a3aae45 fix(screen): support DEC special graphics charsets, REP and DECSTR · vev-vt

M screen.go +12 -0


@@ -106,6 +106,12 @@ type Screen struct {
106	106		colorSchemeMode bool
107	107		colorSchemeLight bool
108	108		colorSchemeSet bool
	109	+	// charsets holds the final byte designated to G0 and G1 (ESC ( F and
	110	+	// ESC ) F); shiftOut selects G1 into GL (SO) instead of G0 (SI).
	111	+	charsets [2]byte
	112	+	shiftOut bool
	113	+	// lastPrinted is the last graphic rune written, repeated by REP.
	114	+	lastPrinted rune
109	115		}
110	116
111	117		func NewScreen(width, height int) *Screen {

@@ -424,6 +430,12 @@ func (s *Screen) consumeEscape(data []byte) (consumed int, partial bool) {
424	430		if len(data) < 3 {
425	431		return 0, true
426	432		}
	433	+	switch data[1] {
	434	+	case '(':
	435	+	s.charsets[0] = data[2]
	436	+	case ')':
	437	+	s.charsets[1] = data[2]
	438	+	}
427	439		return 3, false
428	440		default:
429	441		if data[1] >= 0x30 && data[1] <= 0x7e {


@@ -106,6 +106,12 @@ type Screen struct {
106	colorSchemeMode bool	106		colorSchemeMode bool
107	colorSchemeLight bool	107		colorSchemeLight bool
108	colorSchemeSet bool	108		colorSchemeSet bool
		109	+	// charsets holds the final byte designated to G0 and G1 (ESC ( F and
		110	+	// ESC ) F); shiftOut selects G1 into GL (SO) instead of G0 (SI).
		111	+	charsets [2]byte
		112	+	shiftOut bool
		113	+	// lastPrinted is the last graphic rune written, repeated by REP.
		114	+	lastPrinted rune
109	}	115		}
110		116
111	func NewScreen(width, height int) *Screen {	117		func NewScreen(width, height int) *Screen {

@@ -424,6 +430,12 @@ func (s *Screen) consumeEscape(data []byte) (consumed int, partial bool) {
424	if len(data) < 3 {	430		if len(data) < 3 {
425	return 0, true	431		return 0, true
426	}	432		}
		433	+	switch data[1] {
		434	+	case '(':
		435	+	s.charsets[0] = data[2]
		436	+	case ')':
		437	+	s.charsets[1] = data[2]
		438	+	}
427	return 3, false	439		return 3, false
428	default:	440		default:
429	if data[1] >= 0x30 && data[1] <= 0x7e {	441		if data[1] >= 0x30 && data[1] <= 0x7e {

A screen_charset.go +26 -0

@@ -0,0 +1,26 @@
	1	+	package vt
	2	+
	3	+	// decSpecialGraphics maps 0x5f..0x7e to the DEC Special Graphics set
	4	+	// (designated by ESC ( 0 or ESC ) 0), used by ncurses for line drawing.
	5	+	var decSpecialGraphics = [...]rune{
	6	+	' ', '◆', '▒', '␉', '␌', '␍', '␊', '°', '±', '␤', '␋', '┘', '┐', '┌', '└', '┼',
	7	+	'⎺', '⎻', '─', '⎼', '⎽', '├', '┤', '┴', '┬', '│', '≤', '≥', 'π', '≠', '£', '·',
	8	+	}
	9	+
	10	+	// maxRepeat bounds REP to one full screen: repeating further only rewrites
	11	+	// cells and scrolls, so a hostile count cannot stall the parser.
	12	+	func maxRepeat(width, height int) int {
	13	+	return max(width*height, 1)
	14	+	}
	15	+
	16	+	// translateCharset maps r through the character set currently invoked into GL.
	17	+	func (s *Screen) translateCharset(r rune) rune {
	18	+	g := 0
	19	+	if s.shiftOut {
	20	+	g = 1
	21	+	}
	22	+	if s.charsets[g] == '0' && r >= 0x5f && r <= 0x7e {
	23	+	return decSpecialGraphics[r-0x5f]
	24	+	}
	25	+	return r
	26	+	}

