Fix ansi syntax theme (#581)

* Update to latest version of bat::terminal::to_ansi_color

Fixes #447

* Delete mention of historical syntax theme ansi-light

* Update tests

5 files changed, 72 insertions, 63 deletions

diff --git a/src/bat_utils/terminal.rs b/src/bat_utils/terminal.rs
index 50351c48..15c75d24 100644
--- a/src/bat_utils/terminal.rs
+++ b/src/bat_utils/terminal.rs
@@ -1,21 +1,48 @@
-extern crate ansi_colours;
-
-use ansi_term::Colour::{Fixed, RGB};
+use ansi_term::Color::{self, Fixed, RGB};
 use ansi_term::{self, Style};
 
 use syntect::highlighting::{self, FontStyle};
 
-pub fn to_ansi_color(color: highlighting::Color, true_color: bool) -> ansi_term::Colour {
+pub fn to_ansi_color(color: highlighting::Color, true_color: bool) -> Option<ansi_term::Color> {
     if color.a == 0 {
         // Themes can specify one of the user-configurable terminal colors by
         // encoding them as #RRGGBBAA with AA set to 00 (transparent) and RR set
-        // to the color palette number. The built-in themes ansi-light,
-        // ansi-dark, and base16 use this.
-        Fixed(color.r)
+        // to the 8-bit color palette number. The built-in themes ansi, base16,
+        // and base16-256 use this.
+        Some(match color.r {
+            // For the first 8 colors, use the Color enum to produce ANSI escape
+            // sequences using codes 30-37 (foreground) and 40-47 (background).
+            // For example, red foreground is \x1b[31m. This works on terminals
+            // without 256-color support.
+            0x00 => Color::Black,
+            0x01 => Color::Red,
+            0x02 => Color::Green,
+            0x03 => Color::Yellow,
+            0x04 => Color::Blue,
+            0x05 => Color::Purple,
+            0x06 => Color::Cyan,
+            0x07 => Color::White,
+            // For all other colors, use Fixed to produce escape sequences using
+            // codes 38;5 (foreground) and 48;5 (background). For example,
+            // bright red foreground is \x1b[38;5;9m. This only works on
+            // terminals with 256-color support.
+            //
+            // TODO: When ansi_term adds support for bright variants using codes
+            // 90-97 (foreground) and 100-107 (background), we should use those
+            // for values 0x08 to 0x0f and only use Fixed for 0x10 to 0xff.
+            n => Fixed(n),
+        })
+    } else if color.a == 1 {
+        // Themes can specify the terminal's default foreground/background color
+        // (i.e. no escape sequence) using the encoding #RRGGBBAA with AA set to
+        // 01. The built-in theme ansi uses this.
+        None
     } else if true_color {
-        RGB(color.r, color.g, color.b)
+        Some(RGB(color.r, color.g, color.b))
     } else {
-        Fixed(ansi_colours::ansi256_from_rgb((color.r, color.g, color.b)))
+        Some(Fixed(ansi_colours::ansi256_from_rgb((
+            color.r, color.g, color.b,
+        ))))
     }
 }
 
@@ -35,19 +62,22 @@ pub fn as_terminal_escaped(
     let mut style = if !colored {
         Style::default()
     } else {
-        let color = to_ansi_color(style.foreground, true_color);
-
+        let mut color = Style {
+            foreground: to_ansi_color(style.foreground, true_color),
+            ..Style::default()
+        };
         if style.font_style.contains(FontStyle::BOLD) {
-            color.bold()
-        } else if style.font_style.contains(FontStyle::UNDERLINE) {
-            color.underline()
-        } else if italics && style.font_style.contains(FontStyle::ITALIC) {
-            color.italic()
-        } else {
-            color.normal()
+            color = color.bold();
+        }
+        if style.font_style.contains(FontStyle::UNDERLINE) {
+            color = color.underline();
+        }
+        if italics && style.font_style.contains(FontStyle::ITALIC) {
+            color = color.italic();
         }
+        color
     };
 
