refactor(vt): isolate core model and ANSI package

commit: 2981612693b6b884519b516e0a007e7ed27bb798
author: brice · 2mo ago · 2026-08-09 10:59 UTC
committer: brice · 2mo ago · 2026-08-09 12:00 UTC
parent: e4fd2d1
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

50 files · +911 -110

A docs/vt-extraction-preparation.md +41 -0

@@ -0,0 +1,41 @@
	1	+	# VT extraction preparation checkpoint
	2	+
	3	+	The extraction boundary is ready for standalone ownership. Compatibility
	4	+	coverage and the first dependency-inversion step are complete; VT behavior,
	5	+	renderer output, wire bytes, transport, ACK/rebase, and cursor-tail policy remain
	6	+	unchanged.
	7	+
	8	+	## Evidence
	9	+
	10	+	- The feature worktree was created from a clean checkout.
	11	+	- `make test` passes (`go test ./... -race`).
	12	+	- `make lint` passes (`goimports` has no changes and `go vet ./...` passes).
	13	+	- External-package contract tests pass under `-race` for parsing, callbacks,
	14	+	borrowing, snapshots, history views, stable chunk identity, and single-owner
	15	+	usage.
	16	+	- VTH3 golden vectors round-trip byte-for-byte across empty, plain,
	17	+	continuation, styled/RGB, bounded, and line-bound cases. Truncation,
	18	+	corruption, invalid fields, and trailing bytes are rejected.
	19	+	- The VEVS v4 restore envelope golden decodes through the existing restore path,
	20	+	including sealed history, tail history, and recovery transcript blobs.
	21	+	Truncated, corrupted, trailing, and malformed nested VT payloads are rejected.
	22	+	- Representative VT/history/snapshot benchmarks pass; benchmark output is
	23	+	retained in the implementation run rather than committed as machine-specific
	24	+	data.
	25	+	- `git diff --check` passes.
	26	+	- `pkg/vtcore` owns the frontend-neutral Cell, Style, RGB, Frame, Damage, and
	27	+	RuneWidth model; `pkg/vt` has no production dependency on the ANSI package.
	28	+	- `pkg/ansi` owns ANSI output planning and encoding and consumes `vtcore`; the
	29	+	old `pkg/renderer` path forwards to it without a second implementation owner.
	30	+	- A core-only frame consumer test builds ANSI output without importing the VT
	31	+	parser.
	32	+
	33	+	## Scope guard
	34	+
	35	+	The production changes in this checkpoint only move model ownership behind an
	36	+	explicit core package and adapt ANSI delta commits to the core Frame API. No VT
	37	+	parser behavior, VTH3/VEVS bytes, or wire/protocol definition changed. The
	38	+	compatibility import path is a temporary cutover bridge; the standalone release
	39	+	must not retain it or a local module replacement. Any unrelated behavior, wire,
	40	+	or dependency change discovered while extracting the standalone module must be
	41	+	split into a separate plan.

@@ -0,0 +1,41 @@
	1	+	# VT extraction preparation checkpoint
	2	+
	3	+	The extraction boundary is ready for standalone ownership. Compatibility
	4	+	coverage and the first dependency-inversion step are complete; VT behavior,
	5	+	renderer output, wire bytes, transport, ACK/rebase, and cursor-tail policy remain
	6	+	unchanged.
	7	+
	8	+	## Evidence
	9	+
	10	+	- The feature worktree was created from a clean checkout.
	11	+	- `make test` passes (`go test ./... -race`).
	12	+	- `make lint` passes (`goimports` has no changes and `go vet ./...` passes).
	13	+	- External-package contract tests pass under `-race` for parsing, callbacks,
	14	+	borrowing, snapshots, history views, stable chunk identity, and single-owner
	15	+	usage.
	16	+	- VTH3 golden vectors round-trip byte-for-byte across empty, plain,
	17	+	continuation, styled/RGB, bounded, and line-bound cases. Truncation,
	18	+	corruption, invalid fields, and trailing bytes are rejected.
	19	+	- The VEVS v4 restore envelope golden decodes through the existing restore path,
	20	+	including sealed history, tail history, and recovery transcript blobs.
	21	+	Truncated, corrupted, trailing, and malformed nested VT payloads are rejected.
	22	+	- Representative VT/history/snapshot benchmarks pass; benchmark output is
	23	+	retained in the implementation run rather than committed as machine-specific
	24	+	data.
	25	+	- `git diff --check` passes.
	26	+	- `pkg/vtcore` owns the frontend-neutral Cell, Style, RGB, Frame, Damage, and
	27	+	RuneWidth model; `pkg/vt` has no production dependency on the ANSI package.
	28	+	- `pkg/ansi` owns ANSI output planning and encoding and consumes `vtcore`; the
	29	+	old `pkg/renderer` path forwards to it without a second implementation owner.
	30	+	- A core-only frame consumer test builds ANSI output without importing the VT
	31	+	parser.
	32	+
	33	+	## Scope guard
	34	+
	35	+	The production changes in this checkpoint only move model ownership behind an
	36	+	explicit core package and adapt ANSI delta commits to the core Frame API. No VT
	37	+	parser behavior, VTH3/VEVS bytes, or wire/protocol definition changed. The
	38	+	compatibility import path is a temporary cutover bridge; the standalone release
	39	+	must not retain it or a local module replacement. Any unrelated behavior, wire,
	40	+	or dependency change discovered while extracting the standalone module must be
	41	+	split into a separate plan.

A internal/usecase/snapshot/vevs_v4_golden_test.go +109 -0

@@ -0,0 +1,109 @@
	1	+	package snapshot
	2	+
	3	+	import (
	4	+	"bytes"
	5	+	"encoding/hex"
	6	+	"testing"
	7	+
	8	+	"github.com/bnema/vev/internal/usecase/layout"
	9	+	"github.com/bnema/vev/pkg/vt"
	10	+	)
	11	+
	12	+	func TestVEVSV4GoldenRestoreCompatibility(t *testing.T) {
	13	+	const golden = "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"
	14	+	data, err := hex.DecodeString(golden)
	15	+	if err != nil {
	16	+	t.Fatal(err)
	17	+	}
	18	+
	19	+	got, err := Unmarshal(data)
	20	+	if err != nil {
	21	+	t.Fatalf("Unmarshal golden VEVS: %v", err)
	22	+	}
	23	+	if got.Name != "restore" \|\| got.CreatedAt != 123 \|\| len(got.Tabs) != 1 {
	24	+	t.Fatalf("session header = %#v", got)
	25	+	}
	26	+	tab := got.Tabs[0]
	27	+	if tab.StableID != "tab" \|\| tab.Cols != 80 \|\| tab.Rows != 24 \|\| tab.NextPaneID != 2 \|\| tab.Focus != layout.PaneID("p") \|\| len(tab.Panes) != 1 {
	28	+	t.Fatalf("tab header = %#v", tab)
	29	+	}
	30	+	pane := tab.Panes[0]
	31	+	if pane.ID != layout.PaneID("p") \|\| pane.StableID != "stable" \|\| pane.Cwd != "/tmp" \|\| pane.Process != nil \|\| len(pane.SealedChunks) != 1 {
	32	+	t.Fatalf("pane header = %#v", pane)
	33	+	}
	34	+
	35	+	sealed, err := vt.UnmarshalHistory(pane.SealedChunks[0])
	36	+	if err != nil {
	37	+	t.Fatalf("sealed history: %v", err)
	38	+	}
	39	+	if sealed.RowID(0) != 41 \|\| sealed.Row(0)[0].Rune != 'A' {
	40	+	t.Fatalf("sealed history = row %d %#v", sealed.RowID(0), sealed.Row(0))
	41	+	}
	42	+	tail, err := vt.UnmarshalHistory(pane.Tail)
	43	+	if err != nil {
	44	+	t.Fatalf("history tail: %v", err)
	45	+	}
	46	+	if tail.Len() != 0 \|\| tail.NextRowID() != 42 {
	47	+	t.Fatalf("history tail = len %d next %d", tail.Len(), tail.NextRowID())
	48	+	}
	49	+	transcript, err := vt.UnmarshalHistory(pane.Transcript)
	50	+	if err != nil {
	51	+	t.Fatalf("recovery transcript: %v", err)
	52	+	}
	53	+	if transcript.RowID(0) != 42 \|\| transcript.Row(0)[0].Rune != '界' {
	54	+	t.Fatalf("recovery transcript = row %d %#v", transcript.RowID(0), transcript.Row(0))
	55	+	}
	56	+
	57	+	screen, err := vt.NewScreenWithRecoveryTranscript(8, 2, vt.HistoryConfig{MaxRows: 8, ChunkRows: 2}, pane.SealedChunks, pane.Tail, pane.Transcript)
	58	+	if err != nil {
	59	+	t.Fatalf("restore VT history: %v", err)
	60	+	}
	61	+	view := screen.History().View()
	62	+	if view.Len() != 2 \|\| view.RowID(0) != 41 \|\| view.RowID(1) != 42 \|\| view.NextRowID() != 43 {
	63	+	t.Fatalf("restored history = len %d IDs %d/%d next %d", view.Len(), view.RowID(0), view.RowID(1), view.NextRowID())
	64	+	}
	65	+	}
	66	+
	67	+	func TestVEVSV4GoldenRejectsMalformedInput(t *testing.T) {
	68	+	const golden = "5645565300040000000001291707ae820007726573746f7265000000000000007b0000000100037461620050001800000000000000020001700000017000010001700006737461626c6500042f746d700000000100000078565448310300000001000000000000002a0000000100000000000000290000000200000041000000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff00000000000000010000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff000000000000020000000011565448310300000000000000000000002a0000004f565448310300000001000000000000002b00000001000000000000002a000000010000754cff000ffffffffffffffff9000000000000010101020304050605fffffffffffffff7070809000000010100"
	69	+	valid, err := hex.DecodeString(golden)
	70	+	if err != nil {
	71	+	t.Fatal(err)
	72	+	}
	73	+	mutate := func(fn func([]byte)) []byte {
	74	+	out := append([]byte(nil), valid...)
	75	+	fn(out)
	76	+	return out
	77	+	}
	78	+	cases := []struct {
	79	+	name string
	80	+	data []byte
	81	+	}{
	82	+	{name: "truncated", data: valid[:len(valid)-1]},
	83	+	{name: "trailing bytes", data: append(append([]byte(nil), valid...), 0)},
	84	+	{name: "bad magic", data: mutate(func(data []byte) { data[0] ^= 0xff })},
	85	+	{name: "bad version", data: mutate(func(data []byte) { data[4] = 3 })},
	86	+	{name: "bad flags", data: mutate(func(data []byte) { data[7] = 1 })},
	87	+	{name: "bad crc", data: mutate(func(data []byte) { data[15] ^= 0xff })},
	88	+	}
	89	+
	90	+	body := append([]byte(nil), valid[16:]...)
	91	+	if offset := bytes.Index(body, []byte("VTH1")); offset < 0 {
	92	+	t.Fatal("golden has no VT blob")
	93	+	} else {
	94	+	body[offset+4] = 2
	95	+	cases = append(cases, struct {
	96	+	name string
	97	+	data []byte
	98	+	}{name: "bad nested VT version", data: v4Envelope(4, 0, body)})
	99	+	}
	100	+
	101	+	for _, test := range cases {
	102	+	t.Run(test.name, func(t *testing.T) {
	103	+	reject(t, test.data, nil)
	104	+	})
	105	+	}
	106	+	for length := 0; length < len(valid); length++ {
	107	+	reject(t, valid[:length], nil)
	108	+	}
	109	+	}

@@ -0,0 +1,109 @@
	1	+	package snapshot
	2	+
	3	+	import (
	4	+	"bytes"
	5	+	"encoding/hex"
	6	+	"testing"
	7	+
	8	+	"github.com/bnema/vev/internal/usecase/layout"
	9	+	"github.com/bnema/vev/pkg/vt"
	10	+	)
	11	+
	12	+	func TestVEVSV4GoldenRestoreCompatibility(t *testing.T) {
	13	+	const golden = "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"
	14	+	data, err := hex.DecodeString(golden)
	15	+	if err != nil {
	16	+	t.Fatal(err)
	17	+	}
	18	+
	19	+	got, err := Unmarshal(data)
	20	+	if err != nil {
	21	+	t.Fatalf("Unmarshal golden VEVS: %v", err)
	22	+	}
	23	+	if got.Name != "restore" \|\| got.CreatedAt != 123 \|\| len(got.Tabs) != 1 {
	24	+	t.Fatalf("session header = %#v", got)
	25	+	}
	26	+	tab := got.Tabs[0]
	27	+	if tab.StableID != "tab" \|\| tab.Cols != 80 \|\| tab.Rows != 24 \|\| tab.NextPaneID != 2 \|\| tab.Focus != layout.PaneID("p") \|\| len(tab.Panes) != 1 {
	28	+	t.Fatalf("tab header = %#v", tab)
	29	+	}
	30	+	pane := tab.Panes[0]
	31	+	if pane.ID != layout.PaneID("p") \|\| pane.StableID != "stable" \|\| pane.Cwd != "/tmp" \|\| pane.Process != nil \|\| len(pane.SealedChunks) != 1 {
	32	+	t.Fatalf("pane header = %#v", pane)
	33	+	}
	34	+
	35	+	sealed, err := vt.UnmarshalHistory(pane.SealedChunks[0])
	36	+	if err != nil {
	37	+	t.Fatalf("sealed history: %v", err)
	38	+	}
	39	+	if sealed.RowID(0) != 41 \|\| sealed.Row(0)[0].Rune != 'A' {
	40	+	t.Fatalf("sealed history = row %d %#v", sealed.RowID(0), sealed.Row(0))
	41	+	}
	42	+	tail, err := vt.UnmarshalHistory(pane.Tail)
	43	+	if err != nil {
	44	+	t.Fatalf("history tail: %v", err)
	45	+	}
	46	+	if tail.Len() != 0 \|\| tail.NextRowID() != 42 {
	47	+	t.Fatalf("history tail = len %d next %d", tail.Len(), tail.NextRowID())
	48	+	}
	49	+	transcript, err := vt.UnmarshalHistory(pane.Transcript)
	50	+	if err != nil {
	51	+	t.Fatalf("recovery transcript: %v", err)
	52	+	}
	53	+	if transcript.RowID(0) != 42 \|\| transcript.Row(0)[0].Rune != '界' {
	54	+	t.Fatalf("recovery transcript = row %d %#v", transcript.RowID(0), transcript.Row(0))
	55	+	}
	56	+
	57	+	screen, err := vt.NewScreenWithRecoveryTranscript(8, 2, vt.HistoryConfig{MaxRows: 8, ChunkRows: 2}, pane.SealedChunks, pane.Tail, pane.Transcript)
	58	+	if err != nil {
	59	+	t.Fatalf("restore VT history: %v", err)
	60	+	}
	61	+	view := screen.History().View()
	62	+	if view.Len() != 2 \|\| view.RowID(0) != 41 \|\| view.RowID(1) != 42 \|\| view.NextRowID() != 43 {
	63	+	t.Fatalf("restored history = len %d IDs %d/%d next %d", view.Len(), view.RowID(0), view.RowID(1), view.NextRowID())
	64	+	}
	65	+	}
	66	+
	67	+	func TestVEVSV4GoldenRejectsMalformedInput(t *testing.T) {
	68	+	const golden = "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"
	69	+	valid, err := hex.DecodeString(golden)
	70	+	if err != nil {
	71	+	t.Fatal(err)
	72	+	}
	73	+	mutate := func(fn func([]byte)) []byte {
	74	+	out := append([]byte(nil), valid...)
	75	+	fn(out)
	76	+	return out
	77	+	}
	78	+	cases := []struct {
	79	+	name string
	80	+	data []byte
	81	+	}{
	82	+	{name: "truncated", data: valid[:len(valid)-1]},
	83	+	{name: "trailing bytes", data: append(append([]byte(nil), valid...), 0)},
	84	+	{name: "bad magic", data: mutate(func(data []byte) { data[0] ^= 0xff })},
	85	+	{name: "bad version", data: mutate(func(data []byte) { data[4] = 3 })},
	86	+	{name: "bad flags", data: mutate(func(data []byte) { data[7] = 1 })},
	87	+	{name: "bad crc", data: mutate(func(data []byte) { data[15] ^= 0xff })},
	88	+	}
	89	+
	90	+	body := append([]byte(nil), valid[16:]...)
	91	+	if offset := bytes.Index(body, []byte("VTH1")); offset < 0 {
	92	+	t.Fatal("golden has no VT blob")
	93	+	} else {
	94	+	body[offset+4] = 2
	95	+	cases = append(cases, struct {
	96	+	name string
	97	+	data []byte
	98	+	}{name: "bad nested VT version", data: v4Envelope(4, 0, body)})
	99	+	}
	100	+
	101	+	for _, test := range cases {
	102	+	t.Run(test.name, func(t *testing.T) {
	103	+	reject(t, test.data, nil)
	104	+	})
	105	+	}
	106	+	for length := 0; length < len(valid); length++ {
	107	+	reject(t, valid[:length], nil)
	108	+	}
	109	+	}

