End DCS/OSC strings at any ESC, default the external terminal to Terminal.app

A string with no ST swallowed every later sequence, RIS included, and
Clear Screen could not recover the tab. Any ESC now ends it, as in xterm,
and the sequence it starts is dispatched. The shipped setting needed Kitty.

Also: REP, SCOSC/SCORC, DECOM-relative CPR, `:` subparams and more DECRQM
modes answered; new rows inserted in one edit; controls stripped from
pastes; wide-char mouse columns.

Architecture.md

@@ -11,7 +11,7 @@
 | `vterm/render.py` | Screen → view text, colour overlays, caret, folding, trimming. |
 | `vterm/scheme.py` | `SchemeManager`: generates one theme's colour scheme, the scopes the renderer paints with. `get_scheme_manager` caches one instance per theme name, each terminal frozen to the instance it was opened or rethemed with. |
 | `vterm/themes.py` | The built-in palettes (`default`, `homebrew`, `pro`, `slate`, `red-alert`). |
-| `vterm/commands.py` | The Sublime commands: open, keypress, copy/paste, theme picker, clear, cleanup, close. |
+| `vterm/commands.py` | The Sublime commands: open, keypress, copy/paste, theme picker, clear, cleanup. |
 | `vterm/listeners.py` | `VtermCoreEventListener`: focus, IME capture, copy/paste rerouting, the mousemap context. |
 | `vterm/mouse.py` | Wheel and click handling. |
 | `vterm/keys.py` | Key name + modifiers → escape sequence tables. |
@@ -21,14 +21,15 @@
 
 | File | Role |
 |---|---|
-| `vterm.sublime-settings` | Defaults for the eleven plugin settings. |
+| `vterm.sublime-settings` | Defaults for the twelve plugin settings. |
 | `vterm.sublime-commands` | Four palette entries: open, open terminal in project folder, clear screen, select theme. |
 | `vterm.sublime-syntax` | An intentionally empty hidden syntax, so terminal text is never tokenized. |
 | `Default.sublime-keymap` | 245 generated bindings. **Do not edit by hand** — regenerate with `tools/gen_keymap.py`. |
 | `Default (OSX).sublime-mousemap` | Two wheel bindings and the middle button. |
 | `dependencies.json` | Package Control libraries. |
 
-Generated at runtime, not in the repo: `Packages/User/vterm/vterm.hidden-color-scheme`.
+Generated at runtime, not in the repo: `Packages/User/vterm/vterm-<theme>.hidden-color-scheme`,
+one per theme (`vterm-system` for "no theme").
 
 ## Classes
 
@@ -50,8 +51,8 @@ Generated at runtime, not in the repo: `Packages/User/vterm/vterm.hidden-color-s
   into the next one. Parity is enforced by a differential test (`run_fast_path_cases`).
 - **`Cursor`** (`emulator.py`) — replaces pyte's so the default attribute set can be a
   `Char` carrying the extra `linefeed` field.
-- **`SchemeManager`** (`scheme.py`) — module singleton `scheme_manager`. Owns the
-  generated scheme file and the mapping from colour combination to scope name.
+- **`SchemeManager`** (`scheme.py`) — one per theme name, cached by `get_scheme_manager`.
+  Owns the generated scheme file and the mapping from colour combination to scope name.
 - **`VtermRenderCommand`** (`render.py`) — the per-frame logic. Sublime rebuilds every
   `TextCommand` instance whenever any plugin loads, so the view's render state
   (`RenderState`: `colored_lines`, `row_cache`, `key_counter`, the scrollback chunk
@@ -68,17 +69,15 @@ Generated at runtime, not in the repo: `Packages/User/vterm/vterm.hidden-color-s
 | `vterm_keypress` | `VtermKeypressCommand` | 244 keymap bindings |
 | `vterm_render` | `VtermRenderCommand` | renderer thread |
 | `vterm_show_cursor` | `VtermShowCursorCommand` | internal |
-| `vterm_copy` / `vterm_paste` / `vterm_paste_text` | `commands.py` | `on_text_command`, IME capture |
+| `vterm_copy` / `vterm_paste_text` | `commands.py` | `on_text_command`, IME capture |
 | `vterm_paste_selection` | `commands.py` | mousemap, middle button |
 | `vterm_select_theme` | `VtermSelectThemeCommand` | palette |
 | `vterm_clear_screen` | `VtermClearScreenCommand` | palette, `super+shift+k` |
 | `vterm_cleanup` | `VtermCleanupCommand` | renderer, on process exit |
-| `vterm_close` | `VtermCloseCommand` | nothing — available for a user keybinding |
 | `vterm_clear_undo_stack` / `vterm_noop` | `commands.py` | internal |
-| `vterm_scroll` / `vterm_mouse_click` | `mouse.py` | mousemap, `drag_select` interception |
+| `vterm_scroll` / `vterm_mouse_press` / `vterm_mouse_release` | `mouse.py` | mousemap |
 
-Two application-wide `EventListener`s: `VtermCoreEventListener` (`listeners.py`) and
-`VtermMouseEventListener` (`mouse.py`).
+One application-wide `EventListener`: `VtermCoreEventListener` (`listeners.py`).
 
 
 ---
@@ -101,7 +100,8 @@ are marked ✅.
   truecolor, `ESC[0m` reset. This is what TUIs emit most.
 - **OSC** ✅ — Operating System Command, `ESC ]`, ending at BEL or ST. Carries strings
   rather than numbers: `OSC 0/2` set the window title, `OSC 10/11` query the default
-  foreground/background, `OSC 52` reads or writes the system clipboard.
+  foreground/background, `OSC 52` reads or writes the system clipboard (vterm
+  ignores it: untrusted output must not plant a paste).
 - **DCS / APC** — Device Control String (`ESC P`) and Application Program Command
   (`ESC _`). Long payloads: sixel images, kitty graphics. vterm parses their framing and
   discards the payload, so an image never leaks into the text.

Default (OSX).sublime-mousemap

@@ -11,6 +11,13 @@
         "args": {"up": false},
         "context": [{"key": "vterm_view.wheel_captured", "operand": true}]
     },
+    {
+        // press reports the click, release reports the drag
+        "button": "button1",
+        "press_command": "vterm_mouse_press",
+        "command": "vterm_mouse_release",
+        "context": [{"key": "vterm_view.mouse_reporting", "operand": true}]
+    },
     {
         // press_command: sublime's own button3 binding is a column drag_select,
         // which would clear the selection before a release command could read it

README.md

@@ -79,15 +79,16 @@ or turns it off. Copy/paste use the normal Sublime keys, and pastes are
 bracketed when the app asks for it. Copying re-joins soft-wrapped lines. The
 middle button pastes the current selection straight into the app, X11-style,
 without going near the clipboard; it does nothing when nothing is selected. The
-wheel scrolls the view normally; while the app tracks the mouse the wheel and
-left click go to it instead, and on the alternate screen without tracking each
-wheel tick sends arrow keys (alternate scroll, as kitty/iTerm2 do — this is
-what scrolls Claude Code's fullscreen UI before it enables mouse reporting).
+wheel scrolls the view normally; while the app tracks the mouse the wheel, clicks
+and drags go to it instead (Claude Code's own mouse selection and copy work as in
+kitty), and on the alternate screen without tracking each wheel tick sends arrow
+keys (alternate scroll, as kitty/iTerm2 do — this is what scrolls Claude Code's
+fullscreen UI before it enables mouse reporting).
 Sublime raises no wheel event at all for the trackpad (sublime_text#1838): set
 a utility such as [LinearMouse](https://linearmouse.app/) to discrete scrolling
 for Sublime Text and it arrives as wheel notches like any other. A notch sends the
-app three scroll lines, as iTerm2 does; `wheel_lines` lowers that when a swipe
-scrolls too far. While an app owns the
+app one scroll line; `wheel_lines` raises that (iTerm2 sends 3) when the wheel
+feels slow. While an app owns the
 alternate screen the scrollback above it is folded away, kitty-style, and
 unfolds when the app leaves it.
 
