Added bold-color option (#7168)

As discussed in https://github.com/ghostty-org/ghostty/discussions/3134

To allow for the option to render bold text in a different colour for
better visibility as an extension of `bold-is-bright`.

This is a feature that is available in other terminals.

src/config.zig

@@ -14,6 +14,7 @@ pub const entryFormatter = formatter.entryFormatter;
 pub const formatEntry = formatter.formatEntry;
 
 // Field types
+pub const BoldColor = Config.BoldColor;
 pub const ClipboardAccess = Config.ClipboardAccess;
 pub const Command = Config.Command;
 pub const ConfirmCloseSurface = Config.ConfirmCloseSurface;

src/config/Config.zig

@@ -69,6 +69,10 @@ pub const compatibility = std.StaticStringMap(
     // this behavior. This applies to selection too.
     .{ "cursor-invert-fg-bg", compatCursorInvertFgBg },
     .{ "selection-invert-fg-bg", compatSelectionInvertFgBg },
+
+    // Ghostty 1.2 merged `bold-is-bright` into the new `bold-color`
+    // by setting the value to "bright".
+    .{ "bold-is-bright", compatBoldIsBright },
 });
 
 /// The font families to use.
@@ -2804,8 +2808,24 @@ else
 /// notifications using certain escape sequences such as OSC 9 or OSC 777.
 @"desktop-notifications": bool = true,
 
-/// If `true`, the bold text will use the bright color palette.
-@"bold-is-bright": bool = false,
+/// Modifies the color used for bold text in the terminal.
+///
+/// This can be set to a specific color, using the same format as
+/// `background` or `foreground` (e.g. `#RRGGBB` but other formats
+/// are also supported; see the aforementioned documentation). If a
+/// specific color is set, this color will always be used for all
+/// bold text regardless of the terminal's color scheme.
+///
+/// This can also be set to `bright`, which uses the bright color palette
+/// for bold text. For example, if the text is red, then the bold will
+/// use the bright red color. The terminal palette is set with `palette`
+/// but can also be overridden by the terminal application itself using
+/// escape sequences such as OSC 4. (Since Ghostty 1.2.0, the previous
+/// configuration `bold-is-bright` is deprecated and replaced by this
+/// usage).
+///
+/// Available since Ghostty 1.2.0.
+@"bold-color": ?BoldColor = null,
 
 /// This will be used to set the `TERM` environment variable.
 /// HACK: We set this with an `xterm` prefix because vim uses that to enable key
@@ -3910,6 +3930,23 @@ fn compatSelectionInvertFgBg(
     return true;
 }
 
+fn compatBoldIsBright(
+    self: *Config,
+    alloc: Allocator,
+    key: []const u8,
+    value_: ?[]const u8,
+) bool {
+    _ = alloc;
+    assert(std.mem.eql(u8, key, "bold-is-bright"));
+
+    const set = cli.args.parseBool(value_ orelse "t") catch return false;
+    if (set) {
+        self.@"bold-color" = .bright;
+    }
+
+    return true;
+}
+
 /// Create a shallow copy of this config. This will share all the memory
 /// allocated with the previous config but will have a new arena for
 /// any changes or new allocations. The config should have `deinit`
@@ -4537,6 +4574,58 @@ pub const TerminalColor = union(enum) {
     }
 };
 
