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, 434 insertions, 0 deletions

diff --git a/helix-tui/src/text.rs b/helix-tui/src/text.rs
new file mode 100644
index 00000000..c671e918
--- /dev/null
+++ b/helix-tui/src/text.rs
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+//! Primitives for styled text.
+//!
+//! A terminal UI is at its root a lot of strings. In order to make it accessible and stylish,
+//! those strings may be associated to a set of styles. `tui` has three ways to represent them:
+//! - A single line string where all graphemes have the same style is represented by a [`Span`].
+//! - A single line string where each grapheme may have its own style is represented by [`Spans`].
+//! - A multiple line string where each grapheme may have its own style is represented by a
+//! [`Text`].
+//!
+//! These types form a hierarchy: [`Spans`] is a collection of [`Span`] and each line of [`Text`]
+//! is a [`Spans`].
+//!
+//! Keep it mind that a lot of widgets will use those types to advertise what kind of string is
+//! supported for their properties. Moreover, `tui` provides convenient `From` implementations so
+//! that you can start by using simple `String` or `&str` and then promote them to the previous
+//! primitives when you need additional styling capabilities.
+//!
+//! For example, for the [`crate::widgets::Block`] widget, all the following calls are valid to set
+//! its `title` property (which is a [`Spans`] under the hood):
+//!
+//! ```rust
+//! # use helix_tui::widgets::Block;
+//! # use helix_tui::text::{Span, Spans};
+//! # use helix_tui::style::{Color, Style};
+//! // A simple string with no styling.
+//! // Converted to Spans(vec![
+//! //   Span { content: Cow::Borrowed("My title"), style: Style { .. } }
+//! // ])
+//! let block = Block::default().title("My title");
+//!
+//! // A simple string with a unique style.
+//! // Converted to Spans(vec![
+//! //   Span { content: Cow::Borrowed("My title"), style: Style { fg: Some(Color::Yellow), .. }
+//! // ])
+//! let block = Block::default().title(
+//!     Span::styled("My title", Style::default().fg(Color::Yellow))
+//! );
+//!
+//! // A string with multiple styles.
+//! // Converted to Spans(vec![
+//! //   Span { content: Cow::Borrowed("My"), style: Style { fg: Some(Color::Yellow), .. } },
+//! //   Span { content: Cow::Borrowed(" title"), .. }
+//! // ])
+//! let block = Block::default().title(vec![
+//!     Span::styled("My", Style::default().fg(Color::Yellow)),
+//!     Span::raw(" title"),
+//! ]);
+//! ```
+use crate::style::Style;
+use std::borrow::Cow;
+use unicode_segmentation::UnicodeSegmentation;
+use unicode_width::UnicodeWidthStr;
+
+/// A grapheme associated to a style.
+#[derive(Debug, Clone, PartialEq)]
+pub struct StyledGrapheme<'a> {
+    pub symbol: &'a str,
+    pub style: Style,
+}
+
+/// A string where all graphemes have the same style.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Span<'a> {
+    pub content: Cow<'a, str>,
+    pub style: Style,
+}
+
+impl<'a> Span<'a> {
+    /// Create a span with no style.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::Span;
+    /// Span::raw("My text");
+    /// Span::raw(String::from("My text"));
+    /// ```
+    pub fn raw<T>(content: T) -> Span<'a>
+    where
+        T: Into<Cow<'a, str>>,
+    {
+        Span {
+            content: content.into(),
+            style: Style::default(),
+        }
+    }
+
+    /// Create a span with a style.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::Span;
+    /// # use helix_tui::style::{Color, Modifier, Style};
+    /// let style = Style::default().fg(Color::Yellow).add_modifier(Modifier::ITALIC);
+    /// Span::styled("My text", style);
+    /// Span::styled(String::from("My text"), style);
+    /// ```
+    pub fn styled<T>(content: T, style: Style) -> Span<'a>
+    where
+        T: Into<Cow<'a, str>>,
+    {
+        Span {
+            content: content.into(),
+            style,
+        }
+    }
+
+    /// Returns the width of the content held by this span.
+    pub fn width(&self) -> usize {
+        self.content.width()
+    }
+
+    /// Returns an iterator over the graphemes held by this span.
+    ///
+    /// `base_style` is the [`Style`] that will be patched with each grapheme [`Style`] to get
+    /// the resulting [`Style`].