@@ -125,7 +126,8 @@ terminal protocols — see `Architecture.md`.
   multi-digit OSC. It answers DA1 (Claude Code's query sentinel, which has no
   timeout) and DA2, CPR, XTVERSION + DECRQM 2026 (this is what unlocks Claude
   Code's flicker-free synchronized output on a generic `TERM`), the kitty keyboard
-  probe, and OSC 10/11 colour queries; OSC 52 goes to the Sublime clipboard.
+  probe, and OSC 10/11 colour queries; OSC 52 (clipboard write) is ignored,
+  since any output could plant a command to paste.
   Combining characters are merged as NFC, because Sublime draws decomposed
   sequences badly.
 - `vterm/terminal.py` — pty process, reader and renderer threads at ~33 Hz.
@@ -149,15 +151,16 @@ terminal protocols — see `Architecture.md`.
   into the view: an app that does not echo (vim in normal mode) would otherwise
   leave the character behind. `on_modified` in `vterm/listeners.py` remains the
   fallback for IME and composed input.
-- `vterm/mouse.py` — SGR mouse reporting (wheel, click) when the app enables
+- `vterm/mouse.py` — SGR mouse reporting (wheel, click, drag) when the app enables
   tracking; native selection and scrolling otherwise. The trackpad is not
   handled: it reaches no mousemap on macOS and is converted to wheel notches
   outside the plugin.
 
 Supported: alt screen (1049), synchronized output (2026), bracketed paste (2004),
-mouse tracking 1000/1002/1003 + SGR 1006 (wheel and left click are reported; no
-drag, no right button; the middle button pastes the selection instead of being
-reported), focus events (1004),
+mouse tracking 1000/1002/1003 + SGR 1006 (wheel and left button are reported; a
+drag arrives as one motion at release, since Sublime raises none; no right
+button; the middle button pastes the selection instead of being reported),
+focus events (1004),
 xterm modifyOtherKeys (`CSI > 4 ; n m`, for the modified keys with no
 unambiguous legacy encoding: enter, tab, backspace, space), cursor styles (DECSCUSR —
 block/bar and blink/steady via the view's caret settings; underline falls back
@@ -207,6 +210,6 @@ python3 benchmarks/profiling.py           # feed-path hotspots, per-char micro-b
 `harness_live.py` is the useful one: it drives a real `pi` or `claude` through the
 emulator with no Sublime involved, and prints the queries answered plus the
 resulting screen. Tests import pyte/ptyprocess/wcwidth from Sublime's
-`Lib/python38` (pure Python, so any Python 3 runs them).
+`Lib/python3*` (pure Python, so any Python 3 runs them).
 
 Code style is in `CODE.md`, working agreements in `CLAUDE.md`.

benchmarks/bench_vs_terminus.py

@@ -296,11 +296,12 @@ def drive(feed, need_to_render, render, data, tick):
 def run_vterm(data, tick):
     from vterm.emulator import VtScreen, VtStream
     from vterm.render import VtermRenderCommand
+    from vterm.scheme import get_scheme_manager
     from vterm.terminal import Terminal
 
     counter = collections.Counter()
     view = CountingView(counter)
-    terminal = Terminal(view)
+    terminal = Terminal(view, get_scheme_manager("default"))
     terminal.scrollback_size = SCROLLBACK
     terminal.process = FakeProcess()
     terminal.screen = VtScreen(COLUMNS, ROWS, process=terminal.process, history=SCROLLBACK)

main.py

@@ -12,22 +12,20 @@ from .vterm.commands import (
     VtermClearScreenCommand,
     VtermClearUndoStackCommand,
     VtermCleanupCommand,
-    VtermCloseCommand,
     VtermCopyCommand,
     VtermInitializeViewCommand,
     VtermKeypressCommand,
     VtermNoopCommand,
     VtermOpenCommand,
     VtermOpenTerminalProjectFolderCommand,
-    VtermPasteCommand,
     VtermPasteSelectionCommand,
     VtermPasteTextCommand,
     VtermSelectThemeCommand,
 )
 from .vterm.listeners import VtermCoreEventListener
 from .vterm.mouse import (
-    VtermMouseClickCommand,
-    VtermMouseEventListener,
+    VtermMousePressCommand,
+    VtermMouseReleaseCommand,
     VtermScrollCommand,
 )
 from .vterm.scheme import build_startup_schemes

tests/_bootstrap.py

@@ -3,14 +3,16 @@
 They run as plain scripts (see README), so each imports this first to get the
 sublime stubs and the Package Control libraries on the path.
 """
+import glob
 import os
 import sys
 
 ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-ST_LIB = os.path.expanduser(
-    "~/Library/Application Support/Sublime Text/Lib/python38")
+# Package Control puts the libraries under the plugin host's own directory
+ST_LIBS = sorted(glob.glob(os.path.expanduser(
+    "~/Library/Application Support/Sublime Text/Lib/python3*")))
 
-for path in (ROOT, ST_LIB, os.path.join(ROOT, "tests", "stubs")):
+for path in [ROOT] + ST_LIBS + [os.path.join(ROOT, "tests", "stubs")]:
     if path not in sys.path:
         sys.path.insert(0, path)
 

tests/test_commands.py

@@ -4,7 +4,7 @@ import _bootstrap  # sets sys.path for the imports below
 from _bootstrap import FakeProcess
 
 import sublime
-from vterm.commands import VtermPasteSelectionCommand, VtermSelectThemeCommand, selection_text
+from vterm.commands import VtermPasteSelectionCommand, VtermPasteTextCommand, VtermSelectThemeCommand, selection_text
 from vterm.emulator import VtScreen
 from vterm.render import CONTINUATION
 from vterm.scheme import get_scheme_manager
@@ -25,6 +25,7 @@ class FakeTerminalView:
         self._id = FakeTerminalView._next_id
         FakeTerminalView._next_id += 1
         self._settings = sublime.Settings()
+        self._settings.set("vterm_view", True)
 
     def id(self):
         return self._id
@@ -36,7 +37,24 @@ class FakeTerminalView:
         return True
 
     def style(self):
-        return {}
+        # a terminal view reports its own theme's colours, not the editor's
+        return {"foreground": "#f2f2f2", "background": "#000000"}
+
+
+class FakeEditorView:
+    """An ordinary file view, the one the "No theme" palette is sampled from."""
+
+    def settings(self):
+        return sublime.Settings()
+
+    def is_valid(self):
+        return True
+
+    def style(self):
+        return {"foreground": "#111111", "background": "#eeeeee"}
+
+
+editor = FakeEditorView()
 
 
 class FakeWindow:
@@ -46,6 +64,9 @@ class FakeWindow:
     def active_view(self):
         return self._view
 
+    def views(self):
+        return [self._view, editor]
+
     def show_quick_panel(self, items, on_done, selected_index=-1, on_highlight=None):
         panel.update(items=items, on_done=on_done,
                      selected_index=selected_index, on_highlight=on_highlight)
@@ -105,6 +126,12 @@ command = open_picker(fake_terminal("slate"))
 panel["on_done"](0)
 assert settings.get("theme") is None, settings.get("theme")
 
+# ... and samples the editor's colours, not the themed terminal's own: that
+# would retint every "no theme" terminal with the theme being left
+system = get_scheme_manager(None)
+assert (system.foreground, system.background) == ("#111111", "#eeeeee"), \
+    (system.foreground, system.background)
+
 print("theme picker tests passed ({} themes offered)".format(len(THEMES)))
 
 
@@ -218,3 +245,17 @@ view = FakeView("abcdef", [sublime.Region(2, 2)])
 assert paste(view) == [], view.commands
 
 print("selection tests passed (sentinel stripping, paste, empty no-op)")
+
+
+# a paste is a trust boundary: C0 controls bar tab/LF/CR go, so a pasted
+# ESC[201~ cannot close the bracket and type the rest into the app
+terminal = fake_terminal("default")
+terminal.process = terminal.screen._process
+terminal.screen.set_mode(2004, private=True)
+terminal.view.run_command = lambda name, args=None: None
+command = VtermPasteTextCommand.__new__(VtermPasteTextCommand)
+command.view = terminal.view
+command.run(None, "a\x1b[201~b\x00\tc\nd")
+assert terminal.process.written == "\x1b[200~a[201~b\tc\rd\x1b[201~", repr(terminal.process.written)
+
+print("paste tests passed (controls stripped, bracket kept whole)")

tests/test_emulator.py

@@ -83,13 +83,11 @@ def run_case(char_by_char):
     assert proc.written == "\x1b]11;rgb:1a1a/2b2b/3c3c\x1b\\", (tag, proc.written)
     assert screen.buffer[0][0].data == "y", tag
 
