From 0e99a10e07b5b684b618b0a7a176fa254f8ef884 Mon Sep 17 00:00:00 2001
From: Dan Davison <dandavison7@gmail.com>
Date: Thu, 29 Apr 2021 22:16:23 -0400
Subject: 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
---
 src/bat_utils/terminal.rs | 68 ++++++++++++++++++++++++++++++++++-------------
 1 file changed, 49 insertions(+), 19 deletions(-)

(limited to 'src/bat_utils')

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()
 }
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