R pkg/renderer/benchmark_test.go → pkg/ansi/benchmark_test.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import "testing"
4	4

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import "testing"	3		import "testing"
4			4

A pkg/ansi/cell.go +9 -0

@@ -0,0 +1,9 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// Cell is retained as an alias while vev consumers move to vtcore. New
	6	+	// frontend-neutral code should import github.com/bnema/vev/pkg/vtcore.
	7	+	type Cell = vtcore.Cell
	8	+
	9	+	var BlankCell = vtcore.BlankCell

@@ -0,0 +1,9 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// Cell is retained as an alias while vev consumers move to vtcore. New
	6	+	// frontend-neutral code should import github.com/bnema/vev/pkg/vtcore.
	7	+	type Cell = vtcore.Cell
	8	+
	9	+	var BlankCell = vtcore.BlankCell

A pkg/ansi/consumer_external_test.go +23 -0

@@ -0,0 +1,23 @@
	1	+	package ansi_test
	2	+
	3	+	import (
	4	+	"bytes"
	5	+	"testing"
	6	+
	7	+	"github.com/bnema/vev/pkg/ansi"
	8	+	"github.com/bnema/vev/pkg/vtcore"
	9	+	)
	10	+
	11	+	func TestExternalANSIConsumesCoreFrameIndependently(t *testing.T) {
	12	+	frame := vtcore.NewFrame(2, 1)
	13	+	frame.Set(0, 0, vtcore.Cell{Rune: 'O', Style: vtcore.DefaultStyle()})
	14	+	frame.Set(1, 0, vtcore.Cell{Rune: 'K', Style: vtcore.DefaultStyle()})
	15	+
	16	+	output, err := ansi.New(ansi.Capabilities{}).Draw(frame, []vtcore.Damage{vtcore.FullRedraw()})
	17	+	if err != nil {
	18	+	t.Fatalf("Draw: %v", err)
	19	+	}
	20	+	if !bytes.Contains(output, []byte("OK")) {
	21	+	t.Fatalf("ANSI output = %q, want visible core frame content", output)
	22	+	}
	23	+	}

@@ -0,0 +1,23 @@
	1	+	package ansi_test
	2	+
	3	+	import (
	4	+	"bytes"
	5	+	"testing"
	6	+
	7	+	"github.com/bnema/vev/pkg/ansi"
	8	+	"github.com/bnema/vev/pkg/vtcore"
	9	+	)
	10	+
	11	+	func TestExternalANSIConsumesCoreFrameIndependently(t *testing.T) {
	12	+	frame := vtcore.NewFrame(2, 1)
	13	+	frame.Set(0, 0, vtcore.Cell{Rune: 'O', Style: vtcore.DefaultStyle()})
	14	+	frame.Set(1, 0, vtcore.Cell{Rune: 'K', Style: vtcore.DefaultStyle()})
	15	+
	16	+	output, err := ansi.New(ansi.Capabilities{}).Draw(frame, []vtcore.Damage{vtcore.FullRedraw()})
	17	+	if err != nil {
	18	+	t.Fatalf("Draw: %v", err)
	19	+	}
	20	+	if !bytes.Contains(output, []byte("OK")) {
	21	+	t.Fatalf("ANSI output = %q, want visible core frame content", output)
	22	+	}
	23	+	}

A pkg/ansi/damage.go +16 -0

@@ -0,0 +1,16 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	type DamageKind = vtcore.DamageKind
	6	+
	7	+	type Damage = vtcore.Damage
	8	+
	9	+	const (
	10	+	DamageText = vtcore.DamageText
	11	+	DamageClear = vtcore.DamageClear
	12	+	DamageScrollUp = vtcore.DamageScrollUp
	13	+	DamageFullRedraw = vtcore.DamageFullRedraw
	14	+	)
	15	+
	16	+	var FullRedraw = vtcore.FullRedraw

@@ -0,0 +1,16 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	type DamageKind = vtcore.DamageKind
	6	+
	7	+	type Damage = vtcore.Damage
	8	+
	9	+	const (
	10	+	DamageText = vtcore.DamageText
	11	+	DamageClear = vtcore.DamageClear
	12	+	DamageScrollUp = vtcore.DamageScrollUp
	13	+	DamageFullRedraw = vtcore.DamageFullRedraw
	14	+	)
	15	+
	16	+	var FullRedraw = vtcore.FullRedraw

R pkg/renderer/damage_plan.go → pkg/ansi/damage_plan.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"cmp"

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import (	3		import (
4		"cmp"	4		"cmp"

R pkg/renderer/damage_plan_test.go → pkg/ansi/damage_plan_test.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"math"

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import (	3		import (
4		"math"	4		"math"

R pkg/renderer/delta_plan.go → pkg/ansi/delta_plan.go +5 -23 renamed, 87% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		// Span identifies a changed horizontal range in a logical frame row.
4	4		type Span struct {

@@ -204,30 +204,12 @@ func (c DeltaCandidate) Commit(dst *Frame) {
204	204		dst.ScrollUp(scroll.Y, scroll.Y+scroll.Height-1, scroll.Count)
205	205		}
206	206		for _, span := range c.Plan.Spans {
207		-	dstStart := dst.lineOffset[span.Y] + span.X
208		-	srcStart := c.frame.lineOffset[span.Y] + span.X
209		-	copy(dst.Cells[dstStart:dstStart+span.Width], c.frame.Cells[srcStart:srcStart+span.Width])
	207	+	dstRow := dst.Row(span.Y)
	208	+	srcRow := c.frame.Row(span.Y)
	209	+	copy(dstRow[span.X:span.X+span.Width], srcRow[span.X:span.X+span.Width])
210	210		}
211	211		}
212	212
213	213		func replaceFrame(dst *Frame, src Frame) {
214		-	sameDimensions := dst.Width == src.Width && dst.Height == src.Height
215		-	cellCount := src.Width * src.Height
216		-	if sameDimensions && cap(dst.Cells) >= cellCount {
217		-	dst.Cells = dst.Cells[:cellCount]
218		-	} else {
219		-	dst.Cells = make([]Cell, cellCount)
220		-	}
221		-	if sameDimensions && cap(dst.lineOffset) >= src.Height {
222		-	dst.lineOffset = dst.lineOffset[:src.Height]
223		-	} else {
224		-	dst.lineOffset = make([]int, src.Height)
225		-	}
226		-	dst.Width = src.Width
227		-	dst.Height = src.Height
228		-	for y := range src.Height {
229		-	start := y * src.Width
230		-	copy(dst.Cells[start:start+src.Width], src.Row(y))
231		-	dst.lineOffset[y] = start
232		-	}
	214	+	dst.Replace(src)
233	215		}

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		// Span identifies a changed horizontal range in a logical frame row.	3		// Span identifies a changed horizontal range in a logical frame row.
4		type Span struct {	4		type Span struct {

@@ -204,30 +204,12 @@ func (c DeltaCandidate) Commit(dst *Frame) {
204		dst.ScrollUp(scroll.Y, scroll.Y+scroll.Height-1, scroll.Count)	204		dst.ScrollUp(scroll.Y, scroll.Y+scroll.Height-1, scroll.Count)
205		}	205		}
206		for _, span := range c.Plan.Spans {	206		for _, span := range c.Plan.Spans {
207	-	dstStart := dst.lineOffset[span.Y] + span.X	207	+	dstRow := dst.Row(span.Y)
208	-	srcStart := c.frame.lineOffset[span.Y] + span.X	208	+	srcRow := c.frame.Row(span.Y)
209	-	copy(dst.Cells[dstStart:dstStart+span.Width], c.frame.Cells[srcStart:srcStart+span.Width])	209	+	copy(dstRow[span.X:span.X+span.Width], srcRow[span.X:span.X+span.Width])
210		}	210		}
211		}	211		}
212			212
213		func replaceFrame(dst *Frame, src Frame) {	213		func replaceFrame(dst *Frame, src Frame) {
214	-	sameDimensions := dst.Width == src.Width && dst.Height == src.Height	214	+	dst.Replace(src)
215	-	cellCount := src.Width * src.Height
216	-	if sameDimensions && cap(dst.Cells) >= cellCount {
217	-	dst.Cells = dst.Cells[:cellCount]
218	-	} else {
219	-	dst.Cells = make([]Cell, cellCount)
220	-	}
221	-	if sameDimensions && cap(dst.lineOffset) >= src.Height {
222	-	dst.lineOffset = dst.lineOffset[:src.Height]
223	-	} else {
224	-	dst.lineOffset = make([]int, src.Height)
225	-	}
226	-	dst.Width = src.Width
227	-	dst.Height = src.Height
228	-	for y := range src.Height {
229	-	start := y * src.Width
230	-	copy(dst.Cells[start:start+src.Width], src.Row(y))
231	-	dst.lineOffset[y] = start
232	-	}
233		}	215		}

R pkg/renderer/delta_plan_test.go → pkg/ansi/delta_plan_test.go +7 -9 renamed, 94% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"reflect"

@@ -169,7 +169,7 @@ func TestNoOpDeltaCandidateDoesNotCloneFrame(t *testing.T) {
169	169		if err != nil {
170	170		t.Fatalf("PlanDelta() error = %v", err)
171	171		}
172		-	if candidate.frame.Cells != nil \|\| candidate.frame.lineOffset != nil {
	172	+	if candidate.frame.Width != 0 \|\| candidate.frame.Height != 0 \|\| candidate.frame.Cells != nil {
173	173		t.Fatal("no-op candidate owns frame storage")
174	174		}
175	175

@@ -184,8 +184,7 @@ func TestNoOpDeltaCandidateDoesNotCloneFrame(t *testing.T) {
184	184		func TestPlanDeltaDoesNotMutateCommitted(t *testing.T) {
185	185		committed := testFrame("0000", "1111", "2222", "3333", "4444")
186	186		committed.ScrollUp(1, 3, 1)
187		-	beforeCells := append([]Cell(nil), committed.Cells...)
188		-	beforeOffsets := append([]int(nil), committed.lineOffset...)
	187	+	before := committed.Clone()
189	188		frame := testFrame("0000", "2222", "3333", "new!", "4444")
190	189		damage := []Damage{
191	190		{Kind: DamageScrollUp, X: 0, Y: 1, Width: 4, Height: 3, Count: 1},

@@ -196,11 +195,10 @@ func TestPlanDeltaDoesNotMutateCommitted(t *testing.T) {
196	195		t.Fatalf("PlanDelta() error = %v", err)
197	196		}
198	197
199		-	if !reflect.DeepEqual(committed.Cells, beforeCells) {
200		-	t.Fatal("PlanDelta mutated committed cells")
201		-	}
202		-	if !reflect.DeepEqual(committed.lineOffset, beforeOffsets) {
203		-	t.Fatal("PlanDelta mutated committed row offsets")
	198	+	for y := range committed.Height {
	199	+	if !reflect.DeepEqual(committed.Row(y), before.Row(y)) {
	200	+	t.Fatalf("PlanDelta mutated committed row %d", y)
	201	+	}
204	202		}
205	203		}
206	204

-package renderer
+package ansi
 import (
 	"reflect"
 	if err != nil {
 		t.Fatalf("PlanDelta() error = %v", err)
 	}
-	if candidate.frame.Cells != nil || candidate.frame.lineOffset != nil {
+	if candidate.frame.Width != 0 || candidate.frame.Height != 0 || candidate.frame.Cells != nil {
 		t.Fatal("no-op candidate owns frame storage")
 	}
 func TestPlanDeltaDoesNotMutateCommitted(t *testing.T) {
 	committed := testFrame("0000", "1111", "2222", "3333", "4444")
 	committed.ScrollUp(1, 3, 1)
-	beforeCells := append([]Cell(nil), committed.Cells...)
+	before := committed.Clone()
-	beforeOffsets := append([]int(nil), committed.lineOffset...)
 	frame := testFrame("0000", "2222", "3333", "new!", "4444")
 	damage := []Damage{
 		{Kind: DamageScrollUp, X: 0, Y: 1, Width: 4, Height: 3, Count: 1},
 		t.Fatalf("PlanDelta() error = %v", err)
 	}
-	if !reflect.DeepEqual(committed.Cells, beforeCells) {
+	for y := range committed.Height {
-		t.Fatal("PlanDelta mutated committed cells")
+		if !reflect.DeepEqual(committed.Row(y), before.Row(y)) {
-	}
+			t.Fatalf("PlanDelta mutated committed row %d", y)
-	if !reflect.DeepEqual(committed.lineOffset, beforeOffsets) {
+		}
-		t.Fatal("PlanDelta mutated committed row offsets")
 	}
 }

A pkg/ansi/doc.go +7 -0

@@ -0,0 +1,7 @@
	1	+	// Package ansi emits ANSI terminal output from the frontend-neutral
	2	+	// github.com/bnema/vev/pkg/vtcore model.
	3	+	//
	4	+	// The package owns output planning, ANSI encoding, and a transactional renderer
	5	+	// shadow. It does not own Cell, Style, RGB, Frame, Damage, or RuneWidth; those
	6	+	// values are aliases during this staged extraction and are owned by vtcore.
	7	+	package ansi

