docs: add custom illustrations guide for ui5-illustrated-message

docs/2-advanced/18-using-custom-illustrations.md

@@ -0,0 +1,219 @@
+# Using Custom Illustrations
+
+*Learn how to create and register custom illustrations for the UI5 Web Components IllustratedMessage component.*
+
+The [`ui5-illustrated-message`](https://ui5.github.io/webcomponents/components/fiori/IllustratedMessage/) component enhances user experience by displaying contextual illustrations in empty states, error conditions, onboarding flows, and other scenarios where visual communication improves usability.
+
+While UI5 Web Components includes a comprehensive set of [built-in illustrations](https://ui5.github.io/webcomponents/components/fiori/enums/IllustrationMessageType/), you can extend this collection by registering your own custom illustrations that match your application's brand and design requirements.
+
+## Overview
+
+Custom illustrations in UI5 Web Components consist of four size variants that automatically adapt to different container dimensions and [design contexts](https://ui5.github.io/webcomponents/components/fiori/enums/IllustrationMessageDesign/):
+
+| Variant    | Size        | Breakpoint | Container Width | Design Type |
+|------------|-------------|------------|-----------------|-------------|
+| **Scene**  | Large       | L          | > 681px         | Large       |
+| **Dialog** | Medium      | M          | ≤ 681px         | Medium      |
+| **Spot**   | Small       | S          | ≤ 360px         | Small       |
+| **Dot**    | Extra Small | XS         | ≤ 260px         | ExtraSmall  |
+
+Each custom illustration must include all four variants to ensure optimal display across different use cases and responsive breakpoints.
+
+## Prerequisites
+
+Before implementing custom illustrations, ensure you have:
+
+### 1. Installed the required packages
+
+```bash
+npm install @ui5/webcomponents @ui5/webcomponents-fiori
+```
+
+The [`@ui5/webcomponents`](https://www.npmjs.com/package/@ui5/webcomponents) package provides the base framework and asset registry functionality, while [`@ui5/webcomponents-fiori`](https://www.npmjs.com/package/@ui5/webcomponents-fiori) contains the `IllustratedMessage` component.
+
+### 2. Prepared SVG Assets
+
+Create four SVG files for each illustration following the naming convention:
+```
+{set}-{Variant}-{IllustrationName}.js
+```
+
+**Example file structure:**
+```
+assets/
+├── custom-Scene-EmptyCart.js     # Large variant
+├── custom-Dialog-EmptyCart.js    # Medium variant  
+├── custom-Spot-EmptyCart.js      # Small variant
+└── custom-Dot-EmptyCart.js       # Extra small variant
+```
+
+## Implementation
+
+### Registration
+
+Register your custom illustration using the `registerIllustration` function:
+
+**JavaScript:**
+```js
+import "@ui5/webcomponents-fiori/dist/IllustratedMessage.js";
+import { registerIllustration } from "@ui5/webcomponents-base/dist/asset-registries/Illustrations.js";
+
+// Import SVG assets
+import sceneSvg from "./assets/custom-Scene-EmptyCart.js";
+import dialogSvg from "./assets/custom-Dialog-EmptyCart.js";
+import spotSvg from "./assets/custom-Spot-EmptyCart.js";
+import dotSvg from "./assets/custom-Dot-EmptyCart.js";
+
+// Register the illustration
+registerIllustration("EmptyCart", {
+    sceneSvg,
+    dialogSvg,
+    spotSvg,
+    dotSvg,
+    title: "Your cart is empty",
+    subtitle: "Add items to get started with your order",
+    set: "custom"
+});
+```
+
+**TypeScript:**
+```ts
+import "@ui5/webcomponents-fiori/dist/IllustratedMessage.js";
+import { registerIllustration } from "@ui5/webcomponents-base/dist/asset-registries/Illustrations.js";
+import type { I18nText } from "@ui5/webcomponents-base/dist/i18nBundle.js";
+
+// Import SVG assets
+import sceneSvg from "./assets/custom-Scene-EmptyCart.js";
+import dialogSvg from "./assets/custom-Dialog-EmptyCart.js";
+import spotSvg from "./assets/custom-Spot-EmptyCart.js";
+import dotSvg from "./assets/custom-Dot-EmptyCart.js";
+
+// Register the illustration with proper typing