-    style.background = background_color.map(|c| to_ansi_color(c, true_color));
+    style.background = background_color.and_then(|c| to_ansi_color(c, true_color));
     style.paint(text).to_string()
 }
diff --git a/src/color.rs b/src/color.rs
index d8b8a9f7..10d9cafd 100644
--- a/src/color.rs
+++ b/src/color.rs
@@ -26,7 +26,7 @@ pub fn parse_color(s: &str, true_color: bool) -> Option<Color> {
             .or_else(|| syntect_color::syntect_color_from_ansi_name(s))
             .unwrap_or_else(die)
     };
-    Some(to_ansi_color(syntect_color, true_color))
+    to_ansi_color(syntect_color, true_color)
 }
 
 pub fn color_to_string(color: Color) -> String {
diff --git a/src/options/theme.rs b/src/options/theme.rs
index ef46dbea..fa5cbef0 100644
--- a/src/options/theme.rs
+++ b/src/options/theme.rs
@@ -38,13 +38,12 @@ pub fn is_light_syntax_theme(theme: &str) -> bool {
     LIGHT_SYNTAX_THEMES.contains(&theme)
 }
 
-const LIGHT_SYNTAX_THEMES: [&str; 7] = [
+const LIGHT_SYNTAX_THEMES: [&str; 6] = [
     "GitHub",
     "gruvbox-light",
     "gruvbox-white",
     "Monokai Extended Light",
     "OneHalfLight",
-    "ansi-light",
     "Solarized (light)",
 ];
 
diff --git a/src/paint.rs b/src/paint.rs
index bf85fb13..0c31f094 100644
--- a/src/paint.rs
+++ b/src/paint.rs
@@ -667,7 +667,7 @@ mod superimpose_style_sections {
             if style.is_syntax_highlighted && syntect_style != null_syntect_style {
                 Style {
                     ansi_term_style: ansi_term::Style {
-                        foreground: Some(to_ansi_color(syntect_style.foreground, true_color)),
+                        foreground: to_ansi_color(syntect_style.foreground, true_color),
                         ..style.ansi_term_style
                     },
                     ..style
@@ -755,7 +755,7 @@ mod superimpose_style_sections {
         lazy_static! {
             static ref SUPERIMPOSED_STYLE: Style = Style {
                 ansi_term_style: ansi_term::Style {
-                    foreground: Some(to_ansi_color(SyntectColor::BLACK, true)),
+                    foreground: to_ansi_color(SyntectColor::BLACK, true),
                     background: Some(Color::White),
                     is_underline: true,
                     ..ansi_term::Style::new()
diff --git a/src/parse_style.rs b/src/parse_style.rs
index cf595553..02c455b0 100644
--- a/src/parse_style.rs
+++ b/src/parse_style.rs
@@ -334,8 +334,6 @@ mod tests {
 
     use ansi_term;
 