@@ -0,0 +1,7 @@
	1	+	// Package ansi emits ANSI terminal output from the frontend-neutral
	2	+	// github.com/bnema/vev/pkg/vtcore model.
	3	+	//
	4	+	// The package owns output planning, ANSI encoding, and a transactional renderer
	5	+	// shadow. It does not own Cell, Style, RGB, Frame, Damage, or RuneWidth; those
	6	+	// values are aliases during this staged extraction and are owned by vtcore.
	7	+	package ansi

R pkg/renderer/draw_state.go → pkg/ansi/draw_state.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"bytes"

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import (	3		import (
4		"bytes"	4		"bytes"

A pkg/ansi/frame.go +9 -0

@@ -0,0 +1,9 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// Frame is an alias for the frontend-neutral terminal grid. ANSI rendering
	6	+	// consumes it but does not own its model or storage policy.
	7	+	type Frame = vtcore.Frame
	8	+
	9	+	var NewFrame = vtcore.NewFrame

@@ -0,0 +1,9 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// Frame is an alias for the frontend-neutral terminal grid. ANSI rendering
	6	+	// consumes it but does not own its model or storage policy.
	7	+	type Frame = vtcore.Frame
	8	+
	9	+	var NewFrame = vtcore.NewFrame

R pkg/renderer/frame_test.go → pkg/ansi/frame_test.go +13 -25 renamed, 77% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import "testing"
4	4

@@ -20,11 +20,12 @@ func fillFrame(f Frame, rows []string) {
20	20		}
21	21		}
22	22
23		-	func TestNewFrameCanonicalOffsets(t *testing.T) {
	23	+	func TestNewFrameHasValidLogicalRows(t *testing.T) {
24	24		f := NewFrame(4, 3)
25		-	for y := range f.Height {
26		-	if f.lineOffset[y] != y*f.Width {
27		-	t.Fatalf("lineOffset[%d] = %d, want %d", y, f.lineOffset[y], y*f.Width)
	25	+	fillFrame(f, []string{"aaaa", "bbbb", "cccc"})
	26	+	for y, want := range []string{"aaaa", "bbbb", "cccc"} {
	27	+	if got := rowRunes(f, y); got != want {
	28	+	t.Fatalf("row %d = %q, want %q", y, got, want)
28	29		}
29	30		}
30	31		if err := f.CheckInvariants(); err != nil {

@@ -32,26 +33,13 @@ func TestNewFrameCanonicalOffsets(t *testing.T) {
32	33		}
33	34		}
34	35
35		-	// TestCheckInvariantsDetectsBrokenRotation is the RED guard: a rotation that
36		-	// duplicates a physical offset (the classic off-by-one bug) must be rejected.
37		-	func TestCheckInvariantsDetectsBrokenRotation(t *testing.T) {
38		-	f := NewFrame(4, 3)
39		-	// Corrupt: two logical rows map to the same physical row.
40		-	f.lineOffset[1] = f.lineOffset[0]
41		-	if err := f.CheckInvariants(); err == nil {
42		-	t.Fatal("expected invariant violation for duplicate physical row, got nil")
43		-	}
44		-
45		-	f = NewFrame(4, 3)
46		-	f.lineOffset[0] = 1 // not a multiple of width
47		-	if err := f.CheckInvariants(); err == nil {
48		-	t.Fatal("expected invariant violation for non-multiple offset, got nil")
49		-	}
50		-
51		-	f = NewFrame(4, 3)
52		-	f.lineOffset[2] = 99 // out of range
53		-	if err := f.CheckInvariants(); err == nil {
54		-	t.Fatal("expected invariant violation for out-of-range offset, got nil")
	36	+	func TestFrameCloneIsIndependent(t *testing.T) {
	37	+	f := NewFrame(2, 1)
	38	+	f.Set(0, 0, Cell{Rune: 'a', Style: DefaultStyle()})
	39	+	clone := f.Clone()
	40	+	clone.Set(0, 0, Cell{Rune: 'b', Style: DefaultStyle()})
	41	+	if got := f.At(0, 0).Rune; got != 'a' {
	42	+	t.Fatalf("source changed through clone: %q", got)
55	43		}
56	44		}
57	45

-package renderer
+package ansi
 import "testing"
 	}
 }
-func TestNewFrameCanonicalOffsets(t *testing.T) {
+func TestNewFrameHasValidLogicalRows(t *testing.T) {
 	f := NewFrame(4, 3)
-	for y := range f.Height {
+	fillFrame(f, []string{"aaaa", "bbbb", "cccc"})
-		if f.lineOffset[y] != y*f.Width {
+	for y, want := range []string{"aaaa", "bbbb", "cccc"} {
-			t.Fatalf("lineOffset[%d] = %d, want %d", y, f.lineOffset[y], y*f.Width)
+		if got := rowRunes(f, y); got != want {
+			t.Fatalf("row %d = %q, want %q", y, got, want)
 		}
 	}
 	if err := f.CheckInvariants(); err != nil {
 	}
 }
-// TestCheckInvariantsDetectsBrokenRotation is the RED guard: a rotation that
+func TestFrameCloneIsIndependent(t *testing.T) {
-// duplicates a physical offset (the classic off-by-one bug) must be rejected.
+	f := NewFrame(2, 1)
-func TestCheckInvariantsDetectsBrokenRotation(t *testing.T) {
+	f.Set(0, 0, Cell{Rune: 'a', Style: DefaultStyle()})
-	f := NewFrame(4, 3)
+	clone := f.Clone()
-	// Corrupt: two logical rows map to the same physical row.
+	clone.Set(0, 0, Cell{Rune: 'b', Style: DefaultStyle()})
-	f.lineOffset[1] = f.lineOffset[0]
+	if got := f.At(0, 0).Rune; got != 'a' {
-	if err := f.CheckInvariants(); err == nil {
+		t.Fatalf("source changed through clone: %q", got)
-		t.Fatal("expected invariant violation for duplicate physical row, got nil")
-	}
-	f = NewFrame(4, 3)
-	f.lineOffset[0] = 1 // not a multiple of width
-	if err := f.CheckInvariants(); err == nil {
-		t.Fatal("expected invariant violation for non-multiple offset, got nil")
-	}
-	f = NewFrame(4, 3)
-	f.lineOffset[2] = 99 // out of range
-	if err := f.CheckInvariants(); err == nil {
-		t.Fatal("expected invariant violation for out-of-range offset, got nil")
 	}
 }

R pkg/renderer/output_min_test.go → pkg/ansi/output_min_test.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"bytes"

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import (	3		import (
4		"bytes"	4		"bytes"

R pkg/renderer/renderer.go → pkg/ansi/renderer.go +9 -9 renamed, 96% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"bytes"

@@ -17,11 +17,11 @@ type Capabilities struct {
17	17		}
18	18
19	19		type Renderer struct {
20		-	caps Capabilities
21		-	width int
22		-	height int
23		-	shadow []Cell
24		-	lineOffset []int
	20	+	caps Capabilities
	21	+	width int
	22	+	height int
	23	+	shadow []Cell
	24	+	committed Frame
25	25		}
26	26
27	27		// PreparedDraw owns encoded output and its transactional delta until Commit.

@@ -39,7 +39,7 @@ func (r *Renderer) Reset() {
39	39		r.width = 0
40	40		r.height = 0
41	41		r.shadow = nil
42		-	r.lineOffset = nil
	42	+	r.committed = Frame{}
43	43		}
44	44
45	45		// Bytes returns the prepared ANSI output. The returned bytes remain valid after

@@ -129,14 +129,14 @@ func (r *Renderer) Draw(frame Frame, damage []Damage) ([]byte, error) {
129	129		}
130	130
131	131		func (r *Renderer) committedFrame() Frame {
132		-	return Frame{Width: r.width, Height: r.height, Cells: r.shadow, lineOffset: r.lineOffset}
	132	+	return r.committed
133	133		}
134	134
135	135		func (r *Renderer) setCommittedFrame(frame Frame) {
136	136		r.width = frame.Width
137	137		r.height = frame.Height
138	138		r.shadow = frame.Cells
139		-	r.lineOffset = frame.lineOffset
	139	+	r.committed = frame
140	140		}
141	141
142	142		// copyBytes copies the buffer contents into a fresh byte slice and is used

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import (	3		import (
4		"bytes"	4		"bytes"

@@ -17,11 +17,11 @@ type Capabilities struct {
17		}	17		}
18			18
19		type Renderer struct {	19		type Renderer struct {
20	-	caps Capabilities	20	+	caps Capabilities
21	-	width int	21	+	width int
22	-	height int	22	+	height int
23	-	shadow []Cell	23	+	shadow []Cell
24	-	lineOffset []int	24	+	committed Frame
25		}	25		}
26			26
27		// PreparedDraw owns encoded output and its transactional delta until Commit.	27		// PreparedDraw owns encoded output and its transactional delta until Commit.

@@ -39,7 +39,7 @@ func (r *Renderer) Reset() {
39		r.width = 0	39		r.width = 0
40		r.height = 0	40		r.height = 0
41		r.shadow = nil	41		r.shadow = nil
42	-	r.lineOffset = nil	42	+	r.committed = Frame{}
43		}	43		}
44			44
45		// Bytes returns the prepared ANSI output. The returned bytes remain valid after	45		// Bytes returns the prepared ANSI output. The returned bytes remain valid after

@@ -129,14 +129,14 @@ func (r *Renderer) Draw(frame Frame, damage []Damage) ([]byte, error) {
129		}	129		}
130			130
131		func (r *Renderer) committedFrame() Frame {	131		func (r *Renderer) committedFrame() Frame {
132	-	return Frame{Width: r.width, Height: r.height, Cells: r.shadow, lineOffset: r.lineOffset}	132	+	return r.committed
133		}	133		}
134			134
135		func (r *Renderer) setCommittedFrame(frame Frame) {	135		func (r *Renderer) setCommittedFrame(frame Frame) {
136		r.width = frame.Width	136		r.width = frame.Width
137		r.height = frame.Height	137		r.height = frame.Height
138		r.shadow = frame.Cells	138		r.shadow = frame.Cells
139	-	r.lineOffset = frame.lineOffset	139	+	r.committed = frame
140		}	140		}
141			141
142		// copyBytes copies the buffer contents into a fresh byte slice and is used	142		// copyBytes copies the buffer contents into a fresh byte slice and is used

R pkg/renderer/renderer_test.go → pkg/ansi/renderer_test.go +3 -4 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"bytes"

@@ -146,7 +146,7 @@ func TestPrepareNoOpDoesNotCloneFrame(t *testing.T) {
146	146		if err != nil {
147	147		t.Fatal(err)
148	148		}
149		-	if prepared.candidate.frame.Cells != nil \|\| prepared.candidate.frame.lineOffset != nil {
	149	+	if prepared.candidate.frame.Width != 0 \|\| prepared.candidate.frame.Height != 0 \|\| prepared.candidate.frame.Cells != nil {
150	150		t.Fatal("no-op prepared draw owns frame storage")
151	151		}
152	152		prepared.Commit()

@@ -1400,8 +1400,7 @@ func TestRendererPrepare(t *testing.T) {
1400	1400
1401	1401		func TestPlanDeltaRejectsInvalidCommittedFrame(t *testing.T) {
1402	1402		frame := NewFrame(2, 1)
1403		-	committed := NewFrame(2, 1)
1404		-	committed.lineOffset = nil
	1403	+	committed := Frame{Width: 2, Height: 1, Cells: make([]Cell, 2)}
1405	1404
1406	1405		if _, err := PlanDelta(frame, nil, committed, false); err == nil {
1407	1406		t.Fatal("PlanDelta accepted an invalid committed frame")

-package renderer
+package ansi
 import (
 	"bytes"
 	if err != nil {
 		t.Fatal(err)
 	}
-	if prepared.candidate.frame.Cells != nil || prepared.candidate.frame.lineOffset != nil {
+	if prepared.candidate.frame.Width != 0 || prepared.candidate.frame.Height != 0 || prepared.candidate.frame.Cells != nil {
 		t.Fatal("no-op prepared draw owns frame storage")
 	}
 	prepared.Commit()
 func TestPlanDeltaRejectsInvalidCommittedFrame(t *testing.T) {
 	frame := NewFrame(2, 1)
-	committed := NewFrame(2, 1)
+	committed := Frame{Width: 2, Height: 1, Cells: make([]Cell, 2)}
-	committed.lineOffset = nil
 	if _, err := PlanDelta(frame, nil, committed, false); err == nil {
 		t.Fatal("PlanDelta accepted an invalid committed frame")

A pkg/ansi/rune_width.go +7 -0

@@ -0,0 +1,7 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// RuneWidth is the terminal cell width function from the frontend-neutral
	6	+	// model package.
	7	+	func RuneWidth(r rune) int { return vtcore.RuneWidth(r) }

@@ -0,0 +1,7 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// RuneWidth is the terminal cell width function from the frontend-neutral
	6	+	// model package.
	7	+	func RuneWidth(r rune) int { return vtcore.RuneWidth(r) }

R pkg/renderer/scroll.go → pkg/ansi/scroll.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		import (
4	4		"bytes"

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		import (	3		import (
4		"bytes"	4		"bytes"

A pkg/ansi/style.go +24 -0

@@ -0,0 +1,24 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	type RGB = vtcore.RGB
	6	+	type StyleAttrs = vtcore.StyleAttrs
	7	+	type UnderlineStyle = vtcore.UnderlineStyle
	8	+	type Style = vtcore.Style
	9	+
	10	+	const (
	11	+	AttrDim = vtcore.AttrDim
	12	+	AttrUnderline = vtcore.AttrUnderline
	13	+	AttrBlink = vtcore.AttrBlink
	14	+	AttrStrikethrough = vtcore.AttrStrikethrough
	15	+
	16	+	UnderlineNone = vtcore.UnderlineNone
	17	+	UnderlineSingle = vtcore.UnderlineSingle
	18	+	UnderlineDouble = vtcore.UnderlineDouble
	19	+	UnderlineCurly = vtcore.UnderlineCurly
	20	+	UnderlineDotted = vtcore.UnderlineDotted
	21	+	UnderlineDashed = vtcore.UnderlineDashed
	22	+	)
	23	+
	24	+	var DefaultStyle = vtcore.DefaultStyle

@@ -0,0 +1,24 @@
	1	+	package ansi
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	type RGB = vtcore.RGB
	6	+	type StyleAttrs = vtcore.StyleAttrs
	7	+	type UnderlineStyle = vtcore.UnderlineStyle
	8	+	type Style = vtcore.Style
	9	+
	10	+	const (
	11	+	AttrDim = vtcore.AttrDim
	12	+	AttrUnderline = vtcore.AttrUnderline
	13	+	AttrBlink = vtcore.AttrBlink
	14	+	AttrStrikethrough = vtcore.AttrStrikethrough
	15	+
	16	+	UnderlineNone = vtcore.UnderlineNone
	17	+	UnderlineSingle = vtcore.UnderlineSingle
	18	+	UnderlineDouble = vtcore.UnderlineDouble
	19	+	UnderlineCurly = vtcore.UnderlineCurly
	20	+	UnderlineDotted = vtcore.UnderlineDotted
	21	+	UnderlineDashed = vtcore.UnderlineDashed
	22	+	)
	23	+
	24	+	var DefaultStyle = vtcore.DefaultStyle