+registerIllustration("EmptyCart", {
+    sceneSvg,
+    dialogSvg,
+    spotSvg,
+    dotSvg,
+    title: "Your cart is empty" as I18nText,
+    subtitle: "Add items to get started with your order" as I18nText,
+    set: "custom"
+});
+```
+
+### SVG Asset Structure
+
+Each SVG asset file should export the SVG content as a string:
+
+**custom-Dialog-EmptyCart.js:**
+```js
+export default `<svg 
+    id="custom-Dialog-EmptyCart" 
+    width="160" 
+    height="120" 
+    viewBox="0 0 160 120" 
+    fill="none" 
+    xmlns="http://www.w3.org/2000/svg"
+>
+    <!-- Cart outline -->
+    <path 
+        d="M20 30h120l-8 60H28l-8-60z" 
+        stroke="var(--sapContent_Illustrative_Color1)" 
+        stroke-width="2" 
+        fill="var(--sapContent_Illustrative_Color2)"
+    />
+    <!-- Cart handle -->
+    <path 
+        d="M35 30V20a10 10 0 0 1 20 0v10" 
+        stroke="var(--sapContent_Illustrative_Color3)" 
+        stroke-width="2"
+    />
+    <!-- Empty state indicator -->
+    <circle 
+        cx="80" 
+        cy="60" 
+        r="15" 
+        fill="var(--sapContent_Illustrative_Color4)" 
+        opacity="0.3"
+    />
+</svg>`;
+```
+
+### Design Guidelines
+
+**SVG Requirements:**
+- Include a unique `id` attribute: `{set}-{Variant}-{IllustrationName}`
+- Use responsive dimensions appropriate for each variant
+
+**Theming Support:**
+- Use CSS custom properties for colors
+- Avoid hard-coded colors to ensure theme compatibility
+- Test illustrations across different UI5 themes
+
+**Security Compliance:**
+- ⚠️ **No inline JavaScript**: Avoid `<script>` tags or event handlers
+- ⚠️ **No unsafe styles**: Avoid `style` attributes that violate CSP policies  
+- ✅ **Use CSS custom properties**: Prefer theme-aware styling
+- ✅ **Test with strict CSP**: Validate in CSP-enabled environments
+
+## Usage
+
+### Basic Implementation
+
+Use your registered illustration by referencing it with the format `{set}/{name}`:
+
+**HTML:**
+```html
+<ui5-illustrated-message name="custom/EmptyCart">
+    <ui5-button design="Emphasized">Start Shopping</ui5-button>
+</ui5-illustrated-message>
+```
+
+**React:**
+```jsx
+import { Button, IllustratedMessage } from '@ui5/webcomponents-react';
+
+function EmptyCartView() {
+    return (
+        <IllustratedMessage name="custom/EmptyCart">
+            <Button design="Emphasized">Start Shopping</Button>
+        </IllustratedMessage>
+    );
+}
+```
+
+### Configuration
+
+Control illustration size and behavior using the [`design`](https://ui5.github.io/webcomponents/components/fiori/IllustratedMessage/#design) property:
+
+```html
+<!-- Auto-responsive (default) -->
+<ui5-illustrated-message name="custom/EmptyCart" design="Auto">
+    <ui5-button>Add Items</ui5-button>
+</ui5-illustrated-message>
+
+<!-- Fixed size -->
+<ui5-illustrated-message name="custom/EmptyCart" design="Large">
+    <ui5-button>Add Items</ui5-button>
+</ui5-illustrated-message>
+```
+
+### Accessibility
+
+For accessibility considerations, use the [`decorative`](https://ui5.github.io/webcomponents/components/fiori/IllustratedMessage/#decorative) property when appropriate:
+
+```html
+<!-- Decorative illustrations (no accessibility labels) -->
+<ui5-illustrated-message name="custom/EmptyCart" decorative>
+    <ui5-button>Add Items</ui5-button>
+</ui5-illustrated-message>
+```
+
+**Note:** Use the `decorative` property when the illustration is purely visual and doesn't convey important information. This improves accessibility by preventing screen readers from announcing decorative content.
+
+## Best Practices
+
+- **Consistent Design Language**: Maintain visual consistency with your application's design system
+- **Meaningful Illustrations**: Create illustrations that clearly communicate the intended message
+- **Performance**: Optimize SVG file sizes while maintaining quality
+- **Accessibility**: Ensure illustrations support users with visual impairments through proper titles and descriptions
+- **Testing**: Validate illustrations across different themes, screen sizes, and browsers

