Lazy-load the TUI

src/termvisage/__main__.py

@@ -120,8 +120,8 @@ def finish_multi_logging():
         write_tty(RESTORE_WINDOW_TITLE_b)
         # Explicit cleanup is necessary since the top-level `Image` widgets
         # will still hold references to the `BaseImage` instances
-        for _, image_w in cli.url_images:
-            image_w._ti_image.close()
+        for _, image in cli.url_images:
+            image.close()
 
 
 # Session-specific temporary data directory.

src/termvisage/cli.py

@@ -16,7 +16,17 @@
 from tempfile import mkdtemp
 from threading import current_thread
 from time import sleep
-from typing import Any, Callable, Dict, Generator, List, Optional, Tuple, Union
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Dict,
+    Generator,
+    List,
+    Optional,
+    Tuple,
+    Union,
+)
 from urllib.parse import urlparse
 
 import PIL
@@ -36,12 +46,11 @@
 from term_image.image import BlockImage, ITerm2Image, KittyImage, Size, auto_image_class
 from term_image.utils import get_terminal_name_version, get_terminal_size, write_tty
 
-from . import logging, notify, tui
+from . import logging, notify
 from .config import config_options, init_config
 from .ctlseqs import ERASE_IN_LINE_LEFT_b
 from .exit_codes import FAILURE, INVALID_ARG, NO_VALID_SOURCE, SUCCESS
 from .logging import LoggingThread, init_log, log, log_exception
-from .tui.widgets import Image
 
 try:
     import fcntl  # noqa: F401
@@ -50,6 +59,9 @@
 else:
     OS_HAS_FCNTL = True
 
+if TYPE_CHECKING:
+    from term_image.image import BaseImage
+
 
 # Checks for CL arguments that have possible invalid values and don't have corresponding
 # config options. See `check_arg()`.
@@ -539,15 +551,15 @@ def update_dict(base: dict, update: dict):
 
 def get_urls(
     url_queue: Queue,
-    images: List[Tuple[str, Image]],
+    images: list[tuple[str, BaseImage]],
     ImageClass: type,
 ) -> None:
     """Processes URL sources from a/some separate thread(s)"""
     source = url_queue.get()
     while source:
         log(f"Getting image from {source!r}", logger, verbose=True)
         try:
-            images.append((basename(source), Image(ImageClass.from_url(source))))
+            images.append((basename(source), ImageClass.from_url(source)))
         # Also handles `ConnectionTimeout`
         except requests.exceptions.ConnectionError:
             log(f"Unable to get {source!r}", logger, _logging.ERROR)
@@ -564,14 +576,14 @@ def get_urls(
 
 def open_files(
     file_queue: Queue,
-    images: List[Tuple[str, Image]],
+    images: list[tuple[str, BaseImage]],
     ImageClass: type,
 ) -> None:
     source = file_queue.get()
     while source:
         log(f"Opening {source!r}", logger, verbose=True)
         try:
-            images.append((source, Image(ImageClass.from_file(source))))
+            images.append((source, ImageClass.from_file(source)))
         except PIL.UnidentifiedImageError as e:
             log(str(e), logger, _logging.ERROR)
         except OSError as e:
@@ -904,21 +916,17 @@ def main() -> None:
         log("No valid source!", logger)
         return NO_VALID_SOURCE
     # Sort entries by order on the command line
-    images.sort(
-        key=lambda x: unique_sources[x[0] if x[1] is ... else x[1]._ti_image.source]
-    )
+    images.sort(key=lambda x: unique_sources[x[0] if x[1] is ... else x[1].source])
 
-    if args.cli or (
-        not args.tui and len(images) == 1 and isinstance(images[0][1], Image)
-    ):
+    if args.cli or not args.tui and len(images) == 1 and images[0][1] is not ...:
         log("Running in CLI mode", logger, direct=False)
 
         if style_args.get("native") and len(images) > 1:
             style_args["stall_native"] = False
 
