Match Kitty image sizing and layer order, preserve trailing backgrounds, and add regression coverage.

regress/image-kitty-layers.sh

@@ -0,0 +1,136 @@
+#!/bin/sh
+
+# Kitty output layers must not depend on upload, placement or redraw order.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export TERM
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+export TEST_TMUX
+command -v python3 >/dev/null || exit 0
+
+python3 - <<'PY'
+import base64
+import os
+from pathlib import Path
+import re
+import shlex
+import subprocess
+import tempfile
+import time
+
+binary = str(Path(os.environ['TEST_TMUX']).resolve())
+inner = [binary, '-Lkitty-layers-inner' + str(os.getpid()), '-f/dev/null']
+outer = [binary, '-Lkitty-layers-outer' + str(os.getpid()), '-f/dev/null']
+
+
+# Run one command against the selected test server.
+def run(server, *args):
+    result = subprocess.check_output(server + list(args), text=True).strip()
+    return result
+
+
+# Build a graphics command that leaves the cursor unchanged.
+def graphics(control, payload=''):
+    return '\033_G' + control + (';' + payload if payload else '') + '\033\\'
+
+
+# Replay uploads and placements using Kitty's internal-ID tie breaker.
+def scene(data):
+    images, placements = {}, {}
+    loading = bytearray()
+    upload = None
+    for match in re.finditer(rb'\033_G([^\033]*)\033\\', data):
+        control, _, payload = match[1].partition(b';')
+        fields = dict(item.split(b'=', 1) for item in control.split(b','))
+        action = fields.get(b'a', b't')
+        image_id = int(fields.get(b'i', 0))
+        if action == b't':
+            if image_id:
+                upload = image_id
+                loading.clear()
+            loading.extend(base64.b64decode(payload))
+            if fields.get(b'm', b'0') == b'0':
+                # The one-pixel fixture has a duplicated border on each side.
+                assert len(loading) == 36, len(loading)
+                images[upload] = (len(images), bytes(loading[16:20]))
+        elif action == b'p':
+            placements[image_id, int(fields[b'p'])] = int(fields.get(b'z', 0))
+        elif action == b'd':
+            if b'p' in fields:
+                placements.pop((image_id, int(fields[b'p'])), None)
+            else:
+                placements = {key: z for key, z in placements.items()
+                              if key[0] != image_id}
+    if not placements:
+        return None, len(images)
+    top = max(placements, key=lambda key: (placements[key], images[key[0]][0]))
+    return images[top[0]][1], len(images)
+
+
+# Wait for a rendered scene, rather than only the application's input write.
+def expect(name, colour, uploads):
+    deadline = time.monotonic() + 3
+    while time.monotonic() < deadline:
+        actual, count = scene(capture.read_bytes())
+        if actual == colour and count >= uploads:
+            return
+        time.sleep(0.05)
+    raise AssertionError((name, actual, colour, count, uploads))
+
+
+red = bytes((255, 0, 0, 255))
+white = bytes((255, 255, 255, 255))
+older = graphics('a=t,q=2,i=200,f=32,s=1,v=1', base64.b64encode(red).decode())
+newer = graphics('a=t,q=2,i=100,f=32,s=1,v=1', base64.b64encode(white).decode())
+put_older = graphics('a=p,q=2,C=1,i=200,c=1,r=1')
+put_newer = graphics('a=p,q=2,C=1,i=100,c=1,r=1')
+commands = [older + newer + put_newer, put_older,
+            older + put_older,
+            graphics('a=d,d=I,q=2,i=200') + older + put_older,
+            put_older.replace('C=1', 'C=1,z=2147483646') +
+            put_newer.replace('C=1', 'C=1,z=2147483647')]
+
+with tempfile.TemporaryDirectory(prefix='tmux-kitty-layers-') as tmp:
+    directory = Path(tmp)
+    capture = directory / 'output'
+    capture.touch()
+    helper = directory / 'emit.py'
+    helper.write_text('import os, sys, time\n'
+                      'commands = ' + repr(commands) + '\n'
+                      'for index, command in enumerate(commands):\n'
+                      '    if index: sys.stdin.readline()\n'
+                      '    os.write(1, command.encode())\n'
+                      'time.sleep(30)\n')
+    try:
+        run(inner, 'new-session', '-d', '-x', '40', '-y', '12',
+            shlex.join(['python3', str(helper)]))
+        if run(inner, 'display-message', '-p', '#{image_support}') == '0':
+            raise SystemExit(0)
+        run(inner, 'set', '-g', 'status', 'off')
+        run(inner, 'set', '-as', 'terminal-features', ',*:kitty')
+        pane = run(outer, 'new-session', '-dP', '-F', '#{pane_id}',
+                   '-x', '40', '-y', '12', 'exec sh')
+        run(outer, 'set', '-g', 'status', 'off')
+        run(outer, 'pipe-pane', '-t', pane, '-O',
+            'cat >' + shlex.quote(str(capture)))
+        run(outer, 'send-keys', '-t', pane, '-l', shlex.join(inner + ['attach']))
+        run(outer, 'send-keys', '-t', pane, 'Enter')
+        expect('newer-placed-first', white, 1)
+        run(inner, 'send-keys', 'Enter')
+        expect('older-uploaded-last', white, 2)
+        run(inner, 'refresh-client')
+        time.sleep(0.2)
+        expect('full-redraw', white, 2)
+        run(inner, 'send-keys', 'Enter')
+        expect('older-retransmitted', white, 3)
+        run(inner, 'send-keys', 'Enter')
+        expect('older-recreated', red, 4)
+        run(inner, 'send-keys', 'Enter')
+        expect('maximum-z-order', white, 6)
+    finally:
+        for server in (outer, inner):
+            subprocess.run(server + ['kill-server'], stdout=subprocess.DEVNULL,
+                           stderr=subprocess.DEVNULL)
+PY

