Merge pull request #107 from dandavison/99-103-color-options

Provide CLI options for all colors

5 files changed, 184 insertions, 59 deletions

diff --git a/src/cli.rs b/src/cli.rs
index 41c901e2..67635a97 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -10,38 +10,74 @@ use crate::config;
 use crate::style;
 
 #[derive(StructOpt, Clone, Debug)]
-#[structopt(name = "delta", about = "A syntax-highlighting pager for git")]
+#[structopt(
+    name = "delta",
+    about = "A syntax-highlighter for git and diff output",
+    after_help = "\
+Colors
+------
+
+All delta color options work the same way. There are two ways to specify a color:
+
+1. RGB hex code
+
+   An example of passing an RGB hex code is:
+   --file-color=\"#0e7c0e\"
+
+2. ANSI color name
+
+   There are 8 ANSI color names:
+   black, red, green, yellow, blue, magenta, cyan, white.
+
+   In addition, all of them have a bright form:
+   bright-black, bright-red, bright-green, bright-yellow, bright-blue, bright-magenta, bright-cyan, bright-white
+
+   An example is:
+   --file-color=\"green\"
+
+   Unlike RGB hex codes, ANSI color names are just names: you can choose the exact color that each
+   name corresponds to in the settings of your terminal application (the application you use to run
+   command line programs). This means that if you use ANSI color names, and you change the color
+   theme used by your terminal, then delta's colors will respond automatically, without needing to
+   change the delta command line.
+
+   \"purple\" is accepted as a synonym for \"magenta\". Color names and codes are case-insensitive.
+"
+)]
 pub struct Opt {
-    /// Use colors appropriate for a light terminal background. For
-    /// more control, see --theme, --plus-color, and --minus-color.
+    /// Use default colors appropriate for a light terminal background. For more control, see the other
+    /// color options.
     #[structopt(long = "light")]
     pub light: bool,
 
-    /// Use colors appropriate for a dark terminal background.  For
-    /// more control, see --theme, --plus-color, and --minus-color.
+    /// Use default colors appropriate for a dark terminal background. For more control, see the
+    /// other color options.
     #[structopt(long = "dark")]
     pub dark: bool,
 
     #[structopt(long = "minus-color")]
-    /// The background color (RGB hex) to use for removed lines.
+    /// The background color to use for removed lines.
     pub minus_color: Option<String>,
 
     #[structopt(long = "minus-emph-color")]
-    /// The background color (RGB hex) to use for emphasized sections of removed lines.
+    /// The background color to use for emphasized sections of removed lines.
     pub minus_emph_color: Option<String>,
 
     #[structopt(long = "plus-color")]
-    /// The background color (RGB hex) to use for added lines.
+    /// The background color to use for added lines.
     pub plus_color: Option<String>,
 
     #[structopt(long = "plus-emph-color")]
-    /// The background color (RGB hex) to use for emphasized sections of added lines.
+    /// The background color to use for emphasized sections of added lines.
     pub plus_emph_color: Option<String>,
 
     #[structopt(long = "theme", env = "BAT_THEME")]
-    /// The syntax highlighting theme to use. Use --theme=none to disable syntax highlighting.
-    /// If the theme is not set using this option, it will be taken from the BAT_THEME environment variable,
-    /// if that contains a valid theme name. Use --list-themes and --compare-themes to view available themes.
+    /// The code syntax highlighting theme to use. Use --theme=none to disable syntax highlighting.
+    /// If the theme is not set using this option, it will be taken from the BAT_THEME environment
+    /// variable, if that contains a valid theme name. Use --list-themes and --compare-themes to
+    /// view available themes. Note that the choice of theme only affects code syntax highlighting.
+    /// See --commit-color, --file-color, --hunk-color to configure the colors of other parts of
+    /// the diff output.
     pub theme: Option<String>,
 
     #[structopt(long = "highlight-removed")]
@@ -50,20 +86,32 @@ pub struct Opt {
     pub highlight_removed: bool,
 
     #[structopt(long = "commit-style", default_value = "plain")]
-    /// Formatting style for commit section of git output. Options
+    /// Formatting style for the commit section of git output. Options
     /// are: plain, box.
     pub commit_style: SectionStyle,
 
