Add cursor overlay on our grid

Required updating of underlying TextGrid
Also update bell to change yellow cursor red

escape.go

@@ -7,13 +7,15 @@ func (t *Terminal) handleEscape(code string) {
 	case "2J":
 		t.clearScreen()
 	case "K":
-		t.content.SetText("")
-		// TODO clear from the cursor to end line
+		row := t.content.Row(t.cursorRow)
+		t.content.SetRow(t.cursorRow, row[:t.cursorCol])
 	default:
 		log.Println("Unrecognised Escape:", code)
 	}
 }
 
 func (t *Terminal) clearScreen() {
 	t.content.SetText("")
+	t.cursorCol = 0
+	t.cursorRow = 0
 }

escape_test.go

@@ -14,3 +14,12 @@ func TestClearScreen(t *testing.T) {
 	term.handleEscape("2J")
 	assert.Equal(t, "", term.content.Text())
 }
+
+func TestEraseLine(t *testing.T) {
+	term := NewTerminal()
+	term.content.SetText("Hello")
+	assert.Equal(t, "Hello", term.content.Text())
+
+	term.handleEscape("K")
+	assert.Equal(t, "", term.content.Text())
+}

output.go

@@ -1,15 +1,15 @@
 package terminal
 
 import (
-	"strings"
 	"time"
 )
 
 func (t *Terminal) handleOutput(buf []byte) {
 	out := ""
 	esc := -5
+	osc := false
 	code := ""
-	for i, r := range buf {
+	for i, r := range []rune(string(buf)) {
 		if r == asciiEscape {
 			esc = i
 			continue
@@ -18,15 +18,21 @@ func (t *Terminal) handleOutput(buf []byte) {
 			if r == '[' {
 				continue
 			} else if r == ']' {
-				// TODO only up to BEL or ST
-				t.handleOSC(string(buf[2 : len(buf)-1]))
-				break
+				osc = true
+				continue
 			} else {
 				esc = -5
 			}
 		}
-		if esc != -5 {
-			if (r >= '0' && r <= '9') || r == ';' || r == '=' {
+		if osc {
+			if r == asciiBell || r == 0 {
+				t.handleOSC(out)
+				out = ""
+				osc = false
+				continue
+			}
+		} else if esc != -5 {
+			if (r >= '0' && r <= '9') || r == ';' || r == '=' || r == '?' {
 				code += string(r)
 			} else {
 				code += string(r)
@@ -40,16 +46,36 @@ func (t *Terminal) handleOutput(buf []byte) {
 
 		switch r {
 		case asciiBackspace:
-			runes := []rune(t.content.Text())
-			if len(runes) == 0 {
+			row := t.content.Row(t.cursorRow)
+			if len(row) == 0 {
 				continue
 			}
-			t.content.SetText(string(runes[:len(runes)-1]))
+			t.content.SetRow(t.cursorRow, row[:len(row)-1])
+			t.cursorCol--
+			t.cursorMoved()
+			continue
+		case '\n':
+			row := t.content.Row(t.cursorRow)
+			row = append(row, []rune(out)...)
+			t.content.SetRow(t.cursorRow, row)
+
+			if t.cursorRow == int(t.config.Rows-1) {
+				for i = 0; i < t.cursorRow; i++ {
+					t.content.SetRow(i, t.content.Row(i+1))
+				}
+				t.content.SetRow(i, []rune{})
+			} else {
+				t.cursorRow++
+			}
+
+			out = ""
+			t.cursorCol = 0
 			continue
 		case '\r':
+			t.cursorCol = 0
 			continue
 		case asciiBell:
-			go t.bell()
+			go t.ringBell()
 			continue
 		case '\t': // TODO remove silly approximation
 			out += "    "
@@ -59,21 +85,25 @@ func (t *Terminal) handleOutput(buf []byte) {
 		esc = -5
 		code = ""
 	}
-	t.content.SetText(t.content.Text() + out)
-}
 
-func (t *Terminal) bell() {
-	add := "*BELL* "
-	title := t.config.Title
-	if strings.Index(title, add) == 0 { // don't ring twice at once
+	if osc {
+		t.handleOSC(out)
 		return
 	}
+	row := t.content.Row(t.cursorRow)
+	row = append(row, []rune(out)...)
+	t.content.SetRow(t.cursorRow, row)
+	t.cursorCol += len(out)
+	t.Refresh()
+}
+
+func (t *Terminal) ringBell() {
+	t.bell = true
+	t.Refresh()
 
-	t.config.Title = add + title
-	t.onConfigure()
 	select {
 	case <-time.After(time.Millisecond * 300):
-		t.config.Title = title
-		t.onConfigure()
+		t.bell = false
+		t.Refresh()
 	}
 }

render.go

@@ -4,10 +4,17 @@ import (
 	"image/color"
 
 	"fyne.io/fyne"
+	"fyne.io/fyne/canvas"
+)
+
+var (
+	cursorColor     = color.RGBA{R: 255, G: 255, B: 0, A: 128}
+	cursorBellColor = color.RGBA{R: 255, G: 0, B: 0, A: 128}
 )
 
 type render struct {
-	term *Terminal
+	term   *Terminal
+	cursor *canvas.Rectangle
 }
 
 func (r *render) Layout(s fyne.Size) {
@@ -19,6 +26,9 @@ func (r *render) MinSize() fyne.Size {
 }
 
 func (r *render) Refresh() {
+	r.moveCursor()
+	r.refreshCursor()
+
 	r.term.content.Refresh()
 }
 
@@ -27,13 +37,33 @@ func (r *render) BackgroundColor() color.Color {
 }
 
 func (r *render) Objects() []fyne.CanvasObject {
-	return []fyne.CanvasObject{r.term.content}
+	return []fyne.CanvasObject{r.term.content, r.cursor}
 }
 
 func (r *render) Destroy() {
 }
 
+func (r *render) moveCursor() {
+	cell := r.term.guessCellSize()
+	r.cursor.Move(fyne.NewPos(cell.Width*r.term.cursorCol, cell.Height*r.term.cursorRow))
+}
+
+func (r *render) refreshCursor() {
+	r.cursor.Hidden = !r.term.focused
+	if r.term.bell {
+		r.cursor.FillColor = cursorBellColor
+	} else {
+		r.cursor.FillColor = cursorColor
+	}
+	r.cursor.Refresh()
+}
+
 // CreateRenderer requests a new renderer for this terminal (just a wrapper around the TextGrid)
 func (t *Terminal) CreateRenderer() fyne.WidgetRenderer {
-	return &render{term: t}
+	cur := canvas.NewRectangle(cursorColor)
+	cur.Resize(fyne.NewSize(2, t.guessCellSize().Height))
+
+	r := &render{term: t, cursor: cur}
+	t.cursorMoved = r.moveCursor
+	return r
 }

term.go

@@ -29,8 +29,10 @@ type Terminal struct {
 	listenerLock sync.Mutex
 	listeners    []chan Config
 
-	pty     *os.File
-	focused bool
+	pty                  *os.File
+	focused, bell        bool
+	cursorRow, cursorCol int
+	cursorMoved          func()
 }
 
 // AddListener registers a new outgoing channel that will have our Config sent each time it changes.
@@ -138,7 +140,7 @@ func (t *Terminal) Run() error {
 func NewTerminal() *Terminal {
 	t := &Terminal{}
 	t.ExtendBaseWidget(t)
-	t.content = widget.NewTextGrid("")
+	t.content = widget.NewTextGrid()
 
 	return t
 }