R pkg/renderer/sync_output.go → pkg/ansi/sync_output.go +1 -1 renamed, 95% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package ansi
2	2
3	3		const (
4	4		SyncStartCSI = "\x1b[?2026h"

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package ansi
2			2
3		const (	3		const (
4		SyncStartCSI = "\x1b[?2026h"	4		SyncStartCSI = "\x1b[?2026h"

A pkg/renderer/compat.go +65 -0

@@ -0,0 +1,65 @@
	1	+	package renderer
	2	+
	3	+	import (
	4	+	"github.com/bnema/vev/pkg/ansi"
	5	+	"github.com/bnema/vev/pkg/vtcore"
	6	+	)
	7	+
	8	+	type Capabilities = ansi.Capabilities
	9	+	type Cell = vtcore.Cell
	10	+	type Damage = vtcore.Damage
	11	+	type DamageKind = vtcore.DamageKind
	12	+	type DeltaCandidate = ansi.DeltaCandidate
	13	+	type DeltaPlan = ansi.DeltaPlan
	14	+	type Frame = vtcore.Frame
	15	+	type PreparedDraw = ansi.PreparedDraw
	16	+	type RGB = vtcore.RGB
	17	+	type Renderer = ansi.Renderer
	18	+	type Scroll = ansi.Scroll
	19	+	type Span = ansi.Span
	20	+	type Style = vtcore.Style
	21	+	type StyleAttrs = vtcore.StyleAttrs
	22	+	type UnderlineStyle = vtcore.UnderlineStyle
	23	+
	24	+	const (
	25	+	AttrDim = vtcore.AttrDim
	26	+	AttrUnderline = vtcore.AttrUnderline
	27	+	AttrBlink = vtcore.AttrBlink
	28	+	AttrStrikethrough = vtcore.AttrStrikethrough
	29	+
	30	+	DamageText = vtcore.DamageText
	31	+	DamageClear = vtcore.DamageClear
	32	+	DamageScrollUp = vtcore.DamageScrollUp
	33	+	DamageFullRedraw = vtcore.DamageFullRedraw
	34	+
	35	+	UnderlineNone = vtcore.UnderlineNone
	36	+	UnderlineSingle = vtcore.UnderlineSingle
	37	+	UnderlineDouble = vtcore.UnderlineDouble
	38	+	UnderlineCurly = vtcore.UnderlineCurly
	39	+	UnderlineDotted = vtcore.UnderlineDotted
	40	+	UnderlineDashed = vtcore.UnderlineDashed
	41	+
	42	+	SyncStartCSI = ansi.SyncStartCSI
	43	+	SyncEndCSI = ansi.SyncEndCSI
	44	+	)
	45	+
	46	+	var (
	47	+	BlankCell = vtcore.BlankCell
	48	+	DefaultStyle = vtcore.DefaultStyle
	49	+	FullRedraw = vtcore.FullRedraw
	50	+	NewFrame = vtcore.NewFrame
	51	+	)
	52	+
	53	+	func New(caps Capabilities) *Renderer {
	54	+	return ansi.New(caps)
	55	+	}
	56	+
	57	+	func PlanDelta(frame Frame, damage []Damage, committed Frame, reset bool) (DeltaCandidate, error) {
	58	+	return ansi.PlanDelta(frame, damage, committed, reset)
	59	+	}
	60	+
	61	+	func RuneWidth(r rune) int { return vtcore.RuneWidth(r) }
	62	+
	63	+	func WrapSynchronized(content []byte, enabled bool) []byte {
	64	+	return ansi.WrapSynchronized(content, enabled)
	65	+	}

@@ -0,0 +1,65 @@
	1	+	package renderer
	2	+
	3	+	import (
	4	+	"github.com/bnema/vev/pkg/ansi"
	5	+	"github.com/bnema/vev/pkg/vtcore"
	6	+	)
	7	+
	8	+	type Capabilities = ansi.Capabilities
	9	+	type Cell = vtcore.Cell
	10	+	type Damage = vtcore.Damage
	11	+	type DamageKind = vtcore.DamageKind
	12	+	type DeltaCandidate = ansi.DeltaCandidate
	13	+	type DeltaPlan = ansi.DeltaPlan
	14	+	type Frame = vtcore.Frame
	15	+	type PreparedDraw = ansi.PreparedDraw
	16	+	type RGB = vtcore.RGB
	17	+	type Renderer = ansi.Renderer
	18	+	type Scroll = ansi.Scroll
	19	+	type Span = ansi.Span
	20	+	type Style = vtcore.Style
	21	+	type StyleAttrs = vtcore.StyleAttrs
	22	+	type UnderlineStyle = vtcore.UnderlineStyle
	23	+
	24	+	const (
	25	+	AttrDim = vtcore.AttrDim
	26	+	AttrUnderline = vtcore.AttrUnderline
	27	+	AttrBlink = vtcore.AttrBlink
	28	+	AttrStrikethrough = vtcore.AttrStrikethrough
	29	+
	30	+	DamageText = vtcore.DamageText
	31	+	DamageClear = vtcore.DamageClear
	32	+	DamageScrollUp = vtcore.DamageScrollUp
	33	+	DamageFullRedraw = vtcore.DamageFullRedraw
	34	+
	35	+	UnderlineNone = vtcore.UnderlineNone
	36	+	UnderlineSingle = vtcore.UnderlineSingle
	37	+	UnderlineDouble = vtcore.UnderlineDouble
	38	+	UnderlineCurly = vtcore.UnderlineCurly
	39	+	UnderlineDotted = vtcore.UnderlineDotted
	40	+	UnderlineDashed = vtcore.UnderlineDashed
	41	+
	42	+	SyncStartCSI = ansi.SyncStartCSI
	43	+	SyncEndCSI = ansi.SyncEndCSI
	44	+	)
	45	+
	46	+	var (
	47	+	BlankCell = vtcore.BlankCell
	48	+	DefaultStyle = vtcore.DefaultStyle
	49	+	FullRedraw = vtcore.FullRedraw
	50	+	NewFrame = vtcore.NewFrame
	51	+	)
	52	+
	53	+	func New(caps Capabilities) *Renderer {
	54	+	return ansi.New(caps)
	55	+	}
	56	+
	57	+	func PlanDelta(frame Frame, damage []Damage, committed Frame, reset bool) (DeltaCandidate, error) {
	58	+	return ansi.PlanDelta(frame, damage, committed, reset)
	59	+	}
	60	+
	61	+	func RuneWidth(r rune) int { return vtcore.RuneWidth(r) }
	62	+
	63	+	func WrapSynchronized(content []byte, enabled bool) []byte {
	64	+	return ansi.WrapSynchronized(content, enabled)
	65	+	}

M pkg/renderer/doc.go +6 -1

@@ -1,2 +1,7 @@
1		-	// Package renderer draws terminal state to the screen.
	1	+	// Package renderer is the pre-extraction import path for the concrete ANSI
	2	+	// renderer. New code should import github.com/bnema/vev/pkg/ansi for output and
	3	+	// github.com/bnema/vev/pkg/vtcore for the terminal model.
	4	+	//
	5	+	// This package contains aliases and forwarding functions only; it is not a
	6	+	// renderer-backend interface or a second implementation owner.
2	7		package renderer

@@ -1,2 +1,7 @@
1	-	// Package renderer draws terminal state to the screen.	1	+	// Package renderer is the pre-extraction import path for the concrete ANSI
			2	+	// renderer. New code should import github.com/bnema/vev/pkg/ansi for output and
			3	+	// github.com/bnema/vev/pkg/vtcore for the terminal model.
			4	+	//
			5	+	// This package contains aliases and forwarding functions only; it is not a
			6	+	// renderer-backend interface or a second implementation owner.
2		package renderer	7		package renderer

M pkg/vt/buffer.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		// buffer owns the visible VT grid and the physical-row boundaries needed to
6	6		// reconstruct logical lines. History deliberately is not part of this type:

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		// buffer owns the visible VT grid and the physical-row boundaries needed to	5		// buffer owns the visible VT grid and the physical-row boundaries needed to
6		// reconstruct logical lines. History deliberately is not part of this type:	6		// reconstruct logical lines. History deliberately is not part of this type:

A pkg/vt/core_model.go +36 -0

@@ -0,0 +1,36 @@
	1	+	package vt
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// The public model is re-exported from the frontend-neutral core package while
	6	+	// the extraction is staged. The aliases keep Screen, History, and consumers on
	7	+	// one cell/style/frame representation; vtcore remains the owning package.
	8	+	type Cell = vtcore.Cell
	9	+	type RGB = vtcore.RGB
	10	+	type StyleAttrs = vtcore.StyleAttrs
	11	+	type UnderlineStyle = vtcore.UnderlineStyle
	12	+	type Style = vtcore.Style
	13	+	type Frame = vtcore.Frame
	14	+
	15	+	const (
	16	+	AttrDim = vtcore.AttrDim
	17	+	AttrUnderline = vtcore.AttrUnderline
	18	+	AttrBlink = vtcore.AttrBlink
	19	+	AttrStrikethrough = vtcore.AttrStrikethrough
	20	+
	21	+	UnderlineNone = vtcore.UnderlineNone
	22	+	UnderlineSingle = vtcore.UnderlineSingle
	23	+	UnderlineDouble = vtcore.UnderlineDouble
	24	+	UnderlineCurly = vtcore.UnderlineCurly
	25	+	UnderlineDotted = vtcore.UnderlineDotted
	26	+	UnderlineDashed = vtcore.UnderlineDashed
	27	+	)
	28	+
	29	+	var (
	30	+	BlankCell = vtcore.BlankCell
	31	+	DefaultStyle = vtcore.DefaultStyle
	32	+	FullRedraw = vtcore.FullRedraw
	33	+	NewFrame = vtcore.NewFrame
	34	+	)
	35	+
	36	+	func RuneWidth(r rune) int { return vtcore.RuneWidth(r) }

@@ -0,0 +1,36 @@
	1	+	package vt
	2	+
	3	+	import "github.com/bnema/vev/pkg/vtcore"
	4	+
	5	+	// The public model is re-exported from the frontend-neutral core package while
	6	+	// the extraction is staged. The aliases keep Screen, History, and consumers on
	7	+	// one cell/style/frame representation; vtcore remains the owning package.
	8	+	type Cell = vtcore.Cell
	9	+	type RGB = vtcore.RGB
	10	+	type StyleAttrs = vtcore.StyleAttrs
	11	+	type UnderlineStyle = vtcore.UnderlineStyle
	12	+	type Style = vtcore.Style
	13	+	type Frame = vtcore.Frame
	14	+
	15	+	const (
	16	+	AttrDim = vtcore.AttrDim
	17	+	AttrUnderline = vtcore.AttrUnderline
	18	+	AttrBlink = vtcore.AttrBlink
	19	+	AttrStrikethrough = vtcore.AttrStrikethrough
	20	+
	21	+	UnderlineNone = vtcore.UnderlineNone
	22	+	UnderlineSingle = vtcore.UnderlineSingle
	23	+	UnderlineDouble = vtcore.UnderlineDouble
	24	+	UnderlineCurly = vtcore.UnderlineCurly
	25	+	UnderlineDotted = vtcore.UnderlineDotted
	26	+	UnderlineDashed = vtcore.UnderlineDashed
	27	+	)
	28	+
	29	+	var (
	30	+	BlankCell = vtcore.BlankCell
	31	+	DefaultStyle = vtcore.DefaultStyle
	32	+	FullRedraw = vtcore.FullRedraw
	33	+	NewFrame = vtcore.NewFrame
	34	+	)
	35	+
	36	+	func RuneWidth(r rune) int { return vtcore.RuneWidth(r) }

M pkg/vt/damage.go +8 -6

@@ -1,12 +1,14 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import "github.com/bnema/vev/pkg/vtcore"
4	4
5		-	type Damage = renderer.Damage
	5	+	type Damage = vtcore.Damage
	6	+
	7	+	type DamageKind = vtcore.DamageKind
6	8
7	9		const (
8		-	DamageText = renderer.DamageText
9		-	DamageClear = renderer.DamageClear
10		-	DamageScrollUp = renderer.DamageScrollUp
11		-	DamageFullRedraw = renderer.DamageFullRedraw
	10	+	DamageText = vtcore.DamageText
	11	+	DamageClear = vtcore.DamageClear
	12	+	DamageScrollUp = vtcore.DamageScrollUp
	13	+	DamageFullRedraw = vtcore.DamageFullRedraw
12	14		)

@@ -1,12 +1,14 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import "github.com/bnema/vev/pkg/vtcore"
4			4
5	-	type Damage = renderer.Damage	5	+	type Damage = vtcore.Damage
			6	+
			7	+	type DamageKind = vtcore.DamageKind
6			8
7		const (	9		const (
8	-	DamageText = renderer.DamageText	10	+	DamageText = vtcore.DamageText
9	-	DamageClear = renderer.DamageClear	11	+	DamageClear = vtcore.DamageClear
10	-	DamageScrollUp = renderer.DamageScrollUp	12	+	DamageScrollUp = vtcore.DamageScrollUp
11	-	DamageFullRedraw = renderer.DamageFullRedraw	13	+	DamageFullRedraw = vtcore.DamageFullRedraw
12		)	14		)

M pkg/vt/doc.go +16 -5

@@ -1,4 +1,4 @@
1		-	// Package vt implements the server-side terminal emulator core.
	1	+	// Package vt implements the frontend-neutral terminal emulator core.
2	2		//
3	3		// It tracks the visible cell grid, damage rectangles, scroll regions,
4	4		// alternate-screen state, cursor/reporting modes, and common xterm/VT control

@@ -6,8 +6,19 @@
6	6		// cell, and resize or edit operations repair row-boundary splits instead of
7	7		// leaving orphaned halves.
8	8		//
9		-	// Screen is single-owner. Snapshot returns an owned capture of the active
10		-	// visible viewport and renderer-relevant metadata; callers must serialize it
11		-	// with Write, Resize, and host mutations. Terminal history remains available
12		-	// through HistoryView and HistorySnapshotView rather than ScreenSnapshot.
	9	+	// Stateful values are single-owner and are not internally synchronized. The
	10	+	// owner must serialize Write, Resize, Snapshot, and History mutations. Write
	11	+	// parses synchronously: every callback runs before Write returns and callbacks
	12	+	// are delivered in the order their control sequences are encountered. A line
	13	+	// eviction callback receives a stable row copy; response bytes should be
	14	+	// consumed or copied during the callback. Other callback arguments are values
	15	+	// or strings owned by the callback.
	16	+	//
	17	+	// Snapshot and HistorySnapshotView capture owned state without sealing or
	18	+	// mutating the live owner. Row methods return owned copies. BorrowedRow and
	19	+	// HistoryView.Range expose immutable backing storage: callers must not mutate
	20	+	// it, and Range callbacks must not retain their row after returning. A
	21	+	// HistoryChunk pointer has stable identity for the lifetime of the view, so
	22	+	// consumers can reuse unchanged sealed chunks. Direct Frame.Row access is a
	23	+	// mutable borrow valid only until the frame scrolls or resizes.
13	24		package vt

