Add styles to theme for completion item and meta foreground and background color

This is an attempt to provide higher-contrast color options and to make them configurable as part of a theme.

Author: tleonhardt

CHANGELOG.md

@@ -135,6 +135,8 @@ prompt is displayed.
       full type hints and IDE autocompletion for `self._cmd` without needing to override and cast
       the property.
     - Added `traceback_kwargs` attribute to allow customization of Rich-based tracebacks.
+    - Added ability to customize `prompt-toolkit` completion menu colors by overriding
+      `Cmd2Style.COMPLETION_MENU_ITEM` and `Cmd2Style.COMPLETION_MENU_META` in the `cmd2` theme.
 
 ## 3.5.1 (April 24, 2026)
 

cmd2/cmd2.py

@@ -78,6 +78,8 @@
 from prompt_toolkit.output import DummyOutput, create_output
 from prompt_toolkit.patch_stdout import patch_stdout
 from prompt_toolkit.shortcuts import CompleteStyle, PromptSession, choice, set_title
+from prompt_toolkit.styles import DynamicStyle
+from prompt_toolkit.styles import Style as PtStyle
 from rich.console import (
     Group,
     JustifyMethod,
@@ -714,6 +716,46 @@ def _should_continue_multiline(self) -> bool:
                 # No macro found or already processed. The statement is complete.
                 return False
 
+    def _get_pt_style(self) -> "PtStyle":
+        """Return the prompt_toolkit style for the completion menu."""
+
+        def to_pt_style(rich_style: Style | None) -> str:
+            """Convert a rich Style object to a prompt_toolkit style string."""
+            if not rich_style:
+                return ""
+            parts = ["noreverse"]
+            if rich_style.color:
+                c = rich_style.color.get_truecolor()
+                parts.append(f"fg:#{c.red:02x}{c.green:02x}{c.blue:02x}")
+            else:
+                parts.append("fg:default")
+
+            if rich_style.bgcolor:
+                c = rich_style.bgcolor.get_truecolor()
+                parts.append(f"bg:#{c.red:02x}{c.green:02x}{c.blue:02x}")
+            else:
+                parts.append("bg:default")
+
+            if rich_style.bold is not None:
+                parts.append("bold" if rich_style.bold else "nobold")
+            if rich_style.italic is not None:
+                parts.append("italic" if rich_style.italic else "noitalic")
+            if rich_style.underline is not None:
+                parts.append("underline" if rich_style.underline else "nounderline")
+            return " ".join(parts)
+
+        theme = ru.get_theme()
+        item_style = to_pt_style(theme.styles.get(Cmd2Style.COMPLETION_MENU_ITEM))
+        meta_style = to_pt_style(theme.styles.get(Cmd2Style.COMPLETION_MENU_META))
+
+        return PtStyle.from_dict(
+            {
+                "completion-menu.completion.current": item_style,
+                "completion-menu.meta.completion.current": meta_style,
+                "completion-menu.multi-column-meta": meta_style,
+            }
+        )
+
     def _create_main_session(self, auto_suggest: bool, completekey: str) -> PromptSession[str]:
         """Create and return the main PromptSession for the application.
 
@@ -755,6 +797,7 @@ def _(event: Any) -> None:  # pragma: no cover
             "multiline": filters.Condition(self._should_continue_multiline),
             "prompt_continuation": self.continuation_prompt,
             "rprompt": self.get_rprompt,
+            "style": DynamicStyle(self._get_pt_style),
         }
 
         if self.stdin.isatty() and self.stdout.isatty():
@@ -3578,6 +3621,7 @@ def read_input(
             key_bindings=self.main_session.key_bindings,
             input=self.main_session.input,
             output=self.main_session.output,
+            style=DynamicStyle(self._get_pt_style),
         )
 
         return self._read_raw_input(prompt, temp_session)
@@ -3596,6 +3640,7 @@ def read_secret(
         temp_session: PromptSession[str] = PromptSession(
             input=self.main_session.input,
             output=self.main_session.output,
+            style=DynamicStyle(self._get_pt_style),
         )
 
         return self._read_raw_input(prompt, temp_session, is_password=True)

cmd2/styles.py

@@ -51,6 +51,8 @@ class Cmd2Style(StrEnum):
     """
 