-    # OSC 52 clipboard (base64 "hi")
-    got = []
-    proc = FakeProcess()
-    screen = VtScreen(80, 24, process=proc, clipboard_callback=got.append)
-    stream = VtStream(screen)
-    feed(stream, "\x1b]52;c;aGk=\x07", char_by_char)
-    assert got == ["hi"], (tag, got)
+    # OSC 52 (clipboard write) is dropped, not drawn: untrusted output must
+    # not plant a paste
+    proc, screen, stream = make()
+    feed(stream, "\x1b]52;c;aGk=\x07z", char_by_char)
+    assert screen.buffer[0][0].data == "z" and proc.written == "", tag
 
     # bracketed paste and sync modes tracked
     proc, screen, stream = make()
@@ -119,6 +117,21 @@ def run_case(char_by_char):
     assert screen.buffer[0][0].fg == "ff0000" and screen.buffer[0][0].bold, tag
     assert screen.buffer[0][1].fg == "ff0000", (tag, screen.buffer[0][1].fg)
 
+    # every grey lands inside the palette; 248 used to map to slot 256 and
+    # abort the whole SGR
+    from vterm.emulator import quantize_256
+    assert all(0 <= quantize_256(v, v, v) <= 255 for v in range(256))
+    proc, screen, stream = make()
+    feed(stream, "\x1b[38;2;248;248;248mX", char_by_char)
+    assert screen.buffer[0][0].fg == "ffffff", (tag, screen.buffer[0][0].fg)
+
+    # a zero-width non-combining char (VS16, ZWJ) or a stray control byte is
+    # dropped; the text after it must survive
+    proc, screen, stream = make()
+    feed(stream, "⚠️ warn \U0001F468‍\U0001F4BB ab\x01cd", char_by_char)
+    row = "".join(screen.buffer[0][x].data for x in range(20)).rstrip()
+    assert row == "⚠ warn \U0001F468\U0001F4BB abcd", (tag, repr(row))
+
     # SGR 5/25 (blink): ignored, not a crash — Char has no blink field
     proc, screen, stream = make()
     feed(stream, "\x1b[5;31mX\x1b[25mY", char_by_char)
@@ -141,6 +154,11 @@ def run_case(char_by_char):
     assert len(screen.history) == 1, (tag, len(screen.history))
     assert screen.history[0][0].data == "a", tag
 
+    # an explicit full-screen scroll region still feeds scrollback
+    proc, screen, stream = make(10, 3)
+    feed(stream, "\x1b[1;3ra\r\nb\r\nc\r\nd", char_by_char)
+    assert len(screen.history) == 1, (tag, len(screen.history))
+
     # ED 3 clears history and fires callback
     cleared = []
     proc = FakeProcess()
@@ -310,7 +328,7 @@ GAUNTLET = (
     "\x1b[2;5r\x1b[Sscrolled\x1b[T\x1b[r"
     "\x1b[38:5:100mcolon\x1b[m\r\n"
     "\x1b[2\x073m bel mid-CSI \x1b[3\x18X can cancels\r\n"
-    "wide: 漢字 \x1b[7m漢\x1b[m\r\n"
+    "wide: 漢字 \x1b[7m漢\x1b[m ⚠️ after\r\n"
     "\x1b[m\x1b[;5m\x1b[5;m\x1b[25m params\r\n"
 )
 
@@ -436,8 +454,67 @@ def run_clear_cases():
     print("all clear-screen tests passed")
 
 
+def run_parser_edge_cases():
+    """Sequences the stock collector misread: intermediates, `:` subparams, REP, marks."""
+    for char_by_char in (False, True):
+        tag = "char-by-char" if char_by_char else "chunked"
+
+        # DECSTR (`reset` sends it): `!` is an intermediate, the `p` must not be drawn
+        proc, screen, stream = make(20, 4)
+        feed(stream, "\x1b[!pX", char_by_char)
+        assert screen.display[0].rstrip() == "X", (tag, repr(screen.display[0]))
+
+        # `4:3` is curly underline, not SGR 43 (yellow background)
+        proc, screen, stream = make(20, 4)
+        feed(stream, "\x1b[4:3mX\x1b[38:2:1:2:3mY", char_by_char)
+        cell = screen.buffer[0][0]
+        assert (cell.bg, cell.underscore) == ("default", True), (tag, cell)
+        assert screen.buffer[0][1].data == "Y", (tag, screen.buffer[0][1])
+
+        # REP repeats the last printable; ncurses emits it for runs
+        proc, screen, stream = make(20, 4)
+        feed(stream, "a\x1b[3b\x1b[31mb\x1b[b", char_by_char)
+        assert screen.display[0].rstrip() == "aaaabb", (tag, repr(screen.display[0]))
+        assert screen.buffer[0][5].fg == "red", (tag, screen.buffer[0][5])
+
+        # a Thai vowel sign has combining class 0 but is still a mark: merged, not dropped
+        proc, screen, stream = make(20, 4)
+        feed(stream, "\u0e01\u0e31x", char_by_char)
+        assert screen.buffer[0][0].data == "\u0e01\u0e31", (tag, screen.buffer[0][0])
+        assert screen.buffer[0][1].data == "x", (tag, screen.buffer[0][1])
+
+        # DECRQM: the modes we honour answer set/reset, never "unrecognized"
+        proc, screen, stream = make()
+        feed(stream, "\x1b[?2031$p\x1b[?1h\x1b[?1$p\x1b[4$p\x1b[20$p", char_by_char)
+        assert proc.written == "\x1b[?2031;2$y\x1b[?1;1$y\x1b[4;2$y\x1b[20;2$y", (tag, proc.written)
+
+        # RIS on the alternate screen lands back on a cleared primary screen
+        proc, screen, stream = make(20, 4)
+        feed(stream, "primary\x1b[?1049halt\x1bc", char_by_char)
+        assert not screen.alternate_buffer_mode and not screen.savepoints, tag
+        assert screen.display[0].strip() == "", (tag, repr(screen.display[0]))
+        feed(stream, "\r\n" * 4, char_by_char)
+        assert len(screen.history) == 1, (tag, len(screen.history))
+
+        # SCOSC/SCORC, and CPR relative to the region under DECOM
+        proc, screen, stream = make(20, 4)
+        feed(stream, "ab\x1b[s\x1b[3;3H\x1b[uX\x1b[2;3r\x1b[?6h\x1b[6n", char_by_char)
+        assert screen.display[0].rstrip() == "abX", (tag, repr(screen.display[0]))
+        assert proc.written == "\x1b[1;1R", (tag, proc.written)
+
+        # a string with no terminator ends at the next ESC, as in xterm; a stray
+        # ESC P from a binary must not swallow the rest of the session
+        proc, screen, stream = make(20, 4)
+        feed(stream, "\x1bPgarbage\x1bcX\x1b]0;title\x1b[1mY", char_by_char)
+        assert screen.display[0].rstrip() == "XY", (tag, repr(screen.display[0]))
+        assert screen.title == "title" and screen.buffer[0][1].bold, (tag, screen.title)
+
+    print("all parser edge-case tests passed")
+
+
 run_case(char_by_char=False)
 run_case(char_by_char=True)
+run_parser_edge_cases()
 run_clear_cases()
 run_resize_cases()
 run_private_csi_cases()

tests/test_render.py

@@ -9,7 +9,7 @@ from _bootstrap import FakeProcess
 import sublime
 from vterm.commands import VtermKeypressCommand
 from vterm.emulator import VtScreen, VtStream
-from vterm.mouse import VtermMouseClickCommand, VtermScrollCommand
+from vterm.mouse import VtermMousePressCommand, VtermMouseReleaseCommand, VtermScrollCommand
 from vterm.render import (
     CHUNK,
     RenderState,
@@ -191,17 +191,30 @@ command.trim_history(None, terminal)
 assert terminal.view.text == before, \
     "alt screen view was trimmed: {!r}".format(terminal.view.text)
 