+/// Represents color values that can be used for bold. See `bold-color`.
+pub const BoldColor = union(enum) {
+    color: Color,
+    bright,
+
+    pub fn parseCLI(input_: ?[]const u8) !BoldColor {
+        const input = input_ orelse return error.ValueRequired;
+        if (std.mem.eql(u8, input, "bright")) return .bright;
+        return .{ .color = try Color.parseCLI(input) };
+    }
+
+    /// Used by Formatter
+    pub fn formatEntry(self: BoldColor, formatter: anytype) !void {
+        switch (self) {
+            .color => try self.color.formatEntry(formatter),
+            .bright => try formatter.formatEntry(
+                [:0]const u8,
+                @tagName(self),
+            ),
+        }
+    }
+
+    test "parseCLI" {
+        const testing = std.testing;
+
+        try testing.expectEqual(
+            BoldColor{ .color = Color{ .r = 78, .g = 42, .b = 132 } },
+            try BoldColor.parseCLI("#4e2a84"),
+        );
+        try testing.expectEqual(
+            BoldColor{ .color = Color{ .r = 0, .g = 0, .b = 0 } },
+            try BoldColor.parseCLI("black"),
+        );
+        try testing.expectEqual(
+            BoldColor.bright,
+            try BoldColor.parseCLI("bright"),
+        );
+
+        try testing.expectError(error.InvalidValue, BoldColor.parseCLI("a"));
+    }
+
+    test "formatConfig" {
+        const testing = std.testing;
+        var buf = std.ArrayList(u8).init(testing.allocator);
+        defer buf.deinit();
+
+        var sc: BoldColor = .bright;
+        try sc.formatEntry(formatterpkg.entryFormatter("a", buf.writer()));
+        try testing.expectEqualSlices(u8, "a = bright\n", buf.items);
+    }
+};
+
 pub const ColorList = struct {
     const Self = @This();
 
@@ -8236,3 +8325,23 @@ test "compatibility: removed selection-invert-fg-bg" {
         );
     }
 }
+
+test "compatibility: removed bold-is-bright" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    {
+        var cfg = try Config.default(alloc);
+        defer cfg.deinit();
+        var it: TestIterator = .{ .data = &.{
+            "--bold-is-bright",
+        } };
+        try cfg.loadIter(alloc, &it);
+        try cfg.finalize();
+
+        try testing.expectEqual(
+            BoldColor.bright,
+            cfg.@"bold-color",
+        );
+    }
+}

src/renderer/generic.zig

@@ -519,7 +519,7 @@ pub fn Renderer(comptime GraphicsAPI: type) type {
             foreground: terminal.color.RGB,
             selection_background: ?configpkg.Config.TerminalColor,
             selection_foreground: ?configpkg.Config.TerminalColor,
-            bold_is_bright: bool,
+            bold_color: ?configpkg.BoldColor,
             min_contrast: f32,
             padding_color: configpkg.WindowPaddingColor,
             custom_shaders: configpkg.RepeatablePath,
@@ -580,7 +580,8 @@ pub fn Renderer(comptime GraphicsAPI: type) type {
 
                     .background = config.background.toTerminalRGB(),
                     .foreground = config.foreground.toTerminalRGB(),
-                    .bold_is_bright = config.@"bold-is-bright",
+                    .bold_color = config.@"bold-color",
+
                     .min_contrast = @floatCast(config.@"minimum-contrast"),
                     .padding_color = config.@"window-padding-color",
 
@@ -2540,10 +2541,11 @@ pub fn Renderer(comptime GraphicsAPI: type) type {
                     // the cell style (SGR), before applying any additional
                     // configuration, inversions, selections, etc.
                     const bg_style = style.bg(cell, color_palette);
-                    const fg_style = style.fg(
-                        color_palette,
-                        self.config.bold_is_bright,
-                    ) orelse self.foreground_color orelse self.default_foreground_color;
+                    const fg_style = style.fg(.{
+                        .default = self.foreground_color orelse self.default_foreground_color,
+                        .palette = color_palette,
+                        .bold = self.config.bold_color,
+                    });
 