     COMMAND_LINE = "cmd2.example"  # Command line examples in help text
+    COMPLETION_MENU_ITEM = "cmd2.completion_menu.item"  # Selected completion item
+    COMPLETION_MENU_META = "cmd2.completion_menu.meta"  # Selected completion help/meta text
     ERROR = "cmd2.error"  # Error text (used by perror())
     HELP_HEADER = "cmd2.help.header"  # Help table header text
     HELP_LEADER = "cmd2.help.leader"  # Text right before the help tables are listed
@@ -63,6 +65,8 @@ class Cmd2Style(StrEnum):
 # Tightly coupled with the Cmd2Style enum.
 DEFAULT_CMD2_STYLES: dict[str, StyleType] = {
     Cmd2Style.COMMAND_LINE: Style(color=Color.CYAN, bold=True),
+    Cmd2Style.COMPLETION_MENU_ITEM: Style(color=Color.BLACK, bgcolor=Color.GREEN),
+    Cmd2Style.COMPLETION_MENU_META: Style(color=Color.BLACK, bgcolor=Color.LIGHT_GREEN),
     Cmd2Style.ERROR: Style(color=Color.BRIGHT_RED),
     Cmd2Style.HELP_HEADER: Style(color=Color.BRIGHT_GREEN),
     Cmd2Style.HELP_LEADER: Style(color=Color.CYAN),

docs/features/completion.md

@@ -116,6 +116,13 @@ demonstration of how this is used.
 [read_input](https://github.com/python-cmd2/cmd2/blob/main/examples/read_input.py) example for a
 demonstration.
 
+## Custom Completion Menu Colors
+
+`cmd2` provides the ability to customize the foreground and background colors of the completion menu
+items and their associated help text. See
+[Customizing Completion Menu Colors](./theme.md#customizing-completion-menu-colors) in the Theme
+documentation for more details.
+
 ## For More Information
 
 See [cmd2's argparse_utils API](../api/argparse_utils.md) for a more detailed discussion of argparse

docs/features/theme.md

@@ -6,5 +6,19 @@
 information. You can use this to brand your application and set an overall consistent look and feel
 that is appealing to your user base.
 
+## Customizing Completion Menu Colors
+
+`cmd2` leverages `prompt-toolkit` for its tab completion menu. You can customize the colors of the
+completion menu by overriding the following styles in your `cmd2` theme:
+
+- `Cmd2Style.COMPLETION_MENU_ITEM`: The background and foreground color of the selected completion
+  item.
+- `Cmd2Style.COMPLETION_MENU_META`: The background and foreground color of the selected completion
+  item's help/meta text.
+
+By default, these are styled with black text on a green background to provide contrast.
+
+## Example
+
 See [rich_theme.py](https://github.com/python-cmd2/cmd2/blob/main/examples/rich_theme.py) for a
 simple example of configuring a custom theme for your `cmd2` application.

docs/upgrades.md

@@ -46,6 +46,16 @@ See the
 example for a demonstration of how to implement a background thread that refreshes the toolbar
 periodically.
 
+### Custom Completion Menu Colors
+
+`cmd2` now leverages `prompt-toolkit` for its tab completion menu and provides the ability to
+customize its appearance using the `cmd2` theme.
+
+- **Customization**: Override the `Cmd2Style.COMPLETION_MENU_ITEM` and
+  `Cmd2Style.COMPLETION_MENU_META` styles using `cmd2.rich_utils.set_theme()`. See
+  [Customizing Completion Menu Colors](features/theme.md#customizing-completion-menu-colors) for
+  more details.
+
 ### Deleted Modules
 
 Removed `rl_utils.py` and `terminal_utils.py` since `prompt-toolkit` provides this functionality.