Inline tui as helix-tui fork.

We only rely on some of the rendering primitives and implement our
Cursive-style compositor on top.

1 files changed, 249 insertions, 0 deletions

diff --git a/helix-tui/src/widgets/list.rs b/helix-tui/src/widgets/list.rs
new file mode 100644
index 00000000..e913ce78
--- /dev/null
+++ b/helix-tui/src/widgets/list.rs
@@ -0,0 +1,249 @@
+use crate::{
+    buffer::Buffer,
+    layout::{Corner, Rect},
+    style::Style,
+    text::Text,
+    widgets::{Block, StatefulWidget, Widget},
+};
+use std::iter::{self, Iterator};
+use unicode_width::UnicodeWidthStr;
+
+#[derive(Debug, Clone)]
+pub struct ListState {
+    offset: usize,
+    selected: Option<usize>,
+}
+
+impl Default for ListState {
+    fn default() -> ListState {
+        ListState {
+            offset: 0,
+            selected: None,
+        }
+    }
+}
+
+impl ListState {
+    pub fn selected(&self) -> Option<usize> {
+        self.selected
+    }
+
+    pub fn select(&mut self, index: Option<usize>) {
+        self.selected = index;
+        if index.is_none() {
+            self.offset = 0;
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct ListItem<'a> {
+    content: Text<'a>,
+    style: Style,
+}
+
+impl<'a> ListItem<'a> {
+    pub fn new<T>(content: T) -> ListItem<'a>
+    where
+        T: Into<Text<'a>>,
+    {
+        ListItem {
+            content: content.into(),
+            style: Style::default(),
+        }
+    }
+
+    pub fn style(mut self, style: Style) -> ListItem<'a> {
+        self.style = style;
+        self
+    }
+
+    pub fn height(&self) -> usize {
+        self.content.height()
+    }
+}
+
+/// A widget to display several items among which one can be selected (optional)
+///
+/// # Examples
+///
+/// ```
+/// # use helix_tui::widgets::{Block, Borders, List, ListItem};
+/// # use helix_tui::style::{Style, Color, Modifier};
+/// let items = [ListItem::new("Item 1"), ListItem::new("Item 2"), ListItem::new("Item 3")];
+/// List::new(items)
+///     .block(Block::default().title("List").borders(Borders::ALL))
+///     .style(Style::default().fg(Color::White))
+///     .highlight_style(Style::default().add_modifier(Modifier::ITALIC))
+///     .highlight_symbol(">>");
+/// ```
+#[derive(Debug, Clone)]
+pub struct List<'a> {
+    block: Option<Block<'a>>,
+    items: Vec<ListItem<'a>>,
+    /// Style used as a base style for the widget
+    style: Style,
+    start_corner: Corner,
+    /// Style used to render selected item
+    highlight_style: Style,
+    /// Symbol in front of the selected item (Shift all items to the right)
+    highlight_symbol: Option<&'a str>,
+}
+
+impl<'a> List<'a> {
+    pub fn new<T>(items: T) -> List<'a>
+    where
+        T: Into<Vec<ListItem<'a>>>,
+    {
+        List {
+            block: None,
+            style: Style::default(),
+            items: items.into(),
+            start_corner: Corner::TopLeft,
+            highlight_style: Style::default(),
+            highlight_symbol: None,
+        }
+    }
+
+    pub fn block(mut self, block: Block<'a>) -> List<'a> {
+        self.block = Some(block);
+        self
+    }
+
+    pub fn style(mut self, style: Style) -> List<'a> {
+        self.style = style;
+        self
+    }
+
+    pub fn highlight_symbol(mut self, highlight_symbol: &'a str) -> List<'a> {
+        self.highlight_symbol = Some(highlight_symbol);
+        self
+    }
+
+    pub fn highlight_style(mut self, style: Style) -> List<'a> {
+        self.highlight_style = style;
+        self
+    }
+
+    pub fn start_corner(mut self, corner: Corner) -> List<'a> {
+        self.start_corner = corner;
+        self
+    }
+}
+
+impl<'a> StatefulWidget for List<'a> {
+    type State = ListState;
+
+    fn render(mut self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
+        buf.set_style(area, self.style);
+        let list_area = match self.block.take() {
+            Some(b) => {
+                let inner_area = b.inner(area);
+                b.render(area, buf);
+                inner_area
+            }
+            None => area,
+        };
+
+        if list_area.width < 1 || list_area.height < 1 {
+            return;
+        }
+
+        if self.items.is_empty() {
+            return;
+        }
+        let list_height = list_area.height as usize;
+
+        let mut start = state.offset;
+        let mut end = state.offset;
+        let mut height = 0;
+        for item in self.items.iter().skip(state.offset) {
+            if height + item.height() > list_height {
+                break;
+            }
+            height += item.height();
+            end += 1;
+        }
+
+        let selected = state.selected.unwrap_or(0).min(self.items.len() - 1);
+        while selected >= end {
+            height = height.saturating_add(self.items[end].height());
+            end += 1;
+            while height > list_height {
+                height = height.saturating_sub(self.items[start].height());
+                start += 1;
+            }
+        }
+        while selected < start {
+            start -= 1;
+            height = height.saturating_add(self.items[start].height());
+            while height > list_height {
+                end -= 1;
+                height = height.saturating_sub(self.items[end].height());
+            }
+        }
+        state.offset = start;
+
+        let highlight_symbol = self.highlight_symbol.unwrap_or("");
+        let blank_symbol = iter::repeat(" ")
+            .take(highlight_symbol.width())
+            .collect::<String>();
+
+        let mut current_height = 0;
+        let has_selection = state.selected.is_some();
+        for (i, item) in self
+            .items
+            .iter_mut()
+            .enumerate()
+            .skip(state.offset)
+            .take(end - start)
+        {
+            let (x, y) = match self.start_corner {
+                Corner::BottomLeft => {
+                    current_height += item.height() as u16;
+                    (list_area.left(), list_area.bottom() - current_height)
+                }
+                _ => {
+                    let pos = (list_area.left(), list_area.top() + current_height);
+                    current_height += item.height() as u16;
+                    pos
+                }
+            };
+            let area = Rect {
+                x,
+                y,
+                width: list_area.width,
+                height: item.height() as u16,
+            };
+            let item_style = self.style.patch(item.style);
+            buf.set_style(area, item_style);
+
+            let is_selected = state.selected.map(|s| s == i).unwrap_or(false);
+            let elem_x = if has_selection {
+                let symbol = if is_selected {
+                    highlight_symbol
+                } else {
+                    &blank_symbol
+                };
+                let (x, _) = buf.set_stringn(x, y, symbol, list_area.width as usize, item_style);
+                x
+            } else {
+                x
+            };
+            let max_element_width = (list_area.width - (elem_x - x)) as usize;
+            for (j, line) in item.content.lines.iter().enumerate() {
+                buf.set_spans(elem_x, y + j as u16, line, max_element_width as u16);
+            }
+            if is_selected {
+                buf.set_style(area, self.highlight_style);
+            }
+        }
+    }
+}
+
+impl<'a> Widget for List<'a> {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        let mut state = ListState::default();
+        StatefulWidget::render(self, area, buf, &mut state);
+    }
+}