+    #[structopt(long = "commit-color", default_value = "yellow")]
+    /// Color for the commit section of git output.
+    pub commit_color: String,
+
     #[structopt(long = "file-style", default_value = "underline")]
-    /// Formatting style for file section of git output. Options
+    /// Formatting style for the file section of git output. Options
     /// are: plain, box, underline.
     pub file_style: SectionStyle,
 
+    #[structopt(long = "file-color", default_value = "blue")]
+    /// Color for the file section of git output.
+    pub file_color: String,
+
     #[structopt(long = "hunk-style", default_value = "box")]
-    /// Formatting style for hunk section of git output. Options
+    /// Formatting style for the hunk-marker section of git output. Options
     /// are: plain, box.
     pub hunk_style: SectionStyle,
 
+    #[structopt(long = "hunk-color", default_value = "blue")]
+    /// Color for the hunk-marker section of git output.
+    pub hunk_color: String,
+
     /// The width (in characters) of the background color
     /// highlighting. By default, the width is the current terminal
     /// width. Use --width=variable to apply background colors to the
diff --git a/src/config.rs b/src/config.rs
index 500c5e2e..2135efe8 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,3 +1,4 @@
+use std::process;
 use std::str::FromStr;
 
 use syntect::highlighting::{Color, Style, StyleModifier, Theme, ThemeSet};
@@ -5,6 +6,7 @@ use syntect::parsing::SyntaxSet;
 
 use crate::cli;
 use crate::env;
+use crate::paint;
 use crate::style;
 
 pub struct Config<'a> {
@@ -14,6 +16,9 @@ pub struct Config<'a> {
     pub minus_emph_style_modifier: StyleModifier,
     pub plus_style_modifier: StyleModifier,
     pub plus_emph_style_modifier: StyleModifier,
+    pub commit_color: Color,
+    pub file_color: Color,
+    pub hunk_color: Color,
     pub syntax_set: &'a SyntaxSet,
     pub terminal_width: usize,
     pub width: Option<usize>,
@@ -45,7 +50,7 @@ pub fn get_config<'a>(
     };
 
     let minus_style_modifier = StyleModifier {
-        background: Some(color_from_arg(
+        background: Some(color_from_arg_or_mode_default(
             opt.minus_color.as_ref(),
             is_light_mode,
             style::LIGHT_THEME_MINUS_COLOR,
@@ -60,7 +65,7 @@ pub fn get_config<'a>(
     };
 
     let minus_emph_style_modifier = StyleModifier {
-        background: Some(color_from_arg(
+        background: Some(color_from_arg_or_mode_default(
             opt.minus_emph_color.as_ref(),
             is_light_mode,
             style::LIGHT_THEME_MINUS_EMPH_COLOR,
@@ -75,7 +80,7 @@ pub fn get_config<'a>(
     };
 
     let plus_style_modifier = StyleModifier {
-        background: Some(color_from_arg(
+        background: Some(color_from_arg_or_mode_default(
             opt.plus_color.as_ref(),
             is_light_mode,
             style::LIGHT_THEME_PLUS_COLOR,
@@ -86,7 +91,7 @@ pub fn get_config<'a>(
     };
 
     let plus_emph_style_modifier = StyleModifier {
-        background: Some(color_from_arg(
+        background: Some(color_from_arg_or_mode_default(
             opt.plus_emph_color.as_ref(),
             is_light_mode,
             style::LIGHT_THEME_PLUS_EMPH_COLOR,
@@ -103,6 +108,9 @@ pub fn get_config<'a>(
         minus_emph_style_modifier,
         plus_style_modifier,
         plus_emph_style_modifier,
+        commit_color: color_from_rgb_or_ansi_code(&opt.commit_color),
+        file_color: color_from_rgb_or_ansi_code(&opt.file_color),
+        hunk_color: color_from_rgb_or_ansi_code(&opt.hunk_color),
         terminal_width,
         width,
         tab_width: opt.tab_width,
@@ -168,18 +176,32 @@ fn valid_theme_name_or_none(theme_name: Option<&String>, theme_set: &ThemeSet) -
     }
 }
 
