Add a standalone Modal layout

examples/reference/layouts/Modal.ipynb

@@ -0,0 +1,89 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5c557435-c052-4622-8023-81ed6f63f231",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import panel as pn\n",
+    "pn.extension('modal')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "a44c5eae-9c73-4626-96ff-019cf959d647",
+   "metadata": {},
+   "source": [
+    "The `Modal` layout provides a dialog windows on top of the layout. It is built on-top of [a11y-dialog](https://a11y-dialog.netlify.app/). It has a list-like API with methods to `append`, `extend`, `clear`, `insert`, `pop`, `remove` and `__setitem__`, which make it possible to interactively update and modify the layout. Components inside it are laid out like a `Column`.\n",
+    "\n",
+    "#### Parameters:\n",
+    "\n",
+    "* **`open`** (boolean): Whether to open the modal.\n",
+    "* **`show_close_button`** (boolean): Whether to show a close button in the modal.\n",
+    "* **`background_close`** (boolean): Whether to enable closing the modal when clicking outside the modal.\n",
+    "\n",
+    "#### Methods:\n",
+    "\n",
+    "* **`show`**: Show the modal.\n",
+    "* **`hide`**: Hide the modal.\n",
+    "* **`toggle`**: toggle the modal.\n",
+    "* **`create_button`**: Create a button which can either show, hide, or toggle the modal.\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "2b3a8784-7e78-4414-a1a5-600b0ff14664",
+   "metadata": {},
+   "source": [
+    "A `Modal` layout can either be instantiated as empty and populated after the fact or using a list of objects provided as positional arguments. If the objects are not already panel components they will each be converted to one using the `pn.panel` conversion method."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "9fd46bf9-a63e-457c-bcc2-a1578b8f9bda",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "w1 = pn.widgets.TextInput(name='Text:')\n",
+    "w2 = pn.widgets.FloatSlider(name='Slider')\n",
+    "\n",
+    "modal = pn.Modal(w1, w2, name='Basic FloatPanel', margin=20)\n",
+    "toggle_button = modal.create_button(\"toggle\", name=\"Toggle modal\")\n",
+    "\n",
+    "pn.Column('**Example: Basic `Modal`**', toggle_button, modal)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "558852dd-9a11-4099-bae3-6da3e38f79f9",
+   "metadata": {},
+   "source": [
+    "### Controls\n",
+    "\n",
+    "The `Modal` widget exposes a number of options which can be changed from both Python and Javascript. Try out the effect of these parameters interactively:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b49ed4d6-b06b-47e1-a917-88ff3141936b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "modal.controls(jslink=True)"
+   ]
+  }
+ ],
+ "metadata": {
+  "language_info": {
+   "name": "python",
+   "pygments_lexer": "ipython3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

panel/__init__.py

@@ -64,7 +64,7 @@
 )
 from .layout import (  # noqa
     Accordion, Card, Column, Feed, FlexBox, FloatPanel, GridBox, GridSpec,
-    GridStack, HSpacer, Row, Spacer, Swipe, Tabs, VSpacer, WidgetBox,
+    GridStack, HSpacer, Modal, Row, Spacer, Swipe, Tabs, VSpacer, WidgetBox,
 )
 from .pane import panel  # noqa
 from .param import Param, ReactiveExpr  # noqa
@@ -88,6 +88,7 @@
     "GridSpec",
     "GridStack",
     "HSpacer",
+    "Modal",
     "Param",
     "ReactiveExpr",
     "Row",

panel/config.py

@@ -671,6 +671,7 @@ class panel_extension(_pyviz_extension):
         'jsoneditor': 'panel.models.jsoneditor',
         'katex': 'panel.models.katex',
         'mathjax': 'panel.models.mathjax',
+        'modal': 'panel.models.modal',
         'perspective': 'panel.models.perspective',
         'plotly': 'panel.models.plotly',
         'tabulator': 'panel.models.tabulator',

panel/layout/__init__.py

@@ -38,6 +38,7 @@
 from .float import FloatPanel  # noqa
 from .grid import GridBox, GridSpec  # noqa
 from .gridstack import GridStack  # noqa
+from .modal import Modal
 from .spacer import (  # noqa
     Divider, HSpacer, Spacer, VSpacer,
 )
@@ -58,6 +59,7 @@
     "HSpacer",
     "ListLike",
     "ListPanel",
+    "Modal",
     "Panel",
     "Row",
     "Spacer",