@@ -1,4 +1,4 @@
1	-	// Package vt implements the server-side terminal emulator core.	1	+	// Package vt implements the frontend-neutral terminal emulator core.
2		//	2		//
3		// It tracks the visible cell grid, damage rectangles, scroll regions,	3		// It tracks the visible cell grid, damage rectangles, scroll regions,
4		// alternate-screen state, cursor/reporting modes, and common xterm/VT control	4		// alternate-screen state, cursor/reporting modes, and common xterm/VT control

@@ -6,8 +6,19 @@
6		// cell, and resize or edit operations repair row-boundary splits instead of	6		// cell, and resize or edit operations repair row-boundary splits instead of
7		// leaving orphaned halves.	7		// leaving orphaned halves.
8		//	8		//
9	-	// Screen is single-owner. Snapshot returns an owned capture of the active	9	+	// Stateful values are single-owner and are not internally synchronized. The
10	-	// visible viewport and renderer-relevant metadata; callers must serialize it	10	+	// owner must serialize Write, Resize, Snapshot, and History mutations. Write
11	-	// with Write, Resize, and host mutations. Terminal history remains available	11	+	// parses synchronously: every callback runs before Write returns and callbacks
12	-	// through HistoryView and HistorySnapshotView rather than ScreenSnapshot.	12	+	// are delivered in the order their control sequences are encountered. A line
			13	+	// eviction callback receives a stable row copy; response bytes should be
			14	+	// consumed or copied during the callback. Other callback arguments are values
			15	+	// or strings owned by the callback.
			16	+	//
			17	+	// Snapshot and HistorySnapshotView capture owned state without sealing or
			18	+	// mutating the live owner. Row methods return owned copies. BorrowedRow and
			19	+	// HistoryView.Range expose immutable backing storage: callers must not mutate
			20	+	// it, and Range callbacks must not retain their row after returning. A
			21	+	// HistoryChunk pointer has stable identity for the lifetime of the view, so
			22	+	// consumers can reuse unchanged sealed chunks. Direct Frame.Row access is a
			23	+	// mutable borrow valid only until the frame scrolls or resizes.
13		package vt	24		package vt

A pkg/vt/extraction_contract_external_test.go +183 -0

@@ -0,0 +1,183 @@
	1	+	package vt_test
	2	+
	3	+	import (
	4	+	"reflect"
	5	+	"testing"
	6	+
	7	+	"github.com/bnema/vev/pkg/vt"
	8	+	"github.com/bnema/vev/pkg/vtcore"
	9	+	)
	10	+
	11	+	func TestExternalScreenParserPreservesPublicTerminalModel(t *testing.T) {
	12	+	screen := vt.NewScreen(6, 2)
	13	+	screen.Write([]byte("A界"))
	14	+
	15	+	if got := screen.Frame.At(0, 0); got.Rune != 'A' {
	16	+	t.Fatalf("ASCII cell = %#v, want A", got)
	17	+	}
	18	+	if got := screen.Frame.At(1, 0); got.Rune != '界' \|\| got.Continuation {
	19	+	t.Fatalf("wide-rune lead cell = %#v, want 界 lead", got)
	20	+	}
	21	+	if got := screen.Frame.At(2, 0); !got.Continuation {
	22	+	t.Fatalf("wide-rune continuation = %#v, want continuation", got)
	23	+	}
	24	+	if got := vt.RuneWidth('界'); got != 2 {
	25	+	t.Fatalf("RuneWidth(界) = %d, want 2", got)
	26	+	}
	27	+
	28	+	// The parser owns incomplete escape sequences across writes, so callers can
	29	+	// provide arbitrary PTY chunk boundaries.
	30	+	screen.Write([]byte("\x1b[2;2H\x1b[3"))
	31	+	screen.Write([]byte("1mX"))
	32	+	cell := screen.Frame.At(1, 1)
	33	+	if cell.Rune != 'X' \|\| cell.Style.Foreground != 1 {
	34	+	t.Fatalf("split ANSI write = %#v, want red X", cell)
	35	+	}
	36	+
	37	+	screen.Write([]byte("\x1b]2;public title\a"))
	38	+	if got := screen.Snapshot().Title(); got != "public title" {
	39	+	t.Fatalf("terminal title = %q, want public title", got)
	40	+	}
	41	+	}
	42	+
	43	+	func TestExternalCallbacksAreSynchronousAndOrdered(t *testing.T) {
	44	+	screen := vt.NewScreen(8, 2)
	45	+	inWrite := false
	46	+	var events []string
	47	+	assertInWrite := func(name string) {
	48	+	if !inWrite {
	49	+	t.Errorf("%s callback ran after Write returned", name)
	50	+	}
	51	+	}
	52	+
	53	+	screen.OnBell = func() {
	54	+	assertInWrite("bell")
	55	+	events = append(events, "bell")
	56	+	}
	57	+	screen.OnResponse = func(response []byte) {
	58	+	assertInWrite("response")
	59	+	events = append(events, "response:"+string(response))
	60	+	}
	61	+	screen.OnNotify = func(title, body string) {
	62	+	assertInWrite("notify")
	63	+	events = append(events, "notify:"+title+":"+body)
	64	+	}
	65	+	screen.OnProgress = func(errored bool) {
	66	+	assertInWrite("progress")
	67	+	if errored {
	68	+	events = append(events, "progress:error")
	69	+	} else {
	70	+	events = append(events, "progress:clear")
	71	+	}
	72	+	}
	73	+	screen.OnClipboard = func(data string) {
	74	+	assertInWrite("clipboard")
	75	+	events = append(events, "clipboard:"+data)
	76	+	}
	77	+
	78	+	inWrite = true
	79	+	screen.Write([]byte("\a\x1b[5n\x1b]9;body\a\x1b]777;notify;title;body\a" +
	80	+	"\x1b]9;4;1\a\x1b]9;4;0\a\x1b]9;4;2\a" +
	81	+	"\x1b]52;c;SGVsbG8=\a"))
	82	+	inWrite = false
	83	+
	84	+	want := []string{
	85	+	"bell",
	86	+	"response:\x1b[0n",
	87	+	"notify::body",
	88	+	"notify:title:body",
	89	+	"progress:clear",
	90	+	"progress:error",
	91	+	"clipboard:SGVsbG8=",
	92	+	}
	93	+	if !reflect.DeepEqual(events, want) {
	94	+	t.Fatalf("callback events = %#v, want %#v", events, want)
	95	+	}
	96	+	}
	97	+
	98	+	func TestExternalSnapshotsAndHistoryRespectOwnershipContracts(t *testing.T) {
	99	+	screen := vt.NewScreenWithHistory(4, 2, vt.HistoryConfig{MaxRows: 8, ChunkRows: 2})
	100	+	screen.Write([]byte("A"))
	101	+	snapshot := screen.Snapshot()
	102	+
	103	+	owned := snapshot.Row(0)
	104	+	owned[0] = vtcore.Cell{Rune: 'X'}
	105	+	if got := snapshot.Row(0)[0].Rune; got != 'A' {
	106	+	t.Fatalf("owned snapshot row mutation changed snapshot to %q", got)
	107	+	}
	108	+
	109	+	screen.Write([]byte("\rX"))
	110	+	if got := snapshot.Row(0)[0].Rune; got != 'A' {
	111	+	t.Fatalf("snapshot changed after later screen write: %q", got)
	112	+	}
	113	+	if got := snapshot.RowIDs(); len(got) != 2 \|\| got[0] == 0 \|\| got[1] == 0 {
	114	+	t.Fatalf("snapshot row IDs = %#v, want stable nonzero IDs", got)
	115	+	}
	116	+	rowIDs := snapshot.RowIDs()
	117	+	rowIDs[0] = 0
	118	+	if snapshot.RowID(0) == 0 {
	119	+	t.Fatal("RowIDs did not return an owned copy")
	120	+	}
	121	+
	122	+	history := vt.NewHistory(vt.HistoryConfig{MaxRows: 8, ChunkRows: 2})
	123	+	appendHistoryRow(t, history, 'a', 10)
	124	+	appendHistoryRow(t, history, 'b', 11)
	125	+	before := history.View()
	126	+	chunk := before.Chunk(0)
	127	+	if chunk == nil \|\| before.FindRowID(11) != 1 {
	128	+	t.Fatalf("history view = len %d chunk %#v IDs %d/%d", before.Len(), chunk, before.RowID(0), before.RowID(1))
	129	+	}
	130	+
	131	+	copyOfRow := before.Row(0)
	132	+	copyOfRow[0] = vtcore.Cell{Rune: 'x'}
	133	+	if got := before.Row(0)[0].Rune; got != 'a' {
	134	+	t.Fatalf("owned history row mutation changed view to %q", got)
	135	+	}
	136	+	if borrowed := before.BorrowedRow(0); &borrowed[0] == &copyOfRow[0] {
	137	+	t.Fatal("Row returned borrowed history storage instead of an owned copy")
	138	+	}
	139	+
	140	+	appendHistoryRow(t, history, 'c', 12)
	141	+	after := history.View()
	142	+	if after.Chunk(0) != chunk {
	143	+	t.Fatal("sealed history chunk identity changed after an append")
	144	+	}
	145	+	if before.Len() != 2 \|\| before.RowID(0) != 10 \|\| before.RowID(1) != 11 {
	146	+	t.Fatalf("retained history view changed after append: len=%d IDs=%d/%d", before.Len(), before.RowID(0), before.RowID(1))
	147	+	}
	148	+
	149	+	persistenceView := history.SnapshotView()
	150	+	appendHistoryRow(t, history, 'd', 13)
	151	+	if got := persistenceView.Tail().Row(0)[0].Rune; got != 'c' {
	152	+	t.Fatalf("snapshot tail changed after history append to %q", got)
	153	+	}
	154	+	}
	155	+
	156	+	func TestExternalSingleOwnerUsageSerializesMutationAndCapture(t *testing.T) {
	157	+	screen := vt.NewScreen(4, 1)
	158	+	operations := make(chan func(), 3)
	159	+	done := make(chan struct{})
	160	+	go func() {
	161	+	defer close(done)
	162	+	for operation := range operations {
	163	+	operation()
	164	+	}
	165	+	}()
	166	+
	167	+	operations <- func() { screen.Write([]byte("A")) }
	168	+	captured := make(chan vt.ScreenSnapshot, 1)
	169	+	operations <- func() { captured <- screen.Snapshot() }
	170	+	close(operations)
	171	+	<-done
	172	+
	173	+	if got := (<-captured).Row(0)[0].Rune; got != 'A' {
	174	+	t.Fatalf("single-owner capture = %q, want A", got)
	175	+	}
	176	+	}
	177	+
	178	+	func appendHistoryRow(t testing.T, history vt.History, runeValue rune, id vt.RowID) {
	179	+	t.Helper()
	180	+	if err := history.AppendWithID([]vtcore.Cell{{Rune: runeValue}}, vt.LineBound{End: 1}, id); err != nil {
	181	+	t.Fatalf("AppendWithID(%d): %v", id, err)
	182	+	}
	183	+	}

