touchpad initial support

tests/test_render.py

@@ -421,6 +421,125 @@ assert terminal.process.written == "", repr(terminal.process.written)
 print("alternate scroll tests passed (3 lines per tick: arrows on alt screen, SGR when tracking, inert otherwise)")
 
 
+# the trackpad never fires the mousemap on macOS (#1838): the poller harvests
+# viewport displacement from the follow anchor into wheel lines, snaps back.
+# ticks are stepped one at a time — the poller reschedules itself, so a
+# blanket sublime.run_timeouts() would loop forever
+terminal, stream = make_terminal(rows=5, cols=20)
+Terminal._terminals[id(terminal)] = terminal
+terminal.view.id = lambda: id(terminal)
+terminal.view.text = "\n".join("row {}".format(i) for i in range(8))
+terminal.offset = 3
+ANCHOR = 3 * LINE_HEIGHT
+terminal.viewport_y = ANCHOR
+terminal.view.viewport = (0, ANCHOR)
+stream.feed("\x1b[?1002h\x1b[?1006h")
+
+del sublime._timeouts[:]
+terminal._sync_wheel_flag()
+assert terminal._trackpad_running
+terminal._sync_wheel_flag()
+assert len(sublime._timeouts) == 1, "one timer chain per terminal"
+
+
+def tick():
+    sublime._timeouts.pop(0)()
+
+
+def displace(pixels):
+    terminal.process.written = ""
+    terminal.view.viewport = (0, ANCHOR + pixels)
+    tick()
+    return terminal.process.written
+
+
+# the first tick only arms the baseline; a gesture on it must stay silent
+assert displace(50) == "", repr(terminal.process.written)
+assert terminal.view.viewport == (0, ANCHOR + 50), "arming must not snap"
+
+# 2.5 lines down: two wheel-down reports, snap back, the fraction kept
+assert displace(50) == "\x1b[<65;1;3M" * 2
+assert terminal.view.viewport == (0, ANCHOR), terminal.view.viewport
+assert terminal._trackpad_acc == 0.5, terminal._trackpad_acc
+
+# half a line more completes the kept fraction into one report
+assert displace(10) == "\x1b[<65;1;3M"
+
+# a resting tick clears the remainder, so it cannot fire a gesture later
+assert displace(10) == ""
+assert displace(0) == ""
+assert terminal._trackpad_acc == 0, terminal._trackpad_acc
+
+# upward displacement reports wheel-up
+assert displace(-30) == "\x1b[<64;1;3M"
+
+# a renderer re-anchor (fold reset, follow-scroll) is not a gesture
+displace(0)
+terminal.viewport_y = 0
+terminal.view.viewport = (0, 0)
+tick()
+assert terminal.process.written == "", repr(terminal.process.written)
+terminal.viewport_y = ANCHOR
+terminal.view.viewport = (0, ANCHOR)
+tick()
+
+# a queued follow-scroll must not starve the poller: apps repaint while
+# scrolling (less redraws per line, claude constantly), so this races every
+# gesture and used to read as shaking
+terminal._scroll_pending = True
+assert displace(40) == "\x1b[<65;1;3M" * 2
+terminal._scroll_pending = False
+
+# nor may the follow-scroll itself discard un-harvested displacement while
+# the anchor is unchanged: the poller owns the pin
+terminal.view.viewport = (0, ANCHOR + 30)
+scroll_to_cursor(terminal.view, terminal)
+assert terminal.view.viewport == (0, ANCHOR + 30), terminal.view.viewport
+terminal.process.written = ""
+tick()
+assert terminal.process.written == "\x1b[<65;1;3M", repr(terminal.process.written)
+assert terminal.view.viewport == (0, ANCHOR), terminal.view.viewport
+displace(0)  # drop the half-line remainder
+
+# a real anchor change still pins: that is the follow-scroll's job
+terminal.view.text += "row 8\n"
+scroll_to_cursor(terminal.view, terminal)
+assert terminal.viewport_y == ANCHOR + LINE_HEIGHT, terminal.viewport_y
+assert terminal.view.viewport == (0, ANCHOR + LINE_HEIGHT), terminal.view.viewport
+terminal.view.text = terminal.view.text[:-len("row 8\n")]
+terminal.viewport_y = ANCHOR
+terminal.view.viewport = (0, ANCHOR)
+tick()  # settle back on the restored anchor
+
+# a jump of a viewport or more (scrollbar, page scroll) disengages: the user
+# browses the scrollback natively until they come back to the anchor
+extent = terminal.view.viewport_extent()[1]
+assert displace(-extent) == ""
+assert not terminal._trackpad_engaged
+assert terminal.view.viewport == (0, ANCHOR - extent), "browsing must not snap"
+assert displace(-30) == "", "still browsing"
+terminal.view.viewport = (0, ANCHOR)
+tick()  # back at the anchor: re-engage
+assert terminal._trackpad_engaged
+assert displace(20) == "\x1b[<65;1;3M"
+
+# on the alt screen without tracking the same displacement turns into arrows
+stream.feed("\x1b[?1002l\x1b[?1006l\x1b[?1049h")
+terminal._sync_wheel_flag()
+assert len(sublime._timeouts) == 1, "capture never lapsed, no second chain"
+tick()  # alt entry left the anchor alone, but spend a tick anyway
+assert displace(-20) == "\x1b[A"
+
+# capture released: the poller stops and unhooks itself
+stream.feed("\x1b[?1049l")
+terminal._sync_wheel_flag()
+tick()
+assert not terminal._trackpad_running
+assert sublime._timeouts == [], sublime._timeouts
+
+print("trackpad tests passed (displacement harvested, fractions kept, jumps browse, poller unhooks)")
+
+
 # PgUp/PgDn with the configured modifier pages the view instead of reaching the
 # app; every other combination is sent as before. 24 scrollback rows above an
 # 8-row screen, viewport at the follow anchor
@@ -546,34 +665,56 @@ stream.feed("\x1b[?1049h")
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [(0, fold_end)], terminal.view.folds
 assert terminal.viewport_y == 0, terminal.viewport_y
-assert terminal.view.settings().get("scroll_past_end") is False, "alt screen must not be scrollable"
+assert terminal.view.settings().get("scroll_past_end") is True, \
+    "the scroll range must stay: the trackpad poller reads it"
 
