Script to record custom shader demo videos

kitty/shaders/custom/demo.py

@@ -0,0 +1,129 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2026, Kovid Goyal <kovid at kovidgoyal.net>
+
+import json
+import os
+import signal
+import subprocess
+import sys
+import time
+from contextlib import suppress
+from typing import Any
+
+metadata: dict[str, dict[str, Any]] = {}
+
+
+def get_hyprland_window_id(pid: int) -> str:
+    try:
+        result = subprocess.run(['hyprctl', 'clients', '-j'], capture_output=True, text=True, check=True)
+        clients = json.loads(result.stdout)
+        for client in clients:
+            if client.get('pid') == pid:
+                return client.get('address')
+    except (subprocess.CalledProcessError, json.JSONDecodeError):
+        pass
+    return ''
+
+
+def get_window_geometry(window_id: str) -> tuple[int, int, int, int]:
+    if not window_id.startswith('0x'):
+        window_id = f'0x{window_id}'
+    result = subprocess.run(['hyprctl', 'clients', '-j'], capture_output=True, text=True, check=True)
+    clients = json.loads(result.stdout)
+    for client in clients:
+        if client.get('address') == window_id:
+            x, y = client.get('at', [0, 0])
+            width, height = client.get('size', [0, 0])
+            return (x, y, width, height)
+    raise KeyError(f'No window with id: {window_id} found')
+
+
+def record_window_geometry(geometry: tuple[int, int, int, int], m: dict[str, Any], output_filename: str) -> str:
+    x, y, width, height = geometry
+    geometry_string = f'{x},{y} {width}x{height}'
+    duration_seconds = m.get('duration', 5)
+    output_filename += '.mkv'
+    with suppress(FileNotFoundError):
+        os.remove(output_filename)
+    cmd = ['wf-recorder', '-g', geometry_string, '-f', output_filename, '-y']
+    # lossless recording
+    cmd += '-c libx264rgb -p crf=0'.split()
+    try:
+        print(f'🎬 Starting recording of {geometry_string} for {duration_seconds} seconds...')
+        process = subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        time.sleep(duration_seconds)
+        print('🛑 Stopping recording and saving file...')
+        process.send_signal(signal.SIGINT)
+        process.wait(timeout=5)
+        return output_filename
+    except subprocess.TimeoutExpired:
+        process.kill()
+        raise SystemExit('⚠️ wf-recorder hung and had to be forcefully killed.')
+    except FileNotFoundError:
+        raise SystemExit("❌ Error: 'wf-recorder' is not installed or not in your PATH.")
+    except Exception as e:
+        raise SystemExit(f'❌ An error occurred: {e}')
+
+
+def drive_loop(kitty: subprocess.Popen, which: str, m: dict[str, Any], destdir: str) -> None:
+    time.sleep(m.get('initial_sleep', 1))
+    winid = ''
+    st = time.monotonic()
+    while not winid and time.monotonic() - st < 2:
+        winid = get_hyprland_window_id(kitty.pid)
+    if not winid:
+        raise SystemExit('Could not get Hyprland window id for kitty process')
+    geom = get_window_geometry(winid)
+    output_file = os.path.join(destdir, which)
+    lossless_file = record_window_geometry(geom, m, output_file)
+    kitty.terminate()
+    kitty.wait()
+    print('Transcoding saved recording...')
+    try:
+        for fmt, cmd in {
+            'webm': '-c:v libsvtav1 -preset 3 -crf 55 -pix_fmt yuv420p -svtav1-params tune=0:scm=1:enable-intrabc=1:scd=0:enable-hdr=0:aq-mode=0 -g 99999'
+        }.items():
+            of = f'{output_file}.{fmt}'
+            with suppress(FileNotFoundError):
+                os.remove(of)
+            subprocess.run(['ffmpeg', '-i', lossless_file] + cmd.split() + [of], check=True, capture_output=True)
+            print(f'Recording saved: {of}')
+    finally:
+        os.remove(lossless_file)
+
+
+def main() -> None:
+    if len(sys.argv) != 2:
+        raise SystemExit('Must specify exactly one command line argument')
+    self = os.path.abspath(__file__)
+    which = sys.argv[-1]
+    m = metadata.get(which) or {}
+    cmd = m.get('cmd', ['nvim', '-R', self])
+    kcmd = [
+        'kitty',
+        '--class=float',
+        '--config=NONE',
+        '-o',
+        'remember_window_size=no',
+        '-o',
+        'font_size=8',
+        '-o',
+        'initial_window_width=70c',
+        '-o',
+        'initial_window_height=20c',
+        '-o',
+        f'custom_shaders={which}',
+    ]
+    kitty = subprocess.Popen(kcmd + cmd)
+    d = os.path.dirname
+    destdir = os.path.join(d(d(d(d(self)))), 'docs', 'screenshots')
+    try:
+        drive_loop(kitty, which, m, destdir)
+    finally:
+        if kitty.returncode is None:
+            kitty.terminate()
+            kitty.wait()
+
+
+if __name__ == '__main__':
+    main()