@@ -0,0 +1,26 @@
	1	+	package vt
	2	+
	3	+	// decSpecialGraphics maps 0x5f..0x7e to the DEC Special Graphics set
	4	+	// (designated by ESC ( 0 or ESC ) 0), used by ncurses for line drawing.
	5	+	var decSpecialGraphics = [...]rune{
	6	+	' ', '◆', '▒', '␉', '␌', '␍', '␊', '°', '±', '␤', '␋', '┘', '┐', '┌', '└', '┼',
	7	+	'⎺', '⎻', '─', '⎼', '⎽', '├', '┤', '┴', '┬', '│', '≤', '≥', 'π', '≠', '£', '·',
	8	+	}
	9	+
	10	+	// maxRepeat bounds REP to one full screen: repeating further only rewrites
	11	+	// cells and scrolls, so a hostile count cannot stall the parser.
	12	+	func maxRepeat(width, height int) int {
	13	+	return max(width*height, 1)
	14	+	}
	15	+
	16	+	// translateCharset maps r through the character set currently invoked into GL.
	17	+	func (s *Screen) translateCharset(r rune) rune {
	18	+	g := 0
	19	+	if s.shiftOut {
	20	+	g = 1
	21	+	}
	22	+	if s.charsets[g] == '0' && r >= 0x5f && r <= 0x7e {
	23	+	return decSpecialGraphics[r-0x5f]
	24	+	}
	25	+	return r
	26	+	}

A screen_charset_test.go +53 -0

@@ -0,0 +1,53 @@
	1	+	package vt
	2	+
	3	+	import (
	4	+	"strings"
	5	+	"testing"
	6	+	)
	7	+
	8	+	func TestCharsetsAndRepeat(t *testing.T) {
	9	+	tests := []struct {
	10	+	name string
	11	+	input string
	12	+	want string
	13	+	}{
	14	+	{name: "G0 DEC special graphics draws lines", input: "\x1b(0lqqk\x1b(Bq", want: "┌──┐q"},
	15	+	{name: "G1 via SO and SI", input: "\x1b)0q\x0eqx\x0fq", want: "q─│q"},
	16	+	{name: "SO without G1 designation stays ASCII", input: "\x0eq\x0f", want: "q"},
	17	+	{name: "chars outside the graphics range pass through", input: "\x1b(0Aa~", want: "A▒·"},
	18	+	{name: "DECSC and DECRC restore charsets", input: "\x1b(0\x1b7\x1b(B\x1b8q", want: "─"},
	19	+	{name: "DECSTR resets charsets", input: "\x1b(0q\x1b[!pq", want: "─q"},
	20	+	{name: "RIS resets charsets", input: "\x1b(0\x1bcq", want: "q"},
	21	+	{name: "REP repeats the last graphic char", input: "\x1b(0q\x1b[4b", want: "─────"},
	22	+	{name: "REP defaults to one", input: "a\x1b[b", want: "aa"},
	23	+	{name: "REP without a prior char is ignored", input: "\x1b[3bx", want: "x"},
	24	+	{name: "REP after control repeats last graphic", input: "ab\r\x1b[2b", want: "bb"},
	25	+	{name: "partial charset escape across writes", input: "\x1b(", want: ""},
	26	+	}
	27	+	for _, tt := range tests {
	28	+	t.Run(tt.name, func(t *testing.T) {
	29	+	s := NewScreen(10, 3)
	30	+	s.Write([]byte(tt.input))
	31	+	if got := strings.TrimRight(lineText(s, 0), " "); got != tt.want {
	32	+	t.Fatalf("line = %q, want %q", got, tt.want)
	33	+	}
	34	+	})
	35	+	}
	36	+	}
	37	+
	38	+	func TestCharsetDesignationSplitAcrossWrites(t *testing.T) {
	39	+	s := NewScreen(10, 1)
	40	+	s.Write([]byte("\x1b("))
	41	+	s.Write([]byte("0q"))
	42	+	if got := strings.TrimRight(lineText(s, 0), " "); got != "─" {
	43	+	t.Fatalf("line = %q, want %q", got, "─")
	44	+	}
	45	+	}
	46	+
	47	+	func TestRepeatIsBounded(t *testing.T) {
	48	+	s := NewScreen(4, 2)
	49	+	s.Write([]byte("x\x1b[999999999b"))
	50	+	if got := lineText(s, 0); got != "xxxx" {
	51	+	t.Fatalf("line = %q, want %q", got, "xxxx")
	52	+	}
	53	+	}