@@ -0,0 +1,183 @@
	1	+	package vt_test
	2	+
	3	+	import (
	4	+	"reflect"
	5	+	"testing"
	6	+
	7	+	"github.com/bnema/vev/pkg/vt"
	8	+	"github.com/bnema/vev/pkg/vtcore"
	9	+	)
	10	+
	11	+	func TestExternalScreenParserPreservesPublicTerminalModel(t *testing.T) {
	12	+	screen := vt.NewScreen(6, 2)
	13	+	screen.Write([]byte("A界"))
	14	+
	15	+	if got := screen.Frame.At(0, 0); got.Rune != 'A' {
	16	+	t.Fatalf("ASCII cell = %#v, want A", got)
	17	+	}
	18	+	if got := screen.Frame.At(1, 0); got.Rune != '界' \|\| got.Continuation {
	19	+	t.Fatalf("wide-rune lead cell = %#v, want 界 lead", got)
	20	+	}
	21	+	if got := screen.Frame.At(2, 0); !got.Continuation {
	22	+	t.Fatalf("wide-rune continuation = %#v, want continuation", got)
	23	+	}
	24	+	if got := vt.RuneWidth('界'); got != 2 {
	25	+	t.Fatalf("RuneWidth(界) = %d, want 2", got)
	26	+	}
	27	+
	28	+	// The parser owns incomplete escape sequences across writes, so callers can
	29	+	// provide arbitrary PTY chunk boundaries.
	30	+	screen.Write([]byte("\x1b[2;2H\x1b[3"))
	31	+	screen.Write([]byte("1mX"))
	32	+	cell := screen.Frame.At(1, 1)
	33	+	if cell.Rune != 'X' \|\| cell.Style.Foreground != 1 {
	34	+	t.Fatalf("split ANSI write = %#v, want red X", cell)
	35	+	}
	36	+
	37	+	screen.Write([]byte("\x1b]2;public title\a"))
	38	+	if got := screen.Snapshot().Title(); got != "public title" {
	39	+	t.Fatalf("terminal title = %q, want public title", got)
	40	+	}
	41	+	}
	42	+
	43	+	func TestExternalCallbacksAreSynchronousAndOrdered(t *testing.T) {
	44	+	screen := vt.NewScreen(8, 2)
	45	+	inWrite := false
	46	+	var events []string
	47	+	assertInWrite := func(name string) {
	48	+	if !inWrite {
	49	+	t.Errorf("%s callback ran after Write returned", name)
	50	+	}
	51	+	}
	52	+
	53	+	screen.OnBell = func() {
	54	+	assertInWrite("bell")
	55	+	events = append(events, "bell")
	56	+	}
	57	+	screen.OnResponse = func(response []byte) {
	58	+	assertInWrite("response")
	59	+	events = append(events, "response:"+string(response))
	60	+	}
	61	+	screen.OnNotify = func(title, body string) {
	62	+	assertInWrite("notify")
	63	+	events = append(events, "notify:"+title+":"+body)
	64	+	}
	65	+	screen.OnProgress = func(errored bool) {
	66	+	assertInWrite("progress")
	67	+	if errored {
	68	+	events = append(events, "progress:error")
	69	+	} else {
	70	+	events = append(events, "progress:clear")
	71	+	}
	72	+	}
	73	+	screen.OnClipboard = func(data string) {
	74	+	assertInWrite("clipboard")
	75	+	events = append(events, "clipboard:"+data)
	76	+	}
	77	+
	78	+	inWrite = true
	79	+	screen.Write([]byte("\a\x1b[5n\x1b]9;body\a\x1b]777;notify;title;body\a" +
	80	+	"\x1b]9;4;1\a\x1b]9;4;0\a\x1b]9;4;2\a" +
	81	+	"\x1b]52;c;SGVsbG8=\a"))
	82	+	inWrite = false
	83	+
	84	+	want := []string{
	85	+	"bell",
	86	+	"response:\x1b[0n",
	87	+	"notify::body",
	88	+	"notify:title:body",
	89	+	"progress:clear",
	90	+	"progress:error",
	91	+	"clipboard:SGVsbG8=",
	92	+	}
	93	+	if !reflect.DeepEqual(events, want) {
	94	+	t.Fatalf("callback events = %#v, want %#v", events, want)
	95	+	}
	96	+	}
	97	+
	98	+	func TestExternalSnapshotsAndHistoryRespectOwnershipContracts(t *testing.T) {
	99	+	screen := vt.NewScreenWithHistory(4, 2, vt.HistoryConfig{MaxRows: 8, ChunkRows: 2})
	100	+	screen.Write([]byte("A"))
	101	+	snapshot := screen.Snapshot()
	102	+
	103	+	owned := snapshot.Row(0)
	104	+	owned[0] = vtcore.Cell{Rune: 'X'}
	105	+	if got := snapshot.Row(0)[0].Rune; got != 'A' {
	106	+	t.Fatalf("owned snapshot row mutation changed snapshot to %q", got)
	107	+	}
	108	+
	109	+	screen.Write([]byte("\rX"))
	110	+	if got := snapshot.Row(0)[0].Rune; got != 'A' {
	111	+	t.Fatalf("snapshot changed after later screen write: %q", got)
	112	+	}
	113	+	if got := snapshot.RowIDs(); len(got) != 2 \|\| got[0] == 0 \|\| got[1] == 0 {
	114	+	t.Fatalf("snapshot row IDs = %#v, want stable nonzero IDs", got)
	115	+	}
	116	+	rowIDs := snapshot.RowIDs()
	117	+	rowIDs[0] = 0
	118	+	if snapshot.RowID(0) == 0 {
	119	+	t.Fatal("RowIDs did not return an owned copy")
	120	+	}
	121	+
	122	+	history := vt.NewHistory(vt.HistoryConfig{MaxRows: 8, ChunkRows: 2})
	123	+	appendHistoryRow(t, history, 'a', 10)
	124	+	appendHistoryRow(t, history, 'b', 11)
	125	+	before := history.View()
	126	+	chunk := before.Chunk(0)
	127	+	if chunk == nil \|\| before.FindRowID(11) != 1 {
	128	+	t.Fatalf("history view = len %d chunk %#v IDs %d/%d", before.Len(), chunk, before.RowID(0), before.RowID(1))
	129	+	}
	130	+
	131	+	copyOfRow := before.Row(0)
	132	+	copyOfRow[0] = vtcore.Cell{Rune: 'x'}
	133	+	if got := before.Row(0)[0].Rune; got != 'a' {
	134	+	t.Fatalf("owned history row mutation changed view to %q", got)
	135	+	}
	136	+	if borrowed := before.BorrowedRow(0); &borrowed[0] == &copyOfRow[0] {
	137	+	t.Fatal("Row returned borrowed history storage instead of an owned copy")
	138	+	}
	139	+
	140	+	appendHistoryRow(t, history, 'c', 12)
	141	+	after := history.View()
	142	+	if after.Chunk(0) != chunk {
	143	+	t.Fatal("sealed history chunk identity changed after an append")
	144	+	}
	145	+	if before.Len() != 2 \|\| before.RowID(0) != 10 \|\| before.RowID(1) != 11 {
	146	+	t.Fatalf("retained history view changed after append: len=%d IDs=%d/%d", before.Len(), before.RowID(0), before.RowID(1))
	147	+	}
	148	+
	149	+	persistenceView := history.SnapshotView()
	150	+	appendHistoryRow(t, history, 'd', 13)
	151	+	if got := persistenceView.Tail().Row(0)[0].Rune; got != 'c' {
	152	+	t.Fatalf("snapshot tail changed after history append to %q", got)
	153	+	}
	154	+	}
	155	+
	156	+	func TestExternalSingleOwnerUsageSerializesMutationAndCapture(t *testing.T) {
	157	+	screen := vt.NewScreen(4, 1)
	158	+	operations := make(chan func(), 3)
	159	+	done := make(chan struct{})
	160	+	go func() {
	161	+	defer close(done)
	162	+	for operation := range operations {
	163	+	operation()
	164	+	}
	165	+	}()
	166	+
	167	+	operations <- func() { screen.Write([]byte("A")) }
	168	+	captured := make(chan vt.ScreenSnapshot, 1)
	169	+	operations <- func() { captured <- screen.Snapshot() }
	170	+	close(operations)
	171	+	<-done
	172	+
	173	+	if got := (<-captured).Row(0)[0].Rune; got != 'A' {
	174	+	t.Fatalf("single-owner capture = %q, want A", got)
	175	+	}
	176	+	}
	177	+
	178	+	func appendHistoryRow(t testing.T, history vt.History, runeValue rune, id vt.RowID) {
	179	+	t.Helper()
	180	+	if err := history.AppendWithID([]vtcore.Cell{{Rune: runeValue}}, vt.LineBound{End: 1}, id); err != nil {
	181	+	t.Fatalf("AppendWithID(%d): %v", id, err)
	182	+	}
	183	+	}

A pkg/vt/extraction_line_callback_external_test.go +35 -0

@@ -0,0 +1,35 @@
	1	+	package vt_test
	2	+
	3	+	import (
	4	+	"testing"
	5	+
	6	+	"github.com/bnema/vev/pkg/vt"
	7	+	"github.com/bnema/vev/pkg/vtcore"
	8	+	)
	9	+
	10	+	func TestExternalLineEvictionCallbackReceivesStableCopy(t *testing.T) {
	11	+	screen := vt.NewScreen(4, 3)
	12	+	inWrite := false
	13	+	var evicted [][]vtcore.Cell
	14	+	screen.OnLineEvicted = func(row []vtcore.Cell) {
	15	+	if !inWrite {
	16	+	t.Error("line eviction callback ran after Write returned")
	17	+	}
	18	+	evicted = append(evicted, row)
	19	+	}
	20	+
	21	+	inWrite = true
	22	+	screen.Write([]byte("AAAA\r\nBBBB\r\nCCCC\r\n"))
	23	+	inWrite = false
	24	+
	25	+	if len(evicted) != 1 \|\| len(evicted[0]) != 4 \|\| evicted[0][0].Rune != 'A' {
	26	+	t.Fatalf("evicted rows = %#v, want one stable AAAA row", evicted)
	27	+	}
	28	+	evicted[0][0] = vtcore.Cell{Rune: 'X'}
	29	+	if got := screen.Frame.At(0, 0).Rune; got != 'B' {
	30	+	t.Fatalf("mutating callback row changed live frame to %q", got)
	31	+	}
	32	+	if got := evicted[0][0].Rune; got != 'X' {
	33	+	t.Fatalf("callback row was not retained as a stable copy: %q", got)
	34	+	}
	35	+	}

@@ -0,0 +1,35 @@
	1	+	package vt_test
	2	+
	3	+	import (
	4	+	"testing"
	5	+
	6	+	"github.com/bnema/vev/pkg/vt"
	7	+	"github.com/bnema/vev/pkg/vtcore"
	8	+	)
	9	+
	10	+	func TestExternalLineEvictionCallbackReceivesStableCopy(t *testing.T) {
	11	+	screen := vt.NewScreen(4, 3)
	12	+	inWrite := false
	13	+	var evicted [][]vtcore.Cell
	14	+	screen.OnLineEvicted = func(row []vtcore.Cell) {
	15	+	if !inWrite {
	16	+	t.Error("line eviction callback ran after Write returned")
	17	+	}
	18	+	evicted = append(evicted, row)
	19	+	}
	20	+
	21	+	inWrite = true
	22	+	screen.Write([]byte("AAAA\r\nBBBB\r\nCCCC\r\n"))
	23	+	inWrite = false
	24	+
	25	+	if len(evicted) != 1 \|\| len(evicted[0]) != 4 \|\| evicted[0][0].Rune != 'A' {
	26	+	t.Fatalf("evicted rows = %#v, want one stable AAAA row", evicted)
	27	+	}
	28	+	evicted[0][0] = vtcore.Cell{Rune: 'X'}
	29	+	if got := screen.Frame.At(0, 0).Rune; got != 'B' {
	30	+	t.Fatalf("mutating callback row changed live frame to %q", got)
	31	+	}
	32	+	if got := evicted[0][0].Rune; got != 'X' {
	33	+	t.Fatalf("callback row was not retained as a stable copy: %q", got)
	34	+	}
	35	+	}

M pkg/vt/history.go +1 -1


@@ -5,7 +5,7 @@ import (
5	5		"math"
6	6		"slices"
7	7
8		-	"github.com/bnema/vev/pkg/renderer"
	8	+	renderer "github.com/bnema/vev/pkg/vtcore"
9	9		)
10	10
11	11		// ErrHistoryRowTooWide is returned when a row cannot fit within the configured


@@ -5,7 +5,7 @@ import (
5		"math"	5		"math"
6		"slices"	6		"slices"
7			7
8	-	"github.com/bnema/vev/pkg/renderer"	8	+	renderer "github.com/bnema/vev/pkg/vtcore"
9		)	9		)
10			10
11		// ErrHistoryRowTooWide is returned when a row cannot fit within the configured	11		// ErrHistoryRowTooWide is returned when a row cannot fit within the configured

M pkg/vt/history_codec.go +1 -1


@@ -8,7 +8,7 @@ import (
8	8		"slices"
9	9		"unicode/utf8"
10	10
11		-	"github.com/bnema/vev/pkg/renderer"
	11	+	renderer "github.com/bnema/vev/pkg/vtcore"
12	12		)
13	13
14	14		const (


@@ -8,7 +8,7 @@ import (
8		"slices"	8		"slices"
9		"unicode/utf8"	9		"unicode/utf8"
10			10
11	-	"github.com/bnema/vev/pkg/renderer"	11	+	renderer "github.com/bnema/vev/pkg/vtcore"
12		)	12		)
13			13
14		const (	14		const (

A pkg/vt/history_vth3_golden_external_test.go +150 -0

@@ -0,0 +1,150 @@
	1	+	package vt_test
	2	+
	3	+	import (
	4	+	"bytes"
	5	+	"encoding/binary"
	6	+	"encoding/hex"
	7	+	"testing"
	8	+
	9	+	"github.com/bnema/vev/pkg/vt"
	10	+	"github.com/bnema/vev/pkg/vtcore"
	11	+	)
	12	+
	13	+	func TestExternalVTH3GoldenVectors(t *testing.T) {
	14	+	vectors := []struct {
	15	+	name string
	16	+	hex string
	17	+	stats vt.DecodeStats
	18	+	}{
	19	+	{
	20	+	name: "empty",
	21	+	hex: "565448310300000000000000000000002a",
	22	+	stats: vt.DecodeStats{},
	23	+	},
	24	+	{
	25	+	name: "plain and continuation cells",
	26	+	hex: "565448310300000001000000000000002a0000000100000000000000290000000200000041000000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff00000000000000010000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff0000000000000200",
	27	+	stats: vt.DecodeStats{Chunks: 1, Rows: 1, Cells: 2, Styles: 2, Bytes: 82},
	28	+	},
	29	+	{
	30	+	name: "all style fields",
	31	+	hex: "565448310300000001000000000000002b00000001000000000000002a000000010000754cff000ffffffffffffffff9000000000000010101020304050605fffffffffffffff70708090000000101",
	32	+	stats: vt.DecodeStats{Chunks: 1, Rows: 1, Cells: 1, Styles: 1, Bytes: 41},
	33	+	},
	34	+	}
	35	+
	36	+	for _, vector := range vectors {
	37	+	t.Run(vector.name, func(t *testing.T) {
	38	+	data, err := hex.DecodeString(vector.hex)
	39	+	if err != nil {
	40	+	t.Fatal(err)
	41	+	}
	42	+	stats, err := vt.PreflightHistoryBlob(data)
	43	+	if err != nil {
	44	+	t.Fatalf("PreflightHistoryBlob: %v", err)
	45	+	}
	46	+	if stats != vector.stats {
	47	+	t.Fatalf("decode stats = %#v, want %#v", stats, vector.stats)
	48	+	}
	49	+
	50	+	view, err := vt.UnmarshalHistory(data)
	51	+	if err != nil {
	52	+	t.Fatalf("UnmarshalHistory: %v", err)
	53	+	}
	54	+	reencoded, err := vt.MarshalHistory(view)
	55	+	if err != nil {
	56	+	t.Fatalf("MarshalHistory: %v", err)
	57	+	}
	58	+	if !bytes.Equal(reencoded, data) {
	59	+	t.Fatalf("canonical bytes changed:\n got %x\nwant %x", reencoded, data)
	60	+	}
	61	+
	62	+	switch vector.name {
	63	+	case "empty":
	64	+	if view.Len() != 0 \|\| view.ChunkCount() != 0 \|\| view.NextRowID() != 42 {
	65	+	t.Fatalf("empty view = len %d chunks %d next %d", view.Len(), view.ChunkCount(), view.NextRowID())
	66	+	}
	67	+	case "plain and continuation cells":
	68	+	if view.Len() != 1 \|\| view.RowID(0) != 41 \|\| view.Bound(0) != (vt.LineBound{End: 2}) \|\| view.NextRowID() != 42 {
	69	+	t.Fatalf("plain view = len %d row %d bound %#v next %d", view.Len(), view.RowID(0), view.Bound(0), view.NextRowID())
	70	+	}
	71	+	row := view.Row(0)
	72	+	if len(row) != 2 \|\| row[0].Rune != 'A' \|\| row[1].Rune != 0 \|\| !row[1].Continuation {
	73	+	t.Fatalf("plain row = %#v", row)
	74	+	}
	75	+	case "all style fields":
	76	+	wantStyle := vtcore.Style{
	77	+	Bold: true,
	78	+	Italic: true,
	79	+	Inverse: true,
	80	+	Attrs: vtcore.StyleAttrs(0x000f),
	81	+	Foreground: -7,
	82	+	Background: 257,
	83	+	HasForegroundRGB: true,
	84	+	ForegroundRGB: vtcore.RGB{R: 1, G: 2, B: 3},
	85	+	HasBackgroundRGB: true,
	86	+	BackgroundRGB: vtcore.RGB{R: 4, G: 5, B: 6},
	87	+	UnderlineStyle: vtcore.UnderlineDashed,
	88	+	UnderlineColor: -9,
	89	+	HasUnderlineColorRGB: true,
	90	+	UnderlineColorRGB: vtcore.RGB{R: 7, G: 8, B: 9},
	91	+	}
	92	+	if view.Len() != 1 \|\| view.RowID(0) != 42 \|\| view.Bound(0) != (vt.LineBound{End: 1, Soft: true}) \|\| view.NextRowID() != 43 {
	93	+	t.Fatalf("styled view = len %d row %d bound %#v next %d", view.Len(), view.RowID(0), view.Bound(0), view.NextRowID())
	94	+	}
	95	+	row := view.Row(0)
	96	+	if len(row) != 1 \|\| row[0].Rune != '界' \|\| !row[0].Style.Equal(wantStyle) {
	97	+	t.Fatalf("styled row = %#v, want %#v", row, wantStyle)
	98	+	}
	99	+	}
	100	+	})
	101	+	}
	102	+	}
	103	+
	104	+	func TestExternalVTH3RejectsMalformedVectors(t *testing.T) {
	105	+	valid, err := hex.DecodeString("565448310300000001000000000000002a0000000100000000000000290000000200000041000000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff00000000000000010000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff0000000000000200")
	106	+	if err != nil {
	107	+	t.Fatal(err)
	108	+	}
	109	+
	110	+	mutate := func(fn func([]byte)) []byte {
	111	+	out := append([]byte(nil), valid...)
	112	+	fn(out)
	113	+	return out
	114	+	}
	115	+	const (
	116	+	rowIDOffset = 21
	117	+	cellOffset = 33
	118	+	boundOffset = 115
	119	+	)
	120	+	cases := []struct {
	121	+	name string
	122	+	data []byte
	123	+	}{
	124	+	{name: "truncated", data: valid[:len(valid)-1]},
	125	+	{name: "trailing bytes", data: append(append([]byte(nil), valid...), 0)},
	126	+	{name: "bad magic", data: mutate(func(data []byte) { data[0] ^= 0xff })},
	127	+	{name: "bad version", data: mutate(func(data []byte) { data[4] = 2 })},
	128	+	{name: "zero next row ID", data: mutate(func(data []byte) { clear(data[9:17]) })},
	129	+	{name: "zero row ID", data: mutate(func(data []byte) { clear(data[rowIDOffset : rowIDOffset+8]) })},
	130	+	{name: "invalid rune", data: mutate(func(data []byte) { binary.BigEndian.PutUint32(data[cellOffset:], ^uint32(0)) })},
	131	+	{name: "invalid underline style", data: mutate(func(data []byte) { data[cellOffset+29] = byte(vtcore.UnderlineDashed + 1) })},
	132	+	{name: "bound exceeds row", data: mutate(func(data []byte) { binary.BigEndian.PutUint32(data[boundOffset:], 3) })},
	133	+	}
	134	+
	135	+	for _, test := range cases {
	136	+	t.Run(test.name, func(t *testing.T) {
	137	+	if _, err := vt.PreflightHistoryBlob(test.data); err == nil {
	138	+	t.Fatal("PreflightHistoryBlob accepted malformed data")
	139	+	}
	140	+	if _, err := vt.UnmarshalHistory(test.data); err == nil {
	141	+	t.Fatal("UnmarshalHistory accepted malformed data")
	142	+	}
	143	+	})
	144	+	}
	145	+	for length := 0; length < len(valid); length++ {
	146	+	if _, err := vt.UnmarshalHistory(valid[:length]); err == nil {
	147	+	t.Fatalf("accepted truncated prefix of length %d", length)
	148	+	}
	149	+	}
	150	+	}

