First, create a global App with the default plugin set. For more details, see: Lesson 18 - Refactor with ECS

import { App, DefaultPlugins } from '@infinite-canvas-tutorial/ecs';
import { UIPlugin } from '@infinite-canvas-tutorial/webcomponents';

const app = new App().addPlugins(...DefaultPlugins, UIPlugin);
app.run();

Then you can create one or more canvases. Here we use UI components implemented based on WebComponents.

Using WebComponents

First, import the component library:

import '@infinite-canvas-tutorial/webcomponents';

Declare the component in HTML:

<ic-spectrum-canvas
    id="canvas"
    style="width: 100%; height: 100%;"
    app-state='{"topbarVisible":true, "cameraZoom": 1}'
    renderer="webgl"
></ic-spectrum-canvas>

The following parameters can be passed via HTML attributes:

• renderer Renderer. Options are 'webgl' | 'webgpu', default is 'webgl'
• shader-compiler-path Used to transpile GLSL to WGSL. For more details, see Lesson 1 - Hardware abstraction layers. Default value is 'https://unpkg.com/@antv/[email protected]/dist/pkg/glsl_wgsl_compiler_bg.wasm'
• theme Theme. Options are 'dark' | 'light', default is 'light'
• app-state Application state in JSON string format, which can control initialization parameters such as camera
• nodes List of shapes in JSON string format

Getting the API

By listening to the canvas initialization event Event.READY, you can get the API instance from the event object, and then call the various methods mentioned above:

import { Event } from '@infinite-canvas-tutorial/webcomponents';

const canvas = document.querySelector<HTMLElement>('#canvas')!;
canvas.addEventListener(Event.READY, async (e) => {
    const api = e.detail;
});

Canvas events

The following are custom events triggered on canvas DOM nodes, which can be accessed via the event object e.detail.

Event.READY

Triggered when the canvas initialization is complete. ExtendedAPI can be obtained.

Event.RESIZED

Triggered when the canvas resizes. You can retrieve the current canvas dimensions: { width: number; height: number }

Event.ZOOM_CHANGED

Triggered when the canvas camera's zoom level changes. The current zoom level can be retrieved: { zoom: number }

Event.SCREENSHOT_DOWNLOADED

Triggered when the image export request completes. You can retrieve the export result: { dataURL: string; svg: string }

Event.NODES_UPDATED

Event.NODE_UPDATED

Event.NODE_DELETED

Event.SELECTED_NODES_CHANGED

Event.TRANSFORMABLE_STATUS_CHANGED

Event.COMMENT_ADDED

Let's see how it's implemented internally.

Internal Implementation

In the InitCanvas System, we use Lit's context functionality:

const stateManagement = new LitStateManagement(appStateProvider, nodesProvider);
const api = new ExtendedAPI(stateManagement, this.commands, container);