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helix-plus/helix-tui/src/style.rs

282 lines
8.5 KiB
Rust

//! `style` contains the primitives used to control how your user interface will look.
use bitflags::bitflags;
#[derive(Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum Color {
Reset,
Black,
Red,
Green,
Yellow,
Blue,
Magenta,
Cyan,
Gray,
DarkGray,
LightRed,
LightGreen,
LightYellow,
LightBlue,
LightMagenta,
LightCyan,
White,
Rgb(u8, u8, u8),
Indexed(u8),
}
bitflags! {
/// Modifier changes the way a piece of text is displayed.
///
/// They are bitflags so they can easily be composed.
///
/// ## Examples
///
/// ```rust
/// # use helix_tui::style::Modifier;
///
/// let m = Modifier::BOLD | Modifier::ITALIC;
/// ```
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct Modifier: u16 {
const BOLD = 0b0000_0000_0001;
const DIM = 0b0000_0000_0010;
const ITALIC = 0b0000_0000_0100;
const UNDERLINED = 0b0000_0000_1000;
const SLOW_BLINK = 0b0000_0001_0000;
const RAPID_BLINK = 0b0000_0010_0000;
const REVERSED = 0b0000_0100_0000;
const HIDDEN = 0b0000_1000_0000;
const CROSSED_OUT = 0b0001_0000_0000;
}
}
/// Style let you control the main characteristics of the displayed elements.
///
/// ```rust
/// # use helix_tui::style::{Color, Modifier, Style};
/// Style::default()
/// .fg(Color::Black)
/// .bg(Color::Green)
/// .add_modifier(Modifier::ITALIC | Modifier::BOLD);
/// ```
///
/// It represents an incremental change. If you apply the styles S1, S2, S3 to a cell of the
/// terminal buffer, the style of this cell will be the result of the merge of S1, S2 and S3, not
/// just S3.
///
/// ```rust
/// # use helix_tui::style::{Color, Modifier, Style};
/// # use helix_tui::buffer::Buffer;
/// # use helix_tui::layout::Rect;
/// let styles = [
/// Style::default().fg(Color::Blue).add_modifier(Modifier::BOLD | Modifier::ITALIC),
/// Style::default().bg(Color::Red),
/// Style::default().fg(Color::Yellow).remove_modifier(Modifier::ITALIC),
/// ];
/// let mut buffer = Buffer::empty(Rect::new(0, 0, 1, 1));
/// for style in &styles {
/// buffer.get_mut(0, 0).set_style(*style);
/// }
/// assert_eq!(
/// Style {
/// fg: Some(Color::Yellow),
/// bg: Some(Color::Red),
/// add_modifier: Modifier::BOLD,
/// sub_modifier: Modifier::empty(),
/// },
/// buffer.get(0, 0).style(),
/// );
/// ```
///
/// The default implementation returns a `Style` that does not modify anything. If you wish to
/// reset all properties until that point use [`Style::reset`].
///
/// ```
/// # use helix_tui::style::{Color, Modifier, Style};
/// # use helix_tui::buffer::Buffer;
/// # use helix_tui::layout::Rect;
/// let styles = [
/// Style::default().fg(Color::Blue).add_modifier(Modifier::BOLD | Modifier::ITALIC),
/// Style::reset().fg(Color::Yellow),
/// ];
/// let mut buffer = Buffer::empty(Rect::new(0, 0, 1, 1));
/// for style in &styles {
/// buffer.get_mut(0, 0).set_style(*style);
/// }
/// assert_eq!(
/// Style {
/// fg: Some(Color::Yellow),
/// bg: Some(Color::Reset),
/// add_modifier: Modifier::empty(),
/// sub_modifier: Modifier::empty(),
/// },
/// buffer.get(0, 0).style(),
/// );
/// ```
#[derive(Debug, Clone, Copy, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct Style {
pub fg: Option<Color>,
pub bg: Option<Color>,
pub add_modifier: Modifier,
pub sub_modifier: Modifier,
}
impl Default for Style {
fn default() -> Style {
Style {
fg: None,
bg: None,
add_modifier: Modifier::empty(),
sub_modifier: Modifier::empty(),
}
}
}
impl Style {
/// Returns a `Style` resetting all properties.
pub fn reset() -> Style {
Style {
fg: Some(Color::Reset),
bg: Some(Color::Reset),
add_modifier: Modifier::empty(),
sub_modifier: Modifier::all(),
}
}
/// Changes the foreground color.
