c01e026 Stabilize chat rendering: remove forced full repaints, fix scroll/diff edge cases · zut

M internal/agent/modes/interactive.go +11 -49


@@ -727,21 +727,13 @@ func (i *Interactive) buildChatLocked(cols int) []string {
727	727		}
728	728		}
729	729		i.view.Err = i.statusErr
730		-	i.liveBlock = i.view.BuildLive(cols)
731		-
732		-	streamingActive := i.view.StreamingActive
733		-	streaming := i.view.Streaming
734		-	toolCalls := i.view.ToolCalls
735		-	errLine := i.view.Err
736		-	i.view.StreamingActive = false
737		-	i.view.Streaming = ""
738		-	i.view.ToolCalls = nil
739		-	i.view.Err = ""
	730	+	// Live streaming/tool rows are appended to the chat buffer (not
	731	+	// hoisted into a separate live block above the editor). That keeps
	732	+	// the renderer's diff view append-only: when a tool finishes the
	733	+	// rows update in place at the end of the buffer, instead of the
	734	+	// whole bottom band shrinking and shifting chat lines around.
	735	+	i.liveBlock = nil
740	736		chat := i.view.Build(cols)
741		-	i.view.StreamingActive = streamingActive
742		-	i.view.Streaming = streaming
743		-	i.view.ToolCalls = toolCalls
744		-	i.view.Err = errLine
745	737
746	738		// Welcome banner: shown at the top of the chat area when there is
747	739		// no transcript yet. Disappears after the first message is sent.

@@ -1015,15 +1007,7 @@ func (i *Interactive) redraw() {
1015	1007		// content. The status block and editor get their own dedicated
1016	1008		// blanks so spacing stays consistent whether or not a dialog or
1017	1009		// popup is showing.
1018		-	bottom := make([]string, 0, len(i.liveBlock)+len(dialog)+len(suggest)+len(queue)+len(edLines)+9)
1019		-	if len(i.liveBlock) > 0 {
1020		-	// Live streaming/tool rows are rendered outside the immutable
1021		-	// transcript so native scrollback stays stable while the agent
1022		-	// works. Add the same breathing row the finalized transcript path
1023		-	// gets between adjacent messages.
1024		-	bottom = append(bottom, "")
1025		-	bottom = append(bottom, i.liveBlock...)
1026		-	}
	1010	+	bottom := make([]string, 0, len(dialog)+len(suggest)+len(queue)+len(edLines)+9)
1027	1011		if len(dialog) > 0 {
1028	1012		bottom = append(bottom, "")
1029	1013		}

@@ -1151,29 +1135,23 @@ func (i *Interactive) redraw() {
1151	1135		// statusLines and edLines (input breathing room). Without
1152	1136		// these the rendered cursor would land on a blank instead of
1153	1137		// inside the editor row.
1154		-	liveRows := len(i.liveBlock)
1155		-	if liveRows > 0 {
1156		-	// Account for the leading separator row inserted before live
1157		-	// streaming/tool content in the bottom block.
1158		-	liveRows++
1159		-	}
1160		-	cursorRow := liveRows + dialogLead + len(dialog) + len(suggest) + len(queue) + 1 + len(statusLines) + 1 + curR
	1138	+	cursorRow := dialogLead + len(dialog) + len(suggest) + len(queue) + 1 + len(statusLines) + 1 + curR
1161	1139		cursorCol := curC
1162	1140		if i.btwDialog.Active() {
1163	1141		if r, c := i.btwDialog.CursorPos(cols); r >= 0 {
1164		-	cursorRow = liveRows + dialogLead + r
	1142	+	cursorRow = dialogLead + r
1165	1143		cursorCol = c
1166	1144		}
1167	1145		}
1168	1146		if i.dialog.Active() {
1169	1147		if r, c := i.dialog.CursorPos(cols); r >= 0 {
1170		-	cursorRow = liveRows + dialogLead + r
	1148	+	cursorRow = dialogLead + r
1171	1149		cursorCol = c
1172	1150		}
1173	1151		}
1174	1152		if i.sessionDialog.Active() {
1175	1153		if r, c := i.sessionDialog.CursorPos(); r >= 0 {
1176		-	cursorRow = liveRows + dialogLead + r
	1154	+	cursorRow = dialogLead + r
1177	1155		cursorCol = c
1178	1156		}
1179	1157		}