@@ -0,0 +1,53 @@
	1	+	package vt
	2	+
	3	+	import (
	4	+	"strings"
	5	+	"testing"
	6	+	)
	7	+
	8	+	func TestCharsetsAndRepeat(t *testing.T) {
	9	+	tests := []struct {
	10	+	name string
	11	+	input string
	12	+	want string
	13	+	}{
	14	+	{name: "G0 DEC special graphics draws lines", input: "\x1b(0lqqk\x1b(Bq", want: "┌──┐q"},
	15	+	{name: "G1 via SO and SI", input: "\x1b)0q\x0eqx\x0fq", want: "q─│q"},
	16	+	{name: "SO without G1 designation stays ASCII", input: "\x0eq\x0f", want: "q"},
	17	+	{name: "chars outside the graphics range pass through", input: "\x1b(0Aa~", want: "A▒·"},
	18	+	{name: "DECSC and DECRC restore charsets", input: "\x1b(0\x1b7\x1b(B\x1b8q", want: "─"},
	19	+	{name: "DECSTR resets charsets", input: "\x1b(0q\x1b[!pq", want: "─q"},
	20	+	{name: "RIS resets charsets", input: "\x1b(0\x1bcq", want: "q"},
	21	+	{name: "REP repeats the last graphic char", input: "\x1b(0q\x1b[4b", want: "─────"},
	22	+	{name: "REP defaults to one", input: "a\x1b[b", want: "aa"},
	23	+	{name: "REP without a prior char is ignored", input: "\x1b[3bx", want: "x"},
	24	+	{name: "REP after control repeats last graphic", input: "ab\r\x1b[2b", want: "bb"},
	25	+	{name: "partial charset escape across writes", input: "\x1b(", want: ""},
	26	+	}
	27	+	for _, tt := range tests {
	28	+	t.Run(tt.name, func(t *testing.T) {
	29	+	s := NewScreen(10, 3)
	30	+	s.Write([]byte(tt.input))
	31	+	if got := strings.TrimRight(lineText(s, 0), " "); got != tt.want {
	32	+	t.Fatalf("line = %q, want %q", got, tt.want)
	33	+	}
	34	+	})
	35	+	}
	36	+	}
	37	+
	38	+	func TestCharsetDesignationSplitAcrossWrites(t *testing.T) {
	39	+	s := NewScreen(10, 1)
	40	+	s.Write([]byte("\x1b("))
	41	+	s.Write([]byte("0q"))
	42	+	if got := strings.TrimRight(lineText(s, 0), " "); got != "─" {
	43	+	t.Fatalf("line = %q, want %q", got, "─")
	44	+	}
	45	+	}
	46	+
	47	+	func TestRepeatIsBounded(t *testing.T) {
	48	+	s := NewScreen(4, 2)
	49	+	s.Write([]byte("x\x1b[999999999b"))
	50	+	if got := lineText(s, 0); got != "xxxx" {
	51	+	t.Fatalf("line = %q, want %q", got, "xxxx")
	52	+	}
	53	+	}

M screen_csi.go +13 -0


@@ -63,6 +63,10 @@ func (s *Screen) applyCSI(params string, cmd byte) {
63	63		s.respond(resp)
64	64		}
65	65		case 'p':
	66	+	if params == "!" {
	67	+	s.softReset()
	68	+	return
	69	+	}
66	70		if modeText, ok := strings.CutSuffix(params, "$"); ok {
67	71		if private {
68	72		modeText = strings.TrimPrefix(modeText, "?")

@@ -83,6 +87,15 @@ func (s *Screen) applyCSI(params string, cmd byte) {
83	87		resp = append(resp, "$y"...)
84	88		s.respond(resp)
85	89		}
	90	+	case 'b':
	91	+	// REP repeats the last printed graphic character; ncurses relies on it
	92	+	// for long runs when terminfo advertises rep (xterm-256color does).
	93	+	if private \|\| s.lastPrinted == 0 {
	94	+	return
	95	+	}
	96	+	for n := min(firstPositive(parts, 1), maxRepeat(s.frame.Width, s.frame.Height)); n > 0; n-- {
	97	+	s.putPrintable(s.lastPrinted)
	98	+	}
86	99		case 'm':
87	100		if strings.HasPrefix(params, ">") {
88	101		return