///
/// ## Examples
///
/// ```rust
/// # use helix_tui::style::{Color, Style};
/// let style = Style::default().fg(Color::Blue);
/// let diff = Style::default().fg(Color::Red);
/// assert_eq!(style.patch(diff), Style::default().fg(Color::Red));
/// ```
pub fn fg(mut self, color: Color) -> Style {
self.fg = Some(color);
self
}
/// Changes the background color.
///
/// ## Examples
///
/// ```rust
/// # use helix_tui::style::{Color, Style};
/// let style = Style::default().bg(Color::Blue);
/// let diff = Style::default().bg(Color::Red);
/// assert_eq!(style.patch(diff), Style::default().bg(Color::Red));
/// ```
pub fn bg(mut self, color: Color) -> Style {
self.bg = Some(color);
self
}
/// Changes the text emphasis.
///
/// When applied, it adds the given modifier to the `Style` modifiers.
///
/// ## Examples
///
/// ```rust
/// # use helix_tui::style::{Color, Modifier, Style};
/// let style = Style::default().add_modifier(Modifier::BOLD);
/// let diff = Style::default().add_modifier(Modifier::ITALIC);
/// let patched = style.patch(diff);
/// assert_eq!(patched.add_modifier, Modifier::BOLD | Modifier::ITALIC);
/// assert_eq!(patched.sub_modifier, Modifier::empty());
/// ```
pub fn add_modifier(mut self, modifier: Modifier) -> Style {
self.sub_modifier.remove(modifier);
self.add_modifier.insert(modifier);
self
}
/// Changes the text emphasis.
///
/// When applied, it removes the given modifier from the `Style` modifiers.
///
/// ## Examples
///
/// ```rust
/// # use helix_tui::style::{Color, Modifier, Style};
/// let style = Style::default().add_modifier(Modifier::BOLD | Modifier::ITALIC);
/// let diff = Style::default().remove_modifier(Modifier::ITALIC);
/// let patched = style.patch(diff);
/// assert_eq!(patched.add_modifier, Modifier::BOLD);
/// assert_eq!(patched.sub_modifier, Modifier::ITALIC);
/// ```
pub fn remove_modifier(mut self, modifier: Modifier) -> Style {
self.add_modifier.remove(modifier);
self.sub_modifier.insert(modifier);
self
}
/// Results in a combined style that is equivalent to applying the two individual styles to
/// a style one after the other.
///
/// ## Examples
/// ```
/// # use helix_tui::style::{Color, Modifier, Style};
/// let style_1 = Style::default().fg(Color::Yellow);
/// let style_2 = Style::default().bg(Color::Red);
/// let combined = style_1.patch(style_2);
/// assert_eq!(
/// Style::default().patch(style_1).patch(style_2),
/// Style::default().patch(combined));
/// ```
pub fn patch(mut self, other: Style) -> Style {
self.fg = other.fg.or(self.fg);
self.bg = other.bg.or(self.bg);
self.add_modifier.remove(other.sub_modifier);
self.add_modifier.insert(other.add_modifier);
self.sub_modifier.remove(other.add_modifier);
self.sub_modifier.insert(other.sub_modifier);
self
}
}
#[cfg(test)]
mod tests {
use super::*;
fn styles() -> Vec<Style> {
vec![
Style::default(),
Style::default().fg(Color::Yellow),
Style::default().bg(Color::Yellow),
Style::default().add_modifier(Modifier::BOLD),
Style::default().remove_modifier(Modifier::BOLD),
Style::default().add_modifier(Modifier::ITALIC),
Style::default().remove_modifier(Modifier::ITALIC),
Style::default().add_modifier(Modifier::ITALIC | Modifier::BOLD),
Style::default().remove_modifier(Modifier::ITALIC | Modifier::BOLD),
]
}
#[test]
fn combined_patch_gives_same_result_as_individual_patch() {
let styles = styles();
for &a in &styles {
for &b in &styles {
for &c in &styles {
for &d in &styles {
let combined = a.patch(b.patch(c.patch(d)));
assert_eq!(
Style::default().patch(a).patch(b).patch(c).patch(d),
Style::default().patch(combined)
);
}
}
}
}
}
}