Reworked the gamescope to work better with scaling and maximize window.

ptlinux/runtime.py

@@ -18,7 +18,12 @@ from typing import Mapping, Sequence
 from .command import CommandOutcome, CommandRunner, OutputLineFilter
 from .container_host import container_host_error, inspect_container_host
 from .depot import DEFAULT_DEPOT_START_OPTION, DepotStartOption
-from .gamebox import build_gamebox_command
+from .gamebox import (
+	GameboxConfigurationError,
+	build_gamebox_command,
+	find_gamescope,
+	read_game_canvas_size,
+)
 from .paths import AppPaths
 from .settings import Settings
 from .umu import find_umu_launcher
@@ -376,6 +381,18 @@ def game_runtime_ready(paths: AppPaths, selection: RuntimeSelection) -> bool:
 	return False
 
 
+def _read_game_canvas_size_or_warn(game_config: Path) -> tuple[int, int] | None:
+	try:
+		return read_game_canvas_size(game_config)
+	except GameboxConfigurationError as exc:
+		print(
+			f"Warning: {exc}; using a fixed game window.",
+			file=sys.stderr,
+			flush=True,
+		)
+		return None
+
+
 def run_game(
 	paths: AppPaths,
 	settings: Settings,
@@ -441,10 +458,39 @@ def run_game(
 		environment["PROTON_VERB"] = (
 			"runinprefix" if concurrent_prefix_launch else "waitforexitandrun"
 		)
-	if use_gamebox:
-		game_command = build_gamebox_command(game_command, settings)
 	if extra_environment:
 		environment.update(extra_environment)
+	if use_gamebox:
+		gamescope_path = None
+		game_size = None
+		if settings.allow_window_resizing:
+			gamescope_environment = os.environ.copy()
+			gamescope_environment.update(environment)
+			gamescope_path = find_gamescope(gamescope_environment)
+			if gamescope_path is None:
+				print(
+					"Warning: a resizable Gamescope window was requested, but "
+					"Gamescope was not found; using a fixed game window.",
+					file=sys.stderr,
+					flush=True,
+				)
+			else:
+				game_size = _read_game_canvas_size_or_warn(paths.game_config)
+				if game_size is not None:
+					width, height = game_size
+					print(
+						"Optimized stable resize enabled through Gamescope: the game "
+						f"starts at {width}x{height} and keeps its aspect ratio while "
+						"the outer window scales.",
+						file=sys.stderr,
+						flush=True,
+					)
+		game_command = build_gamebox_command(
+			game_command,
+			settings,
+			game_size=game_size,
+			gamescope_path=gamescope_path,
+		)
 	environment["PYTHONPATH"] = _runtime_python_path(
 		os.environ.get("PYTHONPATH"),
 	)