@@ -3437,10 +3415,6 @@ func (i *Interactive) handleEvent(ev core.AgentEvent) {
3437	3415		return
3438	3416		}
3439	3417		i.resetStreamingStateLocked()
3440		-	// Force full repaint: assistant text committed, layout shifts.
3441		-	if i.rend != nil {
3442		-	i.rend.Invalidate()
3443		-	}
3444	3418		case core.EvToolUseStart:
3445	3419		// Live streaming: pre-create the view so the user sees the
3446	3420		// tool call being composed in real time. Any subsequent

@@ -3500,12 +3474,6 @@ func (i *Interactive) handleEvent(ev core.AgentEvent) {
3500	3474		}
3501	3475		tc.Result = text.String()
3502	3476		}
3503		-	// Force full repaint: tool completion shifts the layout
3504		-	// (collapsed body replaces streaming) and the diff renderer
3505		-	// may leave stale code fragments on status bar rows.
3506		-	if i.rend != nil {
3507		-	i.rend.Invalidate()
3508		-	}
3509	3477		if i.cfg.OnToolResult != nil {
3510	3478		i.cfg.OnToolResult(e.ID, e.Result)
3511	3479		}

@@ -3515,12 +3483,6 @@ func (i *Interactive) handleEvent(ev core.AgentEvent) {
3515	3483		i.lastCtxInput = e.Usage.InputTokens + e.Usage.CacheReadTokens + e.Usage.CacheWriteTokens
3516	3484		}
3517	3485		case core.EvTurnEnd:
3518		-	// Force full repaint: the turn ending shifts layout (streaming
3519		-	// buffer flushed, status bar updates) and the diff renderer
3520		-	// may leave stale content on reused rows.
3521		-	if i.rend != nil {
3522		-	i.rend.Invalidate()
3523		-	}
3524	3486		if e.Stop == provider.StopAborted {
3525	3487		i.resetStreamingStateLocked()
3526	3488		i.statusErr = ""


@@ -727,21 +727,13 @@ func (i *Interactive) buildChatLocked(cols int) []string {
727		}	727		}
728		}	728		}
729		i.view.Err = i.statusErr	729		i.view.Err = i.statusErr
730	-	i.liveBlock = i.view.BuildLive(cols)	730	+	// Live streaming/tool rows are appended to the chat buffer (not
731	-		731	+	// hoisted into a separate live block above the editor). That keeps
732	-	streamingActive := i.view.StreamingActive	732	+	// the renderer's diff view append-only: when a tool finishes the
733	-	streaming := i.view.Streaming	733	+	// rows update in place at the end of the buffer, instead of the
734	-	toolCalls := i.view.ToolCalls	734	+	// whole bottom band shrinking and shifting chat lines around.
735	-	errLine := i.view.Err	735	+	i.liveBlock = nil
736	-	i.view.StreamingActive = false
737	-	i.view.Streaming = ""
738	-	i.view.ToolCalls = nil
739	-	i.view.Err = ""
740		chat := i.view.Build(cols)	736		chat := i.view.Build(cols)
741	-	i.view.StreamingActive = streamingActive
742	-	i.view.Streaming = streaming
743	-	i.view.ToolCalls = toolCalls
744	-	i.view.Err = errLine
745			737
746		// Welcome banner: shown at the top of the chat area when there is	738		// Welcome banner: shown at the top of the chat area when there is
747		// no transcript yet. Disappears after the first message is sent.	739		// no transcript yet. Disappears after the first message is sent.