-fn color_from_arg(
+fn color_from_rgb_or_ansi_code(s: &str) -> Color {
+    let die = || {
+        eprintln!("Invalid color: {}", s);
+        process::exit(1);
+    };
+    if s.starts_with("#") {
+        Color::from_str(s).unwrap_or_else(|_| die())
+    } else {
+        paint::color_from_ansi_name(s).unwrap_or_else(die)
+    }
+}
+
+fn color_from_arg_or_mode_default(
     arg: Option<&String>,
     is_light_mode: bool,
     light_theme_default: Color,
     dark_theme_default: Color,
 ) -> Color {
-    arg.and_then(|s| Color::from_str(s).ok())
-        .unwrap_or_else(|| {
+    match arg {
+        Some(string) => color_from_rgb_or_ansi_code(&string),
+        None => {
             if is_light_mode {
                 light_theme_default
             } else {
                 dark_theme_default
             }
-        })
+        }
+    }
 }
diff --git a/src/delta.rs b/src/delta.rs
index 7f8aff5a..9c6d16f9 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -1,6 +1,5 @@
 use std::io::Write;
 
-use ansi_term::Colour::{Blue, Yellow};
 use console::strip_ansi_codes;
 use unicode_segmentation::UnicodeSegmentation;
 
@@ -8,7 +7,7 @@ use crate::bat::assets::HighlightingAssets;
 use crate::cli;
 use crate::config::Config;
 use crate::draw;
-use crate::paint::Painter;
+use crate::paint::{self, Painter};
 use crate::parse;
 use crate::style;
 
@@ -203,7 +202,7 @@ fn handle_commit_meta_header_line(
         painter.writer,
         line,
         config.terminal_width,
-        Yellow.normal(),
+        config.commit_color,
         true,
     )?;
     Ok(())
@@ -232,13 +231,12 @@ fn handle_generic_file_meta_header_line(
         cli::SectionStyle::Underline => draw::write_underlined,
         cli::SectionStyle::Plain => panic!(),
     };
-    let ansi_style = Blue.normal();
     writeln!(painter.writer)?;
     draw_fn(
         painter.writer,
-        &ansi_style.paint(line),
+        &paint::paint_text_foreground(line, config.file_color),
         config.terminal_width,
-        ansi_style,
+        config.file_color,
         false,
     )?;
     Ok(())
@@ -254,7 +252,6 @@ fn handle_hunk_meta_line(
         cli::SectionStyle::Underline => draw::write_underlined,
         cli::SectionStyle::Plain => panic!(),
     };
-    let ansi_style = Blue.normal();
     let (raw_code_fragment, line_number) = parse::parse_hunk_metadata(&line);
     let code_fragment = prepare(raw_code_fragment, config.tab_width, false);
     if !code_fragment.is_empty() {
@@ -280,12 +277,16 @@ fn handle_hunk_meta_line(
             painter.writer,
             &painter.output_buffer,
             config.terminal_width,
-            ansi_style,
+            config.hunk_color,
             false,
         )?;
         painter.output_buffer.clear();
     }
-    writeln!(painter.writer, "\n{}", ansi_style.paint(line_number))?;
+    writeln!(
+        painter.writer,
+        "\n{}",
+        paint::paint_text_foreground(line_number, config.hunk_color)
+    )?;
     Ok(())
 }
 
@@ -617,8 +618,11 @@ mod tests {
             theme: None,
             highlight_removed: false,
             commit_style: cli::SectionStyle::Plain,
+            commit_color: "Yellow".to_string(),
             file_style: cli::SectionStyle::Underline,
+            file_color: "Blue".to_string(),
             hunk_style: cli::SectionStyle::Box,
+            hunk_color: "blue".to_string(),
             width: Some("variable".to_string()),
             tab_width: 4,
             show_background_colors: false,
diff --git a/src/draw.rs b/src/draw.rs
index 9487c557..751f99f9 100644
--- a/src/draw.rs
+++ b/src/draw.rs
@@ -1,17 +1,19 @@
 use std::io::Write;
 
-use ansi_term::Style;
 use box_drawing;
 use console::strip_ansi_codes;
+use syntect::highlighting::Color;
 use unicode_segmentation::UnicodeSegmentation;
 
