Provide CLI options for all colors

- Fixes #99, #103
- Support both RGB and ANSI codes
- Eliminate (almost) ansi_term crate in favor of syntect for representing colors

src/cli.rs

@@ -10,7 +10,22 @@ 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 accept an RGB hex string. An example of passing an RGB hex string is
+--plus-color=\"#002800\".
+
+It is also possible to specify one of the 16 ANSI terminal color codes. To do this, pass an RGBA
+hex string, with the alpha channel set to 00, and use the red channel to specify the ANSI terminal
+color code. The blue and green channels are ignored. For example, to specify ANSI terminal code
+34 (blue), one could pass --plus-color=\"#12000000\".
+"
+)]
 pub struct Opt {
     /// Use colors appropriate for a light terminal background. For
     /// more control, see --theme, --plus-color, and --minus-color.
@@ -54,16 +69,28 @@ pub struct Opt {
     /// are: plain, box.
     pub commit_style: SectionStyle,
 
+    #[structopt(long = "commit-color", default_value = "33")]
+    /// Color for commit section of git output. See below for how to specify colors.
+    pub commit_color: String,
+
     #[structopt(long = "file-style", default_value = "underline")]
     /// Formatting style for file section of git output. Options
     /// are: plain, box, underline.
     pub file_style: SectionStyle,
 
+    #[structopt(long = "file-color", default_value = "34")]
+    /// Color for file section of git output. See below for how to specify colors.
+    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 = "34")]
+    /// Color for the hunk-marker section of git output. See below for how to specify colors.
+    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

src/config.rs

@@ -5,6 +5,7 @@ use syntect::parsing::SyntaxSet;
 
 use crate::cli;
 use crate::env;
+use crate::paint;
 use crate::style;
 
 pub struct Config<'a> {
@@ -14,6 +15,9 @@ 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 +49,7 @@ 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 +64,7 @@ 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 +79,7 @@ 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 +90,7 @@ 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 +107,9 @@ 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,
@@ -168,7 +175,14 @@ 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 {
+    match s.len() {
+        2 => paint::color_from_ansi_code(s),
+        _ => Color::from_str(s).expect(&format!("Invalid color: {}", s)),
+    }
+}
+
+fn color_from_arg_or_mode_default(
     arg: Option<&String>,
     is_light_mode: bool,
     light_theme_default: Color,

src/delta.rs

@@ -1,14 +1,13 @@
 use std::io::Write;
 
-use ansi_term::Colour::{Blue, Yellow};
 use console::strip_ansi_codes;
 use unicode_segmentation::UnicodeSegmentation;
 
 use crate::bat::assets::HighlightingAssets;
 use crate::cli;
 use crate::config::Config;
 use crate::draw;
-use crate::paint::Painter;
+use crate::paint::{paint, 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(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(line_number, config.hunk_color)
+    )?;
     Ok(())
 }
 
@@ -617,8 +618,11 @@ mod tests {
             theme: None,
             highlight_removed: false,
             commit_style: cli::SectionStyle::Plain,
+            commit_color: "33".to_string(),
             file_style: cli::SectionStyle::Underline,
+            file_color: "34".to_string(),
             hunk_style: cli::SectionStyle::Box,
+            hunk_color: "34".to_string(),
             width: Some("variable".to_string()),
             tab_width: 4,
             show_background_colors: false,

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::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(up_left, color))?;
     Ok(())
 }
 
@@ -31,19 +33,19 @@ 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 {
             line_width - box_width - 1
         } else {
             0
         },
-        line_style,
+        color,
         heavy,
     )?;
     write!(writer, "\n")?;
@@ -54,55 +56,51 @@ 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(text, color))?;
+    write_horizontal_line(writer, line_width - 1, color, heavy)?;
     write!(writer, "\n")?;
     Ok(())
 }
 
 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 {
         box_drawing::heavy::HORIZONTAL
     } else {
         box_drawing::light::HORIZONTAL
     };
-    write!(
-        writer,
-        "{}",
-        line_style.paint(horizontal.repeat(line_width),)
-    )
+    write!(writer, "{}", paint(&horizontal.repeat(line_width), color))
 }
 
 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 {
         box_drawing::heavy::UP_HORIZONTAL
     } 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(up_horizontal, color))?;
     Ok(())
 }
 
 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 +123,10 @@ 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(&horizontal_edge, color),
+        paint(down_left, color),
+        paint(text, color),
+        paint(vertical, color),
+        paint(&horizontal_edge, color),
     )
 }

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};
@@ -204,6 +205,11 @@ impl<'a> Painter<'a> {
     }
 }
 
+/// Return text together with shell escape codes specifying the color.
+pub fn paint(text: &str, color: Color) -> String {
+    format!("{}{}", get_color_code(color, true), text)
+}
+
 /// Write section text to buffer with color escape codes.
 pub fn paint_text(text: &str, style: Style, output_buffer: &mut String) {
     if text.is_empty() {
@@ -218,7 +224,7 @@ pub fn paint_text(text: &str, style: Style, output_buffer: &mut String) {
     output_buffer.push_str(text);
 }
 
-/// ANSI color escape code.
+/// Return shell escape codes specifying either an RGB color, or a user-customizable ANSI color 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 {
     if color.a == 0 {
@@ -235,6 +241,16 @@ fn get_color_code(color: Color, foreground: bool) -> String {
     }
 }
 
+/// 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_code(s: &str) -> Color {
+    Color::from_str(&format!(
+        "#{:02x}000000",
+        s.parse::<u8>().expect(&format!("Invalid color: {}", s)),
+    ))
+    .unwrap()
+}
+
 mod superimpose_style_sections {
     use syntect::highlighting::{Style, StyleModifier};