-# the configured cap still applies on the primary screen
+# the configured cap still applies on the primary screen: that many rows of
+# scrollback above the screen
 terminal, stream = make_terminal(rows=5, scrollback=20)
 terminal.offset = 40
 terminal.view = FakeView("\n".join("row {}".format(i) for i in range(40)))
 command = make_command(terminal)
 command.trim_history(None, terminal)
 rows_left = terminal.view.text.count("\n") + 1
-assert rows_left <= 20, rows_left
+assert rows_left <= 25, rows_left
 assert "row 39" in terminal.view.text, "newest rows must survive"
 assert "row 0" not in terminal.view.text, "oldest rows must be dropped"
 
+# a cap below the screen height (0: no scrollback) must never cut the screen
+terminal, stream = make_terminal(rows=10, cols=20, scrollback=0)
+command = make_command(terminal)
+for i in range(3):
+    stream.feed("\r\n".join("row{}".format(i * 10 + j) for j in range(10)) + "\r\n")
+    command.update_lines(None, terminal)
+    command.trim_trailing_spaces(None, terminal)
+    command.trim_history(None, terminal)
+    terminal.screen.dirty.clear()
+assert terminal.offset >= 0, terminal.offset
+assert "row29" in terminal.view.text, terminal.view.text
+
 # below the cap nothing is dropped
 terminal, stream = make_terminal(rows=5, scrollback=5000)
 terminal.offset = 3
@@ -344,7 +357,13 @@ command = make_command(terminal)
 stream.feed("".join("\x1b[31mr{}\x1b[0m\r\n".format(i) for i in range(300)))
 command.update_lines(None, terminal)
 terminal.screen.dirty.clear()
-assert set(command.state.archived_chunks) == {0}, command.state.archived_chunks
+# rows new to the view went in as one insert, coloured straight onto their
+# chunk keys; only row 0 and the two coloured screen rows have a key of their own
+assert set(command.state.archived_chunks) == {0, 1}, command.state.archived_chunks
+assert len(terminal.view.regions["vterm@1@vterm.red.default"][1]) == terminal.offset - CHUNK
+row_keys = [k for k in terminal.view.regions if k.startswith("vterm#")]
+assert len(row_keys) == 3, row_keys
+assert terminal.view.text.split("\n")[:3] == ["r0", "r1", "r2"], terminal.view.text[:20]
 command.trim_history(None, terminal)
 assert "vterm@0@vterm.red.default" not in terminal.view.regions, "trimmed chunk key left behind"
 assert 0 not in command.state.archived_chunks
@@ -442,6 +461,8 @@ Terminal._terminals[id(terminal)] = terminal
 terminal.view.id = lambda: id(terminal)
 scroll = VtermScrollCommand.__new__(VtermScrollCommand)
 scroll.view = terminal.view
+# three per notch, so "one report per line" is visible
+sublime.load_settings(SETTINGS_FILE).set("wheel_lines", 3)
 
 stream.feed("\x1b[?1049h")
 scroll.run(None, up=True)
@@ -626,19 +647,39 @@ terminal.view.window_to_text = lambda xy: 0
 window = FakeWindow(active=object())
 terminal.view.window = lambda: window
 stream.feed("\x1b[?1002h\x1b[?1006h")
-click = VtermMouseClickCommand.__new__(VtermMouseClickCommand)
-click.view = terminal.view
+mouse_press = VtermMousePressCommand.__new__(VtermMousePressCommand)
+mouse_press.view = terminal.view
+mouse_release = VtermMouseReleaseCommand.__new__(VtermMouseReleaseCommand)
+mouse_release.view = terminal.view
 event = {"x": 0, "y": 0, "button": 1}
 
-click.run(None, event)
+mouse_press.run(None, event)
 assert window.active_view() is terminal.view, "click did not focus the tab"
+mouse_release.run(None, event)
 assert terminal.process.written == "", repr(terminal.process.written)
 
-# once focused, the same click reports as before
-click.run(None, event)
+# once focused, press and release at one cell report a click
+mouse_press.run(None, event)
+mouse_release.run(None, event)
 assert terminal.process.written == "\x1b[<0;1;1M\x1b[<0;1;1m", repr(terminal.process.written)
 
-print("click focus tests passed (first click focuses only, then reports)")
+# a release elsewhere reports one drag motion first
+terminal.process.writes.clear()
+terminal.view.text = "r0    \nr1    \nr2    \nr3    \nr4    \n"
+mouse_press.run(None, event)
+terminal.view.window_to_text = lambda xy: terminal.view.text_point(2, 4)
+mouse_release.run(None, event)
+assert terminal.process.written == "\x1b[<0;1;1M\x1b[<32;5;3M\x1b[<0;5;3m", repr(terminal.process.written)
+
+# the column is counted in cells: a wide char before the point takes two
+terminal.process.writes.clear()
+terminal.view.text = "\u65e5\u672cx   \nr1    \nr2    \nr3    \nr4    \n"
+terminal.view.window_to_text = lambda xy: terminal.view.text_point(0, 2)
+mouse_press.run(None, event)
+mouse_release.run(None, event)
+assert terminal.process.written == "\x1b[<0;5;1M\x1b[<0;5;1m", repr(terminal.process.written)
+
+print("click tests passed (first click focuses only; press, drag and release report; wide chars)")
 
 
 # entering the alt screen folds the scrollback away (kitty hides it); leaving
@@ -724,4 +765,12 @@ line[0] = Char("r", "red", "default", False, False, False, False, True)
 runs = [r for r in segment_buffer_line(line) if r[1] != r[2]]
 assert runs == [("r", 0, 1, "reverse_default", "red", "")], runs
 
-print("segmenter tests passed (leading gap, wide char, orphan filler, reverse)")
+# a cell can hold two code points (a mark NFC could not compose): the spans
+# that follow are offsets into the row text, so they move by two
+line = StaticDefaultDict(Char(" "))
+line[0] = Char("q\u0301", "default", "default")
+line[1] = Char("x", "blue", "default")
+runs = [r for r in segment_buffer_line(line) if r[1] != r[2]]
+assert runs == [("q\u0301", 0, 2, "default", "default", ""), ("x", 2, 3, "blue", "default", "")], runs
+
+print("segmenter tests passed (leading gap, wide char, orphan filler, reverse, two-code-point cell)")

vterm.sublime-settings

@@ -33,12 +33,12 @@
 
     // External terminal for "vterm: Open Terminal in Project Folder".
     // %CWD% in parameters is replaced with the project folder.
-    // "terminal": "/usr/bin/open",
-    // "parameters": ["-a", "Terminal", "%CWD%"],
+    "terminal": "/usr/bin/open",
+    "parameters": ["-a", "Terminal", "%CWD%"],
 
     // kitty instead of Apple Terminal:
-    "terminal": "/opt/homebrew/bin/kitty",
-    "parameters": ["-d", "%CWD%"],
+    // "terminal": "/usr/bin/open",
+    // "parameters": ["-a", "Kitty", "%CWD%"],
 
     "debug": false
 }

vterm/commands.py

@@ -18,6 +18,12 @@ LOG = logging.getLogger(__name__)
 SCROLL_KEYS = ("pageup", "pagedown", "up", "down")
 
 
+def editor_view(window):
+    """A view to sample the editor's colours from: never a terminal, whose
+    colours are its own theme's."""
+    return next((v for v in window.views() if not v.settings().get("vterm_view")), None)
+
+
 class VtermOpenCommand(sublime_plugin.WindowCommand):
     """Open a terminal in a new tab. `vterm_open`, the only entry point users bind."""
 