regress/image-kitty-protocol.sh

@@ -327,14 +327,52 @@ with tempfile.TemporaryDirectory(prefix='tmux-kitty-protocol-') as tmp:
         check('placeholder-erase', virtual + colours + ph + '\033[H\033[2K', '0,0',
               text='', render=r'^\s*$')
         white_pixel = '/////w=='
-        check('letterbox', graphics('a=T,q=2,f=32,s=1,v=1,c=2,r=2,C=1', white_pixel),
-              '0,0', render='▄▄')
-        check('pillarbox', graphics('a=T,q=2,f=32,s=1,v=1,c=4,r=1,C=1', white_pixel),
-              '0,0', render=(r'^(?:\x1b\[[0-9;]+m)* '
-                             r'(?:\x1b\[[0-9;]+m)*\x1b\[48;2;255;255;255m {2}'))
+        # Ordinary placements stretch; placeholders retain aspect ratio.
+        check('stretch-tall', graphics('a=T,q=2,f=32,s=1,v=1,c=2,r=2,C=1',
+                                      white_pixel),
+              '0,0', render=r'48;2;255;255;255m {2}')
+        check('stretch-wide', graphics('a=T,q=2,f=32,s=1,v=1,c=4,r=1,C=1',
+                                      white_pixel),
+              '0,0', render=r'48;2;255;255;255m {4}')
+        check('stretch-crop', graphics('a=T,q=2,f=32,s=24,v=32,x=4,y=8,w=8,h=8,'
+                                      'c=2,r=2,C=1', white),
+              '0,0', render=r'48;2;255;255;255m {2}')
+        check('virtual-letterbox', graphics('a=T,q=2,U=1,i=7,p=1,f=32,s=1,v=1,'
+                                           'c=2,r=2', white_pixel) + colours +
+              ph + '\u0305\u0305' + ph + '\u0305\u030d',
+              '2,0', render='▄▄')
+        check('virtual-pillarbox', graphics('a=T,q=2,U=1,i=7,p=1,f=32,s=1,v=1,'
+                                           'c=4,r=1', white_pixel) + colours +
+              ph + '\u0305\u0305' + ph + '\u0305\u030d',
+              '2,0', render=(r'^(?:\x1b\[[0-9;]+m)* '
+                             r'(?:\x1b\[[0-9;]+m)*\x1b\[48;2;255;255;255m '))
+        # Equal-z images follow source creation order, even with descending IDs.
+        older = graphics('a=t,q=2,i=200,f=32,s=1,v=1', pixel)
+        newer = graphics('a=t,q=2,i=100,f=32,s=1,v=1', white_pixel)
+        put_older = graphics('a=p,q=2,C=1,i=200,c=1,r=1')
+        put_newer = graphics('a=p,q=2,C=1,i=100,c=1,r=1')
+        check('same-z-descending-ids', older + newer + put_older + put_newer,
+              '0,0', render=r'48;2;255;255;255m ')
+        check('same-z-reversed-placements',
+              older + newer + put_newer + put_older,
+              '0,0', render=r'48;2;255;255;255m ')
+        check('same-z-retransmit',
+              older + newer + put_newer + older + put_older,
+              '0,0', render=r'48;2;255;255;255m ')
+        check('same-z-recreate', older + newer + put_newer +
+              graphics('a=d,d=I,q=2,i=200') + older + put_older,
+              '0,0', render=r'48;2;255;0;0m ')
+        # An empty line tail must not discard the preceding background run.
+        background = '\033[11GX\033[17G\033[42m    \033[0m'
+        check('background-tail', background, '20,0', render=r'42m {4}')
+        check('background-tail-image',
+              graphics('a=T,q=2,C=1,f=32,s=1,v=1,c=20,r=1,z=-1073741825',
+                       white_pixel) +
+              background, '20,0', render=r'42m {4}')
         offset_source = base64.b64encode(b'\xff' * (8 * 32 * 4)).decode()
         check('scaled-offset', graphics('a=T,q=2,f=32,s=8,v=32,c=1,r=1,X=4,C=1',
-                                       offset_source), '0,0', render=r'12[78];12[78];12[78]m')
+                                       offset_source),
+              '0,0', render=r'191;191;191m')
         square = base64.b64encode(b'\xff' * (8 * 8 * 4)).decode()
         check('vertical-offset', graphics('a=T,q=2,f=32,s=8,v=8,c=1,r=1,Y=8,C=1',
                                          square), '0,0', render='▄')