Add basic curtains.

demo/DemoApp.tsx

@@ -2,7 +2,7 @@ import React, {useState} from "react";
 import "../index";
 import {Checkbox} from "../src/Components/Forms/Checkbox";
 import { Radio } from "../src/Components/Forms/Radio";
-import {AirTrafficControl, Basket, FloppyDisk, House, TrashSimple, XCircle} from "@phosphor-icons/react";
+import {AirTrafficControl, Basket, FloppyDisk, House, TrashSimple, X, XCircle} from "@phosphor-icons/react";
 import {Card} from "../src/Components/Card";
 import {PasswordInput} from "../src/Components/Forms/PasswordInput";
 import {RequiredField} from "../src/Components/Forms/RequiredField";
@@ -25,9 +25,12 @@ import {Outlet} from "react-router-dom";
 import {ToggleSwitch} from "../src/Components/Forms/ToggleSwitch";
 import {Step, Steps} from "../src/Components/Steps/Steps";
 import {AsyncPaginate, AutoPaginate, Paginate} from "../src/Components/Pagination/Paginate";
+import {useCurtains} from "../src/Components/Curtains/Curtains";
 
 export function DemoApp()
 {
+	const curtains = useCurtains();
+
 	const [datetime, setDatetime] = useState(null);
 
 	const [selected, setSelected] = useState(null);
@@ -63,14 +66,6 @@ export function DemoApp()
 
 			<h1>KernelUI</h1>
 
-			<h2>TODO</h2>
-
-			<ul>
-				<li>Errors</li>
-				<li>Subapps</li>
-				<li>Modals</li>
-			</ul>
-
 			<h2>Headings</h2>
 
 			<h1>Demo app</h1>
@@ -442,6 +437,30 @@ export function DemoApp()
 				)}
 			</AsyncPaginate>
 
+			<h2>Curtains & co</h2>
+
+			<h3>Curtains</h3>
+
+			<Card>
+				<button onClick={() => {
+					const curtainId = curtains.open(
+						<button className={"close"} onClick={() => { curtains.close(curtainId); }}><X /> Close the curtain</button>
+					);
+				}}>Open a curtain</button>
+			</Card>
+
+			<h3>Subapps</h3>
+
+			<Card>
+				<button>Open a subapp</button>
+			</Card>
+
+			<h3>Modals</h3>
+
+			<Card>
+				<button>Open a modal</button>
+			</Card>
+
 		</Application>
 	);
 }

package.json

@@ -18,11 +18,13 @@
     "@phosphor-icons/react": "^2.1.5",
     "react": "^18.3.1",
     "react-merge-refs": "^2.1.1",
-    "react-router-dom": "^6.24.1"
+    "react-router-dom": "^6.24.1",
+    "uuid": "^10.0.0"
   },
   "devDependencies": {
     "@types/react": "^18.3.3",
     "@types/react-dom": "^18.3.0",
+    "@types/uuid": "^10",
     "@vitejs/plugin-react": "^4.3.0",
     "less": "^4.2.0",
     "react-dom": "^18.3.1",

src/Application/Kernel.tsx

@@ -1,6 +1,7 @@
 import { IconContext } from "@phosphor-icons/react";
 import React from "react";
 import {createBrowserRouter, RouterProvider} from "react-router-dom";
+import {Curtains} from "../Components/Curtains/Curtains";
 
 /**
  * Main Kernel UI app component which initializes everything.
@@ -16,9 +17,11 @@ export function Kernel({header, footer, router}: {
 			size: 16,
 			weight: "bold",
 		}}>
-			{header}
-			<RouterProvider router={router} />
-			{footer}
+			<Curtains>
+				{header}
+				<RouterProvider router={router} />
+				{footer}
+			</Curtains>
 		</IconContext.Provider>
 	);
 }