@@ -0,0 +1,150 @@
	1	+	package vt_test
	2	+
	3	+	import (
	4	+	"bytes"
	5	+	"encoding/binary"
	6	+	"encoding/hex"
	7	+	"testing"
	8	+
	9	+	"github.com/bnema/vev/pkg/vt"
	10	+	"github.com/bnema/vev/pkg/vtcore"
	11	+	)
	12	+
	13	+	func TestExternalVTH3GoldenVectors(t *testing.T) {
	14	+	vectors := []struct {
	15	+	name string
	16	+	hex string
	17	+	stats vt.DecodeStats
	18	+	}{
	19	+	{
	20	+	name: "empty",
	21	+	hex: "565448310300000000000000000000002a",
	22	+	stats: vt.DecodeStats{},
	23	+	},
	24	+	{
	25	+	name: "plain and continuation cells",
	26	+	hex: "565448310300000001000000000000002a0000000100000000000000290000000200000041000000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff00000000000000010000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff0000000000000200",
	27	+	stats: vt.DecodeStats{Chunks: 1, Rows: 1, Cells: 2, Styles: 2, Bytes: 82},
	28	+	},
	29	+	{
	30	+	name: "all style fields",
	31	+	hex: "565448310300000001000000000000002b00000001000000000000002a000000010000754cff000ffffffffffffffff9000000000000010101020304050605fffffffffffffff70708090000000101",
	32	+	stats: vt.DecodeStats{Chunks: 1, Rows: 1, Cells: 1, Styles: 1, Bytes: 41},
	33	+	},
	34	+	}
	35	+
	36	+	for _, vector := range vectors {
	37	+	t.Run(vector.name, func(t *testing.T) {
	38	+	data, err := hex.DecodeString(vector.hex)
	39	+	if err != nil {
	40	+	t.Fatal(err)
	41	+	}
	42	+	stats, err := vt.PreflightHistoryBlob(data)
	43	+	if err != nil {
	44	+	t.Fatalf("PreflightHistoryBlob: %v", err)
	45	+	}
	46	+	if stats != vector.stats {
	47	+	t.Fatalf("decode stats = %#v, want %#v", stats, vector.stats)
	48	+	}
	49	+
	50	+	view, err := vt.UnmarshalHistory(data)
	51	+	if err != nil {
	52	+	t.Fatalf("UnmarshalHistory: %v", err)
	53	+	}
	54	+	reencoded, err := vt.MarshalHistory(view)
	55	+	if err != nil {
	56	+	t.Fatalf("MarshalHistory: %v", err)
	57	+	}
	58	+	if !bytes.Equal(reencoded, data) {
	59	+	t.Fatalf("canonical bytes changed:\n got %x\nwant %x", reencoded, data)
	60	+	}
	61	+
	62	+	switch vector.name {
	63	+	case "empty":
	64	+	if view.Len() != 0 \|\| view.ChunkCount() != 0 \|\| view.NextRowID() != 42 {
	65	+	t.Fatalf("empty view = len %d chunks %d next %d", view.Len(), view.ChunkCount(), view.NextRowID())
	66	+	}
	67	+	case "plain and continuation cells":
	68	+	if view.Len() != 1 \|\| view.RowID(0) != 41 \|\| view.Bound(0) != (vt.LineBound{End: 2}) \|\| view.NextRowID() != 42 {
	69	+	t.Fatalf("plain view = len %d row %d bound %#v next %d", view.Len(), view.RowID(0), view.Bound(0), view.NextRowID())
	70	+	}
	71	+	row := view.Row(0)
	72	+	if len(row) != 2 \|\| row[0].Rune != 'A' \|\| row[1].Rune != 0 \|\| !row[1].Continuation {
	73	+	t.Fatalf("plain row = %#v", row)
	74	+	}
	75	+	case "all style fields":
	76	+	wantStyle := vtcore.Style{
	77	+	Bold: true,
	78	+	Italic: true,
	79	+	Inverse: true,
	80	+	Attrs: vtcore.StyleAttrs(0x000f),
	81	+	Foreground: -7,
	82	+	Background: 257,
	83	+	HasForegroundRGB: true,
	84	+	ForegroundRGB: vtcore.RGB{R: 1, G: 2, B: 3},
	85	+	HasBackgroundRGB: true,
	86	+	BackgroundRGB: vtcore.RGB{R: 4, G: 5, B: 6},
	87	+	UnderlineStyle: vtcore.UnderlineDashed,
	88	+	UnderlineColor: -9,
	89	+	HasUnderlineColorRGB: true,
	90	+	UnderlineColorRGB: vtcore.RGB{R: 7, G: 8, B: 9},
	91	+	}
	92	+	if view.Len() != 1 \|\| view.RowID(0) != 42 \|\| view.Bound(0) != (vt.LineBound{End: 1, Soft: true}) \|\| view.NextRowID() != 43 {
	93	+	t.Fatalf("styled view = len %d row %d bound %#v next %d", view.Len(), view.RowID(0), view.Bound(0), view.NextRowID())
	94	+	}
	95	+	row := view.Row(0)
	96	+	if len(row) != 1 \|\| row[0].Rune != '界' \|\| !row[0].Style.Equal(wantStyle) {
	97	+	t.Fatalf("styled row = %#v, want %#v", row, wantStyle)
	98	+	}
	99	+	}
	100	+	})
	101	+	}
	102	+	}
	103	+
	104	+	func TestExternalVTH3RejectsMalformedVectors(t *testing.T) {
	105	+	valid, err := hex.DecodeString("565448310300000001000000000000002a0000000100000000000000290000000200000041000000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff00000000000000010000ffffffffffffffffffffffffffffffff00000000000000ffffffffffffffff0000000000000200")
	106	+	if err != nil {
	107	+	t.Fatal(err)
	108	+	}
	109	+
	110	+	mutate := func(fn func([]byte)) []byte {
	111	+	out := append([]byte(nil), valid...)
	112	+	fn(out)
	113	+	return out
	114	+	}
	115	+	const (
	116	+	rowIDOffset = 21
	117	+	cellOffset = 33
	118	+	boundOffset = 115
	119	+	)
	120	+	cases := []struct {
	121	+	name string
	122	+	data []byte
	123	+	}{
	124	+	{name: "truncated", data: valid[:len(valid)-1]},
	125	+	{name: "trailing bytes", data: append(append([]byte(nil), valid...), 0)},
	126	+	{name: "bad magic", data: mutate(func(data []byte) { data[0] ^= 0xff })},
	127	+	{name: "bad version", data: mutate(func(data []byte) { data[4] = 2 })},
	128	+	{name: "zero next row ID", data: mutate(func(data []byte) { clear(data[9:17]) })},
	129	+	{name: "zero row ID", data: mutate(func(data []byte) { clear(data[rowIDOffset : rowIDOffset+8]) })},
	130	+	{name: "invalid rune", data: mutate(func(data []byte) { binary.BigEndian.PutUint32(data[cellOffset:], ^uint32(0)) })},
	131	+	{name: "invalid underline style", data: mutate(func(data []byte) { data[cellOffset+29] = byte(vtcore.UnderlineDashed + 1) })},
	132	+	{name: "bound exceeds row", data: mutate(func(data []byte) { binary.BigEndian.PutUint32(data[boundOffset:], 3) })},
	133	+	}
	134	+
	135	+	for _, test := range cases {
	136	+	t.Run(test.name, func(t *testing.T) {
	137	+	if _, err := vt.PreflightHistoryBlob(test.data); err == nil {
	138	+	t.Fatal("PreflightHistoryBlob accepted malformed data")
	139	+	}
	140	+	if _, err := vt.UnmarshalHistory(test.data); err == nil {
	141	+	t.Fatal("UnmarshalHistory accepted malformed data")
	142	+	}
	143	+	})
	144	+	}
	145	+	for length := 0; length < len(valid); length++ {
	146	+	if _, err := vt.UnmarshalHistory(valid[:length]); err == nil {
	147	+	t.Fatalf("accepted truncated prefix of length %d", length)
	148	+	}
	149	+	}
	150	+	}

M pkg/vt/recovery_transcript.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		// RecoveryTranscriptSnapshot is an owned, immutable capture of the viewport
6	6		// rows that should be replayed after retained terminal history during recovery.

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		// RecoveryTranscriptSnapshot is an owned, immutable capture of the viewport	5		// RecoveryTranscriptSnapshot is an owned, immutable capture of the viewport
6		// rows that should be replayed after retained terminal history during recovery.	6		// rows that should be replayed after retained terminal history during recovery.

M pkg/vt/screen.go +1 -1


@@ -3,7 +3,7 @@ package vt
3	3		import (
4	4		"unicode/utf8"
5	5
6		-	"github.com/bnema/vev/pkg/renderer"
	6	+	renderer "github.com/bnema/vev/pkg/vtcore"
7	7		)
8	8
9	9		// maxEscapeBufferLen must stay large enough for OSC 52 clipboard payloads


@@ -3,7 +3,7 @@ package vt
3		import (	3		import (
4		"unicode/utf8"	4		"unicode/utf8"
5			5
6	-	"github.com/bnema/vev/pkg/renderer"	6	+	renderer "github.com/bnema/vev/pkg/vtcore"
7		)	7		)
8			8
9		// maxEscapeBufferLen must stay large enough for OSC 52 clipboard payloads	9		// maxEscapeBufferLen must stay large enough for OSC 52 clipboard payloads

M pkg/vt/screen_csi.go +1 -1


@@ -4,7 +4,7 @@ import (
4	4		"strconv"
5	5		"strings"
6	6
7		-	"github.com/bnema/vev/pkg/renderer"
	7	+	renderer "github.com/bnema/vev/pkg/vtcore"
8	8		)
9	9
10	10		func (s *Screen) consumeCSI(data []byte) (consumed int, partial bool) {


@@ -4,7 +4,7 @@ import (
4		"strconv"	4		"strconv"
5		"strings"	5		"strings"
6			6
7	-	"github.com/bnema/vev/pkg/renderer"	7	+	renderer "github.com/bnema/vev/pkg/vtcore"
8		)	8		)
9			9
10		func (s *Screen) consumeCSI(data []byte) (consumed int, partial bool) {	10		func (s *Screen) consumeCSI(data []byte) (consumed int, partial bool) {

M pkg/vt/screen_cursor.go +1 -1


@@ -4,7 +4,7 @@ import (
4	4		"strconv"
5	5		"strings"
6	6
7		-	"github.com/bnema/vev/pkg/renderer"
	7	+	renderer "github.com/bnema/vev/pkg/vtcore"
8	8		)
9	9
10	10		type cursorState struct {


@@ -4,7 +4,7 @@ import (
4		"strconv"	4		"strconv"
5		"strings"	5		"strings"
6			6
7	-	"github.com/bnema/vev/pkg/renderer"	7	+	renderer "github.com/bnema/vev/pkg/vtcore"
8		)	8		)
9			9
10		type cursorState struct {	10		type cursorState struct {

M pkg/vt/screen_damage.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		// maxPendingDamage bounds metadata retained while no render transaction can
6	6		// acknowledge a screen. Saturation falls back to one exact full redraw.

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		// maxPendingDamage bounds metadata retained while no render transaction can	5		// maxPendingDamage bounds metadata retained while no render transaction can
6		// acknowledge a screen. Saturation falls back to one exact full redraw.	6		// acknowledge a screen. Saturation falls back to one exact full redraw.