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::{Span, StyledGrapheme};
+    /// # use helix_tui::style::{Color, Modifier, Style};
+    /// # use std::iter::Iterator;
+    /// let style = Style::default().fg(Color::Yellow);
+    /// let span = Span::styled("Text", style);
+    /// let style = Style::default().fg(Color::Green).bg(Color::Black);
+    /// let styled_graphemes = span.styled_graphemes(style);
+    /// assert_eq!(
+    ///     vec![
+    ///         StyledGrapheme {
+    ///             symbol: "T",
+    ///             style: Style {
+    ///                 fg: Some(Color::Yellow),
+    ///                 bg: Some(Color::Black),
+    ///                 add_modifier: Modifier::empty(),
+    ///                 sub_modifier: Modifier::empty(),
+    ///             },
+    ///         },
+    ///         StyledGrapheme {
+    ///             symbol: "e",
+    ///             style: Style {
+    ///                 fg: Some(Color::Yellow),
+    ///                 bg: Some(Color::Black),
+    ///                 add_modifier: Modifier::empty(),
+    ///                 sub_modifier: Modifier::empty(),
+    ///             },
+    ///         },
+    ///         StyledGrapheme {
+    ///             symbol: "x",
+    ///             style: Style {
+    ///                 fg: Some(Color::Yellow),
+    ///                 bg: Some(Color::Black),
+    ///                 add_modifier: Modifier::empty(),
+    ///                 sub_modifier: Modifier::empty(),
+    ///             },
+    ///         },
+    ///         StyledGrapheme {
+    ///             symbol: "t",
+    ///             style: Style {
+    ///                 fg: Some(Color::Yellow),
+    ///                 bg: Some(Color::Black),
+    ///                 add_modifier: Modifier::empty(),
+    ///                 sub_modifier: Modifier::empty(),
+    ///             },
+    ///         },
+    ///     ],
+    ///     styled_graphemes.collect::<Vec<StyledGrapheme>>()
+    /// );
+    /// ```
+    pub fn styled_graphemes(
+        &'a self,
+        base_style: Style,
+    ) -> impl Iterator<Item = StyledGrapheme<'a>> {
+        UnicodeSegmentation::graphemes(self.content.as_ref(), true)
+            .map(move |g| StyledGrapheme {
+                symbol: g,
+                style: base_style.patch(self.style),
+            })
+            .filter(|s| s.symbol != "\n")
+    }
+}
+
+impl<'a> From<String> for Span<'a> {
+    fn from(s: String) -> Span<'a> {
+        Span::raw(s)
+    }
+}
+
+impl<'a> From<&'a str> for Span<'a> {
+    fn from(s: &'a str) -> Span<'a> {
+        Span::raw(s)
+    }
+}
+
+/// A string composed of clusters of graphemes, each with their own style.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Spans<'a>(pub Vec<Span<'a>>);
+
+impl<'a> Default for Spans<'a> {
+    fn default() -> Spans<'a> {
+        Spans(Vec::new())
+    }
+}
+
+impl<'a> Spans<'a> {
+    /// Returns the width of the underlying string.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::{Span, Spans};
+    /// # use helix_tui::style::{Color, Style};
+    /// let spans = Spans::from(vec![
+    ///     Span::styled("My", Style::default().fg(Color::Yellow)),
+    ///     Span::raw(" text"),
+    /// ]);
+    /// assert_eq!(7, spans.width());
+    /// ```
+    pub fn width(&self) -> usize {
+        self.0.iter().map(Span::width).sum()
+    }
+}
+
+impl<'a> From<String> for Spans<'a> {
+    fn from(s: String) -> Spans<'a> {
+        Spans(vec![Span::from(s)])
+    }
+}
+
+impl<'a> From<&'a str> for Spans<'a> {
+    fn from(s: &'a str) -> Spans<'a> {
+        Spans(vec![Span::from(s)])
+    }
+}
+
+impl<'a> From<Vec<Span<'a>>> for Spans<'a> {
+    fn from(spans: Vec<Span<'a>>) -> Spans<'a> {
+        Spans(spans)
+    }
+}
+
+impl<'a> From<Span<'a>> for Spans<'a> {
+    fn from(span: Span<'a>) -> Spans<'a> {
+        Spans(vec![span])
+    }
+}
+
+impl<'a> From<Spans<'a>> for String {
+    fn from(line: Spans<'a>) -> String {
+        line.0.iter().fold(String::new(), |mut acc, s| {
+            acc.push_str(s.content.as_ref());
+            acc
+        })
+    }
+}
+
+/// A string split over multiple lines where each line is composed of several clusters, each with
+/// their own style.
+///
+/// A [`Text`], like a [`Span`], can be constructed using one of the many `From` implementations
+/// or via the [`Text::raw`] and [`Text::styled`] methods. Helpfully, [`Text`] also implements
+/// [`core::iter::Extend`] which enables the concatenation of several [`Text`] blocks.