@@ -1015,15 +1007,7 @@ func (i *Interactive) redraw() {
1015		// content. The status block and editor get their own dedicated	1007		// content. The status block and editor get their own dedicated
1016		// blanks so spacing stays consistent whether or not a dialog or	1008		// blanks so spacing stays consistent whether or not a dialog or
1017		// popup is showing.	1009		// popup is showing.
1018	-	bottom := make([]string, 0, len(i.liveBlock)+len(dialog)+len(suggest)+len(queue)+len(edLines)+9)	1010	+	bottom := make([]string, 0, len(dialog)+len(suggest)+len(queue)+len(edLines)+9)
1019	-	if len(i.liveBlock) > 0 {
1020	-	// Live streaming/tool rows are rendered outside the immutable
1021	-	// transcript so native scrollback stays stable while the agent
1022	-	// works. Add the same breathing row the finalized transcript path
1023	-	// gets between adjacent messages.
1024	-	bottom = append(bottom, "")
1025	-	bottom = append(bottom, i.liveBlock...)
1026	-	}
1027		if len(dialog) > 0 {	1011		if len(dialog) > 0 {
1028		bottom = append(bottom, "")	1012		bottom = append(bottom, "")
1029		}	1013		}

@@ -1151,29 +1135,23 @@ func (i *Interactive) redraw() {
1151		// statusLines and edLines (input breathing room). Without	1135		// statusLines and edLines (input breathing room). Without
1152		// these the rendered cursor would land on a blank instead of	1136		// these the rendered cursor would land on a blank instead of
1153		// inside the editor row.	1137		// inside the editor row.
1154	-	liveRows := len(i.liveBlock)	1138	+	cursorRow := dialogLead + len(dialog) + len(suggest) + len(queue) + 1 + len(statusLines) + 1 + curR
1155	-	if liveRows > 0 {
1156	-	// Account for the leading separator row inserted before live
1157	-	// streaming/tool content in the bottom block.
1158	-	liveRows++
1159	-	}
1160	-	cursorRow := liveRows + dialogLead + len(dialog) + len(suggest) + len(queue) + 1 + len(statusLines) + 1 + curR
1161		cursorCol := curC	1139		cursorCol := curC
1162		if i.btwDialog.Active() {	1140		if i.btwDialog.Active() {
1163		if r, c := i.btwDialog.CursorPos(cols); r >= 0 {	1141		if r, c := i.btwDialog.CursorPos(cols); r >= 0 {
1164	-	cursorRow = liveRows + dialogLead + r	1142	+	cursorRow = dialogLead + r
1165		cursorCol = c	1143		cursorCol = c
1166		}	1144		}
1167		}	1145		}
1168		if i.dialog.Active() {	1146		if i.dialog.Active() {
1169		if r, c := i.dialog.CursorPos(cols); r >= 0 {	1147		if r, c := i.dialog.CursorPos(cols); r >= 0 {
1170	-	cursorRow = liveRows + dialogLead + r	1148	+	cursorRow = dialogLead + r
1171		cursorCol = c	1149		cursorCol = c
1172		}	1150		}
1173		}	1151		}
1174		if i.sessionDialog.Active() {	1152		if i.sessionDialog.Active() {
1175		if r, c := i.sessionDialog.CursorPos(); r >= 0 {	1153		if r, c := i.sessionDialog.CursorPos(); r >= 0 {
1176	-	cursorRow = liveRows + dialogLead + r	1154	+	cursorRow = dialogLead + r
1177		cursorCol = c	1155		cursorCol = c
1178		}	1156		}
1179		}	1157		}

