core: implement setting colors with OSC 4, 10, and 11

src/renderer/Thread.zig

@@ -262,6 +262,14 @@ fn drainMailbox(self: *Thread) !void {
                 try self.renderer.setFontSize(size);
             },
 
+            .foreground_color => |color| {
+                self.renderer.config.foreground = color;
+            },
+
+            .background_color => |color| {
+                self.renderer.config.background = color;
+            },
+
             .resize => |v| {
                 try self.renderer.setScreenSize(v.screen_size, v.padding);
             },

src/renderer/message.zig

@@ -3,6 +3,7 @@ const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const font = @import("../font/main.zig");
 const renderer = @import("../renderer.zig");
+const terminal = @import("../terminal/main.zig");
 
 /// The messages that can be sent to a renderer thread.
 pub const Message = union(enum) {
@@ -20,6 +21,14 @@ pub const Message = union(enum) {
     /// the size changes.
     font_size: font.face.DesiredSize,
 
+    /// Change the foreground color. This can be done separately from changing
+    /// the config file in response to an OSC 10 command
+    foreground_color: terminal.color.RGB,
+
+    /// Change the background color. This can be done separately from changing
+    /// the config file in response to an OSC 11 command
+    background_color: terminal.color.RGB,
+
     /// Changes the screen size.
     resize: struct {
         /// The full screen (drawable) size. This does NOT include padding.

src/terminal/osc.zig

@@ -105,6 +105,15 @@ pub const Command = union(enum) {
         terminator: Terminator = .st,
     },
 
+    set_default_color: struct {
+        /// OSC 4 sets a palette color, OSC 10 sets the foreground color, OSC 11
+        /// the background color.
+        kind: DefaultColorKind,
+
+        /// The color spec as a string
+        value: []const u8,
+    },
+
     pub const DefaultColorKind = union(enum) {
         foreground,
         background,
@@ -387,7 +396,16 @@ pub const Parser = struct {
 
                     self.complete = true;
                 },
-                else => self.state = .invalid,
+                else => {
+                    self.command = .{ .set_default_color = .{
+                        .kind = .{ .palette = @intCast(self.temp_state.num) },
+                        .value = "",
+                    } };
+
+                    self.state = .string;
+                    self.temp_state = .{ .str = &self.command.set_default_color.value };
+                    self.buf_start = self.buf_idx - 1;
+                },
             },
 
             .@"5" => switch (c) {
@@ -441,7 +459,16 @@ pub const Parser = struct {
                     self.command = .{ .report_default_color = .{ .kind = .foreground } };
                     self.complete = true;
                 },
-                else => self.state = .invalid,
+                else => {
+                    self.command = .{ .set_default_color = .{
+                        .kind = .foreground,
+                        .value = "",
+                    } };
+
+                    self.state = .string;
+                    self.temp_state = .{ .str = &self.command.set_default_color.value };
+                    self.buf_start = self.buf_idx - 1;
+                },
             },
 
             .query_default_bg => switch (c) {
@@ -449,7 +476,16 @@ pub const Parser = struct {
                     self.command = .{ .report_default_color = .{ .kind = .background } };
                     self.complete = true;
                 },
-                else => self.state = .invalid,
+                else => {
+                    self.command = .{ .set_default_color = .{
+                        .kind = .background,
+                        .value = "",
+                    } };
+
+                    self.state = .string;
+                    self.temp_state = .{ .str = &self.command.set_default_color.value };
+                    self.buf_start = self.buf_idx - 1;
+                },
             },
 
             .semantic_prompt => switch (c) {
@@ -949,6 +985,20 @@ test "OSC: report default foreground color" {
     try testing.expectEqual(cmd.report_default_color.terminator, .st);
 }
 
+test "OSC: set foreground color" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "10;rgbi:0.0/0.5/1.0";
+    for (input) |ch| p.next(ch);
+
+    const cmd = p.end('\x07').?;
+    try testing.expect(cmd == .set_default_color);
+    try testing.expectEqual(cmd.set_default_color.kind, .foreground);
+    try testing.expectEqualStrings(cmd.set_default_color.value, "rgbi:0.0/0.5/1.0");
+}
+
 test "OSC: report default background color" {
     const testing = std.testing;
 
@@ -964,6 +1014,20 @@ test "OSC: report default background color" {
     try testing.expectEqual(cmd.report_default_color.terminator, .bel);
 }
 
+test "OSC: set background color" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "11;rgb:f/ff/ffff";
+    for (input) |ch| p.next(ch);
+
+    const cmd = p.end('\x1b').?;
+    try testing.expect(cmd == .set_default_color);
+    try testing.expectEqual(cmd.set_default_color.kind, .background);
+    try testing.expectEqualStrings(cmd.set_default_color.value, "rgb:f/ff/ffff");
+}
+
 test "OSC: get palette color" {
     const testing = std.testing;
 
