+use odds::vec::VecExt;
+
+use std::rc::Rc;
+
+use {Printer, XY};
+use direction::Direction;
+use vec::Vec2;
+use event::{Event, EventResult, Key};
+use utils::{LinesIterator, Row, prefix_length};
+use view::{ScrollBase, SizeCache, View};
+use theme::{ColorStyle, Effect};
+
+/// Multi-lines text editor.
+///
+/// A `TextArea` by itself doesn't have a well-defined size.
+/// You should wrap it in a `BoxView` to control its size.
+pub struct TextArea {
+    // TODO: use a smarter data structure (rope?)
+    content: String,
+    /// Byte offsets within `content` representing text rows
+    rows: Vec<Row>,
+
+    /// When `false`, we don't take any input.
+    enabled: bool,
+
+    /// Base for scrolling features
+    scrollbase: ScrollBase,
+
+    /// Cache to avoid re-computing layout on no-op events
+    last_size: Option<XY<SizeCache>>,
+
+    /// Byte offset of the currently selected grapheme.
+    cursor: usize,
+}
+
+fn make_rows(text: &str, width: usize) -> Vec<Row> {
+    LinesIterator::new(text, width)
+        .show_spaces()
+        .collect()
+}
+
+impl TextArea {
+    /// Creates a new, empty TextArea.
+    pub fn new() -> Self {
+        TextArea {
+            content: String::new(),
+            rows: vec![Row {
+                           start: 0,
+                           end: 0,
+                           width: 0,
+                       }],
+            enabled: true,
+            scrollbase: ScrollBase::new(),
+            last_size: None,
+            cursor: 0,
+        }
+    }
+
+    /// Retrieves the content of the view.
+    pub fn get_content(&self) -> &str {
+        &self.content
+    }
+
+    /// Finds the row containing the grapheme at the given offset
+    fn row_at(&self, offset: usize) -> usize {
+        self.rows
+            .iter()
+            .enumerate()
+            .take_while(|&(_, row)| row.start <= offset)
+            .map(|(i, _)| i)
+            .last()
+            .unwrap()
+    }
+
+    /// Finds the row containing the cursor
+    fn selected_row(&self) -> usize {
+        self.row_at(self.cursor)
+    }
+
+    fn page_up(&mut self) {
+        for _ in 0..5 {
+            self.move_up();
+        }
+    }
+
+    fn page_down(&mut self) {
+        for _ in 0..5 {
+            self.move_down();
+        }
+    }
+
+    fn move_up(&mut self) {
+        let row_id = self.selected_row();
+        if row_id == 0 {
+            return;
+        }
+
+        let row = self.rows[row_id];
+        // Number of cells to the left of the cursor
+        let x = self.content[row.start..self.cursor].width();
+
+        let prev_row = self.rows[row_id - 1];
+        let prev_text = &self.content[prev_row.start..prev_row.end];
+        let offset = prefix_length(prev_text.graphemes(true), x, "");
+        self.cursor = prev_row.start + offset;
+    }
+
+    fn move_down(&mut self) {
+        let row_id = self.selected_row();
+        if row_id + 1 == self.rows.len() {
+            return;
+        }
+        let row = self.rows[row_id];
+        // Number of cells to the left of the cursor
+        let x = self.content[row.start..self.cursor].width();
+
+        let next_row = self.rows[row_id + 1];
+        let next_text = &self.content[next_row.start..next_row.end];
+        let offset = prefix_length(next_text.graphemes(true), x, "");
+        self.cursor = next_row.start + offset;
+    }
+
+    /// Moves the cursor to the left.
+    ///
+    /// Wraps the previous line if required.
+    fn move_left(&mut self) {
+        let len = {
+            // We don't want to utf8-parse the entire content.
+            // So restrict to the last row.
+            let mut row = self.selected_row();
+            if self.rows[row].start == self.cursor {
+                row -= 1;
+            }
+
+            let text = &self.content[self.rows[row].start..self.cursor];
+            text.graphemes(true)
+                .last()
+                .unwrap()
+                .len()
+        };
+        self.cursor -= len;
+    }
+
+    /// Moves the cursor to the right.
+    ///
+    /// Jumps to the next line is required.
+    fn move_right(&mut self) {
+        let len = self.content[self.cursor..]
+            .graphemes(true)
+            .next()
+            .unwrap()
+            .len();
+        self.cursor += len;
+    }
+
+    fn is_cache_valid(&self, size: Vec2) -> bool {
+        false
+    }
+
+    fn compute_rows(&mut self, size: Vec2) {
+        let mut available = size.x;
+        let content = format!("{} ", self.content);
+        self.rows = make_rows(&content, available);
+        if self.rows.len() > size.y {
+            available -= 1;
+            // Doh :(
+            self.rows = make_rows(&content, available);
+        }
+
+
+        if !self.rows.is_empty() {
+            // The last row probably contains a fake whitespace.