@@ -3437,10 +3415,6 @@ func (i *Interactive) handleEvent(ev core.AgentEvent) {
3437		return	3415		return
3438		}	3416		}
3439		i.resetStreamingStateLocked()	3417		i.resetStreamingStateLocked()
3440	-	// Force full repaint: assistant text committed, layout shifts.
3441	-	if i.rend != nil {
3442	-	i.rend.Invalidate()
3443	-	}
3444		case core.EvToolUseStart:	3418		case core.EvToolUseStart:
3445		// Live streaming: pre-create the view so the user sees the	3419		// Live streaming: pre-create the view so the user sees the
3446		// tool call being composed in real time. Any subsequent	3420		// tool call being composed in real time. Any subsequent

@@ -3500,12 +3474,6 @@ func (i *Interactive) handleEvent(ev core.AgentEvent) {
3500		}	3474		}
3501		tc.Result = text.String()	3475		tc.Result = text.String()
3502		}	3476		}
3503	-	// Force full repaint: tool completion shifts the layout
3504	-	// (collapsed body replaces streaming) and the diff renderer
3505	-	// may leave stale code fragments on status bar rows.
3506	-	if i.rend != nil {
3507	-	i.rend.Invalidate()
3508	-	}
3509		if i.cfg.OnToolResult != nil {	3477		if i.cfg.OnToolResult != nil {
3510		i.cfg.OnToolResult(e.ID, e.Result)	3478		i.cfg.OnToolResult(e.ID, e.Result)
3511		}	3479		}

@@ -3515,12 +3483,6 @@ func (i *Interactive) handleEvent(ev core.AgentEvent) {
3515		i.lastCtxInput = e.Usage.InputTokens + e.Usage.CacheReadTokens + e.Usage.CacheWriteTokens	3483		i.lastCtxInput = e.Usage.InputTokens + e.Usage.CacheReadTokens + e.Usage.CacheWriteTokens
3516		}	3484		}
3517		case core.EvTurnEnd:	3485		case core.EvTurnEnd:
3518	-	// Force full repaint: the turn ending shifts layout (streaming
3519	-	// buffer flushed, status bar updates) and the diff renderer
3520	-	// may leave stale content on reused rows.
3521	-	if i.rend != nil {
3522	-	i.rend.Invalidate()
3523	-	}
3524		if e.Stop == provider.StopAborted {	3486		if e.Stop == provider.StopAborted {
3525		i.resetStreamingStateLocked()	3487		i.resetStreamingStateLocked()
3526		i.statusErr = ""	3488		i.statusErr = ""

M internal/tui/render.go +47 -46


@@ -58,6 +58,12 @@ func NewRenderer(out io.Writer) *Renderer {
58	58		// starts from a blank slate. Without the clear, characters from the
59	59		// old (wider) layout linger past the new right edge and rows from
60	60		// before the new bottom hang around as garbage.
	61	+	func (r *Renderer) ResetScrollRegion() {
	62	+	if r.out != nil {
	63	+	_, _ = io.WriteString(r.out, SeqResetScrollRegion)
	64	+	}
	65	+	}
	66	+
61	67		func (r *Renderer) Resize(cols, rows int) {
62	68		if cols != r.cols \|\| rows != r.rows {
63	69		r.cols = cols