@@ -977,3 +1041,17 @@ test "OSC: get palette color" {
     try testing.expectEqual(cmd.report_default_color.kind, .{ .palette = 1 });
     try testing.expectEqual(cmd.report_default_color.terminator, .st);
 }
+
+test "OSC: set palette color" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "4;17;rgb:aa/bb/cc";
+    for (input) |ch| p.next(ch);
+
+    const cmd = p.end('\x1b').?;
+    try testing.expect(cmd == .set_default_color);
+    try testing.expectEqual(cmd.set_default_color.kind, .{ .palette = 17 });
+    try testing.expectEqualStrings(cmd.set_default_color.value, "rgb:aa/bb/cc");
+}

src/terminal/stream.zig

@@ -1052,6 +1052,13 @@ pub fn Stream(comptime Handler: type) type {
                     } else log.warn("unimplemented OSC callback: {}", .{cmd});
                 },
 
+                .set_default_color => |v| {
+                    if (@hasDecl(T, "setDefaultColor")) {
+                        try self.handler.setDefaultColor(v.kind, v.value);
+                        return;
+                    } else log.warn("unimplemented OSC callback: {}", .{cmd});
+                },
+
                 else => if (@hasDecl(T, "oscUnimplemented"))
                     try self.handler.oscUnimplemented(cmd)
                 else

src/termio/Exec.zig

@@ -2200,4 +2200,123 @@ const StreamHandler = struct {
         msg.write_small.len = @intCast(resp.len);
         self.messageWriter(msg);
     }
+
+    /// Parse a color from a string of hexadecimal digits or a floating point
+    /// intensity value.
+    ///
+    /// If `intensity` is false, the string can contain 1, 2, 3, or 4 characters
+    /// and represents the color value scaled in 4, 8, 12, or 16 bits,
+    /// respectively.
+    ///
+    /// If `intensity` is true, the string should contain a floating point value
+    /// between 0.0 and 1.0, inclusive.
+    fn parseColor(value: []const u8, intensity: bool) !u8 {
+        if (intensity) {
+            const i = try std.fmt.parseFloat(f64, value);
+            if (i < 0.0 or i > 1.0) {
+                return error.InvalidValue;
+            }
+
+            return @intFromFloat(i * std.math.maxInt(u8));
+        }
+
+        if (value.len == 0 or value.len > 4) {
+            return error.InvalidValue;
+        }
+
+        const color = try std.fmt.parseUnsigned(u16, value, 16);
+        const divisor: usize = switch (value.len) {
+            1 => std.math.maxInt(u4),
+            2 => std.math.maxInt(u8),
+            3 => std.math.maxInt(u12),
+            4 => std.math.maxInt(u16),
+            else => unreachable,
+        };
+
+        return @intCast(color * std.math.maxInt(u8) / divisor);
+    }
+
+    /// Parse a color specification of the form
+    ///
+    ///     rgb:<red>/<green>/<blue>
+    ///
+    ///     <red>, <green>, <blue> := h | hh | hhh | hhhh
+    ///
+    /// where `h` is a single hexadecimal digit.
+    ///
+    /// Alternatively, the form
+    ///
+    ///     rgbi:<red>/<green>/<blue>
+    ///
+    /// where <red>, <green>, and <blue> are floating point values between 0.0
+    /// and 1.0 (inclusive) is also accepted.
+    fn parseColorSpec(value: []const u8) !terminal.color.RGB {
+        const minimum_length = "rgb:a/a/a".len;
+        if (value.len < minimum_length or !std.mem.eql(u8, value[0..3], "rgb")) {
+            return error.InvalidFormat;
+        }
+
+        var i: usize = 3;
+
+        const use_intensity = if (value[i] == 'i') blk: {
+            i += 1;
+            break :blk true;
+        } else false;
+
+        if (value[i] != ':') {
+            return error.InvalidFormat;
+        }
+
+        i += 1;
+
+        const r = r: {
+            const slash_i = std.mem.indexOfScalarPos(u8, value, i, '/') orelse
+                return error.InvalidFormat;
+
+            const r = try parseColor(value[i..slash_i], use_intensity);
+            i = slash_i + 1;
+            break :r r;
+        };
+
+        const g = g: {
+            const slash_i = std.mem.indexOfScalarPos(u8, value, i, '/') orelse
+                return error.InvalidFormat;
+
+            const g = try parseColor(value[i..slash_i], use_intensity);
+            i = slash_i + 1;
+            break :g g;
+        };
+
+        const b = try parseColor(value[i..], use_intensity);
+
+        return terminal.color.RGB{
+            .r = r,
+            .g = g,
+            .b = b,
+        };
+    }
+
+    pub fn setDefaultColor(
+        self: *StreamHandler,
+        kind: terminal.osc.Command.DefaultColorKind,
+        value: []const u8,
+    ) !void {
+        const color = try parseColorSpec(value);
+
+        switch (kind) {
+            .foreground => {
+                self.default_foreground_color = color;
+                _ = self.ev.renderer_mailbox.push(.{
+                    .foreground_color = color,
+                }, .{ .forever = {} });
+            },
+            .background => {
+                self.default_background_color = color;
+                _ = self.ev.renderer_mailbox.push(.{
+                    .background_color = color,
+                }, .{ .forever = {} });
+            },
+            .palette => |i| self.terminal.color_palette[i] = color,
+        }
+    }
 };