cli: show colors in +list-colors if possible (#8393)

Fixes #8386

This is a fairly simple implementaion, there's no interactivity or
searching. It will adapt the number of columns to the available width of
the display though.

Will fallback to a plain text dump if there's no tty or the `--plain`
argument is specified on the CLI.

<img width="2112" height="1278" alt="image"
src="https://github.com/user-attachments/assets/0dbeec72-2092-4ed5-b1ed-0df43e5c64a3"
/>

src/cli/list_colors.zig

@@ -1,13 +1,20 @@
 const std = @import("std");
+const builtin = @import("builtin");
+const Allocator = std.mem.Allocator;
 const Action = @import("ghostty.zig").Action;
 const args = @import("args.zig");
 const x11_color = @import("../terminal/main.zig").x11_color;
+const vaxis = @import("vaxis");
+const tui = @import("tui.zig");
 
 pub const Options = struct {
     pub fn deinit(self: Options) void {
         _ = self;
     }
 
+    /// If `true`, print without formatting even if printing to a tty
+    plain: bool = false,
+
     /// Enables "-h" and "--help" to work.
     pub fn help(self: Options) !void {
         _ = self;
@@ -17,7 +24,12 @@ pub const Options = struct {
 
 /// The `list-colors` command is used to list all the named RGB colors in
 /// Ghostty.
-pub fn run(alloc: std.mem.Allocator) !u8 {
+///
+/// Flags:
+///
+///   * `--plain`: will disable formatting and make the output more
+///     friendly for Unix tooling. This is default when not printing to a tty.
+pub fn run(alloc: Allocator) !u8 {
     var opts: Options = .{};
     defer opts.deinit();
 
@@ -27,7 +39,7 @@ pub fn run(alloc: std.mem.Allocator) !u8 {
         try args.parse(Options, alloc, &opts, &iter);
     }
 
-    const stdout = std.io.getStdOut().writer();
+    const stdout = std.io.getStdOut();
 
     var keys = std.ArrayList([]const u8).init(alloc);
     defer keys.deinit();
@@ -39,15 +51,163 @@ pub fn run(alloc: std.mem.Allocator) !u8 {
         }
     }.lessThan);
 
-    for (keys.items) |name| {
-        const rgb = x11_color.map.get(name).?;
-        try stdout.print("{s} = #{x:0>2}{x:0>2}{x:0>2}\n", .{
-            name,
-            rgb.r,
-            rgb.g,
-            rgb.b,
-        });
+    // Despite being under the posix namespace, this also works on Windows as of zig 0.13.0
+    if (tui.can_pretty_print and !opts.plain and std.posix.isatty(stdout.handle)) {
+        var arena = std.heap.ArenaAllocator.init(alloc);
+        defer arena.deinit();
+        return prettyPrint(arena.allocator(), keys.items);
+    } else {
+        const writer = stdout.writer();
+        for (keys.items) |name| {
+            const rgb = x11_color.map.get(name).?;
+            try writer.print("{s} = #{x:0>2}{x:0>2}{x:0>2}\n", .{
+                name,
+                rgb.r,
+                rgb.g,
+                rgb.b,
+            });
+        }
     }
 
     return 0;
 }
+
+fn prettyPrint(alloc: Allocator, keys: [][]const u8) !u8 {
+    // Set up vaxis
+    var tty = try vaxis.Tty.init();
+    defer tty.deinit();
+    var vx = try vaxis.init(alloc, .{});
+    defer vx.deinit(alloc, tty.anyWriter());
+
+    // We know we are ghostty, so let's enable mode 2027. Vaxis normally does this but you need an
+    // event loop to auto-enable it.
+    vx.caps.unicode = .unicode;
+    try tty.anyWriter().writeAll(vaxis.ctlseqs.unicode_set);
+    defer tty.anyWriter().writeAll(vaxis.ctlseqs.unicode_reset) catch {};
+
+    var buf_writer = tty.bufferedWriter();
+    const writer = buf_writer.writer().any();
+
+    const winsize: vaxis.Winsize = switch (builtin.os.tag) {
+        // We use some default, it doesn't really matter for what
+        // we're doing because we don't do any wrapping.
+        .windows => .{
+            .rows = 24,
+            .cols = 120,
+            .x_pixel = 1024,
+            .y_pixel = 768,
+        },
+
+        else => try vaxis.Tty.getWinsize(tty.fd),
+    };
+    try vx.resize(alloc, tty.anyWriter(), winsize);
+
+    const win = vx.window();
+
+    var max_name_len: usize = 0;
+    for (keys) |name| {
+        if (name.len > max_name_len) max_name_len = name.len;
+    }
+
+    // max name length plus " = #RRGGBB XX" plus "  " gutter between columns
+    const column_size = max_name_len + 15;
+    // add two to take into account lack of gutter after last column
+    const columns: usize = @divFloor(win.width + 2, column_size);
+
+    var i: usize = 0;
+    const step = @divFloor(keys.len, columns) + 1;
+    while (i < step) : (i += 1) {
+        win.clear();
+
+        var result: vaxis.Window.PrintResult = .{ .col = 0, .row = 0, .overflow = false };
+
+        for (0..columns) |j| {
+            const k = i + (step * j);
+            if (k >= keys.len) continue;
+
+            const name = keys[k];
+            const rgb = x11_color.map.get(name).?;
+
+            const style1: vaxis.Style = .{
+                .fg = .{
+                    .rgb = .{ rgb.r, rgb.g, rgb.b },
+                },
+            };
+            const style2: vaxis.Style = .{
+                .fg = .{
+                    .rgb = .{ rgb.r, rgb.g, rgb.b },
+                },
+                .bg = .{
+                    .rgb = .{ rgb.r, rgb.g, rgb.b },
+                },
+            };
+
+            // name of the color
+            result = win.printSegment(
+                .{ .text = name },
+                .{ .col_offset = result.col },
+            );
+            // push the color data to the end of the column
+            for (0..max_name_len - name.len) |_| {
+                result = win.printSegment(
+                    .{ .text = " " },
+                    .{ .col_offset = result.col },
+                );
+            }
+            result = win.printSegment(
+                .{ .text = " = " },
+                .{ .col_offset = result.col },
+            );
+            // rgb triple
+            result = win.printSegment(.{
+                .text = try std.fmt.allocPrint(
+                    alloc,
+                    "#{x:0>2}{x:0>2}{x:0>2}",
+                    .{
+                        rgb.r, rgb.g, rgb.b,
+                    },
+                ),
+                .style = style1,
+            }, .{ .col_offset = result.col });
+            result = win.printSegment(
+                .{ .text = " " },
+                .{ .col_offset = result.col },
+            );
+            // colored block
+            result = win.printSegment(
+                .{
+                    .text = "  ",
+                    .style = style2,
+                },
+                .{ .col_offset = result.col },
+            );
+            // add the gutter if needed
+            if (j + 1 < columns) {
+                result = win.printSegment(
+                    .{
+                        .text = "  ",
+                    },
+                    .{ .col_offset = result.col },
+                );
+            }
+        }
+
+        // clear the rest of the line
+        while (result.col != 0) {
+            result = win.printSegment(
+                .{
+                    .text = " ",
+                },
+                .{ .col_offset = result.col },
+            );
+        }
+
+        // output the data
+        try vx.prettyPrint(writer);
+    }
+
+    // be sure to flush!
+    try buf_writer.flush();
+
+    return 0;
+}