+            // Unless... the whitespace was used as an implicit newline.
+            // This means the last row ends in a newline-d whitespace.
+            // How do we detect that?
+            // By checking if the last row takes all the available width.
+            if self.rows.last().unwrap().width != available {
+                self.rows.last_mut().unwrap().end -= 1;
+            }
+            self.last_size = Some(SizeCache::build(size, size));
+        }
+    }
+
+    fn backspace(&mut self) {
+        if self.cursor != 0 {
+            self.move_left();
+            self.delete();
+        }
+    }
+
+    fn delete(&mut self) {
+        let len = self.content[self.cursor..]
+            .graphemes(true)
+            .next()
+            .unwrap()
+            .len();
+        let start = self.cursor;
+        let end = self.cursor + len;
+        for _ in self.content.drain(start..end) {}
+
+        let size = self.last_size.unwrap().map(|s| s.value);
+        self.compute_rows(size);
+    }
+
+    fn insert(&mut self, ch: char) {
+        let cursor = self.cursor;
+        self.content.insert(cursor, ch);
+
+        let shift = ch.len_utf8();
+        let selected_row = self.selected_row();
+        self.rows[selected_row].end += shift;
+
+        if selected_row < self.rows.len() {
+            for row in &mut self.rows[1 + selected_row..] {
+                row.start += shift;
+                row.end += shift;
+            }
+        }
+
+        let size = self.last_size.unwrap().map(|s| s.value);
+        self.compute_rows(size);
+        self.cursor += shift;
+    }
+}
+
+impl View for TextArea {
+    fn draw(&self, printer: &Printer) {
+        printer.with_color(ColorStyle::Secondary, |printer| {
+            let effect = if self.enabled {
+                Effect::Reverse
+            } else {
+                Effect::Simple
+            };
+
+            let w = if self.scrollbase.scrollable() {
+                printer.size.x - 1
+            } else {
+                printer.size.x
+            };
+            printer.with_effect(effect, |printer| {
+                for y in 0..printer.size.y {
+                    printer.print_hline((0, y), w, " ");
+                }
+            });
+
+            self.scrollbase.draw(printer, |printer, i| {
+                let row = &self.rows[i];
+                let text = &self.content[row.start..row.end];
+                printer.with_effect(effect, |printer| {
+                    printer.print((0, 0), text);
+                });
+
+                if printer.focused && i == self.selected_row() {
+                    let cursor_offset = self.cursor - row.start;
+                    let c = if cursor_offset == text.len() {
+                        "_"
+                    } else {
+                        text[cursor_offset..]
+                            .graphemes(true)
+                            .next()
+                            .expect("Found no char!")
+                    };
+                    let offset = text[..cursor_offset].width();
+                    printer.print((offset, 0), c);
+                }
+
+            });
+        });
+    }
+
+    fn on_event(&mut self, event: Event) -> EventResult {
+        match event {
+            Event::Char(ch) => self.insert(ch),
+            Event::Key(Key::Enter) => self.insert('\n'),
+            Event::Key(Key::Backspace) if self.cursor > 0 => self.backspace(),
+            Event::Key(Key::Del) if self.cursor < self.content.len() => {
+                self.delete()
+            }
+
+            Event::Key(Key::End) => {
+                let row = self.selected_row();
+                self.cursor = self.rows[row].end;
+                if row + 1 < self.rows.len() &&
+                   self.cursor == self.rows[row + 1].start {
+                    self.move_left();
+                }
+            }
+            Event::Ctrl(Key::Home) => {
+                self.cursor = 0
+            }
+            Event::Ctrl(Key::End) => {
+                self.cursor = self.content.len()
+            }
+            Event::Key(Key::Home) => {
+                self.cursor = self.rows[self.selected_row()].start
+            }
+            Event::Key(Key::Up) if self.selected_row() > 0 => self.move_up(),
+            Event::Key(Key::Down) if self.selected_row() + 1 <
+                                     self.rows.len() => self.move_down(),
+            Event::Key(Key::PageUp) => self.page_up(),
+            Event::Key(Key::PageDown) => self.page_down(),
+            Event::Key(Key::Left) if self.cursor > 0 => self.move_left(),
+            Event::Key(Key::Right) if self.cursor < self.content.len() => {
+                self.move_right()
+            }
+            _ => return EventResult::Ignored,
+        }
+
+        let focus = self.selected_row();
+        self.scrollbase.scroll_to(focus);
+
+        EventResult::Consumed(None)
+    }
+
+    fn take_focus(&mut self, _: Direction) -> bool {
+        self.enabled
+    }
+
+    fn layout(&mut self, size: Vec2) {
+        self.last_size = Some(SizeCache::build(size, size));
+        self.scrollbase.set_heights(size.y, self.rows.len());
+    }
+}