                     // The final background color for the cell.
                     const bg = bg: {
@@ -2801,10 +2803,11 @@ pub fn Renderer(comptime GraphicsAPI: type) type {
                         .@"cell-background",
                         => |_, tag| {
                             const sty = screen.cursor.page_pin.style(screen.cursor.page_cell);
-                            const fg_style = sty.fg(
-                                color_palette,
-                                self.config.bold_is_bright,
-                            ) orelse self.foreground_color orelse self.default_foreground_color;
+                            const fg_style = sty.fg(.{
+                                .default = self.foreground_color orelse self.default_foreground_color,
+                                .palette = color_palette,
+                                .bold = self.config.bold_color,
+                            });
                             const bg_style = sty.bg(
                                 screen.cursor.page_cell,
                                 color_palette,
@@ -2852,7 +2855,11 @@ pub fn Renderer(comptime GraphicsAPI: type) type {
                         }
 
                         const sty = screen.cursor.page_pin.style(screen.cursor.page_cell);
-                        const fg_style = sty.fg(color_palette, self.config.bold_is_bright) orelse self.foreground_color orelse self.default_foreground_color;
+                        const fg_style = sty.fg(.{
+                            .default = self.foreground_color orelse self.default_foreground_color,
+                            .palette = color_palette,
+                            .bold = self.config.bold_color,
+                        });
                         const bg_style = sty.bg(screen.cursor.page_cell, color_palette) orelse self.background_color orelse self.default_background_color;
 
                         break :blk switch (txt) {

src/terminal/style.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
 const assert = std.debug.assert;
+const configpkg = @import("../config.zig");
 const color = @import("color.zig");
 const sgr = @import("sgr.zig");
 const page = @import("page.zig");
@@ -115,24 +116,68 @@ pub const Style = struct {
         };
     }
 
-    /// Returns the fg color for a cell with this style given the palette.
+    pub const Fg = struct {
+        /// The default color to use if the style doesn't specify a
+        /// foreground color and no configuration options override
+        /// it.
+        default: color.RGB,
+
+        /// The current color palette. Required to map palette indices to
+        /// real color values.
+        palette: *const color.Palette,
+
+        /// If specified, the color to use for bold text.
+        bold: ?configpkg.BoldColor = null,
+    };
+
+    /// Returns the fg color for a cell with this style given the palette
+    /// and various configuration options.
     pub fn fg(
         self: Style,
-        palette: *const color.Palette,
-        bold_is_bright: bool,
-    ) ?color.RGB {
+        opts: Fg,
+    ) color.RGB {
+        // Note we don't pull the bold check to the top-level here because
+        // we don't want to duplicate the conditional multiple times since
+        // certain colors require more checks (e.g. `bold_is_bright`).
+
         return switch (self.fg_color) {
-            .none => null,
-            .palette => |idx| palette: {
-                if (bold_is_bright and self.flags.bold) {
-                    const bright_offset = @intFromEnum(color.Name.bright_black);
-                    if (idx < bright_offset)
-                        break :palette palette[idx + bright_offset];
+            .none => default: {
+                if (self.flags.bold) {
+                    if (opts.bold) |bold| switch (bold) {
+                        .bright => {},
+                        .color => |v| break :default v.toTerminalRGB(),
+                    };
                 }
 
-                break :palette palette[idx];
+                break :default opts.default;
+            },
+
+            .palette => |idx| palette: {
+                if (self.flags.bold) {
+                    if (opts.bold) |bold| switch (bold) {
+                        .color => |v| break :palette v.toTerminalRGB(),
+                        .bright => {
+                            const bright_offset = @intFromEnum(color.Name.bright_black);
+                            if (idx < bright_offset) {
+                                break :palette opts.palette[idx + bright_offset];
+                            }
+                        },
+                    };
+                }
+
+                break :palette opts.palette[idx];
+            },
+
+            .rgb => |rgb| rgb: {
+                if (self.flags.bold and rgb.eql(opts.default)) {
+                    if (opts.bold) |bold| switch (bold) {
+                        .color => |v| break :rgb v.toTerminalRGB(),
+                        .bright => {},
+                    };
+                }
+
+                break :rgb rgb;
             },
-            .rgb => |rgb| rgb,
         };
     }