src/Components/Curtains/Curtains.tsx

@@ -0,0 +1,136 @@
+import React, {useCallback, useContext, useEffect, useMemo, useRef, useState} from "react";
+import ReactDOM from "react-dom";
+import {v4 as uuidv4} from "uuid";
+
+/**
+ * Curtain UUID type.
+ */
+export type CurtainUuidType = string;
+
+/**
+ * The function that opens a curtain.
+ */
+export type OpenCurtainFunction = (content: React.ReactNode) => CurtainUuidType;
+
+/**
+ * The function that closes a curtain.
+ */
+export type CloseCurtainFunction = (uuid: CurtainUuidType) => void;
+
+/**
+ * Interface of curtains state.
+ */
+export interface CurtainsContextState
+{
+	/**
+	 * Open a new curtain.
+	 * @param content The curtain content.
+	 * @return UUID of the curtain.
+	 */
+	open: OpenCurtainFunction;
+
+	/**
+	 * Close the given curtain.
+	 * @param uuid UUID of the curtain to close.
+	 */
+	close: CloseCurtainFunction;
+}
+
+const CurtainsContext = React.createContext<CurtainsContextState>({
+	// Empty functions.
+	open() { return ""; },
+	close() {},
+});
+
+/**
+ * Hook to interact with curtains (open or close).
+ */
+export function useCurtains(): CurtainsContextState
+{
+	return useContext(CurtainsContext);
+}
+
+/**
+ * Page curtains system.
+ */
+export function Curtains({children}: React.PropsWithChildren<{}>)
+{
+	// Curtains state.
+	const [curtains, setCurtains] = useState<Record<CurtainUuidType, React.ReactNode>>({});
+
+	// Initialize open curtain function.
+	const open = useRef<OpenCurtainFunction>();
+	open.current = useCallback((content: React.ReactNode) => {
+		// Generate a new curtain UUID for the new curtain to open.
+		const curtainUuid = uuidv4();
+
+		// Add the curtain to open to the list of curtains, with the generated UUID.
+		setCurtains({
+			...curtains,
+			[curtainUuid]: content,
+		});
+
+		// Return the curtain UUID.
+		return curtainUuid;
+	}, [curtains, setCurtains]);
+
+	// Initialize close curtain function.
+	const close = useRef<CloseCurtainFunction>();
+	close.current = useCallback((uuid: CurtainUuidType) => {
+		// Copy the curtains list.
+		const newCurtains = {...curtains};
+		// Remove the given curtain from the list.
+		delete newCurtains[uuid];
+		// Set the new curtains list.
+		setCurtains(newCurtains);
+	}, [curtains, setCurtains]);
+
+	// Initialize context state from action functions.
+	const contextState = useMemo(() => ({
+		open: (content: React.ReactNode) => open.current(content),
+		close: (uuid: CurtainUuidType) => close.current(uuid),
+	}), [open, close]);
+
+	// Show dimmed main content.
+	useEffect(() => {
+		if (Object.entries(curtains).length > 0 && !document.body.classList.contains("dimmed"))
+			// We should dim content and it's currently not.
+			document.body.classList.add("dimmed");
+		else
+			// We shouldn't dim content.
+			document.body.classList.remove("dimmed");
+	}, [curtains]);
+
+	return (
+		<CurtainsContext.Provider value={contextState}>
+			{children}
+			<CurtainsPortal curtains={curtains} />
+		</CurtainsContext.Provider>
+	);
+}
+
+/**
+ * Curtains portal manager.
+ */
+function CurtainsPortal({curtains}: {
+	curtains: Record<CurtainUuidType, React.ReactNode>;
+})
+{
+	return ReactDOM.createPortal(Object.entries(curtains).map(([uuid, curtainContent]) => (
+		<CurtainInstance key={uuid}>
+			{curtainContent}
+		</CurtainInstance>
+	)), document.body);
+}
+
+/**
+ * Component of an opened curtain instance.
+ */
+function CurtainInstance({children}: React.PropsWithChildren<{}>)
+{
+	return (
+		<div className={"curtain"}>
+			{children}
+		</div>
+	);
+}

src/styles/_colors.less

@@ -15,6 +15,8 @@
 	@foreground-darkest: #000000; --foreground-darkest: @foreground-darkest;
 
