画像切り替えサムネイル付き switcher スイッチャー swiper スワイパー
サムネイルはスマホサイズでは折り返し

/**
 * 画像切り替え
 *
 * @author ao-system, Inc.
 * @date 2024-04-09
 *

<section class="switchpanel">
	<div>
		<div id="switchPanelStage"></div>
		<div id="switchPanelThumbnail"></div>
	</div>
</section>

<style>
section.switchpanel {
	> div {
		max-width: 1920px;
		margin: 0 auto;
		overflow: hidden;
		> #switchPanelStage {
			user-select: none;
			display: grid;
			grid-template-rows: 1fr;
			grid-template-columns: 1fr;
			> div {
				grid-row: 1/2;
				grid-column: 1/2;
				&:nth-of-type(1) {
					z-index: 0;
				}
				&:nth-of-type(2) {
					z-index: 1;
					transition: 0.5s;
					cursor: ew-resize;
				}
				> picture {
					> img {
						width: 100%;
						display: block;
					}
				}
			}
		}
		> #switchPanelThumbnail {
			padding: 4px 0;
			display: grid;
			grid-template-columns: repeat(6,1fr);
			gap: 4px;
			@media (width < 530px) {
				grid-template-columns: repeat(5,1fr);
			}
			@media (width < 430px) {
				grid-template-columns: repeat(4,1fr);
			}
			@media (width < 330px) {
				grid-template-columns: repeat(3,1fr);
			}
			> div {
				border: solid 1px #999;
				&.on {
					border-color: #f00;
				}
				> picture {
					> img {
						width: 100%;
						display: block;
					}
				}
			}
		}
	}
}
</style>
 *
 */