+///
+/// ```rust
+/// # use helix_tui::text::Text;
+/// # use helix_tui::style::{Color, Modifier, Style};
+/// let style = Style::default().fg(Color::Yellow).add_modifier(Modifier::ITALIC);
+///
+/// // An initial two lines of `Text` built from a `&str`
+/// let mut text = Text::from("The first line\nThe second line");
+/// assert_eq!(2, text.height());
+///
+/// // Adding two more unstyled lines
+/// text.extend(Text::raw("These are two\nmore lines!"));
+/// assert_eq!(4, text.height());
+///
+/// // Adding a final two styled lines
+/// text.extend(Text::styled("Some more lines\nnow with more style!", style));
+/// assert_eq!(6, text.height());
+/// ```
+#[derive(Debug, Clone, PartialEq)]
+pub struct Text<'a> {
+    pub lines: Vec<Spans<'a>>,
+}
+
+impl<'a> Default for Text<'a> {
+    fn default() -> Text<'a> {
+        Text { lines: Vec::new() }
+    }
+}
+
+impl<'a> Text<'a> {
+    /// Create some text (potentially multiple lines) with no style.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::Text;
+    /// Text::raw("The first line\nThe second line");
+    /// Text::raw(String::from("The first line\nThe second line"));
+    /// ```
+    pub fn raw<T>(content: T) -> Text<'a>
+    where
+        T: Into<Cow<'a, str>>,
+    {
+        Text {
+            lines: match content.into() {
+                Cow::Borrowed(s) => s.lines().map(Spans::from).collect(),
+                Cow::Owned(s) => s.lines().map(|l| Spans::from(l.to_owned())).collect(),
+            },
+        }
+    }
+
+    /// Create some text (potentially multiple lines) with a style.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::Text;
+    /// # use helix_tui::style::{Color, Modifier, Style};
+    /// let style = Style::default().fg(Color::Yellow).add_modifier(Modifier::ITALIC);
+    /// Text::styled("The first line\nThe second line", style);
+    /// Text::styled(String::from("The first line\nThe second line"), style);
+    /// ```
+    pub fn styled<T>(content: T, style: Style) -> Text<'a>
+    where
+        T: Into<Cow<'a, str>>,
+    {
+        let mut text = Text::raw(content);
+        text.patch_style(style);
+        text
+    }
+
+    /// Returns the max width of all the lines.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// use helix_tui::text::Text;
+    /// let text = Text::from("The first line\nThe second line");
+    /// assert_eq!(15, text.width());
+    /// ```
+    pub fn width(&self) -> usize {
+        self.lines
+            .iter()
+            .map(Spans::width)
+            .max()
+            .unwrap_or_default()
+    }
+
+    /// Returns the height.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// use helix_tui::text::Text;
+    /// let text = Text::from("The first line\nThe second line");
+    /// assert_eq!(2, text.height());
+    /// ```
+    pub fn height(&self) -> usize {
+        self.lines.len()
+    }
+
+    /// Apply a new style to existing text.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use helix_tui::text::Text;
+    /// # use helix_tui::style::{Color, Modifier, Style};
+    /// let style = Style::default().fg(Color::Yellow).add_modifier(Modifier::ITALIC);
+    /// let mut raw_text = Text::raw("The first line\nThe second line");
+    /// let styled_text = Text::styled(String::from("The first line\nThe second line"), style);
+    /// assert_ne!(raw_text, styled_text);
+    ///
+    /// raw_text.patch_style(style);
+    /// assert_eq!(raw_text, styled_text);
+    /// ```
+    pub fn patch_style(&mut self, style: Style) {
+        for line in &mut self.lines {
+            for span in &mut line.0 {
+                span.style = span.style.patch(style);
+            }
+        }
+    }
+}
+
+impl<'a> From<String> for Text<'a> {
+    fn from(s: String) -> Text<'a> {
+        Text::raw(s)
+    }
+}
+
+impl<'a> From<&'a str> for Text<'a> {
+    fn from(s: &'a str) -> Text<'a> {
+        Text::raw(s)
+    }
+}
+
+impl<'a> From<Span<'a>> for Text<'a> {
+    fn from(span: Span<'a>) -> Text<'a> {
+        Text {
+            lines: vec![Spans::from(span)],
+        }
+    }
+}
+
+impl<'a> From<Spans<'a>> for Text<'a> {
+    fn from(spans: Spans<'a>) -> Text<'a> {
+        Text { lines: vec![spans] }
+    }
+}
+
+impl<'a> From<Vec<Spans<'a>>> for Text<'a> {
+    fn from(lines: Vec<Spans<'a>>) -> Text<'a> {
+        Text { lines }
+    }
+}
+
+impl<'a> IntoIterator for Text<'a> {
+    type Item = Spans<'a>;
+    type IntoIter = std::vec::IntoIter<Self::Item>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.lines.into_iter()
+    }
+}
+
+impl<'a> Extend<Spans<'a>> for Text<'a> {
+    fn extend<T: IntoIterator<Item = Spans<'a>>>(&mut self, iter: T) {
+        self.lines.extend(iter);
+    }
+}