feat: handle line and screen cleanup

vt/csi.go

@@ -7,6 +7,11 @@ import (
 	"github.com/charmbracelet/x/cellbuf"
 )
 
+var spaceCell = cellbuf.Cell{
+	Content: " ",
+	Width:   1,
+}
+
 // handleCsi handles a CSI escape sequences.
 func (t *Terminal) handleCsi(seq []byte) {
 	// params := t.parser.Params[:t.parser.ParamsLen]
@@ -15,13 +20,135 @@ func (t *Terminal) handleCsi(seq []byte) {
 	case 'A', 'B', 'C', 'D', 'E', 'F', 'H':
 		t.handleCursor()
 	case 'm': // SGR - Select Graphic Rendition
-		handleSgr(t.parser, &t.scr.cur.Pen)
+		t.handleSgr()
+	case 'J':
+		t.handleScreen()
+	case 'K', 'L', 'M', 'S', 'T':
+		t.handleLine()
+	}
+}
+
+func (t *Terminal) handleScreen() {
+	var count int
+	if t.parser.ParamsLen > 0 {
+		count = ansi.Param(t.parser.Params[0]).Param()
+	}
+
+	scr := t.scr
+	cur := scr.Cursor()
+	w, h := scr.Width(), scr.Height()
+	x, y := cur.Pos.X, cur.Pos.Y
+
+	cmd := ansi.Cmd(t.parser.Cmd)
+	switch cmd.Command() {
+	case 'J':
+		switch count {
+		case 0: // Erase screen below (including cursor)
+			for i := y; i < h; i++ {
+				for j := 0; j < w; j++ {
+					if i == y && j < x {
+						continue
+					}
+					t.scr.SetCell(j, i, spaceCell)
+				}
+			}
+		case 1: // Erase screen above (including cursor)
+			for i := 0; i <= y; i++ {
+				for j := 0; j < w; j++ {
+					if i == y && j > x {
+						break
+					}
+					t.scr.SetCell(j, i, spaceCell)
+				}
+			}
+		case 2: // erase screen
+			t.scr = NewScreen(w, h)
+		case 3: // erase display
+			t.scr = NewScreen(w, h)
+		}
+	}
+}
+
+func (t *Terminal) handleLine() {
+	var count int
+	if t.parser.ParamsLen > 0 {
+		count = ansi.Param(t.parser.Params[0]).Param()
+	}
+
+	cmd := ansi.Cmd(t.parser.Cmd)
+	switch cmd.Command() {
+	case 'K':
+		cur := t.scr.Cursor()
+		x, y := cur.Pos.X, cur.Pos.Y
+		w := t.scr.Width()
+		switch count {
+		case 0: // Erase from cursor to end of line
+			for i := x; i < w; i++ {
+				t.scr.SetCell(i, y, cellbuf.Cell{})
+			}
+		case 1: // Erase from start of line to cursor
+			for i := 0; i <= x; i++ {
+				t.scr.SetCell(i, y, cellbuf.Cell{})
+			}
+		case 2: // Erase entire line
+			for i := 0; i < w; i++ {
+				t.scr.SetCell(i, y, cellbuf.Cell{})
+			}
+		}
+	case 'L': // TODO: insert n blank lines
+	case 'M': // TODO: delete n lines
+	case 'S': // TODO: scroll up n lines
+	case 'T': // TODO: scroll down n lines
+	}
+}
+
+func (t *Terminal) handleCursor() {
+	p := t.parser
+	width, height := t.scr.Width(), t.scr.Height()
+	cmd := ansi.Cmd(p.Cmd)
+	n := 1
+	if p.ParamsLen > 0 {
+		n = int(p.Params[0])
+	}
+
+	x, y := t.scr.cur.Pos.X, t.scr.cur.Pos.Y
+	switch cmd.Command() {
+	case 'A':
+		// CUU - Cursor Up
+		y = max(0, y-n)
+	case 'B':
+		// CUD - Cursor Down
+		y = min(height-1, y+n)
+	case 'C':
+		// CUF - Cursor Forward
+		x = min(width-1, x+n)
+	case 'D':
+		// CUB - Cursor Back
+		x = max(0, x-n)
+	case 'E':
+		// Cursor next line
+		y = min(height-1, y+n)
+		x = 0
+	case 'F':
+		// Cursor previous line
+		y = max(0, y-n)
+		x = 0
+	case 'H':
+		// Set cursor position
+		if p.ParamsLen >= 2 {
+			y = min(height-1, max(0, int(p.Params[0])-1))
+			x = min(width-1, max(0, int(p.Params[1])-1))
+		} else {
+			x, y = 0, 0
+		}
 	}
+	t.scr.moveCursor(x, y)
 }
 
 // handleSgr handles SGR escape sequences.
 // handleSgr handles Select Graphic Rendition (SGR) escape sequences.
-func handleSgr(p *ansi.Parser, pen *Style) {
+func (t *Terminal) handleSgr() {
+	p, pen := t.parser, t.scr.cur.Pen
 	if p.ParamsLen == 0 {
 		pen.Reset()
 		return
@@ -144,49 +271,6 @@ func readColor(idxp *int, params []int) (c ansi.Color) {
 	return
 }
 
-func (t *Terminal) handleCursor() {
-	p := t.parser
-	width, height := t.scr.Width(), t.scr.Height()
-	cmd := ansi.Cmd(p.Cmd)
-	n := 1
-	if p.ParamsLen > 0 {
-		n = int(p.Params[0])
-	}
-
-	x, y := t.scr.cur.Pos.X, t.scr.cur.Pos.Y
-	switch cmd.Command() {
-	case 'A':
-		// CUU - Cursor Up
-		y = max(0, y-n)
-	case 'B':
-		// CUD - Cursor Down
-		y = min(height-1, y+n)
-	case 'C':
-		// CUF - Cursor Forward
-		x = min(width-1, x+n)
-	case 'D':
-		// CUB - Cursor Back
-		x = max(0, x-n)
-	case 'E':
-		// Cursor next line
-		y = min(height-1, y+n)
-		x = 0
-	case 'F':
-		// Cursor previous line
-		y = max(0, y-n)
-		x = 0
-	case 'H':
-		// Set cursor position
-		if p.ParamsLen >= 2 {
-			y = min(height-1, max(0, int(p.Params[0])-1))
-			x = min(width-1, max(0, int(p.Params[1])-1))
-		} else {
-			x, y = 0, 0
-		}
-	}
-	t.scr.moveCursor(x, y)
-}
-
 func max(a, b int) int {
 	if a > b {
 		return a

vt/terminal.go

@@ -101,6 +101,9 @@ func (t *Terminal) Write(p []byte) (n int, err error) {
 		state = newState
 		p = p[m:]
 		n += m
+
+		// x, y := t.Cursor().Pos.X, t.Cursor().Pos.Y
+		// fmt.Printf("%q: %d %d\n", seq, x, y)
 	}
 
 	return