-    use crate::color::ansi_16_color_name_to_number;
-
     #[test]
     fn test_parse_ansi_term_style() {
         assert_eq!(
@@ -346,9 +344,7 @@ mod tests {
             parse_ansi_term_style("red", None, false),
             (
                 ansi_term::Style {
-                    foreground: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("red").unwrap()
-                    )),
+                    foreground: Some(ansi_term::Color::Red),
                     ..ansi_term::Style::new()
                 },
                 false,
@@ -360,12 +356,8 @@ mod tests {
             parse_ansi_term_style("red green", None, false),
             (
                 ansi_term::Style {
-                    foreground: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("red").unwrap()
-                    )),
-                    background: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("green").unwrap()
-                    )),
+                    foreground: Some(ansi_term::Color::Red),
+                    background: Some(ansi_term::Color::Green),
                     ..ansi_term::Style::new()
                 },
                 false,
@@ -377,12 +369,8 @@ mod tests {
             parse_ansi_term_style("bold red underline green blink", None, false),
             (
                 ansi_term::Style {
-                    foreground: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("red").unwrap()
-                    )),
-                    background: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("green").unwrap()
-                    )),
+                    foreground: Some(ansi_term::Color::Red),
+                    background: Some(ansi_term::Color::Green),
                     is_blink: true,
                     is_bold: true,
                     is_underline: true,
@@ -405,9 +393,7 @@ mod tests {
             parse_ansi_term_style("syntax italic white hidden", None, false),
             (
                 ansi_term::Style {
-                    background: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("white").unwrap()
-                    )),
+                    background: Some(ansi_term::Color::White),
                     is_italic: true,
                     is_hidden: true,
                     ..ansi_term::Style::new()
@@ -421,9 +407,7 @@ mod tests {
             parse_ansi_term_style("bold syntax italic white hidden", None, false),
             (
                 ansi_term::Style {
-                    background: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("white").unwrap()
-                    )),
+                    background: Some(ansi_term::Color::White),
                     is_bold: true,
                     is_italic: true,
                     is_hidden: true,
@@ -447,9 +431,7 @@ mod tests {
             parse_ansi_term_style("omit syntax italic white hidden", None, false),
             (
                 ansi_term::Style {
-                    background: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("white").unwrap()
-                    )),
+                    background: Some(ansi_term::Color::White),
                     is_italic: true,
                     is_hidden: true,
                     ..ansi_term::Style::new()
@@ -472,9 +454,7 @@ mod tests {
             parse_ansi_term_style("raw syntax italic white hidden", None, false),
             (
                 ansi_term::Style {
-                    background: Some(ansi_term::Color::Fixed(
-                        ansi_16_color_name_to_number("white").unwrap()
-                    )),
+                    background: Some(ansi_term::Color::White),
                     is_italic: true,
                     is_hidden: true,
                     ..ansi_term::Style::new()
@@ -542,8 +522,8 @@ mod tests {
         assert_eq!(
             DecorationStyle::from_str("ol red box bold green ul", true),
             DecorationStyle::BoxWithUnderOverline(ansi_term::Style {
-                foreground: Some(ansi_term::Color::Fixed(1)),
-                background: Some(ansi_term::Color::Fixed(2)),
+                foreground: Some(ansi_term::Color::Red),
+                background: Some(ansi_term::Color::Green),
                 is_bold: true,
                 ..ansi_term::Style::new()
             })
@@ -560,8 +540,8 @@ mod tests {
             false,
         );
         let red_green_bold = ansi_term::Style {
-            foreground: Some(ansi_term::Color::Fixed(1)),
-            background: Some(ansi_term::Color::Fixed(2)),
+            foreground: Some(ansi_term::Color::Red),
+            background: Some(ansi_term::Color::Green),
             is_bold: true,
             ..ansi_term::Style::new()
         };
@@ -594,8 +574,8 @@ mod tests {
     fn test_style_from_str_decoration_style_only() {
         let actual_style = Style::from_str("", None, Some("ol red box bold green ul"), true, false);
         let red_green_bold = ansi_term::Style {
-            foreground: Some(ansi_term::Color::Fixed(1)),
-            background: Some(ansi_term::Color::Fixed(2)),
+            foreground: Some(ansi_term::Color::Red),
+            background: Some(ansi_term::Color::Green),
             is_bold: true,
             ..ansi_term::Style::new()
         };
@@ -618,8 +598,8 @@ mod tests {
             false,
         );
         let expected_decoration_style = DecorationStyle::BoxWithUnderOverline(ansi_term::Style {
-            foreground: Some(ansi_term::Color::Fixed(1)),
-            background: Some(ansi_term::Color::Fixed(2)),
+            foreground: Some(ansi_term::Color::Red),
+            background: Some(ansi_term::Color::Green),
             is_bold: true,
             ..ansi_term::Style::new()
         });
@@ -657,8 +637,8 @@ mod tests {
     fn test_style_from_str_with_handling_of_special_decoration_attributes_and_respecting_deprecated_foreground_color_arg(
     ) {
         let expected_decoration_style = DecorationStyle::BoxWithUnderOverline(ansi_term::Style {
-            foreground: Some(ansi_term::Color::Fixed(1)),
-            background: Some(ansi_term::Color::Fixed(2)),
+            foreground: Some(ansi_term::Color::Red),
+            background: Some(ansi_term::Color::Green),
             is_bold: true,
             ..ansi_term::Style::new()
         });