panel/layout/modal.py

@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING, ClassVar, Literal, Mapping, Optional,
+)
+
+import param
+
+from pyviz_comms import JupyterComm
+
+from ..models.modal import ModalDialogEvent
+from ..util import lazy_load
+from ..util.warnings import PanelUserWarning, warn
+from .base import ListPanel
+
+if TYPE_CHECKING:
+    from bokeh.document import Document
+    from bokeh.model import Model
+    from pyviz_comms import Comm
+
+
+class Modal(ListPanel):
+    """Create a modal dialog that can be opened and closed."""
+
+    open = param.Boolean(default=False, doc="Whether to open the modal.")
+
+    show_close_button = param.Boolean(default=True, doc="Whether to show a close button in the modal.")
+
+    background_close = param.Boolean(default=True, doc="Whether to enable closing the modal when clicking the background.")
+
+    _rename: ClassVar[Mapping[str, str | None]] = {}
+
+    _source_transforms: ClassVar[Mapping[str, str | None]] = {'objects': None}
+
+    def _get_model(
+        self, doc: Document, root: Optional[Model] = None,
+        parent: Optional[Model] = None, comm: Optional[Comm] = None
+    ) -> Model:
+        Modal._bokeh_model = lazy_load(
+            'panel.models.modal', 'Modal', isinstance(comm, JupyterComm), root
+        )
+        return super()._get_model(doc, root, parent, comm)
+
+    def show(self):
+        self.open = True
+
+    def hide(self):
+        self.open = False
+
+    def toggle(self):
+        self.open = not self.open
+
+    @param.depends("open", watch=True)
+    def _open(self):
+        if not self._models:
+            msg = "To use the Modal, you must use '.servable' in a server setting or output the Modal in Jupyter Notebook."
+            warn(msg, category=PanelUserWarning)
+        self._send_event(ModalDialogEvent, open=self.open)
+
+    def create_button(self, action: Literal["show", "hide", "toggle"], **kwargs):
+        """Create a button to show, hide or toggle the modal."""
+        from panel.widgets import Button
+
+        button = Button(**kwargs)
+        match action:
+            case "show":
+                button.on_click(lambda *e: self.show())
+            case "hide":
+                button.on_click(lambda *e: self.hide())
+            case "toggle":
+                button.on_click(lambda *e: self.toggle())
+            case _:
+                raise TypeError(f"Invalid action: {action}")
+
+        return button

panel/models/index.ts

@@ -28,6 +28,7 @@ export {JSONEditor} from "./jsoneditor"
 export {KaTeX} from "./katex"
 export {Location} from "./location"
 export {MathJax} from "./mathjax"
+export {Modal} from "./modal"
 export {PDF} from "./pdf"
 export {Perspective} from "./perspective"
 export {Player} from "./player"

panel/models/modal.py

@@ -0,0 +1,54 @@
+from typing import Any
+
+from bokeh.core.properties import Bool
+from bokeh.events import ModelEvent
+from bokeh.model import Model
+
+from ..config import config
+from ..io.resources import bundled_files
+from ..util import classproperty
+from .layout import Column
+
+__all__ = (
+    "Modal",
+    "ModalDialogEvent",
+)
+
+
+class Modal(Column):
+
+    __javascript_raw__ = [
+        f"{config.npm_cdn}/a11y-dialog@7/dist/a11y-dialog.min.js"
+    ]
+
+    @classproperty
+    def __javascript__(cls):
+        return bundled_files(cls)
+
+    @classproperty
+    def __js_skip__(cls):
+        return {'A11yDialog': cls.__javascript__[:1]}
+
+    __js_require__ = {
+        'paths': {
+            'a11y-dialog': f"{config.npm_cdn}/a11y-dialog@7/dist/a11y-dialog.min",
+        },
+        'exports': {
+            'A11yDialog': 'a11y-dialog',
+        }
+    }
+
+    open = Bool(default=False, help="Whether or not the modal is open.")
+    show_close_button = Bool(True, help="Whether to show a close button in the modal.")
+    background_close = Bool(True, help="Whether to enable closing the modal when clicking the background.")
+
+
+class ModalDialogEvent(ModelEvent):
+    event_name = 'modal-dialog-event'
+
+    def __init__(self, model: Model | None, open: bool):
+        self.open = open
+        super().__init__(model=model)
+
+    def event_values(self) -> dict[str, Any]:
+        return dict(super().event_values(), open=self.open)