Description of change

DOM Container Support

This PR adds support for integrating DOM elements within the PixiJS scene graph, allowing HTML elements to be positioned and transformed alongside other PixiJS objects.

Features

• New DOMContainer class for wrapping HTML elements
• New DOMPipe for managing DOM elements in the scene
• Proper transform support (position, scale, rotation, skew)
• Anchor point support
• Opacity/visibility handling
• Automatic cleanup on destroy

Performance Considerations

• Uses CSS transforms instead of top/left for better performance
• Efficiently handles DOM element positioning using translate
• Minimal DOM operations by tracking element state

Example Usage

import 'pixi.js/dom'

// Create a DOM element
const element = document.createElement('div');
element.innerHTML = 'Hello World!';

// Create a DOM container
const domContainer = new DOMContainer({ element });

// Add it to your scene
app.stage.addChild(domContainer);

// Position and transform like any other DisplayObject
domContainer.x = 100;
domContainer.y = 100;
domContainer.rotation = 0.5;
domContainer.anchor.set(0.5);

Notes

• DOM elements are rendered in a separate layer above the canvas
• Elements maintain proper stacking order and transforms
• Full support for PixiJS transform hierarchy
• Handles window resize and canvas position changes

Open questions

• Is DOMContainer the best name?
• @Zyie , will this PR cause issues with offscreen canvas or other things that don't have access to the dom?
• should this be imported - or included by default?

Pre-Merge Checklist

• Tests and/or benchmarks are included
• Documentation is changed or added
• Lint process passed (npm run lint)
• Tests passed (npm run test)