Set up development features for gallery app

src/textual_paint/auto_restart.py

@@ -9,6 +9,7 @@ from textual.app import ScreenStackError
 
 if TYPE_CHECKING:
     from .paint import PaintApp
+    from .gallery import GalleryApp
 
 def restart_program() -> None:
     """Restarts the current program, after resetting terminal state, and cleaning up file objects and descriptors."""
@@ -57,7 +58,7 @@ def restart_program() -> None:
     # os.execl(python, python, *sys.argv)
     os.execl(sys.executable, *sys.orig_argv)
 
-def restart_on_changes(app: PaintApp) -> None:
+def restart_on_changes(app: PaintApp|GalleryApp) -> None:
     """Restarts the current program when a file is changed"""
 
     from watchdog.events import PatternMatchingEventHandler, FileSystemEvent, EVENT_TYPE_CLOSED, EVENT_TYPE_OPENED
@@ -80,7 +81,7 @@ def restart_on_changes(app: PaintApp) -> None:
             # or else nothing happens.
             # However, when _app.action_reload is called from the key binding,
             # it seems to work fine with or without unsaved changes.
-            if _app.is_document_modified():
+            if isinstance(_app, PaintApp) and _app.is_document_modified():
                 _app.call_from_thread(_app.action_reload)
             else:
                 restart_program()

src/textual_paint/gallery.css

@@ -0,0 +1,5 @@
+GalleryItem {
+    layout: vertical;
+    width: 100%;
+    content-align: center middle;
+}

src/textual_paint/gallery.py

@@ -2,20 +2,29 @@
 
 import argparse
 import os
-import re
 
 from textual.app import App, ComposeResult
-from textual.widgets import Footer, Header, Static
+from textual.binding import Binding
 from textual.containers import HorizontalScroll, Vertical
+from textual.widgets import Footer, Header, Static
 
-from .paint import AnsiArtDocument
 from .__init__ import __version__
+from .auto_restart import restart_on_changes, restart_program
+from .paint import AnsiArtDocument
 
 parser = argparse.ArgumentParser(description='ANSI art gallery', usage='%(prog)s [folder]', prog="python -m src.textual_paint.gallery")
 parser.add_argument('folder', nargs='?', default=None, help='Path to a folder containing ANSI art.')
 
+dev_options = parser.add_argument_group('development options')
+dev_options.add_argument('--inspect-layout', action='store_true', help='Enables DOM inspector (F12) and middle click highlight')
+dev_options.add_argument('--restart-on-changes', action='store_true', help='Restart the app when the source code is changed')
+
 args = parser.parse_args()
 
+def _(text: str) -> str:
+    """Placeholder for localization function."""
+    return text
+
 class GalleryItem(Vertical):
     """An image with a caption."""
 
@@ -32,11 +41,31 @@ class GalleryItem(Vertical):
         yield Static(text)
         yield Static(self.caption)
 
-class Gallery(App[None]):
+class GalleryApp(App[None]):
     """ANSI art gallery TUI"""
 
     TITLE = f"ANSI art gallery v{__version__}"
 
+    CSS_PATH = "gallery.css"
+
+    BINDINGS = [
+        Binding("ctrl+q", "exit", _("Quit")),
+        # dev helper
+        # f5 would be more traditional, but I need something not bound to anything
+        # in the context of the terminal in VS Code, and not used by this app, like Ctrl+R, and detectable in the terminal.
+        # This isn't as important now that I have automatic reloading,
+        # but I still use it regularly.
+        Binding("f2", "reload", _("Reload")),
+        # Temporary quick access to work on a specific dialog.
+        # Can be used together with `--press f3` when using `textual run` to open the dialog at startup.
+        # Would be better if all dialogs were accessible from the keyboard.
+        # Binding("f3", "custom_zoom", _("Custom Zoom")),
+        # Dev tool to inspect the widget tree.
+        Binding("f12", "toggle_inspector", _("Toggle Inspector")),
+        # Update screenshot on readme.
+        # Binding("ctrl+j", "update_screenshot", _("Update Screenshot")),
+    ]
+
     def compose(self) -> ComposeResult:
         """Add widgets to the layout."""
         yield Header(show_clock=True)
@@ -46,6 +75,15 @@ class Gallery(App[None]):
 
         yield Footer()
 
+        if not args.inspect_layout:
+            return
+        # importing the inspector adds instrumentation which can slow down startup
+        from .inspector import Inspector
+        inspector = Inspector()
+        inspector.display = False
+        yield inspector
+
+
     def on_mount(self) -> None:
         """Called when the app is mounted to the DOM."""
         self._load()
@@ -68,8 +106,25 @@ class Gallery(App[None]):
             
             self.scroll.mount(GalleryItem(image, caption=filename))
 
+    def action_reload(self) -> None:
+        """Reload the program."""
+        restart_program()
 
-app = Gallery()
+    def action_toggle_inspector(self) -> None:
+        if not args.inspect_layout:
+            return
+        # importing the inspector adds instrumentation which can slow down startup
+        from .inspector import Inspector
+        inspector = self.query_one(Inspector)
+        inspector.display = not inspector.display
+        if not inspector.display:
+            inspector.picking = False
+
+
+app = GalleryApp()
+
+if args.restart_on_changes:
+    restart_on_changes(app)
 
 if __name__ == "__main__":
     app.run()