three.js/examples/js/interactive/HTMLMesh.js

( function () {

	class HTMLMesh extends THREE.Mesh {

		constructor( dom ) {

			const texture = new HTMLTexture( dom );
			const geometry = new THREE.PlaneGeometry( texture.image.width * 0.001, texture.image.height * 0.001 );
			const material = new THREE.MeshBasicMaterial( {
				map: texture,
				toneMapped: false,
				transparent: true
			} );
			super( geometry, material );
			function onEvent( event ) {

				material.map.dispatchDOMEvent( event );

			}

			this.addEventListener( 'mousedown', onEvent );
			this.addEventListener( 'mousemove', onEvent );
			this.addEventListener( 'mouseup', onEvent );
			this.addEventListener( 'click', onEvent );
			this.dispose = function () {

				geometry.dispose();
				material.dispose();
				material.map.dispose();
				canvases.delete( dom );
				this.removeEventListener( 'mousedown', onEvent );
				this.removeEventListener( 'mousemove', onEvent );
				this.removeEventListener( 'mouseup', onEvent );
				this.removeEventListener( 'click', onEvent );

			};

		}

	}
	class HTMLTexture extends THREE.CanvasTexture {

		constructor( dom ) {

			super( html2canvas( dom ) );
			this.dom = dom;
			this.anisotropy = 16;
			this.encoding = THREE.sRGBEncoding;
			this.minFilter = THREE.LinearFilter;
			this.magFilter = THREE.LinearFilter;

			// Create an observer on the DOM, and run html2canvas update in the next loop
			const observer = new MutationObserver( () => {

				if ( ! this.scheduleUpdate ) {

					// ideally should use xr.requestAnimationFrame, here setTimeout to avoid passing the renderer
					this.scheduleUpdate = setTimeout( () => this.update(), 16 );

				}

			} );
			const config = {
				attributes: true,
				childList: true,
				subtree: true,
				characterData: true
			};
			observer.observe( dom, config );
			this.observer = observer;

		}
		dispatchDOMEvent( event ) {

			if ( event.data ) {

				htmlevent( this.dom, event.type, event.data.x, event.data.y );

			}

		}
		update() {

			this.image = html2canvas( this.dom );
			this.needsUpdate = true;
			this.scheduleUpdate = null;

		}
		dispose() {

			if ( this.observer ) {

				this.observer.disconnect();

			}

			this.scheduleUpdate = clearTimeout( this.scheduleUpdate );
			super.dispose();

		}

	}

	//

	const canvases = new WeakMap();
	function html2canvas( element ) {

		const range = document.createRange();
		const color = new THREE.Color();
		function Clipper( context ) {

			const clips = [];
			let isClipping = false;
			function doClip() {

				if ( isClipping ) {

					isClipping = false;
					context.restore();

				}

				if ( clips.length === 0 ) return;
				let minX = - Infinity,
					minY = - Infinity;
				let maxX = Infinity,
					maxY = Infinity;
				for ( let i = 0; i < clips.length; i ++ ) {

					const clip = clips[ i ];
					minX = Math.max( minX, clip.x );
					minY = Math.max( minY, clip.y );
					maxX = Math.min( maxX, clip.x + clip.width );
					maxY = Math.min( maxY, clip.y + clip.height );

				}

				context.save();
				context.beginPath();
				context.rect( minX, minY, maxX - minX, maxY - minY );
				context.clip();
				isClipping = true;

			}

			return {
				add: function ( clip ) {

					clips.push( clip );
					doClip();

				},
				remove: function () {

					clips.pop();
					doClip();

				}
			};

		}

		function drawText( style, x, y, string ) {

			if ( string !== '' ) {

				if ( style.textTransform === 'uppercase' ) {

					string = string.toUpperCase();

				}

				context.font = style.fontWeight + ' ' + style.fontSize + ' ' + style.fontFamily;
				context.textBaseline = 'top';
				context.fillStyle = style.color;
				context.fillText( string, x, y + parseFloat( style.fontSize ) * 0.1 );

			}

		}

		function buildRectPath( x, y, w, h, r ) {

			if ( w < 2 * r ) r = w / 2;
			if ( h < 2 * r ) r = h / 2;
			context.beginPath();
			context.moveTo( x + r, y );
			context.arcTo( x + w, y, x + w, y + h, r );
			context.arcTo( x + w, y + h, x, y + h, r );
			context.arcTo( x, y + h, x, y, r );
			context.arcTo( x, y, x + w, y, r );
			context.closePath();