@@ -398,36 +404,11 @@ func (r *Renderer) DrawLog(chat, bottom []string, cursorBottomRow, cursorCol int
398	404		w.WriteString(SeqShowCursor)
399	405		}
400	406
401		-	// Selection-highlight workaround: VS Code's terminal (and some
402		-	// others) don't reliably clear background colors when a row is
403		-	// overwritten. When the current OR previous bottom block contains
404		-	// selection-highlight escapes (dialogs with a cursor row), wipe
405		-	// the cached bottom rows so the diff rewrites every one of them.
406		-	// This mirrors the hasSelection guard in Draw().
407		-	if r.logInit && len(r.logLines) > 0 {
408		-	botHasHL := func(block []string) bool {
409		-	for _, l := range block {
410		-	if strings.Contains(l, "\x1b[48;5;") {
411		-	return true
412		-	}
413		-	}
414		-	return false
415		-	}
416		-	if botHasHL(bottomFrame) \|\| botHasHL(r.logBottom) {
417		-	// Invalidate only the bottom portion of the cached lines
418		-	// so the chat region (terminal scrollback) is still
419		-	// diffed cheaply. We do this by replacing the old bottom
420		-	// rows with empty strings so every bottom row looks
421		-	// "changed" to the diff below.
422		-	botStart := len(r.logLines) - len(r.logBottom) - bottomMarginRows
423		-	if botStart < 0 {
424		-	botStart = 0
425		-	}
426		-	for idx := botStart; idx < len(r.logLines); idx++ {
427		-	r.logLines[idx] = "\x00" // sentinel that won't match any real line
428		-	}
429		-	}
430		-	}
	407	+	// Selection-highlight workaround removed: it could mis-invalidate
	408	+	// user-bubble padding rows whose colored bg made botHasHL trip,
	409	+	// causing the next diff pass to leave those rows visually thinned
	410	+	// because the cached entry was the \x00 sentinel rather than the
	411	+	// real previous bg-colored row.
431	412
432	413		full := !r.logInit \|\| len(r.logLines) == 0
433	414		if full {

@@ -456,14 +437,26 @@ func (r *Renderer) DrawLog(chat, bottom []string, cursorBottomRow, cursorCol int
456	437		lastChanged = idx
457	438		}
458	439		}
	440	+	// Buffer grew but the appended rows were empty (or otherwise
	441	+	// equal to the implicit "" past the old end). The diff above
	442	+	// won't flag those rows, yet the renderer still needs to
	443	+	// advance its hardware cursor / viewport tracking past them so
	444	+	// the next render starts from the correct position. Treat the
	445	+	// extension as changed.
	446	+	if len(lines) > len(r.logLines) {
	447	+	if firstChanged == -1 {
	448	+	firstChanged = len(r.logLines)
	449	+	}
	450	+	if lastChanged < len(lines)-1 {
	451	+	lastChanged = len(lines) - 1
	452	+	}
	453	+	}
459	454
460	455		if firstChanged == -1 {
461	456		// No content changes; the final cursor positioning below may still
462	457		// move the hardware cursor if the editor cursor changed.
463		-	} else if len(lines) < len(r.logLines) \|\| firstChanged < r.logViewportTop {
464		-	// Shrinks and changes above the visible viewport cannot be safely
465		-	// patched in terminal scrollback. Replay the current logical buffer
466		-	// instead of risking stale duplicated rows.
	458	+	} else if firstChanged < r.logViewportTop {
	459	+	// Changes above the visible viewport cannot be patched safely.
467	460		writeFull(true)
468	461		} else {
469	462		prevViewportTop := r.logViewportTop

@@ -523,7 +516,26 @@ func (r *Renderer) DrawLog(chat, bottom []string, cursorBottomRow, cursorCol int
523	516		w.WriteString(SeqClearLine)
524	517		w.WriteString(lines[idx])
525	518		}
526		-	r.logHardwareRow = renderEnd
	519	+	finalRow := renderEnd
	520	+	if len(r.logLines) > len(lines) {
	521	+	extra := len(r.logLines) - len(lines)
	522	+	if extra > r.rows {
	523	+	writeFull(true)
	524	+	} else {
	525	+	for e := 0; e < extra; e++ {
	526	+	w.WriteString("\x1b[1B")
	527	+	w.WriteString("\r")
	528	+	w.WriteString("\x1b[0m")
	529	+	w.WriteString(SeqClearLine)
	530	+	finalRow++
	531	+	}
	532	+	if extra > 0 {
	533	+	w.WriteString("\x1b[" + itoa(extra) + "A")
	534	+	finalRow -= extra
	535	+	}
	536	+	}
	537	+	}
	538	+	r.logHardwareRow = finalRow
527	539		r.logViewportTop = viewportTop
528	540		if minTop := r.logHardwareRow - r.rows + 1; minTop > r.logViewportTop {
529	541		r.logViewportTop = minTop