         show_name = len(args.sources) > 1
         for entry in images:
-            image = entry[1]._ti_image
+            image = entry[1]
             if 0 < args.max_pixels < mul(*image._original_size):
                 log(
                     f"Has more than the maximum pixel-count, skipping: {entry[0]!r}",
@@ -1015,6 +1023,8 @@ def main() -> None:
                     sys.stdout.close()
                 break
     elif OS_HAS_FCNTL:
+        from . import tui
+
         tui.init(args, style_args, images, contents, ImageClass)
     else:
         log(
@@ -1043,4 +1053,4 @@ def main() -> None:
 SHOW_HIDDEN: bool
 # # Used in other modules
 args: argparse.Namespace | None = None
-url_images: list[tuple[str, Image]] = []
+url_images: list[tuple[str, BaseImage]] = []

src/termvisage/config.py

@@ -128,8 +128,6 @@ def init_config() -> None:
     context_keys["global"]["Config"][3] = False  # Till the config menu is implemented
     expand_key[3] = False  # "Expand/Collapse Footer" action should be hidden
 
-    reconfigure_tui(_context_keys)
-
 
 def load_config(config_file: str) -> None:
     """Loads a user config file."""

src/termvisage/notify.py

@@ -14,7 +14,6 @@
 from . import __main__, logging, tui
 from .config import config_options
 from .ctlseqs import SGR_FG_BLUE, SGR_FG_DEFAULT, SGR_FG_RED, SGR_FG_YELLOW
-from .tui import main, widgets
 
 DEBUG = INFO = 0
 WARNING = 1
@@ -25,16 +24,16 @@
 def add_notification(msg: Union[str, Tuple[str, str]]) -> None:
     """Adds a message to the TUI notification bar."""
     if _alarms.full():
-        clear_notification(main.loop, None)
-    widgets.notifications.contents.insert(
+        clear_notification(tui.main.loop, None)
+    tui.widgets.notifications.contents.insert(
         0, (urwid.Filler(urwid.Text(msg, wrap="ellipsis")), ("given", 1))
     )
-    _alarms.put(main.loop.set_alarm_in(5, clear_notification))
+    _alarms.put(tui.main.loop.set_alarm_in(5, clear_notification))
 
 
 def clear_notification(loop: urwid.MainLoop, data: Any) -> None:
     """Removes the oldest message in the TUI notification bar."""
-    widgets.notifications.contents.pop()
+    tui.widgets.notifications.contents.pop()
     loop.remove_alarm(_alarms.get())
 
 
@@ -70,9 +69,6 @@ def load() -> None:
     - elipsis-style for the CLI
     - braille-style for the TUI
     """
-    from .tui.main import update_screen
-    from .tui.widgets import loading
-
     global _n_loading
 
     stream = stdout if stdout.isatty() else stderr
@@ -108,6 +104,10 @@ def load() -> None:
     _loading.clear()  # Signal "not loading"
     _loading.wait()  # Wait for a loading operation
 
+    if _n_loading > -1:  # Not skipping TUI phase?
+        from .tui.main import update_screen
+        from .tui.widgets import loading
+
     while _n_loading > -1:  # TUI phase hasn't ended?
         while _n_loading > 0:  # Anything loading?
             # Animate the TUI loading indicator
@@ -188,7 +188,7 @@ def start_loading() -> None:
     """Signals the start of a progressive operation."""
     global _n_loading
 
-    if not (QUIET or __main__.interrupted or main.quitting):
+    if not (QUIET or __main__.interrupted or tui.quitting):
         _n_loading += 1
         _loading.set()
 

src/termvisage/tui/__init__.py

@@ -2,38 +2,57 @@
 
 from __future__ import annotations
 
-import argparse
 import logging as _logging
 import os
 from pathlib import Path
-from typing import Any, Dict, Iterable, Iterator, Tuple, Union
+from typing import TYPE_CHECKING, Any, Dict
 
-import urwid
-from term_image.image import GraphicsImage
-from term_image.utils import get_cell_size, lock_tty
-from term_image.widget import UrwidImageScreen
+if TYPE_CHECKING:
+    import argparse
 
