From dfec3fb6a9cdfe5f88c8ede156df1cd5b2433598 Mon Sep 17 00:00:00 2001
From: Michael Renzmann <mrenzmann@otaku42.de>
Date: Sat, 13 May 2023 01:06:38 +0200
Subject: [PATCH] Improve help text

---
 examples/v4l2py-ctl.py | 52 ++++++++++++++++++++++++------------------
 1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/examples/v4l2py-ctl.py b/examples/v4l2py-ctl.py
index 2b020a1..dc25f34 100644
--- a/examples/v4l2py-ctl.py
+++ b/examples/v4l2py-ctl.py
@@ -188,60 +188,74 @@ def csv(string: str) -> list:
 
 
 if __name__ == "__main__":
-    parser = argparse.ArgumentParser()
+    parser = argparse.ArgumentParser(
+        prog="v4l2py-ctl",
+        description="Example utility to control video capture devices.",
+        epilog="When no action is given, the control status of the selected device is shown.",
+    )
     parser.add_argument(
+        "--device",
+        type=str,
+        default="0",
+        metavar="<dev>",
+        help="use device <dev> instead of /dev/video0; if <dev> starts with a digit, then /dev/video<dev> is used",
+    )
+
+    flags = parser.add_argument_group("Flags")
+    flags.add_argument(
         "--legacy",
         default=False,
         action="store_true",
         help="use legacy controls (default: %(default)s)",
     )
-    parser.add_argument(
+    flags.add_argument(
         "--clipping",
         default=False,
         action="store_true",
         help="when changing numeric controls, enforce the written value to be within allowed range (default: %(default)s)",
     )
-    parser.add_argument(
+    flags.add_argument(
+        "--pedantic",
+        default=False,
+        action="store_true",
+        help="be pedantic when validating a loaded configuration (default: %(default)s)"
+    )
+
+    actions = parser.add_argument_group("Actions")
+    actions.add_argument(
         "--list-devices",
         default=False,
         action="store_true",
         help="list all video capture devices",
     )
-    parser.add_argument(
-        "--device",
-        type=str,
-        default="0",
-        metavar="<dev>",
-        help="use device <dev> instead of /dev/video0; if <dev> starts with a digit, then /dev/video<dev> is used",
-    )
-    parser.add_argument(
+    actions.add_argument(
         "--get-ctrl",
         type=csv,
         default=[],
         metavar="<ctrl>[,<ctrl>...]",
         help="get the values of the specified controls",
     )
-    parser.add_argument(
+    actions.add_argument(
         "--set-ctrl",
         type=csv,
         default=[],
         metavar="<ctrl>=<val>[,<ctrl>=<val>...]",
         help="set the values of the specified controls",
     )
-    parser.add_argument(
+    actions.add_argument(
         "--reset-ctrl",
         type=csv,
         default=[],
         metavar="<ctrl>[,<ctrl>...]",
         help="reset the specified controls to their default values",
     )
-    parser.add_argument(
+    actions.add_argument(
         "--reset-all",
         default=False,
         action="store_true",
         help="reset all controls to their default value",
     )
-    parser.add_argument(
+    actions.add_argument(
         "--save",
         type=str,
         dest="save_file",
@@ -249,7 +263,7 @@ def csv(string: str) -> list:
         metavar="<filename>",
         help="save current configuration to <filename>",
     )
-    parser.add_argument(
+    actions.add_argument(
         "--load",
         type=str,
         dest="load_file",
@@ -257,12 +271,6 @@ def csv(string: str) -> list:
         metavar="<filename>",
         help="load configuration from <filename> and apply it to selected device",
     )
-    parser.add_argument(
-        "--pedantic",
-        default=False,
-        action="store_true",
-        help="be pedantic when validating a configuration (--load only)"
-    )
 
     args = parser.parse_args()