		}

		function drawBorder( style, which, x, y, width, height ) {

			const borderWidth = style[ which + 'Width' ];
			const borderStyle = style[ which + 'Style' ];
			const borderColor = style[ which + 'Color' ];
			if ( borderWidth !== '0px' && borderStyle !== 'none' && borderColor !== 'transparent' && borderColor !== 'rgba(0, 0, 0, 0)' ) {

				context.strokeStyle = borderColor;
				context.lineWidth = parseFloat( borderWidth );
				context.beginPath();
				context.moveTo( x, y );
				context.lineTo( x + width, y + height );
				context.stroke();

			}

		}

		function drawElement( element, style ) {

			let x = 0,
				y = 0,
				width = 0,
				height = 0;
			if ( element.nodeType === Node.TEXT_NODE ) {

				// text

				range.selectNode( element );
				const rect = range.getBoundingClientRect();
				x = rect.left - offset.left - 0.5;
				y = rect.top - offset.top - 0.5;
				width = rect.width;
				height = rect.height;
				drawText( style, x, y, element.nodeValue.trim() );

			} else if ( element.nodeType === Node.COMMENT_NODE ) {

				return;

			} else if ( element instanceof HTMLCanvasElement ) {

				// Canvas element
				if ( element.style.display === 'none' ) return;
				context.save();
				const dpr = window.devicePixelRatio;
				context.scale( 1 / dpr, 1 / dpr );
				context.drawImage( element, 0, 0 );
				context.restore();

			} else {

				if ( element.style.display === 'none' ) return;
				const rect = element.getBoundingClientRect();
				x = rect.left - offset.left - 0.5;
				y = rect.top - offset.top - 0.5;
				width = rect.width;
				height = rect.height;
				style = window.getComputedStyle( element );

				// Get the border of the element used for fill and border

				buildRectPath( x, y, width, height, parseFloat( style.borderRadius ) );
				const backgroundColor = style.backgroundColor;
				if ( backgroundColor !== 'transparent' && backgroundColor !== 'rgba(0, 0, 0, 0)' ) {

					context.fillStyle = backgroundColor;
					context.fill();

				}

				// If all the borders match then stroke the round rectangle

				const borders = [ 'borderTop', 'borderLeft', 'borderBottom', 'borderRight' ];
				let match = true;
				let prevBorder = null;
				for ( const border of borders ) {

					if ( prevBorder !== null ) {

						match = style[ border + 'Width' ] === style[ prevBorder + 'Width' ] && style[ border + 'Color' ] === style[ prevBorder + 'Color' ] && style[ border + 'Style' ] === style[ prevBorder + 'Style' ];

					}

					if ( match === false ) break;
					prevBorder = border;

				}

				if ( match === true ) {

					// They all match so stroke the rectangle from before allows for border-radius

					const width = parseFloat( style.borderTopWidth );
					if ( style.borderTopWidth !== '0px' && style.borderTopStyle !== 'none' && style.borderTopColor !== 'transparent' && style.borderTopColor !== 'rgba(0, 0, 0, 0)' ) {

						context.strokeStyle = style.borderTopColor;
						context.lineWidth = width;
						context.stroke();

					}

				} else {

					// Otherwise draw individual borders

					drawBorder( style, 'borderTop', x, y, width, 0 );
					drawBorder( style, 'borderLeft', x, y, 0, height );
					drawBorder( style, 'borderBottom', x, y + height, width, 0 );
					drawBorder( style, 'borderRight', x + width, y, 0, height );

				}

				if ( element instanceof HTMLInputElement ) {

					let accentColor = style.accentColor;
					if ( accentColor === undefined || accentColor === 'auto' ) accentColor = style.color;
					color.set( accentColor );
					const luminance = Math.sqrt( 0.299 * color.r ** 2 + 0.587 * color.g ** 2 + 0.114 * color.b ** 2 );
					const accentTextColor = luminance < 0.5 ? 'white' : '#111111';
					if ( element.type === 'radio' ) {

						buildRectPath( x, y, width, height, height );
						context.fillStyle = 'white';
						context.strokeStyle = accentColor;
						context.lineWidth = 1;
						context.fill();
						context.stroke();
						if ( element.checked ) {

							buildRectPath( x + 2, y + 2, width - 4, height - 4, height );
							context.fillStyle = accentColor;
							context.strokeStyle = accentTextColor;
							context.lineWidth = 2;
							context.fill();
							context.stroke();