@@ -534,17 +546,6 @@ func (r *Renderer) DrawLog(chat, bottom []string, cursorBottomRow, cursorCol int
534	546		}
535	547		}
536	548
537		-	// Re-anchor the terminal viewport at the true end of the logical
538		-	// buffer on every frame. During busy turns most redraws only mutate
539		-	// spinner/live rows above the editor; without touching the final margin
540		-	// row, the terminal can visually lose the bottom padding even though it
541		-	// still exists in r.logLines.
542		-	if len(lines) > 0 {
543		-	moveToLogicalRow(len(lines) - 1)
544		-	w.WriteString("\r")
545		-	w.WriteString("\x1b[0m")
546		-	w.WriteString(SeqClearLine)
547		-	}
548	549		positionCursor()
549	550		w.WriteString(SeqSynchronizedOff)
550	551		_, _ = io.WriteString(r.out, w.String())

 // starts from a blank slate. Without the clear, characters from the
 // old (wider) layout linger past the new right edge and rows from
 // before the new bottom hang around as garbage.
+func (r *Renderer) ResetScrollRegion() {
+	if r.out != nil {
+		_, _ = io.WriteString(r.out, SeqResetScrollRegion)
+	}
+}
 func (r *Renderer) Resize(cols, rows int) {
 	if cols != r.cols || rows != r.rows {
 		r.cols = cols
 		w.WriteString(SeqShowCursor)
 	}
-	// Selection-highlight workaround: VS Code's terminal (and some
+	// Selection-highlight workaround removed: it could mis-invalidate
-	// others) don't reliably clear background colors when a row is
+	// user-bubble padding rows whose colored bg made botHasHL trip,
-	// overwritten. When the current OR previous bottom block contains
+	// causing the next diff pass to leave those rows visually thinned
-	// selection-highlight escapes (dialogs with a cursor row), wipe
+	// because the cached entry was the \x00 sentinel rather than the
-	// the cached bottom rows so the diff rewrites every one of them.
+	// real previous bg-colored row.
-	// This mirrors the hasSelection guard in Draw().
-	if r.logInit && len(r.logLines) > 0 {
-		botHasHL := func(block []string) bool {
-			for _, l := range block {
-				if strings.Contains(l, "\x1b[48;5;") {
-					return true
-				}
-			}
-			return false
-		}
-		if botHasHL(bottomFrame) || botHasHL(r.logBottom) {
-			// Invalidate only the bottom portion of the cached lines
-			// so the chat region (terminal scrollback) is still
-			// diffed cheaply. We do this by replacing the old bottom
-			// rows with empty strings so every bottom row looks
-			// "changed" to the diff below.
-			botStart := len(r.logLines) - len(r.logBottom) - bottomMarginRows
-			if botStart < 0 {
-				botStart = 0
-			}
-			for idx := botStart; idx < len(r.logLines); idx++ {
-				r.logLines[idx] = "\x00" // sentinel that won't match any real line
-			}
-		}
-	}
 	full := !r.logInit || len(r.logLines) == 0
 	if full {
 				lastChanged = idx
 			}
 		}
+		// Buffer grew but the appended rows were empty (or otherwise
+		// equal to the implicit "" past the old end). The diff above
+		// won't flag those rows, yet the renderer still needs to
+		// advance its hardware cursor / viewport tracking past them so
+		// the next render starts from the correct position. Treat the
+		// extension as changed.
+		if len(lines) > len(r.logLines) {
+			if firstChanged == -1 {
+				firstChanged = len(r.logLines)
+			}
+			if lastChanged < len(lines)-1 {
+				lastChanged = len(lines) - 1
+			}
+		}
 		if firstChanged == -1 {
 			// No content changes; the final cursor positioning below may still
 			// move the hardware cursor if the editor cursor changed.
-		} else if len(lines) < len(r.logLines) || firstChanged < r.logViewportTop {
+		} else if firstChanged < r.logViewportTop {
-			// Shrinks and changes above the visible viewport cannot be safely
+			// Changes above the visible viewport cannot be patched safely.
-			// patched in terminal scrollback. Replay the current logical buffer
-			// instead of risking stale duplicated rows.
 			writeFull(true)
 		} else {
 			prevViewportTop := r.logViewportTop
 				w.WriteString(SeqClearLine)
 				w.WriteString(lines[idx])
 			}
-			r.logHardwareRow = renderEnd
+			finalRow := renderEnd
+			if len(r.logLines) > len(lines) {
+				extra := len(r.logLines) - len(lines)
+				if extra > r.rows {
+					writeFull(true)
+				} else {
+					for e := 0; e < extra; e++ {
+						w.WriteString("\x1b[1B")
+						w.WriteString("\r")
+						w.WriteString("\x1b[0m")
+						w.WriteString(SeqClearLine)
+						finalRow++
+					}
+					if extra > 0 {
+						w.WriteString("\x1b[" + itoa(extra) + "A")
+						finalRow -= extra
+					}
+				}
+			}
+			r.logHardwareRow = finalRow
 			r.logViewportTop = viewportTop
 			if minTop := r.logHardwareRow - r.rows + 1; minTop > r.logViewportTop {
 				r.logViewportTop = minTop
 		}
 	}
-	// Re-anchor the terminal viewport at the true end of the logical
-	// buffer on every frame. During busy turns most redraws only mutate
-	// spinner/live rows above the editor; without touching the final margin
-	// row, the terminal can visually lose the bottom padding even though it
-	// still exists in r.logLines.
-	if len(lines) > 0 {
-		moveToLogicalRow(len(lines) - 1)
-		w.WriteString("\r")
-		w.WriteString("\x1b[0m")
-		w.WriteString(SeqClearLine)
-	}
 	positionCursor()
 	w.WriteString(SeqSynchronizedOff)
 	_, _ = io.WriteString(r.out, w.String())