+use crate::paint;
+
 /// Write text to stream, surrounded by a box, leaving the cursor just
 /// beyond the bottom right corner.
 pub fn write_boxed(
     writer: &mut dyn Write,
     text: &str,
     _line_width: usize, // ignored
-    line_style: Style,
+    color: Color,
     heavy: bool,
 ) -> std::io::Result<()> {
     let up_left = if heavy {
@@ -20,8 +22,8 @@ pub fn write_boxed(
         box_drawing::light::UP_LEFT
     };
     let box_width = strip_ansi_codes(text).graphemes(true).count() + 1;
-    write_boxed_partial(writer, text, box_width, line_style, heavy)?;
-    write!(writer, "{}", line_style.paint(up_left))?;
+    write_boxed_partial(writer, text, box_width, color, heavy)?;
+    write!(writer, "{}", paint::paint_text_foreground(up_left, color))?;
     Ok(())
 }
 
@@ -31,11 +33,11 @@ pub fn write_boxed_with_line(
     writer: &mut dyn Write,
     text: &str,
     line_width: usize,
-    line_style: Style,
+    color: Color,
     heavy: bool,
 ) -> std::io::Result<()> {
     let box_width = strip_ansi_codes(text).graphemes(true).count() + 1;
-    write_boxed_with_horizontal_whisker(writer, text, box_width, line_style, heavy)?;
+    write_boxed_with_horizontal_whisker(writer, text, box_width, color, heavy)?;
     write_horizontal_line(
         writer,
         if line_width > box_width {
@@ -43,7 +45,7 @@ pub fn write_boxed_with_line(
         } else {
             0
         },
-        line_style,
+        color,
         heavy,
     )?;
     write!(writer, "\n")?;
@@ -54,11 +56,11 @@ pub fn write_underlined(
     writer: &mut dyn Write,
     text: &str,
     line_width: usize,
-    line_style: Style,
+    color: Color,
     heavy: bool,
 ) -> std::io::Result<()> {
-    writeln!(writer, "{}", line_style.paint(text))?;
-    write_horizontal_line(writer, line_width - 1, line_style, heavy)?;
+    writeln!(writer, "{}", paint::paint_text_foreground(text, color))?;
+    write_horizontal_line(writer, line_width - 1, color, heavy)?;
     write!(writer, "\n")?;
     Ok(())
 }
@@ -66,7 +68,7 @@ pub fn write_underlined(
 fn write_horizontal_line(
     writer: &mut dyn Write,
     line_width: usize,
-    line_style: Style,
+    color: Color,
     heavy: bool,
 ) -> std::io::Result<()> {
     let horizontal = if heavy {
@@ -77,7 +79,7 @@ fn write_horizontal_line(
     write!(
         writer,
         "{}",
-        line_style.paint(horizontal.repeat(line_width),)
+        paint::paint_text_foreground(&horizontal.repeat(line_width), color)
     )
 }
 
@@ -85,7 +87,7 @@ pub fn write_boxed_with_horizontal_whisker(
     writer: &mut dyn Write,
     text: &str,
     box_width: usize,
-    line_style: Style,
+    color: Color,
     heavy: bool,
 ) -> std::io::Result<()> {
     let up_horizontal = if heavy {
@@ -93,8 +95,12 @@ pub fn write_boxed_with_horizontal_whisker(
     } else {
         box_drawing::light::UP_HORIZONTAL
     };
-    write_boxed_partial(writer, text, box_width, line_style, heavy)?;
-    write!(writer, "{}", line_style.paint(up_horizontal))?;
+    write_boxed_partial(writer, text, box_width, color, heavy)?;
+    write!(
+        writer,
+        "{}",
+        paint::paint_text_foreground(up_horizontal, color)
+    )?;
     Ok(())
 }
 