 # a second render leaves the fold alone
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [(0, fold_end)], terminal.view.folds
 
-# a disturbed fold is re-asserted on the next render
+# a disturbed fold is re-asserted on the next render, keeping the anchor:
+# apps repaint the boundary row every scroll, and a per-repair reset made the
+# poller read the thrashing anchor as phantom down-lines (dead trackpad-up)
+terminal.viewport_y = 60
 terminal.view.folds = [(0, fold_end - 2)]
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [(0, fold_end)], terminal.view.folds
+assert terminal.viewport_y == 60, terminal.viewport_y
 
 stream.feed("\x1b[?1049l")
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [], terminal.view.folds
-assert terminal.view.settings().get("scroll_past_end") is True, "primary screen scrolls past end again"
+assert terminal.view.settings().get("scroll_past_end") is True, "left untouched"
 
-# without scrollback there is nothing to fold, but the scroll lock still applies
+# without scrollback there is nothing to fold
 terminal, stream = make_terminal(rows=5, cols=20)
 terminal.view = FakeView("r0\nr1\nr2\nr3\nr4\n")
 command = make_command(terminal.view)
 stream.feed("\x1b[?1049h")
 command.sync_alt_fold(terminal)
 assert terminal.view.folds == [], terminal.view.folds
-assert terminal.view.settings().get("scroll_past_end") is False, "alt screen must not be scrollable"
 
 print("alt fold tests passed (scrollback folded on entry, restored on exit)")
 
 
+# a fresh view gets one blank scrollback row: sublime has no layout above row
+# 0, so without it the trackpad poller has no upward slack — and on the alt
+# screen no line ever retires to provide it (trackpad-up was dead in less)
+terminal, stream = make_terminal(rows=5, cols=20)
+Terminal._terminals[id(terminal)] = terminal
+terminal.view.id = lambda: id(terminal)
+command = make_command(terminal.view)
+stream.feed("hello")
+command.run(None)
+assert terminal.offset == 1, terminal.offset
+assert terminal.view.text.startswith("\nhello"), repr(terminal.view.text)
+command.run(None)  # only a fresh view is seeded
+assert terminal.offset == 1, terminal.offset
+del sublime._timeouts[:]  # drop the follow-scrolls the renders queued
+
+print("seed row tests passed (blank row above a fresh screen, seeded once)")
+
+
 # a row whose first cells were never written: they read back as default cells
 # (StaticDefaultDict), so they form their own uncoloured run and the coloured
 # run that follows keeps the right column