 	@foreground-shadow: fade(@foreground, 50%); --foreground-shadow: @foreground-shadow;
+	@curtain-dim: fade(@foreground, 50%); --curtain-dim: @curtain-dim;
+	@curtain-inset: fade(@foreground, 20%); --curtain-inset: @curtain-inset;
 
 
 

src/styles/_components.less

@@ -1,6 +1,7 @@
 
 @import "components/_button";
 @import "components/_card";
+@import "components/_curtains";
 @import "components/_dates";
 @import "components/_errors";
 @import "components/_floating";

src/styles/components/_button.less

@@ -125,7 +125,7 @@ a.button, button, input[type="submit"], input[type="reset"]
 		}
 	}
 
-	&.red, &.delete, &.remove, &.no, &.negative, &.bad
+	&.red, &.delete, &.remove, &.close, &.no, &.negative, &.bad
 	{
 		border-color: var(--red-darker);
 		background: var(--red);

src/styles/components/_curtains.less

@@ -0,0 +1,46 @@
+body > .curtain
+{ // Position the curtain on top of everything and dim the background.
+	position: fixed;
+	top: 0;
+	left: 0;
+	width: 100vw;
+	height: 100vh;
+
+	box-shadow: inset 0 0 5em 0 var(--curtain-inset);
+	background: var(--curtain-dim);
+
+	// Show an animation when entering screen.
+	animation: curtain-in 0.4s ease-in;
+	transform-origin: center;
+
+	z-index: 1000; // On top of main content.
+}
+
+body.dimmed
+{ // Disable scroll and blur the content when the body is dimmed.
+	overflow: hidden;
+
+	> *:not(.curtain)
+	{
+		transition: filter 0.4s ease-in;
+
+		filter: blur(0.2em);
+	}
+}
+
+@keyframes curtain-in
+{ // Screen enter animation.
+	from
+	{
+		transform: scale(1.2);
+		filter: blur(0.5em);
+		opacity: 0;
+	}
+
+	to
+	{
+		transform: scale(1);
+		filter: blur(0);
+		opacity: 1;
+	}
+}

yarn.lock

@@ -923,6 +923,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/uuid@npm:^10":
+  version: 10.0.0
+  resolution: "@types/uuid@npm:10.0.0"
+  checksum: 10c0/9a1404bf287164481cb9b97f6bb638f78f955be57c40c6513b7655160beb29df6f84c915aaf4089a1559c216557dc4d2f79b48d978742d3ae10b937420ddac60
+  languageName: node
+  linkType: hard
+
 "@vitejs/plugin-react@npm:^4.3.0":
   version: 4.3.0
   resolution: "@vitejs/plugin-react@npm:4.3.0"
@@ -1828,6 +1835,7 @@ __metadata:
     "@phosphor-icons/react": "npm:^2.1.5"
     "@types/react": "npm:^18.3.3"
     "@types/react-dom": "npm:^18.3.0"
+    "@types/uuid": "npm:^10"
     "@vitejs/plugin-react": "npm:^4.3.0"
     less: "npm:^4.2.0"
     react: "npm:^18.3.1"
@@ -1835,6 +1843,7 @@ __metadata:
     react-merge-refs: "npm:^2.1.1"
     react-router-dom: "npm:^6.24.1"
     typescript: "npm:^5.4.5"
+    uuid: "npm:^10.0.0"
     vite: "npm:^5.2.11"
     vite-plugin-dts: "npm:^3.9.1"
   languageName: unknown
@@ -2821,6 +2830,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"uuid@npm:^10.0.0":
+  version: 10.0.0
+  resolution: "uuid@npm:10.0.0"
+  bin:
+    uuid: dist/bin/uuid
+  checksum: 10c0/eab18c27fe4ab9fb9709a5d5f40119b45f2ec8314f8d4cf12ce27e4c6f4ffa4a6321dc7db6c515068fa373c075b49691ba969f0010bf37f44c37ca40cd6bf7fe
+  languageName: node
+  linkType: hard
+
 "validator@npm:^13.7.0":
   version: 13.12.0
   resolution: "validator@npm:13.12.0"