@@ -63,6 +63,10 @@ func (s *Screen) applyCSI(params string, cmd byte) {
63	s.respond(resp)	63		s.respond(resp)
64	}	64		}
65	case 'p':	65		case 'p':
		66	+	if params == "!" {
		67	+	s.softReset()
		68	+	return
		69	+	}
66	if modeText, ok := strings.CutSuffix(params, "$"); ok {	70		if modeText, ok := strings.CutSuffix(params, "$"); ok {
67	if private {	71		if private {
68	modeText = strings.TrimPrefix(modeText, "?")	72		modeText = strings.TrimPrefix(modeText, "?")

@@ -83,6 +87,15 @@ func (s *Screen) applyCSI(params string, cmd byte) {
83	resp = append(resp, "$y"...)	87		resp = append(resp, "$y"...)
84	s.respond(resp)	88		s.respond(resp)
85	}	89		}
		90	+	case 'b':
		91	+	// REP repeats the last printed graphic character; ncurses relies on it
		92	+	// for long runs when terminfo advertises rep (xterm-256color does).
		93	+	if private \|\| s.lastPrinted == 0 {
		94	+	return
		95	+	}
		96	+	for n := min(firstPositive(parts, 1), maxRepeat(s.frame.Width, s.frame.Height)); n > 0; n-- {
		97	+	s.putPrintable(s.lastPrinted)
		98	+	}
86	case 'm':	99		case 'm':
87	if strings.HasPrefix(params, ">") {	100		if strings.HasPrefix(params, ">") {
88	return	101		return

M screen_cursor.go +6 -1


@@ -14,6 +14,8 @@ type cursorState struct {
14	14		originMode bool
15	15		insertMode bool
16	16		autoWrapMode bool
	17	+	charsets [2]byte
	18	+	shiftOut bool
17	19		saved bool
18	20		}
19	21

@@ -78,7 +80,8 @@ func (s *Screen) saveCursor() {
78	80		s.savedCursor = cursorState{
79	81		row: s.Row, col: s.Col, style: s.Style,
80	82		originMode: s.originMode, insertMode: s.insertMode,
81		-	autoWrapMode: s.autoWrapMode, saved: true,
	83	+	autoWrapMode: s.autoWrapMode, charsets: s.charsets,
	84	+	shiftOut: s.shiftOut, saved: true,
82	85		}
83	86		}
84	87

@@ -92,4 +95,6 @@ func (s *Screen) restoreCursor() {
92	95		s.originMode = s.savedCursor.originMode
93	96		s.insertMode = s.savedCursor.insertMode
94	97		s.autoWrapMode = s.savedCursor.autoWrapMode
	98	+	s.charsets = s.savedCursor.charsets
	99	+	s.shiftOut = s.savedCursor.shiftOut
95	100		}

 	originMode   bool
 	insertMode   bool
 	autoWrapMode bool
+	charsets     [2]byte
+	shiftOut     bool
 	saved        bool
 }
 	s.savedCursor = cursorState{
 		row: s.Row, col: s.Col, style: s.Style,
 		originMode: s.originMode, insertMode: s.insertMode,
-		autoWrapMode: s.autoWrapMode, saved: true,
+		autoWrapMode: s.autoWrapMode, charsets: s.charsets,
+		shiftOut: s.shiftOut, saved: true,
 	}
 }
 	s.originMode = s.savedCursor.originMode
 	s.insertMode = s.savedCursor.insertMode
 	s.autoWrapMode = s.savedCursor.autoWrapMode
+	s.charsets = s.savedCursor.charsets
+	s.shiftOut = s.savedCursor.shiftOut
 }