@@ -43,7 +49,7 @@ class VtermOpenCommand(sublime_plugin.WindowCommand):
                 cwd = os.path.expanduser("~")
         cwd = sublime.expand_variables(cwd, window.extract_variables())
 
-        scheme = get_scheme_manager(settings().get("theme"), host_view=window.active_view())
+        scheme = get_scheme_manager(settings().get("theme"), host_view=editor_view(window))
 
         view = window.new_file()
         view.run_command("vterm_initialize_view", {"color_scheme": scheme.path})
@@ -54,6 +60,7 @@ class VtermOpenCommand(sublime_plugin.WindowCommand):
         except Exception:
             LOG.exception("failed to start terminal: cmd=%s", cmd)
             view.close()
+            sublime.error_message("vterm: could not start {}".format(" ".join(cmd)))
             return
         window.focus_view(view)
 
@@ -183,14 +190,6 @@ class VtermCopyCommand(sublime_plugin.TextCommand):
         sublime.set_clipboard(selection_text(self.view))
 
 
-class VtermPasteCommand(sublime_plugin.TextCommand):
-    """Pastes the clipboard into the app; replaces sublime's own paste."""
-
-    def run(self, edit):
-        """Hand the clipboard to vterm_paste_text."""
-        self.view.run_command("vterm_paste_text", {"text": sublime.get_clipboard()})
-
-
 class VtermPasteTextCommand(sublime_plugin.TextCommand):
     """Sends arbitrary text to the app, bracketed when it asked for that."""
 
@@ -258,7 +257,7 @@ class VtermSelectThemeCommand(sublime_plugin.WindowCommand):
 
     def _apply(self, name):
         """Retheme the focused terminal alone."""
-        scheme = get_scheme_manager(name, host_view=self.terminal.view)
+        scheme = get_scheme_manager(name, host_view=editor_view(self.window))
         self.terminal.retheme(scheme)
 
     def _preview(self, index):
@@ -328,20 +327,6 @@ class VtermCleanupCommand(sublime_plugin.TextCommand):
         view.sel().clear()
 
 
-class VtermCloseCommand(sublime_plugin.TextCommand):
-    """Kills the process and closes the tab. Registered but bound nowhere; for user keybindings."""
-
-    def run(self, _):
-        """Kill the process, then close the view."""
-        view = self.view
-        if not view.settings().get("vterm_view"):
-            return
-        terminal = Terminal.from_id(view.id())
-        if terminal:
-            terminal.kill()
-        view.close()
-
-
 class VtermClearUndoStackCommand(sublime_plugin.TextCommand):
     """Drops the undo history, so rendered output can never be undone into view."""
 

vterm/emulator.py

@@ -1,5 +1,4 @@
 """ Terminal emulation: the screen and a parser for prefixed CSI, DECRQM and multi-digit OSC """
-import base64
 import logging
 import re
 import time
@@ -41,7 +40,7 @@ FG_AIXTERM = {90 + i: ANSI_COLORS[8 + i] for i in range(8)}
 BG_AIXTERM = {100 + i: ANSI_COLORS[8 + i] for i in range(8)}
 
 # DECRQM answers, as wire numbers (pyte stores modes shifted << 5)
-REPORTABLE_MODES = (mo.DECAWM >> 5, mo.DECTCEM >> 5, 1000, 1002, 1003, 1004, 1006, 1049, 2004, 2026)
+REPORTABLE_MODES = (1, mo.DECAWM >> 5, mo.DECTCEM >> 5, 1000, 1002, 1003, 1004, 1006, 1049, 2004, 2026, 2031)
 
 # DEC private modes, pre-shifted into pyte's internal representation.
 # 1: DECCKM, application cursor keys (arrows send SS3)
@@ -83,7 +82,8 @@ def quantize_256(r, g, b):
     if r == g == b:
         if r < 8:
             return 16
-        if r > 248:
+        # 238 is the top of the grey ramp (255); above the midpoint, white
+        if r > 246:
             return 231
         return 232 + (r - 8) // 10
 
@@ -118,7 +118,7 @@ class Cursor:
 
 class VtScreen(pyte.Screen):
     """Screen with alternate buffer, scrollback, synchronized output,
-    mouse/focus/paste modes, cursor styles, query replies and OSC handling.
+    mouse/focus/paste modes, cursor styles, query replies and OSC titles/colours.
 
     Mutated only by the renderer thread, so it carries no lock.
     """
@@ -136,7 +136,6 @@ class VtScreen(pyte.Screen):
         history=5000,
         erase_scrollback=True,
         clear_callback=lambda: None,
-        clipboard_callback=lambda text: None,
         fg_color="ffffff",
         bg_color="000000",
         is_dark=True,
@@ -145,7 +144,6 @@ class VtScreen(pyte.Screen):
         self._process = process
         self._erase_scrollback = erase_scrollback
         self._clear_callback = clear_callback
-        self._clipboard_callback = clipboard_callback
         self.primary_buffer = {}
         self._default_char = Char(data=" ", fg="default", bg="default", reverse=False)
         # SGR transitions repeat endlessly in TUI output; memoized per (attrs, params)
@@ -155,6 +153,8 @@ class VtScreen(pyte.Screen):
         self._char_caches = {}
         self._char_cache = {}
         self._cache_attrs = None
+        # last printable drawn, for REP
+        self._last_char = ""
         self.history = deque(maxlen=history)
         self.alternate_buffer_mode = False
         self._sync_frame_start = 0
@@ -167,11 +167,16 @@ class VtScreen(pyte.Screen):
 
     def reset(self):
         """RIS: reset the screen along with the cursor, scrollback and caches"""
+        if self.alternate_buffer_mode:
+            # the primary screen is what a reset clears; leave the alt one behind
+            self.reset_mode(1049, private=True)
         self._default_char = Char(data=" ", fg="default", bg="default", reverse=False)
         self._sgr_cache.clear()
         self._char_caches.clear()
         self._cache_attrs = None
+        self._last_char = ""
         super().reset()
+        self.savepoints = []
         self.cursor = Cursor(0, 0)
         self.cursor_style = 0
         self.modify_other_keys = 0
@@ -378,6 +383,7 @@ class VtScreen(pyte.Screen):
                 dirty.add(cursor.y)
                 cursor.x = x + take
                 pos = end
+            self._last_char = data[-1]
             return
 
         line = buffer[cursor.y]
@@ -402,6 +408,7 @@ class VtScreen(pyte.Screen):
                 if cell is None:
                     cell = cache[char] = attrs._replace(data=char)
                 line[cursor.x] = cell
+                self._last_char = char
                 if char_width == 2 and cursor.x + 1 < columns:
                     filler = cache.get("")
                     if filler is None:
@@ -409,7 +416,10 @@ class VtScreen(pyte.Screen):
                     line[cursor.x + 1] = filler
             # a combining mark belongs to the cell before it, which may be the
             # last column of the previous row
-            elif char_width == 0 and unicodedata.combining(char):
+            # a mark: by category, not combining(), which is 0 for Thai/Indic
+            # vowel signs. Variation selectors are marks too but stay dropped:
+            # merged, VS16 would make the cell width 2 and swallow its neighbour
+            elif char_width == 0 and unicodedata.category(char)[0] == "M" and not "\ufe00" <= char <= "\ufe0f":
                 # sublime renders decomposed combining chars poorly; merge as NFC
                 pos = None
                 last = None
@@ -432,7 +442,8 @@ class VtScreen(pyte.Screen):
                     self.buffer[pos[0]][pos[1]] = last._replace(data=normalized)
                     self.dirty.add(pos[0])
             else:
-                break
+                # other zero-width (VS16, ZWJ) or control: drop it, keep the rest
+                continue
 
             if char_width > 0:
                 x = cursor.x + char_width
@@ -440,9 +451,16 @@ class VtScreen(pyte.Screen):
 
         self.dirty.add(cursor.y)
 
+    def repeat_character(self, count=None):
+        """REP: draw the last printable again `count` times."""
+        if self._last_char:
+            self.draw(self._last_char * (count or 1))
+
     def index(self):
         """Line feed; at the bottom of the primary screen the top row goes to scrollback."""
-        if not self.alternate_buffer_mode and self.cursor.y == self.lines - 1 and self.margins is None:
+        # a region spanning the whole screen (CSI 1;<lines> r) is no region
+        full = self.margins is None or self.margins == (0, self.lines - 1)
+        if not self.alternate_buffer_mode and self.cursor.y == self.lines - 1 and full:
             self.push_lines_into_history(1)
         super().index()
 
