mouse: implement mouse parsing and events

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

build.zig

@@ -20,7 +20,7 @@ pub fn build(b: *std.Build) void {
 
     const exe = b.addExecutable(.{
         .name = "vaxis",
-        .root_source_file = .{ .path = "examples/image.zig" },
+        .root_source_file = .{ .path = "examples/text_input.zig" },
         .target = target,
         .optimize = optimize,
     });

examples/text_input.zig

@@ -11,6 +11,7 @@ const log = std.log.scoped(.main);
 // for a single event loop with exhaustive switching. Booya
 const Event = union(enum) {
     key_press: vaxis.Key,
+    mouse: vaxis.Mouse,
     winsize: vaxis.Winsize,
     focus_in,
     focus_out,

src/Mouse.zig

@@ -13,4 +13,34 @@ pub const Shape = enum {
     cell,
 };
 
-// TODO: mouse support
+pub const Button = enum(u8) {
+    left,
+    middle,
+    right,
+    none,
+    wheel_up = 64,
+    wheel_down = 65,
+    button_8 = 128,
+    button_9 = 129,
+    button_10 = 130,
+    button_11 = 131,
+};
+
+pub const Modifiers = packed struct(u3) {
+    shift: bool = false,
+    alt: bool = false,
+    ctrl: bool = false,
+};
+
+pub const Type = enum {
+    press,
+    release,
+    motion,
+    drag,
+};
+
+col: usize,
+row: usize,
+button: Button,
+mods: Modifiers,
+type: Type,

src/Parser.zig

@@ -2,6 +2,7 @@ const std = @import("std");
 const testing = std.testing;
 const Event = @import("event.zig").Event;
 const Key = @import("Key.zig");
+const Mouse = @import("Mouse.zig");
 const CodePointIterator = @import("ziglyph").CodePointIterator;
 const graphemeBreak = @import("ziglyph").graphemeBreak;
 
@@ -32,6 +33,14 @@ const Sequence = struct {
     empty_state: std.StaticBitSet(16) = std.StaticBitSet(16).initEmpty(),
 };
 
+const mouse_bits = struct {
+    const motion: u8 = 0b00100000;
+    const buttons: u8 = 0b11000011;
+    const shift: u8 = 0b00000100;
+    const alt: u8 = 0b00001000;
+    const ctrl: u8 = 0b00010000;
+};
+
 // the state of the parser
 const State = enum {
     ground,
@@ -226,6 +235,49 @@ pub fn parse(self: *Parser, input: []const u8) !Result {
                             'E' => Key.kp_begin,
                             'F' => Key.end,
                             'H' => Key.home,
+                            'M', 'm' => { // mouse event
+                                const priv = seq.private_indicator orelse {
+                                    log.warn("unhandled csi: CSI {s}", .{input[start + 1 .. i + 1]});
+                                    return .{ .event = null, .n = i + 1 };
+                                };
+                                if (priv != '<') {
+                                    log.warn("unhandled csi: CSI {s}", .{input[start + 1 .. i + 1]});
+                                    return .{ .event = null, .n = i + 1 };
+                                }
+                                if (seq.param_idx != 3) {
+                                    log.warn("unhandled csi: CSI {s}", .{input[start + 1 .. i + 1]});
+                                    return .{ .event = null, .n = i + 1 };
+                                }
+                                const button: Mouse.Button = @enumFromInt(seq.params[0] & mouse_bits.buttons);
+                                const motion = seq.params[0] & mouse_bits.motion > 0;
+                                const shift = seq.params[0] & mouse_bits.shift > 0;
+                                const alt = seq.params[0] & mouse_bits.alt > 0;
+                                const ctrl = seq.params[0] & mouse_bits.ctrl > 0;
+                                const col: usize = seq.params[1] - 1;
+                                const row: usize = seq.params[2] - 1;
+
+                                const mouse = Mouse{
+                                    .button = button,
+                                    .mods = .{
+                                        .shift = shift,
+                                        .alt = alt,
+                                        .ctrl = ctrl,
+                                    },
+                                    .col = col,
+                                    .row = row,
+                                    .type = blk: {
+                                        if (motion and button != Mouse.Button.none) {
+                                            break :blk .drag;
+                                        }
+                                        if (motion and button == Mouse.Button.none) {
+                                            break :blk .motion;
+                                        }
+                                        if (b == 'm') break :blk .release;
+                                        break :blk .press;
+                                    },
+                                };
+                                return .{ .event = .{ .mouse = mouse }, .n = i + 1 };
+                            },
                             'P' => Key.f1,
                             'Q' => Key.f2,
                             'R' => Key.f3,

src/Tty.zig

@@ -157,6 +157,11 @@ pub fn run(
                         vx.postEvent(.{ .key_press = mut_key });
                     }
                 },
+                .mouse => |mouse| {
+                    if (@hasField(EventType, "mouse")) {
+                        vx.postEvent(.{ .mouse = mouse });
+                    }
+                },
                 .focus_in => {
                     if (@hasField(EventType, "focus_in")) {
                         vx.postEvent(.focus_in);

src/event.zig

@@ -1,8 +1,10 @@
 pub const Key = @import("Key.zig");
+pub const Mouse = @import("Mouse.zig");
 
 /// The events that Vaxis emits internally
 pub const Event = union(enum) {
     key_press: Key,
+    mouse: Mouse,
     focus_in,
     focus_out,
     paste_start,

src/main.zig

@@ -6,6 +6,7 @@ pub const Cell = cell.Cell;
 pub const Style = cell.Style;
 
 pub const Key = @import("Key.zig");
+pub const Mouse = @import("Mouse.zig");
 pub const Winsize = @import("Tty.zig").Winsize;
 
 pub const widgets = @import("widgets/main.zig");