M screen_modes.go +18 -0


@@ -121,10 +121,28 @@ func (s *Screen) reset() {
121	121		s.bracketedPaste = false
122	122		s.kittyKeyboard = nil
123	123		s.colorSchemeMode = false
	124	+	s.charsets = [2]byte{}
	125	+	s.shiftOut = false
	126	+	s.lastPrinted = 0
124	127		s.resetScrollRegion()
125	128		s.fullRedraw()
126	129		}
127	130
	131	+	// softReset implements DECSTR (CSI ! p): it resets modes, rendition, margins,
	132	+	// and character sets without touching screen contents or the cursor position.
	133	+	func (s *Screen) softReset() {
	134	+	s.Style = renderer.DefaultStyle()
	135	+	s.savedCursor = cursorState{}
	136	+	s.originMode = false
	137	+	s.insertMode = false
	138	+	s.autoWrapMode = true
	139	+	s.applicationCursorMode = false
	140	+	s.cursorVisible = true
	141	+	s.charsets = [2]byte{}
	142	+	s.shiftOut = false
	143	+	s.resetScrollRegion()
	144	+	}
	145	+
128	146		func (s *Screen) setScrollRegion(parts []int) {
129	147		if s.frame.Height == 0 {
130	148		return


@@ -121,10 +121,28 @@ func (s *Screen) reset() {
121	s.bracketedPaste = false	121		s.bracketedPaste = false
122	s.kittyKeyboard = nil	122		s.kittyKeyboard = nil
123	s.colorSchemeMode = false	123		s.colorSchemeMode = false
		124	+	s.charsets = [2]byte{}
		125	+	s.shiftOut = false
		126	+	s.lastPrinted = 0
124	s.resetScrollRegion()	127		s.resetScrollRegion()
125	s.fullRedraw()	128		s.fullRedraw()
126	}	129		}
127		130
		131	+	// softReset implements DECSTR (CSI ! p): it resets modes, rendition, margins,
		132	+	// and character sets without touching screen contents or the cursor position.
		133	+	func (s *Screen) softReset() {
		134	+	s.Style = renderer.DefaultStyle()
		135	+	s.savedCursor = cursorState{}
		136	+	s.originMode = false
		137	+	s.insertMode = false
		138	+	s.autoWrapMode = true
		139	+	s.applicationCursorMode = false
		140	+	s.cursorVisible = true
		141	+	s.charsets = [2]byte{}
		142	+	s.shiftOut = false
		143	+	s.resetScrollRegion()
		144	+	}
		145	+
128	func (s *Screen) setScrollRegion(parts []int) {	146		func (s *Screen) setScrollRegion(parts []int) {
129	if s.frame.Height == 0 {	147		if s.frame.Height == 0 {
130	return	148		return

M screen_write.go +9 -2


@@ -9,7 +9,13 @@ func (s *Screen) putRune(r rune) {
9	9		s.OnBell()
10	10		}
11	11		return
12		-	case 0x00, 0x0e, 0x0f, 0x7f:
	12	+	case 0x0e:
	13	+	s.shiftOut = true
	14	+	return
	15	+	case 0x0f:
	16	+	s.shiftOut = false
	17	+	return
	18	+	case 0x00, 0x7f:
13	19		return
14	20		case '\r':
15	21		s.Col = 0

@@ -35,7 +41,7 @@ func (s *Screen) putRune(r rune) {
35	41		return
36	42		}
37	43		if r >= 0x20 {
38		-	s.putPrintable(r)
	44	+	s.putPrintable(s.translateCharset(r))
39	45		}
40	46		}
41	47		}

@@ -61,6 +67,7 @@ func (s *Screen) putPrintable(r rune) {
61	67		if s.frame.Width == 0 \|\| s.frame.Height == 0 {
62	68		return
63	69		}
	70	+	s.lastPrinted = r
64	71		// Deferred wrap: cursor sits past the last column. Disabling DECAWM
65	72		// cancels a pending wrap and leaves subsequent output at the right margin.
66	73		if s.Col >= s.frame.Width {

 			s.OnBell()
 		}
 		return
-	case 0x00, 0x0e, 0x0f, 0x7f:
+	case 0x0e:
+		s.shiftOut = true
+		return
+	case 0x0f:
+		s.shiftOut = false
+		return
+	case 0x00, 0x7f:
 		return
 	case '\r':
 		s.Col = 0
 			return
 		}
 		if r >= 0x20 {
-			s.putPrintable(r)
+			s.putPrintable(s.translateCharset(r))
 		}
 	}
 }
 	if s.frame.Width == 0 || s.frame.Height == 0 {
 		return
 	}
+	s.lastPrinted = r
 	// Deferred wrap: cursor sits past the last column. Disabling DECAWM
 	// cancels a pending wrap and leaves subsequent output at the right margin.
 	if s.Col >= s.frame.Width {