@@ -614,6 +632,8 @@ class VtScreen(pyte.Screen):
         elif mode == 6:
             x = min(self.cursor.x, self.columns - 1) + 1
             y = self.cursor.y + 1
+            if mo.DECOM in self.mode and self.margins:
+                y -= self.margins.top
             marker = "?" if private else ""
             self.write_process_input("\x1b[{}{};{}R".format(marker, y, x))
         elif mode == 996 and private:
@@ -631,7 +651,10 @@ class VtScreen(pyte.Screen):
     def report_mode_status(self, mode, private):
         """DECRQM: answer 1 set, 2 reset, 0 for modes we do not implement."""
         if not private:
-            self.write_process_input("\x1b[{};0$y".format(mode))
+            value = 0
+            if mode in (mo.IRM, mo.LNM):
+                value = 1 if mode in self.mode else 2
+            self.write_process_input("\x1b[{};{}$y".format(mode, value))
             return
         if mode in REPORTABLE_MODES:
             value = 1 if (mode << 5) in self.mode else 2
@@ -646,7 +669,7 @@ class VtScreen(pyte.Screen):
         self.write_process_input("\x1b[?0u")
 
     def handle_osc(self, code, payload, terminator):
-        """Dispatch an OSC: 0/2 title, 1 icon, 10/11 colour query, 52 clipboard."""
+        """Dispatch an OSC: 0/2 title, 1 icon, 10/11 colour query."""
         if code in (0, 2):
             self.set_title(payload)
         elif code == 1:
@@ -657,14 +680,8 @@ class VtScreen(pyte.Screen):
                 rgb = "rgb:{0}{0}/{1}{1}/{2}{2}".format(color[0:2], color[2:4], color[4:6])
                 # answer with the terminator asked with: meli only ends an OSC at ST
                 self.write_process_input("\x1b]{};{}{}".format(code, rgb, terminator))
-        elif code == 52:
-            parts = payload.split(";", 1)
-            if len(parts) == 2 and parts[1] and parts[1] != "?":
-                try:
-                    self._clipboard_callback(base64.b64decode(parts[1]).decode("utf-8", "replace"))
-                except ValueError:
-                    LOG.warning("osc52: undecodable payload", exc_info=True)
-        # other OSC codes are intentionally dropped
+        # other OSC codes are intentionally dropped, 52 (clipboard write) among
+        # them: any output, cat'd or remote, could plant a command to paste
 
 
 # a complete plain CSI: params then a final byte. No private marker, prefix or
@@ -688,6 +705,9 @@ class VtStream(pyte.Stream):
         self.csi = dict(self.csi)
         self.csi["S"] = "scroll_up"
         self.csi["T"] = "scroll_down"
+        self.csi["b"] = "repeat_character"
+        self.csi["s"] = "save_cursor"
+        self.csi["u"] = "restore_cursor"
         self._carry = ""
         # param-string -> parsed tuple; SGR strings repeat across a whole frame
         self._params_cache = {}
@@ -751,7 +771,8 @@ class VtStream(pyte.Stream):
                         raw = match.group(1)
                         params = cache.get(raw)
                         if params is None:
-                            params = tuple(min(int(p), 9999) if p else 0 for p in raw.split(";"))
+                            # no parameters is (), not (0,): save_cursor takes none
+                            params = tuple(min(int(p), 9999) if p else 0 for p in raw.split(";")) if raw else ()
                             if len(cache) > 4096:
                                 cache.clear()
                             cache[raw] = params
@@ -810,24 +831,33 @@ class VtStream(pyte.Stream):
         escape_dispatch = create_dispatcher(self.escape)
         csi_dispatch = create_dispatcher(self.csi)
 
+        # the byte after an ESC that cut a string short: any ESC ends a string,
+        # as in xterm, or one with no ST would swallow every later sequence
+        pending = None
         while True:
-            char = yield True
+            char = (yield True) if pending is None else ESC
 
             # ESC introducer: fold the 7-bit forms onto their C1 equivalents
             if char == ESC:
-                char = yield None
+                if pending is None:
+                    char = yield None
+                else:
+                    char, pending = pending, None
                 if char == "[":
                     char = CSI_C1
                 elif char == "]":
                     char = OSC_C1
                 elif char in "PX^_":
                     # consume the payload so it never reaches the screen
-                    prev = ""
                     while True:
                         c = yield None
-                        if c == ctrl.ST_C1 or (prev == ESC and c == "\\"):
+                        if c == ESC:
+                            c = yield None
+                            if c != "\\":
+                                pending = c
+                            break
+                        if c == ctrl.ST_C1:
                             break
-                        prev = c
                     continue
                 else:
                     if char == "#":
@@ -853,13 +883,15 @@ class VtStream(pyte.Stream):
                 private = False
                 prefix = ""
                 intermediate = ""
+                # inside a `:` subparameter list, which is dropped (4:3 must not read as 43)
+                sub = False
                 while True:
                     char = yield None
                     if char == "?":
                         private = True
                     elif char in "><=":
                         prefix = char
-                    elif char in " $":
+                    elif " " <= char <= "/":
                         intermediate = char
                     elif char in ALLOWED_IN_CSI:
                         basic_dispatch[char]()
@@ -867,15 +899,17 @@ class VtStream(pyte.Stream):
                         draw(char)
                         break
                     elif char.isdigit():
-                        current += char
+                        if not sub:
+                            current += char
                     elif char == ":":
-                        # SGR subparameters, which we do not support
-                        pass
+                        sub = True
                     elif char == ";":
                         params.append(min(int(current or 0), 9999))
                         current = ""
+                        sub = False
                     else:
-                        params.append(min(int(current or 0), 9999))
+                        if current or params:
+                            params.append(min(int(current or 0), 9999))
                         self._dispatch_csi(csi_dispatch, listener, char, params, private, prefix, intermediate)
                         break
             # OSC: a code of up to 8 digits, then a payload up to MAX_OSC,
@@ -890,18 +924,19 @@ class VtStream(pyte.Stream):
                         break
 
                 payload = ""
-                if char == ";" or (char not in OSC_TERMINATORS and char != ESC):
-                    while True:
+                if char == ";":
+                    char = yield None
+                while char not in OSC_TERMINATORS:
+                    if char == ESC:
                         char = yield None
-                        if char == ESC:
-                            char += yield None
-                        if char in OSC_TERMINATORS:
-                            break
-                        if len(payload) < MAX_OSC:
-                            payload += char
-                elif char == ESC:
-                    # take the '\' of ST, so char holds the whole terminator
-                    char += yield None
+                        if char != "\\":
+                            pending = char
+                        # char holds the whole terminator, ST for a cut string
+                        char = ctrl.ST_C0
+                        break
+                    if len(payload) < MAX_OSC:
+                        payload += char
+                    char = yield None
 
                 try:
                     listener.handle_osc(int(code or 0), payload, char)

vterm/listeners.py

@@ -88,7 +88,7 @@ class VtermCoreEventListener(sublime_plugin.EventListener):
         """Answer the contexts the mousemap needs"""
         # keymap contexts are native "setting.x"; mousemaps do not evaluate
         # those the same way, so their flags still need the hook
-        if key not in ("vterm_view", "vterm_view.wheel_captured"):
+        if key not in ("vterm_view", "vterm_view.wheel_captured", "vterm_view.mouse_reporting"):
             return None
         value = view.settings().get(key, False)
         if operator == sublime.OP_EQUAL:
@@ -104,6 +104,6 @@ class VtermCoreEventListener(sublime_plugin.EventListener):
         if name == "copy":
             return ("vterm_copy", None)
         elif name in ("paste", "paste_and_indent"):
-            return ("vterm_paste", None)
+            return ("vterm_paste_text", {"text": sublime.get_clipboard()})
         elif name == "undo":
             return ("vterm_noop", None)

vterm/mouse.py

@@ -5,7 +5,9 @@ The trackpad is not handled here. On macOS it never reaches a mousemap binding
 continuous scrolling into discrete wheel events; those arrive as ordinary wheel
 notches and take the path below.
 """
+import sublime
 import sublime_plugin
+from wcwidth import wcswidth
 
 from .terminal import Terminal
 from .utils import settings
@@ -13,6 +15,8 @@ from .utils import settings
 # SGR button numbers for the wheel; 64 is the "scroll" bit plus direction
 WHEEL_UP = 64
 WHEEL_DOWN = 65
+# button 0 with the "moved while held" bit
+MOTION = 32
 
 
 def send_scroll(terminal, up, lines, cell=None):
@@ -36,9 +40,10 @@ def _event_to_cell(view, terminal, event, clamp=False):
     """Map a mouse event to 1-based (col, row) on the live screen, or None.
 