@@ -102,7 +108,7 @@ fn write_boxed_partial(
     writer: &mut dyn Write,
     text: &str,
     box_width: usize,
-    line_style: Style,
+    color: Color,
     heavy: bool,
 ) -> std::io::Result<()> {
     let horizontal = if heavy {
@@ -125,10 +131,10 @@ fn write_boxed_partial(
     write!(
         writer,
         "{}{}\n{} {}\n{}",
-        line_style.paint(&horizontal_edge),
-        line_style.paint(down_left),
-        line_style.paint(text),
-        line_style.paint(vertical),
-        line_style.paint(&horizontal_edge),
+        paint::paint_text_foreground(&horizontal_edge, color),
+        paint::paint_text_foreground(down_left, color),
+        paint::paint_text_foreground(text, color),
+        paint::paint_text_foreground(vertical, color),
+        paint::paint_text_foreground(&horizontal_edge, color),
     )
 }
diff --git a/src/paint.rs b/src/paint.rs
index 5aec3a15..cf6968e1 100644
--- a/src/paint.rs
+++ b/src/paint.rs
@@ -1,4 +1,5 @@
 use std::io::Write;
+use std::str::FromStr;
 
 use syntect::easy::HighlightLines;
 use syntect::highlighting::{Color, Style, StyleModifier};
@@ -204,23 +205,31 @@ impl<'a> Painter<'a> {
     }
 }
 
-/// Write section text to buffer with color escape codes.
+/// Write section text to buffer with shell escape codes specifying foreground and background color.
 pub fn paint_text(text: &str, style: Style, output_buffer: &mut String) {
     if text.is_empty() {
         return;
     }
     if style.background != style::NO_COLOR {
-        output_buffer.push_str(&get_color_code(style.background, false));
+        output_buffer.push_str(&get_color_escape_sequence(style.background, false));
     }
     if style.foreground != style::NO_COLOR {
-        output_buffer.push_str(&get_color_code(style.foreground, true));
+        output_buffer.push_str(&get_color_escape_sequence(style.foreground, true));
     }
     output_buffer.push_str(text);
 }
 
-/// ANSI color escape code.
-// See https://github.com/ogham/rust-ansi-term/blob/ff7eba98d55ad609c7fcc8c7bb0859b37c7545cc/src/ansi.rs#L82-L112
-fn get_color_code(color: Color, foreground: bool) -> String {
+/// Return text together with shell escape codes specifying the foreground color.
+pub fn paint_text_foreground(text: &str, color: Color) -> String {
+    format!("{}{}", get_color_escape_sequence(color, true), text)
+}
+
+/// Return shell escape sequence specifying either an RGB color, or a user-customizable 8-bit ANSI
+/// color code.
+// See
+// https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
+// https://github.com/ogham/rust-ansi-term/blob/ff7eba98d55ad609c7fcc8c7bb0859b37c7545cc/src/ansi.rs#L82-L112
+fn get_color_escape_sequence(color: Color, foreground: bool) -> String {
     if color.a == 0 {
         // See https://github.com/sharkdp/bat/pull/543
         format!("\x1b[{};5;{}m", if foreground { 38 } else { 48 }, color.r)
@@ -235,6 +244,42 @@ fn get_color_code(color: Color, foreground: bool) -> String {
     }
 }
 
+// See
+// https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
+pub fn ansi_color_name_to_number(name: &str) -> Option<u8> {
+    match name.to_lowercase().as_ref() {
+        "black" => Some(0),
+        "red" => Some(1),
+        "green" => Some(2),
+        "yellow" => Some(3),
+        "blue" => Some(4),
+        "magenta" => Some(5),
+        "purple" => Some(5),
+        "cyan" => Some(6),
+        "white" => Some(7),
+        "bright-black" => Some(8),
+        "bright-red" => Some(9),
+        "bright-green" => Some(10),
+        "bright-yellow" => Some(11),
+        "bright-blue" => Some(12),
+        "bright-magenta" => Some(13),
+        "bright-purple" => Some(13),
+        "bright-cyan" => Some(14),
+        "bright-white" => Some(15),
+        _ => None,
+    }
+}
+
+pub fn color_from_ansi_name(name: &str) -> Option<Color> {
+    ansi_color_name_to_number(name).and_then(|n| Some(color_from_ansi_number(n)))
+}
+
+/// Convert 8-bit ANSI code to #RGBA string with ANSI code in red channel and 0 in alpha channel.
+// See https://github.com/sharkdp/bat/pull/543
+pub fn color_from_ansi_number(n: u8) -> Color {
+    Color::from_str(&format!("#{:02x}000000", n)).unwrap()
+}
+
 mod superimpose_style_sections {
     use syntect::highlighting::{Style, StyleModifier};