packages/base/src/asset-registries/Illustrations.ts

@@ -2,19 +2,40 @@ import getSharedResource from "../getSharedResource.js";
 import type { I18nText } from "../i18nBundle.js";
 import { getTheme } from "../config/Theme.js";
 
+/**
+ * Loader function for lazy-loading illustration data.
+ */
 type IllustrationLoader = (illustrationName: string) => Promise<IllustrationData>;
 
+/**
+ * Core illustration properties containing SVG variants and metadata.
+ *
+ * @public
+ */
 type IllustrationProperties = {
+	/** SVG content for the medium variant (M breakpoint, ≤ 681px) */
 	dialogSvg: string,
+	/** SVG content for the large variant (L breakpoint, > 681px) */
 	sceneSvg: string,
+	/** SVG content for the small variant (S breakpoint, ≤ 360px) */
 	spotSvg: string,
+	/** SVG content for the extra small variant (XS breakpoint, ≤ 260px) */
 	dotSvg: string,
+	/** The illustration title text (supports i18n) */
 	title: I18nText,
+	/** The illustration subtitle text (supports i18n) */
 	subtitle: I18nText,
 };
 
+/**
+ * Complete illustration data for registration.
+ *
+ * @public
+ */
 type IllustrationData = IllustrationProperties & {
+	/** The illustration set identifier (e.g., "custom") */
 	set: string,
+	/** Collection identifier (defaults to "V4") */
 	collection: string,
 };
 
@@ -65,6 +86,28 @@ const processName = (name: string) => {
 	};
 };
 
+/**
+ * Registers a custom illustration in the global registry.
+ *
+ * @param name - The name of the illustration (without set prefix)
+ * @param data - The illustration data (see {@link IllustrationData})
+ *
+ * @public
+ * @example
+ * ```js
+ * import { registerIllustration } from "@ui5/webcomponents-base/dist/asset-registries/Illustrations.js";
+ *
+ * registerIllustration("EmptyCart", {
+ *   sceneSvg: "<svg>...</svg>",
+ *   dialogSvg: "<svg>...</svg>",
+ *   spotSvg: "<svg>...</svg>",
+ *   dotSvg: "<svg>...</svg>",
+ *   title: "Your cart is empty",
+ *   subtitle: "Add items to get started",
+ *   set: "custom"
+ * });
+ * ```
+ */
 const registerIllustration = (name: string, data: IllustrationData) => {
 	const collection = data.collection || FALLBACK_COLLECTION;
 	registry.set(`${data.set}/${collection}/${name}`, {
@@ -95,11 +138,27 @@ const _loadIllustrationOnce = (illustrationName: string) => {
 	return illustrationPromises.get(registryKey);
 };
 
+/**
+ * Synchronously retrieves illustration data from the registry.
+ *
+ * @param illustrationName - The illustration identifier in format "set/name"
+ * @returns The illustration properties or undefined if not available
+ *
+ * @public
+ */
 const getIllustrationDataSync = (illustrationName: string) => {
 	const { registryKey } = processName(illustrationName);
 	return registry.get(registryKey);
 };
 
+/**
+ * Asynchronously retrieves illustration data, loading it if necessary.
+ *
+ * @param illustrationName - The illustration identifier in format "set/name"
+ * @returns Promise resolving to illustration properties or undefined
+ *
+ * @public
+ */
 const getIllustrationData = async (illustrationName: string) => {
 	const { registryKey } = processName(illustrationName);
 
@@ -113,3 +172,8 @@ export {
 	registerIllustrationLoader,
 	getIllustrationData,
 };
+
+export type {
+	IllustrationData,
+	IllustrationProperties,
+};