M pkg/vt/screen_modes.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		type screenState struct {
6	6		frame renderer.Frame

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		type screenState struct {	5		type screenState struct {
6		frame renderer.Frame	6		frame renderer.Frame

M pkg/vt/screen_osc.go +1 -1


@@ -4,7 +4,7 @@ import (
4	4		"strconv"
5	5		"strings"
6	6
7		-	"github.com/bnema/vev/pkg/renderer"
	7	+	renderer "github.com/bnema/vev/pkg/vtcore"
8	8		)
9	9
10	10		const (


@@ -4,7 +4,7 @@ import (
4		"strconv"	4		"strconv"
5		"strings"	5		"strings"
6			6
7	-	"github.com/bnema/vev/pkg/renderer"	7	+	renderer "github.com/bnema/vev/pkg/vtcore"
8		)	8		)
9			9
10		const (	10		const (

M pkg/vt/screen_resize.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		func (s *Screen) Resize(width, height int) {
6	6		if width == s.Frame.Width && height == s.Frame.Height {

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		func (s *Screen) Resize(width, height int) {	5		func (s *Screen) Resize(width, height int) {
6		if width == s.Frame.Width && height == s.Frame.Height {	6		if width == s.Frame.Width && height == s.Frame.Height {

M pkg/vt/screen_scroll.go +1 -1


@@ -3,7 +3,7 @@ package vt
3	3		import (
4	4		"errors"
5	5
6		-	"github.com/bnema/vev/pkg/renderer"
	6	+	renderer "github.com/bnema/vev/pkg/vtcore"
7	7		)
8	8
9	9		// index moves to the next physical row, scrolling the region when the cursor


@@ -3,7 +3,7 @@ package vt
3		import (	3		import (
4		"errors"	4		"errors"
5			5
6	-	"github.com/bnema/vev/pkg/renderer"	6	+	renderer "github.com/bnema/vev/pkg/vtcore"
7		)	7		)
8			8
9		// index moves to the next physical row, scrolling the region when the cursor	9		// index moves to the next physical row, scrolling the region when the cursor

M pkg/vt/screen_snapshot.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		// CursorSnapshot is the cursor state captured with a visible screen snapshot.
6	6		type CursorSnapshot struct {

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		// CursorSnapshot is the cursor state captured with a visible screen snapshot.	5		// CursorSnapshot is the cursor state captured with a visible screen snapshot.
6		type CursorSnapshot struct {	6		type CursorSnapshot struct {

M pkg/vt/screen_write.go +1 -1

@@ -1,6 +1,6 @@
1	1		package vt
2	2
3		-	import "github.com/bnema/vev/pkg/renderer"
	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4	4
5	5		func (s *Screen) putRune(r rune) {
6	6		switch r {

@@ -1,6 +1,6 @@
1		package vt	1		package vt
2			2
3	-	import "github.com/bnema/vev/pkg/renderer"	3	+	import renderer "github.com/bnema/vev/pkg/vtcore"
4			4
5		func (s *Screen) putRune(r rune) {	5		func (s *Screen) putRune(r rune) {
6		switch r {	6		switch r {

R pkg/renderer/cell.go → pkg/vtcore/cell.go +1 -1 renamed, 97% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package vtcore
2	2
3	3		// Cell is a single terminal grid cell.
4	4		//

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package vtcore
2			2
3		// Cell is a single terminal grid cell.	3		// Cell is a single terminal grid cell.
4		//	4		//

R pkg/renderer/damage.go → pkg/vtcore/damage.go +1 -1 renamed, 94% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package vtcore
2	2
3	3		type DamageKind int
4	4

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package vtcore
2			2
3		type DamageKind int	3		type DamageKind int
4			4

A pkg/vtcore/doc.go +7 -0

@@ -0,0 +1,7 @@
	1	+	// Package vtcore defines the frontend-neutral terminal model shared by the VT
	2	+	// emulator and concrete ANSI renderers.
	3	+	//
	4	+	// Frame and other mutable values are single-owner. Frame.Row returns a backing
	5	+	// slice that is valid until the next scroll or resize; Frame.Clone returns
	6	+	// independent storage. The package has no frontend, transport, or vev policy.
	7	+	package vtcore

@@ -0,0 +1,7 @@
	1	+	// Package vtcore defines the frontend-neutral terminal model shared by the VT
	2	+	// emulator and concrete ANSI renderers.
	3	+	//
	4	+	// Frame and other mutable values are single-owner. Frame.Row returns a backing
	5	+	// slice that is valid until the next scroll or resize; Frame.Clone returns
	6	+	// independent storage. The package has no frontend, transport, or vev policy.
	7	+	package vtcore

R pkg/renderer/frame.go → pkg/vtcore/frame.go +37 -3 renamed, 80% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package vtcore
2	2
3	3		import "fmt"
4	4

@@ -40,6 +40,40 @@ func (f Frame) Clone() Frame {
40	40		return clone
41	41		}
42	42
	43	+	// Replace copies src into f while reusing canonical storage when dimensions
	44	+	// permit. src is read through logical rows so its physical row rotation is
	45	+	// preserved in the resulting contents without exposing layout internals.
	46	+	func (f *Frame) Replace(src Frame) {
	47	+	if f == nil {
	48	+	return
	49	+	}
	50	+	if src.Width <= 0 \|\| src.Height <= 0 \|\| len(src.Cells) != src.Width*src.Height {
	51	+	*f = Frame{}
	52	+	return
	53	+	}
	54	+
	55	+	sameDimensions := f.Width == src.Width && f.Height == src.Height
	56	+	cellCount := src.Width * src.Height
	57	+	if sameDimensions && cap(f.Cells) >= cellCount {
	58	+	f.Cells = f.Cells[:cellCount]
	59	+	} else {
	60	+	f.Cells = make([]Cell, cellCount)
	61	+	}
	62	+	if sameDimensions && cap(f.lineOffset) >= src.Height {
	63	+	f.lineOffset = f.lineOffset[:src.Height]
	64	+	} else {
	65	+	f.lineOffset = make([]int, src.Height)
	66	+	}
	67	+	f.Width = src.Width
	68	+	f.Height = src.Height
	69	+	for y := range f.lineOffset {
	70	+	f.lineOffset[y] = y * f.Width
	71	+	}
	72	+	for y := range src.Height {
	73	+	copy(f.Row(y), src.Row(y))
	74	+	}
	75	+	}
	76	+
43	77		func (f Frame) Validate() error {
44	78		if f.Width <= 0 \|\| f.Height <= 0 {
45	79		return fmt.Errorf("invalid frame size %dx%d", f.Width, f.Height)

@@ -115,8 +149,8 @@ func (f Frame) ScrollUp(top, bottom, n int) {
115	149		}
116	150
117	151		// ScrollDown scrolls the logical rows in [top,bottom] down by n lines by
118		-	// rotating their physical offsets. Rows scrolled off the bottom are recycled to
119		-	// the top and blanked in place. See ScrollUp for preconditions.
	152	+	// rotating their physical offsets. Rows scrolled off the bottom are recycled
	153	+	// to the top and blanked in place. See ScrollUp for preconditions.
120	154		func (f Frame) ScrollDown(top, bottom, n int) {
121	155		for ; n > 0; n-- {
122	156		recycled := f.lineOffset[bottom]

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package vtcore
2			2
3		import "fmt"	3		import "fmt"
4			4

@@ -40,6 +40,40 @@ func (f Frame) Clone() Frame {
40		return clone	40		return clone
41		}	41		}
42			42
			43	+	// Replace copies src into f while reusing canonical storage when dimensions
			44	+	// permit. src is read through logical rows so its physical row rotation is
			45	+	// preserved in the resulting contents without exposing layout internals.
			46	+	func (f *Frame) Replace(src Frame) {
			47	+	if f == nil {
			48	+	return
			49	+	}
			50	+	if src.Width <= 0 \|\| src.Height <= 0 \|\| len(src.Cells) != src.Width*src.Height {
			51	+	*f = Frame{}
			52	+	return
			53	+	}
			54	+
			55	+	sameDimensions := f.Width == src.Width && f.Height == src.Height
			56	+	cellCount := src.Width * src.Height
			57	+	if sameDimensions && cap(f.Cells) >= cellCount {
			58	+	f.Cells = f.Cells[:cellCount]
			59	+	} else {
			60	+	f.Cells = make([]Cell, cellCount)
			61	+	}
			62	+	if sameDimensions && cap(f.lineOffset) >= src.Height {
			63	+	f.lineOffset = f.lineOffset[:src.Height]
			64	+	} else {
			65	+	f.lineOffset = make([]int, src.Height)
			66	+	}
			67	+	f.Width = src.Width
			68	+	f.Height = src.Height
			69	+	for y := range f.lineOffset {
			70	+	f.lineOffset[y] = y * f.Width
			71	+	}
			72	+	for y := range src.Height {
			73	+	copy(f.Row(y), src.Row(y))
			74	+	}
			75	+	}
			76	+
43		func (f Frame) Validate() error {	77		func (f Frame) Validate() error {
44		if f.Width <= 0 \|\| f.Height <= 0 {	78		if f.Width <= 0 \|\| f.Height <= 0 {
45		return fmt.Errorf("invalid frame size %dx%d", f.Width, f.Height)	79		return fmt.Errorf("invalid frame size %dx%d", f.Width, f.Height)

@@ -115,8 +149,8 @@ func (f Frame) ScrollUp(top, bottom, n int) {
115		}	149		}
116			150
117		// ScrollDown scrolls the logical rows in [top,bottom] down by n lines by	151		// ScrollDown scrolls the logical rows in [top,bottom] down by n lines by
118	-	// rotating their physical offsets. Rows scrolled off the bottom are recycled to	152	+	// rotating their physical offsets. Rows scrolled off the bottom are recycled
119	-	// the top and blanked in place. See ScrollUp for preconditions.	153	+	// to the top and blanked in place. See ScrollUp for preconditions.
120		func (f Frame) ScrollDown(top, bottom, n int) {	154		func (f Frame) ScrollDown(top, bottom, n int) {
121		for ; n > 0; n-- {	155		for ; n > 0; n-- {
122		recycled := f.lineOffset[bottom]	156		recycled := f.lineOffset[bottom]

A pkg/vtcore/frame_test.go +61 -0

@@ -0,0 +1,61 @@
	1	+	package vtcore
	2	+
	3	+	import "testing"
	4	+
	5	+	func TestFrameCanonicalOffsetsAndInvariants(t *testing.T) {
	6	+	f := NewFrame(4, 3)
	7	+	for y := range f.Height {
	8	+	if f.lineOffset[y] != y*f.Width {
	9	+	t.Fatalf("lineOffset[%d] = %d, want %d", y, f.lineOffset[y], y*f.Width)
	10	+	}
	11	+	}
	12	+	if err := f.CheckInvariants(); err != nil {
	13	+	t.Fatalf("fresh frame invariants: %v", err)
	14	+	}
	15	+	}
	16	+
	17	+	func TestCheckInvariantsDetectsBrokenRotation(t *testing.T) {
	18	+	f := NewFrame(4, 3)
	19	+	f.lineOffset[1] = f.lineOffset[0]
	20	+	if err := f.CheckInvariants(); err == nil {
	21	+	t.Fatal("expected duplicate physical row to be rejected")
	22	+	}
	23	+
	24	+	f = NewFrame(4, 3)
	25	+	f.lineOffset[0] = 1
	26	+	if err := f.CheckInvariants(); err == nil {
	27	+	t.Fatal("expected non-multiple offset to be rejected")
	28	+	}
	29	+
	30	+	f = NewFrame(4, 3)
	31	+	f.lineOffset[2] = 99
	32	+	if err := f.CheckInvariants(); err == nil {
	33	+	t.Fatal("expected out-of-range offset to be rejected")
	34	+	}
	35	+	}
	36	+
	37	+	func TestReplacePreservesLogicalRows(t *testing.T) {
	38	+	dst := NewFrame(3, 3)
	39	+	dst.Set(0, 0, Cell{Rune: 'x'})
	40	+	dst.ScrollUp(0, 2, 1)
	41	+
	42	+	src := NewFrame(3, 3)
	43	+	for y, row := range []string{"abc", "def", "ghi"} {
	44	+	for x, r := range row {
	45	+	src.Set(x, y, Cell{Rune: r})
	46	+	}
	47	+	}
	48	+	src.ScrollUp(0, 2, 1)
	49	+
	50	+	dst.Replace(src)
	51	+	for y, want := range []string{"def", "ghi", " "} {
	52	+	for x, r := range want {
	53	+	if got := dst.At(x, y).Rune; got != r {
	54	+	t.Fatalf("row %d col %d = %q, want %q", y, x, got, r)
	55	+	}
	56	+	}
	57	+	}
	58	+	if err := dst.CheckInvariants(); err != nil {
	59	+	t.Fatalf("replaced frame invariants: %v", err)
	60	+	}
	61	+	}

@@ -0,0 +1,61 @@
	1	+	package vtcore
	2	+
	3	+	import "testing"
	4	+
	5	+	func TestFrameCanonicalOffsetsAndInvariants(t *testing.T) {
	6	+	f := NewFrame(4, 3)
	7	+	for y := range f.Height {
	8	+	if f.lineOffset[y] != y*f.Width {
	9	+	t.Fatalf("lineOffset[%d] = %d, want %d", y, f.lineOffset[y], y*f.Width)
	10	+	}
	11	+	}
	12	+	if err := f.CheckInvariants(); err != nil {
	13	+	t.Fatalf("fresh frame invariants: %v", err)
	14	+	}
	15	+	}
	16	+
	17	+	func TestCheckInvariantsDetectsBrokenRotation(t *testing.T) {
	18	+	f := NewFrame(4, 3)
	19	+	f.lineOffset[1] = f.lineOffset[0]
	20	+	if err := f.CheckInvariants(); err == nil {
	21	+	t.Fatal("expected duplicate physical row to be rejected")
	22	+	}
	23	+
	24	+	f = NewFrame(4, 3)
	25	+	f.lineOffset[0] = 1
	26	+	if err := f.CheckInvariants(); err == nil {
	27	+	t.Fatal("expected non-multiple offset to be rejected")
	28	+	}
	29	+
	30	+	f = NewFrame(4, 3)
	31	+	f.lineOffset[2] = 99
	32	+	if err := f.CheckInvariants(); err == nil {
	33	+	t.Fatal("expected out-of-range offset to be rejected")
	34	+	}
	35	+	}
	36	+
	37	+	func TestReplacePreservesLogicalRows(t *testing.T) {
	38	+	dst := NewFrame(3, 3)
	39	+	dst.Set(0, 0, Cell{Rune: 'x'})
	40	+	dst.ScrollUp(0, 2, 1)
	41	+
	42	+	src := NewFrame(3, 3)
	43	+	for y, row := range []string{"abc", "def", "ghi"} {
	44	+	for x, r := range row {
	45	+	src.Set(x, y, Cell{Rune: r})
	46	+	}
	47	+	}
	48	+	src.ScrollUp(0, 2, 1)
	49	+
	50	+	dst.Replace(src)
	51	+	for y, want := range []string{"def", "ghi", " "} {
	52	+	for x, r := range want {
	53	+	if got := dst.At(x, y).Rune; got != r {
	54	+	t.Fatalf("row %d col %d = %q, want %q", y, x, got, r)
	55	+	}
	56	+	}
	57	+	}
	58	+	if err := dst.CheckInvariants(); err != nil {
	59	+	t.Fatalf("replaced frame invariants: %v", err)
	60	+	}
	61	+	}

R pkg/renderer/rune_width.go → pkg/vtcore/rune_width.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package vtcore
2	2
3	3		import "unicode"
4	4

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package vtcore
2			2
3		import "unicode"	3		import "unicode"
4			4

R pkg/renderer/style.go → pkg/vtcore/style.go +1 -1 renamed, 99% similar

@@ -1,4 +1,4 @@
1		-	package renderer
	1	+	package vtcore
2	2
3	3		type RGB struct {
4	4		R uint8

@@ -1,4 +1,4 @@
1	-	package renderer	1	+	package vtcore
2			2
3		type RGB struct {	3		type RGB struct {
4		R uint8	4		R uint8