     Clamping pulls a point above or below the screen onto the nearest row: the
-    wheel still belongs to the app there, a click does not."""
+    wheel and a release still belong to the app there, a press does not."""
     pt = view.window_to_text((event["x"], event["y"]))
     row, col = view.rowcol(pt)
+    col = wcswidth(view.substr(sublime.Region(pt - col, pt)))
     row -= terminal.offset
     screen = terminal.screen
     if row < 0 or row >= screen.lines:
@@ -48,46 +53,60 @@ def _event_to_cell(view, terminal, event, clamp=False):
     return (min(col, screen.columns - 1) + 1, row + 1)
 
 
-class VtermMouseEventListener(sublime_plugin.EventListener):
-    """Hands button-1 clicks to the app, but only while it tracks the mouse."""
-
-    def on_text_command(self, view, name, args):
-        """Replace drag_select with a mouse report; other click variants stay native."""
-        terminal = Terminal.from_id(view.id())
-        if not terminal:
-            return
-        if not terminal.screen.mouse_reporting_enabled():
-            # leave selection, caret and scrolling to sublime
-            return
-        if name == "drag_select" and args and args.get("event", {}).get("button") == 1 and len(args) == 1:
-            return ("vterm_mouse_click", {"event": args["event"]})
-
-
-class VtermMouseClickCommand(sublime_plugin.TextCommand):
-    """Reports a click to the app, or focuses the tab if it was not active."""
+class VtermMousePressCommand(sublime_plugin.TextCommand):
+    """Bound to button 1 in the mousemap while the app tracks the mouse."""
 
     def run(self, edit, event):
-        """Focus the tab on the first click, report press and release after that."""
+        """Focus an inactive tab; else report the press and remember its cell."""
         terminal = Terminal.from_id(self.view.id())
         if not terminal:
             return
+        terminal.mouse_press = None  # a release may not come: the context can drop mid-drag
         window = self.view.window()
         if window and window.active_view() != self.view:
-            # we replaced drag_select, which is what focuses the group; this
-            # click only focuses, as clicking an unfocused terminal window does
+            # the mousemap binding displaces drag_select, which is what focuses
+            # the group; this click only focuses, as in a terminal window
             window.focus_view(self.view)
             return
         cell = _event_to_cell(self.view, terminal, event)
         if cell is None:
             return
+        terminal.mouse_press = cell
         terminal.send_mouse(0, cell[0], cell[1], pressed=True)
-        terminal.send_mouse(0, cell[0], cell[1], pressed=False)
+        # native drag_select only previews the selection while dragging; the
+        # app gets the real one at release
+        self.view.run_command("drag_select", {"event": event})
 
     def want_event(self):
         """Ask sublime for the click coordinates."""
         return True
 
 
+class VtermMouseReleaseCommand(sublime_plugin.TextCommand):
+    """Reports the release, after one drag motion when the button came up elsewhere.
+
+    Sublime raises no motion events, so a drag reaches the app as a single
+    move to the release cell; an app's selection then spans press to release.
+    The native preview selection goes, leaving the app's own highlight."""
+
+    def run(self, edit, event):
+        """Report motion and release for the pending press, if any."""
+        terminal = Terminal.from_id(self.view.id())
+        if not terminal or terminal.mouse_press is None:
+            return
+        cell = _event_to_cell(self.view, terminal, event, clamp=True)
+        if cell != terminal.mouse_press:
+            terminal.send_mouse(MOTION, cell[0], cell[1], pressed=True)
+        terminal.send_mouse(0, cell[0], cell[1], pressed=False)
+        terminal.mouse_press = None
+        self.view.sel().clear()
+        self.view.run_command("vterm_show_cursor", {"scroll": False})
+
+    def want_event(self):
+        """Ask sublime for the release coordinates."""
+        return True
+
+
 class VtermScrollCommand(sublime_plugin.TextCommand):
     """Bound to scroll wheel in the mousemap while the app tracks the mouse or is on the alt screen."""
 
@@ -103,7 +122,7 @@ class VtermScrollCommand(sublime_plugin.TextCommand):
         cell = None
         if terminal.screen.mouse_reporting_enabled() and event:
             cell = _event_to_cell(self.view, terminal, event, clamp=True)
-        lines = max(0, int(settings().get("wheel_lines", 3)))
+        lines = max(0, int(settings().get("wheel_lines", 1)))
         send_scroll(terminal, up, lines, cell)
 
     def want_event(self):

vterm/render.py

@@ -1,11 +1,13 @@
 """ Rendering the emulator screen into the Sublime view
 
 The view holds real text: scrollback above `terminal.offset`, the live screen
-window from `offset` on. Dirty rows are whole-line replaced; colors are
-add_regions overlays with scopes served by the dynamic scheme. The ST caret
+window from `offset` on. Dirty rows are whole-line replaced, and rows the view
+does not hold yet are appended in one insert; colors are add_regions overlays
+with scopes served by the dynamic scheme. The ST caret
 doubles as the terminal cursor.
 """
 import math
+from bisect import bisect_left
 from functools import lru_cache
 
 import sublime
@@ -88,8 +90,10 @@ def segment_buffer_line(buffer_line):
 
         # an orphaned wide-char filler (its first half was overwritten) still
         # occupies a column; render a space so later spans stay aligned
-        run.append(char.data or " ")
-        column += 1
+        data = char.data
+        run.append(data or " ")
+        # a cell can hold more than one code point: a mark NFC could not compose
+        column += len(data) or 1
 
     if attrs is not None:
         yield _run(run, start, column, attrs)
@@ -304,23 +308,33 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         # valid for this method only; the trim paths erase rows
         self._lastrow = self.view.rowcol(self.view.size())[0]
         if dirty_lines:
-            # history pops newest-first, so it fills the rows below `offset` backwards
             history = screen.history
             popped = len(history)
             terminal.offset += popped
             offset = terminal.offset
+            first = offset - popped
+            retired = list(history)
+            history.clear()
 
-            for line in range(popped):
-                buffer_line = history.pop()
-                self.update_line(edit, offset - line - 1, buffer_line, columns)
+            # rows the view already holds are rewritten one by one; the rest
+            # are new and go in as one insert, after those edits moved the end
+            split = min(popped, self._lastrow + 1 - first)
+            for i in range(split):
+                self.update_line(edit, first + i, retired[i], columns)
+            if split < popped:
+                self.append_rows(edit, retired[split:], columns, scrollback=True)
 
-            # after the loop: a pop edits an earlier point than the one before
-            # it, so spans measured mid-loop would be stale
-            self.archive_rows(range(offset - popped, offset))
+            # after the edits: spans measured mid-loop would be stale
+            self.archive_rows(range(first, offset))
 
-            for line in dirty_lines:
-                buffer_line = screen.buffer[line]
-                self.update_line(edit, line + offset, buffer_line, columns)
+            # screen rows past the view's end go in as one insert too
+            start = self._lastrow + 1 - offset
+            cut = bisect_left(dirty_lines, start)
+            for line in dirty_lines[:cut]:
+                self.update_line(edit, line + offset, screen.buffer[line], columns)
+            if cut < len(dirty_lines):
+                rows = range(start, dirty_lines[-1] + 1)
+                self.append_rows(edit, [screen.buffer[y] for y in rows], columns, scrollback=False)
 
     def update_line(self, edit, line, buffer_line, columns):
         """Rewrite one view row from a screen row, unless it is unchanged"""
@@ -333,7 +347,17 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         if self.state.row_cache.get(line) == rendered:
             return
         self.state.row_cache[line] = rendered
+        text, by_scope = self.row_text(segments, lf)
 
+        self.ensure_row(edit, line)
+        line_region = view.line(view.text_point(line, 0))
+        self.decolorize_line(line)
+        view.replace(edit, line_region, text)
+        # replacing a line cannot move its start
+        self.colorize_line(line, line_region.begin(), by_scope)
+
+    def row_text(self, segments, lf):
+        """The view text of a row and its colour spans by scope, as char offsets."""
         by_scope = {}
         needed = 0
         scope_of = self._scheme.scope
@@ -350,13 +374,54 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         if len(text) < needed:
             # pad only to the last coloured run, in the same edit as the text
             text += " " * (needed - len(text))
+        return text, by_scope
 