M internal/tui/terminal.go +8 -0


@@ -111,6 +111,14 @@ const (
111	111		SeqEraseToEnd = "\x1b[J"
112	112		)
113	113
	114	+	// SetScrollRegion returns the DECSTBM sequence to set the terminal's
	115	+	// scroll region (1-indexed, inclusive). Lines that scroll out of this
	116	+	// region still flow into the terminal's scrollback, but content above
	117	+	// or below the region is not affected by scroll-induced movement.
	118	+	func SetScrollRegion(top, bottom int) string {
	119	+	return "\x1b[" + itoa(top) + ";" + itoa(bottom) + "r"
	120	+	}
	121	+
114	122		// MoveTo moves the cursor to 1-indexed (row, col).
115	123		func MoveTo(row, col int) string {
116	124		return "\x1b[" + itoa(row) + ";" + itoa(col) + "H"


@@ -111,6 +111,14 @@ const (
111	SeqEraseToEnd = "\x1b[J"	111		SeqEraseToEnd = "\x1b[J"
112	)	112		)
113		113
		114	+	// SetScrollRegion returns the DECSTBM sequence to set the terminal's
		115	+	// scroll region (1-indexed, inclusive). Lines that scroll out of this
		116	+	// region still flow into the terminal's scrollback, but content above
		117	+	// or below the region is not affected by scroll-induced movement.
		118	+	func SetScrollRegion(top, bottom int) string {
		119	+	return "\x1b[" + itoa(top) + ";" + itoa(bottom) + "r"
		120	+	}
		121	+
114	// MoveTo moves the cursor to 1-indexed (row, col).	122		// MoveTo moves the cursor to 1-indexed (row, col).
115	func MoveTo(row, col int) string {	123		func MoveTo(row, col int) string {
116	return "\x1b[" + itoa(row) + ";" + itoa(col) + "H"	124		return "\x1b[" + itoa(row) + ";" + itoa(col) + "H"