						}

					}

					if ( element.type === 'checkbox' ) {

						buildRectPath( x, y, width, height, 2 );
						context.fillStyle = element.checked ? accentColor : 'white';
						context.strokeStyle = element.checked ? accentTextColor : accentColor;
						context.lineWidth = 1;
						context.stroke();
						context.fill();
						if ( element.checked ) {

							const currentTextAlign = context.textAlign;
							context.textAlign = 'center';
							const properties = {
								color: accentTextColor,
								fontFamily: style.fontFamily,
								fontSize: height + 'px',
								fontWeight: 'bold'
							};
							drawText( properties, x + width / 2, y, '✔' );
							context.textAlign = currentTextAlign;

						}

					}

					if ( element.type === 'range' ) {

						const [ min, max, value ] = [ 'min', 'max', 'value' ].map( property => parseFloat( element[ property ] ) );
						const position = ( value - min ) / ( max - min ) * ( width - height );
						buildRectPath( x, y + height / 4, width, height / 2, height / 4 );
						context.fillStyle = accentTextColor;
						context.strokeStyle = accentColor;
						context.lineWidth = 1;
						context.fill();
						context.stroke();
						buildRectPath( x, y + height / 4, position + height / 2, height / 2, height / 4 );
						context.fillStyle = accentColor;
						context.fill();
						buildRectPath( x + position, y, height, height, height / 2 );
						context.fillStyle = accentColor;
						context.fill();

					}

					if ( element.type === 'color' || element.type === 'text' || element.type === 'number' ) {

						clipper.add( {
							x: x,
							y: y,
							width: width,
							height: height
						} );
						drawText( style, x + parseInt( style.paddingLeft ), y + parseInt( style.paddingTop ), element.value );
						clipper.remove();

					}

				}

			}

			/*
    // debug
    context.strokeStyle = '#' + Math.random().toString( 16 ).slice( - 3 );
    context.strokeRect( x - 0.5, y - 0.5, width + 1, height + 1 );
    */

			const isClipping = style.overflow === 'auto' || style.overflow === 'hidden';
			if ( isClipping ) clipper.add( {
				x: x,
				y: y,
				width: width,
				height: height
			} );
			for ( let i = 0; i < element.childNodes.length; i ++ ) {

				drawElement( element.childNodes[ i ], style );

			}

			if ( isClipping ) clipper.remove();

		}

		const offset = element.getBoundingClientRect();
		let canvas = canvases.get( element );
		if ( canvas === undefined ) {

			canvas = document.createElement( 'canvas' );
			canvas.width = offset.width;
			canvas.height = offset.height;
			canvases.set( element, canvas );

		}

		const context = canvas.getContext( '2d' /*, { alpha: false }*/ );

		const clipper = new Clipper( context );

		// console.time( 'drawElement' );

		drawElement( element );

		// console.timeEnd( 'drawElement' );

		return canvas;

	}

	function htmlevent( element, event, x, y ) {

		const mouseEventInit = {
			clientX: x * element.offsetWidth + element.offsetLeft,
			clientY: y * element.offsetHeight + element.offsetTop,
			view: element.ownerDocument.defaultView
		};
		window.dispatchEvent( new MouseEvent( event, mouseEventInit ) );
		const rect = element.getBoundingClientRect();
		x = x * rect.width + rect.left;
		y = y * rect.height + rect.top;
		function traverse( element ) {

			if ( element.nodeType !== Node.TEXT_NODE && element.nodeType !== Node.COMMENT_NODE ) {

				const rect = element.getBoundingClientRect();
				if ( x > rect.left && x < rect.right && y > rect.top && y < rect.bottom ) {

					element.dispatchEvent( new MouseEvent( event, mouseEventInit ) );
					if ( element instanceof HTMLInputElement && element.type === 'range' && ( event === 'mousedown' || event === 'click' ) ) {

						const [ min, max ] = [ 'min', 'max' ].map( property => parseFloat( element[ property ] ) );
						const width = rect.width;
						const offsetX = x - rect.x;
						const proportion = offsetX / width;
						element.value = min + ( max - min ) * proportion;
						element.dispatchEvent( new InputEvent( 'input', {
							bubbles: true
						} ) );

					}

				}

				for ( let i = 0; i < element.childNodes.length; i ++ ) {

					traverse( element.childNodes[ i ] );

				}

			}

		}

		traverse( element );

	}

	THREE.HTMLMesh = HTMLMesh;

} )();