-        self.ensure_row(edit, line)
-        line_region = view.line(view.text_point(line, 0))
-        self.decolorize_line(line)
-        view.replace(edit, line_region, text)
-        # replacing a line cannot move its start
-        self.colorize_line(line, line_region.begin(), by_scope)
+    def append_rows(self, edit, buffer_lines, columns, scrollback):
+        """Add rows below the view's end in one insert.
+
+        Scrollback rows are never rewritten, so their colours go straight onto
+        the chunk keys with no per-row key for flush_chunk to merge. Screen
+        rows are coloured per row as usual; a trailing blank run the trim
+        already erased is still cached as rendered and is left out.
+        """
+        view = self.view
+        rows = [(line, list(segment_buffer_line(buffer_line)), buffer_line[columns - 1].linefeed)
+                for line, buffer_line in enumerate(buffer_lines, self._lastrow + 1)]
+        if not scrollback:
+            while rows and self.state.row_cache.get(rows[-1][0]) == rows[-1][1:]:
+                rows.pop()
+            if not rows:
+                return
+
+        point = view.size() + 1
+        texts = []
+        # scrollback: (chunk, scope) -> regions; screen: (line, start, by_scope)
+        painted = {}
+        colored = []
+        trimmed = self.state.trimmed
+        for line, segments, lf in rows:
+            self.state.row_cache[line] = (segments, lf)
+            text, by_scope = self.row_text(segments, lf)
+            texts.append(text)
+            if scrollback:
+                chunk = (line + trimmed) // CHUNK
+                for scope, spans in by_scope.items():
+                    painted.setdefault((chunk, scope), []).extend(sublime.Region(point + a, point + b) for a, b in spans)
+            elif by_scope:
+                colored.append((line, point, by_scope))
+            point += len(text) + 1
+        view.insert(edit, view.size(), "\n" + "\n".join(texts))
+        self._lastrow = rows[-1][0]
+
+        for (chunk, scope), regions in painted.items():
+            key = chunk_key(chunk, scope)
+            scopes = self.state.archived_chunks.setdefault(chunk, set())
+            if scope in scopes:
+                regions = view.get_regions(key) + regions
+            view.add_regions(key, regions, scope)
+            scopes.add(scope)
+        for line, start, by_scope in colored:
+            self.colorize_line(line, start, by_scope)
 
     def colorize_line(self, line, line_start, by_scope):
         """Lay the colour overlays for one row, one add_regions per scope."""
@@ -470,7 +535,8 @@ class VtermRenderCommand(sublime_plugin.TextCommand):
         view = self.view
         screen = terminal.screen
         lastrow = view.rowcol(view.size())[0]
-        n = terminal.scrollback_size
+        # the setting counts rows above the screen; 0 keeps the screen alone
+        n = terminal.scrollback_size + screen.lines
         if lastrow + 1 > n:
             # queued rows are about to be renumbered or erased: merge them first
             self.flush_chunk()

vterm/terminal.py

@@ -2,6 +2,7 @@
 import codecs
 import logging
 import os
+import re
 import threading
 import time
 from collections import deque
@@ -26,6 +27,9 @@ UNFOCUSED_RENDER_PERIOD = 0.075
 # max chars parsed per tick, so a giant burst still renders intermediate frames.
 FEED_LIMIT = 48 * 1024
 
+# unparsed 8K reads the reader may hold before it pauses: ~10 ticks of parsing
+PENDING_CHUNKS = 64
+
 # SUPPRESS_HISTORY_AFTER_CLEAR in emulator.py must outlast this
 REPAINT_NUDGE_DELAY = 0.25
 
@@ -37,6 +41,10 @@ IDLE_TICK = 0.2
 # a millisecond apart, and drawing between them flashes its showcmd echo
 SETTLE = 0.005
 
+# C0 controls bar tab/LF/CR, stripped from text sent as typed: a pasted
+# ESC[201~ would end the bracket early and type the rest into the app
+CONTROL_CHARS = re.compile("[\x00-\x08\x0b\x0c\x0e-\x1f\x7f]")
+
 # frames between undo-stack clears: every render edit lands on the view's undo
 # stack, which only focus changes clear otherwise, and undo is swallowed anyway
 UNDO_CLEAR_FRAMES = 100
@@ -121,6 +129,8 @@ class Terminal:
         # guards the queue/flag handoff between send_string and the drain thread
         self._send_lock = threading.Lock()
         self._wheel_captured = False
+        self._mouse_reporting = False
+        self.mouse_press = None  # cell of the pending button-1 press, for the release report
         self._scroll_pending = False
         self.pending_clear = False
         self.pending_clear_screen = False
@@ -198,7 +208,6 @@ class Terminal:
             history=self.scrollback_size,
             erase_scrollback=settings().get("honor_erase_scrollback", False),
             clear_callback=self._clear_callback,
-            clipboard_callback=self._clipboard_callback,
             fg_color=self.scheme.foreground.lstrip("#"),
             bg_color=self.scheme.background.lstrip("#"),
             is_dark=self.scheme.is_dark(),
@@ -231,7 +240,8 @@ class Terminal:
         self.alive = False
         self._wake.set()
         try:
-            self.process.terminate()
+            # force: a child ignoring HUP and INT would otherwise outlive the tab
+            self.process.terminate(force=True)
         except Exception:
             LOG.warning("terminate failed", exc_info=True)
         vid = self.view.id()
@@ -242,10 +252,6 @@ class Terminal:
         """Screen asked for a clear; the next render performs it on the UI thread."""
         self.pending_clear = True
 
-    def _clipboard_callback(self, text):
-        """OSC 52 payload; the clipboard may only be touched on the UI thread."""
-        sublime.set_timeout(lambda: sublime.set_clipboard(text))
-
     def _need_to_render(self):
         """Whether anything changed since the last frame: dirty rows, a clear, or the cursor."""
         screen = self.screen
@@ -281,6 +287,10 @@ class Terminal:
                     break
                 chunks.append(self._decoder.decode(raw))
                 self._wake.set()
+                # backpressure: once this much waits unparsed, stop reading so
+                # the pty fills and the child blocks, as under a real terminal
+                while len(chunks) > PENDING_CHUNKS and not done[0] and self.is_hosted():
+                    time.sleep(RENDER_PERIOD)
                 if done[0] or not self.is_hosted():
                     LOG.debug("[reader] stops")
                     break
@@ -329,7 +339,7 @@ class Terminal:
                             if frames >= UNDO_CLEAR_FRAMES:
                                 frames = 0
                                 self.view.run_command("vterm_clear_undo_stack")
-                    self._sync_wheel_flag()
+                    self._sync_mouse_flags()
                     if done[0] or not self.is_hosted():
                         LOG.debug("[renderer] stops")
                         break
@@ -389,7 +399,7 @@ class Terminal:
         # escape sequences go through untouched; typed and pasted text has its
         # line endings canonicalised for the app's LNM setting
         if normalized:
-            string = string.replace("\r\n", "\n")
+            string = CONTROL_CHARS.sub("", string).replace("\r\n", "\n")
             if mo.LNM in self.screen.mode:
                 string = string.replace("\n", "\r\n")
             else:
@@ -425,12 +435,16 @@ class Terminal:
                 continue
             self.process.write(string)
 
-    def _sync_wheel_flag(self):
-        """Publish whether the app owns the wheel, for the mousemap context."""
-        captured = self.screen.mouse_reporting_enabled() or self.screen.alternate_buffer_mode
+    def _sync_mouse_flags(self):
+        """Publish whether the app owns the wheel and the mouse, for the mousemap contexts."""
+        reporting = self.screen.mouse_reporting_enabled()
+        captured = reporting or self.screen.alternate_buffer_mode
         if captured != self._wheel_captured:
             self._wheel_captured = captured
             self.view.settings().set("vterm_view.wheel_captured", captured)
+        if reporting != self._mouse_reporting:
+            self._mouse_reporting = reporting
+            self.view.settings().set("vterm_view.mouse_reporting", reporting)
 
     def send_focus(self, focused):
         """Report focus gain or loss, when the app asked for it (?1004)."""