-from .. import notify
-from ..config import config_options
-from . import main, render
-from .keys import adjust_footer, update_footer_expand_collapse_icon
-from .main import process_input, scan_dir_grid, scan_dir_menu, sort_key_lexi
-from .widgets import Image, info_bar, main as main_widget
+    from term_image.image import BaseImage
 
 
 def init(
     args: argparse.Namespace,
     style_args: Dict[str, Any],
-    images: Iterable[Tuple[str, Union[Image, Iterator]]],
+    images: list[tuple[str, BaseImage | Ellipsis]],
     contents: dict,
     ImageClass: type,
 ) -> None:
     """Initializes the TUI"""
+
+    import urwid
+    from term_image.image import GraphicsImage
+    from term_image.utils import get_cell_size, lock_tty
+    from term_image.widget import UrwidImageScreen
+
+    from .. import notify
     from ..__main__ import TEMP_DIR
+    from ..config import _context_keys, config_options, reconfigure_tui
     from ..logging import LoggingThread, log
-    from . import keys
+    from . import main  # Loaded before `.tui.keys` to prevent circular import
+    from . import keys, render
+    from .keys import adjust_footer, update_footer_expand_collapse_icon
+    from .main import process_input, scan_dir_grid, scan_dir_menu, sort_key_lexi
+    from .widgets import Image, info_bar, main as main_widget
+
+    global active, initialized, quitting
+
+    class Loop(urwid.MainLoop):
+        def start(self):
+            update_footer_expand_collapse_icon()
+            adjust_footer()
+            return super().start()
 
-    global active, initialized
+        def process_input(self, keys):
+            if "window resize" in keys:
+                # "window resize" never reaches `.unhandled_input()`.
+                # Adjust the footer and clear grid cache.
+                keys.append("resized")
+            return super().process_input(keys)
+
+    reconfigure_tui(_context_keys)
 
     if args.debug:
         main_widget.contents.insert(
@@ -60,6 +79,9 @@ def init(
     render.REPEAT = args.repeat
     render.THUMBNAIL_CACHE_SIZE = config_options.thumbnail_cache
 
+    images = [
+        entry if entry[1] is ... else (entry[0], Image(entry[1])) for entry in images
+    ]
     images.sort(
         key=lambda x: sort_key_lexi(
             Path(x[0] if x[1] is ... else x[1]._ti_image.source),
@@ -161,7 +183,7 @@ def init(
         anim_render_manager.join()
         log("Exited TUI normally", logger, direct=False)
     except Exception:
-        main.quitting = True
+        quitting = True
         render.image_render_queue.put((None,) * 3)
         image_render_manager.join()
         render.anim_render_queue.put((None,) * 3)
@@ -173,21 +195,7 @@ def init(
         os.close(main.update_pipe)
 
 
-class Loop(urwid.MainLoop):
-    def start(self):
-        update_footer_expand_collapse_icon()
-        adjust_footer()
-        return super().start()
-
-    def process_input(self, keys):
-        if "window resize" in keys:
-            # "window resize" never reaches `.unhandled_input()`.
-            # Adjust the footer and clear grid cache.
-            keys.append("resized")
-        return super().process_input(keys)
-
-
-active = initialized = False
+active = initialized = quitting = False
 palette = [
     ("default", "", "", "", "", ""),
     ("default bold", "", "", "", "bold", ""),

src/termvisage/tui/keys.py

@@ -14,7 +14,7 @@
 from term_image.image import GraphicsImage
 from term_image.utils import get_cell_size, get_terminal_size
 
-from .. import __version__, logging
+from .. import __version__, logging, tui
 from ..config import config_options, context_keys, expand_key
 from . import main
 from .render import resync_grid_rendering
@@ -312,7 +312,7 @@ def update_footer_expand_collapse_icon():
 # global
 @register_key(("global", "Quit"))
 def quit():
-    main.quitting = True
+    tui.quitting = True
     raise urwid.ExitMainLoop()
 
 

src/termvisage/tui/main.py

@@ -17,7 +17,7 @@
 from term_image.image import BaseImage
 from term_image.utils import write_tty
 
-from .. import logging, notify, tui
+from .. import logging, notify
 from ..config import context_keys, expand_key
 from ..ctlseqs import BEL_b
 from .keys import (
@@ -678,7 +678,6 @@ def update_screen():
 
 
 logger = _logging.getLogger(__name__)
-quitting = False
 
 # For grid scanning/display
 grid_acknowledge = Event()
@@ -708,7 +707,7 @@ def update_screen():
 # Set from `.tui.init()`
 ImageClass: BaseImage
 displayer: Generator[None, int, bool]
-loop: tui.Loop
+loop: urwid.MainLoop
 update_pipe: int
 
 # # Corresponding to (or derived directly from) command-line args and/or config options