T06: terminal view: frame, colors and styles, wide and combining cells, cursor and blink, font, padding, resize; bundled faces and icon font; shot example

src/term/ink.rs

@@ -0,0 +1,176 @@
+use alacritty_terminal::{
+    term::color::Colors,
+    vte::ansi::{Color, NamedColor, Rgb},
+};
+use gpui::{Hsla, Rgba};
+
+use crate::themes::TerminalTheme;
+
+/// The colors a terminal paints with: its theme, under any a program set by OSC 4, 10, 11 or 12.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Ink {
+    pub ansi: [Hsla; 16],
+    pub fg: Hsla,
+    pub bg: Hsla,
+    pub cursor: Hsla,
+    pub cursor_text: Hsla,
+}
+
+impl Ink {
+    pub fn new(theme: &TerminalTheme, set: &Colors) -> Self {
+        let named = |name: NamedColor| set[name].map(hsla);
+        let mut ansi = theme.ansi;
+        for (index, color) in ansi.iter_mut().enumerate() {
+            if let Some(spec) = set[index] {
+                *color = hsla(spec);
+            }
+        }
+        Self {
+            ansi,
+            fg: named(NamedColor::Foreground).unwrap_or(theme.foreground),
+            bg: named(NamedColor::Background).unwrap_or(theme.background),
+            cursor: named(NamedColor::Cursor).unwrap_or(theme.cursor),
+            cursor_text: theme.cursor_text,
+        }
+    }
+
+    pub fn resolve(&self, color: Color, set: &Colors) -> Hsla {
+        match color {
+            Color::Spec(spec) => hsla(spec),
+            Color::Indexed(index) => self.indexed(index.into(), set),
+            Color::Named(name) => self.named(name),
+        }
+    }
+
+    fn named(&self, name: NamedColor) -> Hsla {
+        match name {
+            NamedColor::Foreground | NamedColor::BrightForeground => self.fg,
+            NamedColor::Background => self.bg,
+            NamedColor::Cursor => self.cursor,
+            NamedColor::DimForeground => self.fg.opacity(DIM),
+            dim if (NamedColor::DimBlack as usize..=NamedColor::DimWhite as usize)
+                .contains(&(dim as usize)) =>
+            {
+                self.named(dim.to_bright()).opacity(DIM)
+            }
+            ansi => self.ansi[ansi as usize],
+        }
+    }
+
+    fn indexed(&self, index: usize, set: &Colors) -> Hsla {
+        if let Some(spec) = set[index] {
+            return hsla(spec);
+        }
+        match index {
+            0..16 => self.ansi[index],
+            16..232 => {
+                let step = |level: usize| if level == 0 { 0 } else { 55 + 40 * level as u8 };
+                let cube = index - 16;
+                hsla(Rgb {
+                    r: step(cube / 36),
+                    g: step(cube / 6 % 6),
+                    b: step(cube % 6),
+                })
+            }
+            _ => {
+                let gray = 8 + 10 * (index - 232) as u8;
+                hsla(Rgb {
+                    r: gray,
+                    g: gray,
+                    b: gray,
+                })
+            }
+        }
+    }
+
+    /// Color `index` as an answer to a program's query: 0–255, then 256 text, 257 ground, 258 cursor.
+    pub fn query(&self, index: usize, set: &Colors) -> Rgb {
+        let color = match index {
+            256 => self.fg,
+            257 => self.bg,
+            258 => self.cursor,
+            index => self.indexed(index.min(255), set),
+        };
+        let rgba = color.to_rgb();
+        let byte = |channel: f32| (channel * 255.0).round() as u8;
+        Rgb {
+            r: byte(rgba.r),
+            g: byte(rgba.g),
+            b: byte(rgba.b),
+        }
+    }
+}
+
+/// How much of the text color dim text keeps.
+pub const DIM: f32 = 0.66;
+
+fn hsla(spec: Rgb) -> Hsla {
+    let channel = |value: u8| f32::from(value) / 255.0;
+    Rgba {
+        r: channel(spec.r),
+        g: channel(spec.g),
+        b: channel(spec.b),
+        a: 1.0,
+    }
+    .into()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::themes;
+
+    fn ink(set: &Colors) -> Ink {
+        Ink::new(themes::find("catppuccin-mocha").expect("mocha"), set)
+    }
+
+    #[test]
+    fn indexed_colors_follow_the_xterm_cube_and_ramp() {
+        let set = Colors::default();
+        let ink = ink(&set);
+        assert_eq!(ink.query(196, &set), Rgb { r: 255, g: 0, b: 0 });
+        assert_eq!(ink.query(16, &set), Rgb { r: 0, g: 0, b: 0 });
+        assert_eq!(
+            ink.query(244, &set),
+            Rgb {
+                r: 128,
+                g: 128,
+                b: 128
+            }
+        );
+        assert_eq!(
+            ink.query(1, &set),
+            Rgb {
+                r: 0xf3,
+                g: 0x8b,
+                b: 0xa8
+            },
+            "the theme's red"
+        );
+        assert_eq!(
+            ink.query(257, &set),
+            Rgb {
+                r: 0x1e,
+                g: 0x1e,
+                b: 0x2e
+            }
+        );
+    }
+
+    #[test]
+    fn a_color_the_program_set_wins() {
+        let mut set = Colors::default();
+        set[1] = Some(Rgb { r: 1, g: 2, b: 3 });
+        set[NamedColor::Background] = Some(Rgb { r: 9, g: 9, b: 9 });
+        let ink = ink(&set);
+        assert_eq!(
+            ink.resolve(Color::Named(NamedColor::Red), &set),
+            hsla(Rgb { r: 1, g: 2, b: 3 })
+        );
+        assert_eq!(ink.bg, hsla(Rgb { r: 9, g: 9, b: 9 }));
+        assert_eq!(
+            ink.resolve(Color::Named(NamedColor::DimRed), &set),
+            ink.ansi[1].opacity(DIM)
+        );
+    }
+}