Add basic mouse support

examples/mouse/main.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	tea "github.com/charmbracelet/bubbletea"
+)
+
+func main() {
+	p := tea.NewProgram(initialize, update, view)
+
+	p.EnterAltScreen()
+	defer p.ExitAltScreen()
+	p.EnableMouseAllMotion()
+	defer p.DisableMouseAllMotion()
+
+	if err := p.Start(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+type model struct {
+	init       bool
+	mouseEvent tea.MouseEvent
+}
+
+func initialize() (tea.Model, tea.Cmd) {
+	return model{}, nil
+}
+
+func update(msg tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
+	m, _ := mdl.(model)
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		if msg.Type == tea.KeyCtrlC || (msg.Type == tea.KeyRune && msg.Rune == 'q') {
+			return m, tea.Quit
+		}
+
+	case tea.MouseMsg:
+		m.init = true
+		m.mouseEvent = tea.MouseEvent(msg)
+	}
+
+	return m, nil
+}
+
+func view(mdl tea.Model) string {
+	m, _ := mdl.(model)
+
+	s := "Do mouse stuff. When you're done press q to quit.\n\n"
+
+	if m.init {
+		e := m.mouseEvent
+		s += fmt.Sprintf("(X: %d, Y: %d) %s", e.X, e.Y, e)
+	}
+
+	return s
+}

key.go

@@ -227,15 +227,22 @@ var hexes = map[string]Key{
 	"1b5b313b3344": {Type: KeyLeft, Alt: true},
 }
 
-// ReadKey reads keypress input from a TTY and returns a string representation
-// of a key.
-func ReadKey(r io.Reader) (Key, error) {
+// ReadInput reads keypress and mouse input from a TTY and returns a message
+// containing information about the key or mouse event accordingly
+func ReadInput(r io.Reader) (Msg, error) {
 	var buf [256]byte
 
 	// Read and block
 	numBytes, err := r.Read(buf[:])
 	if err != nil {
-		return Key{}, err
+		return nil, err
+	}
+
+	// See if it's a mouse event. For now we're parsing X10-type mouse events
+	// only.
+	mouseEvent, err := parseX10MouseEvent(buf[:numBytes])
+	if err == nil {
+		return MouseMsg(mouseEvent), nil
 	}
 
 	hex := fmt.Sprintf("%x", buf[:numBytes])
@@ -248,17 +255,17 @@ func ReadKey(r io.Reader) (Key, error) {
 	// Get unicode value
 	char, _ := utf8.DecodeRune(buf[:])
 	if char == utf8.RuneError {
-		return Key{}, errors.New("could not decode rune")
+		return nil, errors.New("could not decode rune")
 	}
 
 	// Is it a control character?
 	if numBytes == 1 && char <= keyUS || char == keyDEL {
-		return Key{Type: KeyType(char)}, nil
+		return KeyMsg(Key{Type: KeyType(char)}), nil
 	}
 
 	// Is it a special sequence, like an arrow key?
 	if k, ok := sequences[string(buf[:numBytes])]; ok {
-		return Key{Type: k}, nil
+		return KeyMsg(Key{Type: k}), nil
 	}
 
 	// Is the alt key pressed? The buffer will be prefixed with an escape
@@ -268,11 +275,11 @@ func ReadKey(r io.Reader) (Key, error) {
 		// character.
 		c, _ := utf8.DecodeRune(buf[1:])
 		if c == utf8.RuneError {
-			return Key{}, errors.New("could not decode rune after removing initial escape")
+			return nil, errors.New("could not decode rune after removing initial escape")
 		}
-		return Key{Alt: true, Type: KeyRune, Rune: c}, nil
+		return KeyMsg(Key{Alt: true, Type: KeyRune, Rune: c}), nil
 	}
 
 	// Just a regular, ol' rune
-	return Key{Type: KeyRune, Rune: char}, nil
+	return KeyMsg(Key{Type: KeyRune, Rune: char}), nil
 }

mouse.go

@@ -0,0 +1,89 @@
+package tea
+
+import "errors"
+
+type MouseMsg MouseEvent
+
+type MouseEvent struct {
+	X      int
+	Y      int
+	Button MouseButton
+	Alt    bool
+	Ctrl   bool
+}
+
+func (m MouseEvent) String() (s string) {
+	if m.Ctrl {
+		s += "ctrl+"
+	}
+	if m.Alt {
+		s += "alt+"
+	}
+	s += mouseButtonNames[m.Button]
+	return s
+}
+
+type MouseButton int
+
+const (
+	MouseLeft MouseButton = iota
+	MouseRight
+	MouseMiddle
+	MouseRelease
+	MouseWheelUp
+	MouseWheelDown
+	MouseMotion
+)
+
+var mouseButtonNames = map[MouseButton]string{
+	MouseLeft:      "left",
+	MouseRight:     "right",
+	MouseMiddle:    "middle",
+	MouseRelease:   "release",
+	MouseWheelUp:   "wheel up",
+	MouseWheelDown: "wheel down",
+	MouseMotion:    "motion",
+}
+
+// Parse an X10-encoded mouse event. The simplest kind. The last release of
+// X10 was December 1986, by the way.
+func parseX10MouseEvent(buf []byte) (m MouseEvent, err error) {
+	if len(buf) != 6 || string(buf[:3]) != "\x1b[M" {
+		return m, errors.New("not an X10 mouse event")
+	}
+
+	e := buf[3] - 32
+
+	switch e {
+	case 35:
+		m.Button = MouseMotion
+	case 64:
+		m.Button = MouseWheelUp
+	case 65:
+		m.Button = MouseWheelDown
+	default:
+		switch e & 3 {
+		case 0:
+			m.Button = MouseLeft
+		case 1:
+			m.Button = MouseMiddle
+		case 2:
+			m.Button = MouseRight
+		case 3:
+			m.Button = MouseRelease
+		}
+	}
+
+	if e&8 != 0 {
+		m.Alt = true
+	}
+	if e&16 != 0 {
+		m.Ctrl = true
+	}
+
+	// (1,1) is the upper left. We subtract 1 to normalize it to (0,0).
+	m.X = int(buf[4]) - 32 - 1
+	m.Y = int(buf[5]) - 32 - 1
+
+	return m, nil
+}

tea.go

@@ -119,11 +119,11 @@ func (p *Program) Start() error {
 	// Subscribe to user input
 	go func() {
 		for {
-			msg, err := ReadKey(os.Stdin)
+			msg, err := ReadInput(os.Stdin)
 			if err != nil {
 				errs <- err
 			}
-			msgs <- KeyMsg(msg)
+			msgs <- msg
 		}
 	}()
 
@@ -201,3 +201,27 @@ func (p *Program) ExitAltScreen() {
 	defer p.mtx.Unlock()
 	fmt.Fprintf(p.output, te.CSI+te.ExitAltScreenSeq)
 }
+
+func (p *Program) EnableMouseCellMotion() {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	fmt.Fprintf(p.output, te.CSI+"?1002h")
+}
+
+func (p *Program) DisableMouseCellMotion() {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	fmt.Fprintf(p.output, te.CSI+"?1002l")
+}
+
+func (p *Program) EnableMouseAllMotion() {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	fmt.Fprintf(p.output, te.CSI+"?1003h")
+}
+
+func (p *Program) DisableMouseAllMotion() {
+	p.mtx.Lock()
+	defer p.mtx.Unlock()
+	fmt.Fprintf(p.output, te.CSI+"?1003l")
+}