(() => {
	'use strict';
	class SwitchImage {
		#constProperties = [
			{prop: 'stage',					value: document.getElementById('switchPanelStage')},
			{prop: 'switchPanelThumbnail',	value: document.getElementById('switchPanelThumbnail')},
			{prop: 'layer0',				value: document.createElement('div')},
			{prop: 'layer1',				value: document.createElement('div')},
			{prop: 'imageChangeInterval',	value: 4000},	//画像と画像の時間間隔
			{prop: 'slideWidth',			value: 50},		//切り替わるスライド幅
			{prop: 'slideTime',				value: 600},	//スライド時間cssの0.5sよりちょっと長め
			{prop: 'swipeShreshold',		value: 50},		//スワイプ判定幅
		];
		#loopTimeoutId	= null;		//自動スライドのタイマー
		#isBusy			= false;	//動作中
		#pausePlayFlag	= true;		//falseで停止
		#focusFlag		= true;		//フォーカスが外れている時は動作させないため
		#valueIndex		= 0;		//this.#valuesの添え字
		#slideDirection	= 1;		//1|-1	正方向,逆方向
		#swipeStartX	= 0;		//スワイプ開始位置
		#isSwiping		= false;	//スワイプ中
		#values			= [];
		//
		constructor(values) {
			this.#values = values;
			this.#constProperties.forEach((obj) => Object.defineProperty(this, obj.prop, {value:obj.value, writable:false}));
			this.#init();
		}
		#init() {
			//this.#switchImage = shuffle(this.#switchImage);	//シャッフルさせる場合
			//window.addEventListener('focus',() => { this.#focusFlag = true;});	//out focusで停止させる場合の処理
			//window.addEventListener('blur',() => { this.#focusFlag = false;});	//out focusで停止させる場合の処理
			//
			this.stage.appendChild(this.layer0);
			this.stage.appendChild(this.layer1);
			this.layer0.innerHTML = this.#values[0].html;
			this.layer1.innerHTML = this.#values[0].html;
			this.layer1.animate(
				[{opacity: 0}],
				{delay:0,duration:1, easing:'linear',fill:'forwards', },
			);
			this.#initThumbnail();
			this.#initSwipe();
			this.#thumbnailOn();
			this.#autoSlide();
		}
		#shuffle(array) {
			for (let i = array.length - 1; i > 0; i--) {
				const j = Math.floor(Math.random() * (i + 1));
				[array[i], array[j]] = [array[j], array[i]];
			}
			return array;
		}
		#initThumbnail() {
			this.#values.map((x,index) => {
				const div = document.createElement('div');
				div.addEventListener('click',() => {
					if (this.#isBusy) {
						return;
					}
					this.#slideAction(index);
				});
				div.innerHTML = x.thumbnail;
				this.switchPanelThumbnail.appendChild(div);
			});
		}
		#initSwipe() {
			this.layer1.addEventListener('click', (e) => { e.preventDefault();});
			this.layer1.addEventListener('mousedown', (e) => { this.#swipeStart(e.clientX); });
			this.layer1.addEventListener('mouseup', (e) => { this.#swipeEnd(e.clientX); });
			this.layer1.addEventListener('touchstart', (e) => { this.#swipeStart(e.touches[0].clientX); });
			this.layer1.addEventListener('touchend', (e) => { this.#swipeEnd(e.changedTouches[0].clientX); });
		}
		#swipeStart(positionX) {
			if (this.#isBusy) {
				return;
			}
			this.#swipeStartX = positionX;
			this.layer1.style.cursor = 'grabbing';
			this.#isSwiping = true;
		}
		#swipeEnd(positionX) {
			if (this.#isSwiping == false) {
				return;
			}
			if (this.#swipeStartX - positionX > this.swipeShreshold) {
				this.#slideAction(this.#withinRange(this.#valueIndex + 1));
			} else if (this.#swipeStartX - positionX < -this.swipeShreshold) {
				this.#slideDirection = -1;
				this.#slideAction(this.#withinRange(this.#valueIndex - 1));
			} else {
				if (this.#values[this.#valueIndex].link) {
					if (this.#values[this.#valueIndex].external) {
						window.open(this.#values[this.#valueIndex].link, '_blank');
					} else {
						window.location.href = this.#values[this.#valueIndex].link;
					}
					return;
				}
			}
			this.layer1.style.cursor = '';
			this.#isSwiping = false;
		}
		#slideForward() {
			if (this.#isBusy) {
				return;
			}
			this.#isBusy = true;
			this.#thumbnailOn();
			this.layer1.innerHTML = this.#values[this.#valueIndex].html;
			this.layer1.animate(
				[
					{opacity: 0, transform: 'translateX(' + (this.slideWidth * this.#slideDirection) + 'px)'},
					{opacity: 1, transform: 'translateX(0px)'},
				],
				{delay:0,duration:this.slideTime, easing:'ease-out',fill:'forwards', },
			);
			setTimeout(() => {
				this.layer0.innerHTML = this.#values[this.#valueIndex].html;
				this.layer1.animate(
					[{opacity: 0}],
					{delay:100,duration:1, easing:'linear',fill:'forwards', },
				);
				this.#slideDirection = 1;
				setTimeout(() => {
					this.#isBusy = false;
				},100);
			},this.slideTime + 100);
		}
		#autoSlide() {
			this.#loopTimeoutId = setTimeout(() => {
				if (this.#pausePlayFlag && this.#focusFlag) {
					this.#slideAction();
				} else {
					this.#autoSlide();
				}
			}, this.imageChangeInterval - this.slideTime);
		}
		#slideAction(num = this.#valueIndex + 1) {
			clearTimeout(this.#loopTimeoutId);
			this.#valueIndex = this.#withinRange(num);
			this.#slideForward();
			this.#autoSlide();
		}
		#thumbnailOn() {
			const divs = this.switchPanelThumbnail.querySelectorAll('div');
			divs.forEach((elm) => elm.classList.remove('on'));
			divs[this.#valueIndex].classList.add('on');
		}
		#withinRange(nextNumber) {
			const num = (nextNumber >= 0) ? nextNumber : this.#values.length - 1;
			return num % this.#values.length;
		}
	}
	//
	new SwitchImage(
		[
			{
				'link': '',
				'external': false,
				'html': '<picture><source srcset="./image/panel01b.webp" media="(width < 700px)"><img src="./image/panel01.webp" draggable="false"></picture>',
				'thumbnail': '<picture><img src="./image/thumb01.webp" draggable="false"></picture>',
			},
			{
				'link': '',
				'external': false,
				'html': '<picture><source srcset="./image/panel02b.webp" media="(width < 700px)"><img src="./image/panel02.webp" draggable="false"></picture>',
				'thumbnail': '<picture><img src="./image/thumb02.webp" draggable="false"></picture>',
			},
			{
				'link': '',
				'external': false,
				'html': '<picture><source srcset="./image/panel03b.webp" media="(width < 700px)"><img src="./image/panel03.webp" draggable="false"></picture>',
				'thumbnail': '<picture><img src="./image/thumb03.webp" draggable="false"></picture>',
			},
			{
				'link': '',
				'external': false,
				'html': '<picture><source srcset="./image/panel04b.webp" media="(width < 700px)"><img src="./image/panel04.webp" draggable="false"></picture>',
				'thumbnail': '<picture><img src="./image/thumb04.webp" draggable="false"></picture>',
			},
			{
				'link': '',
				'external': false,
				'html': '<picture><source srcset="./image/panel05b.webp" media="(width < 700px)"><img src="./image/panel05.webp" draggable="false"></picture>',
				'thumbnail': '<picture><img src="./image/thumb05.webp" draggable="false"></picture>',
			},
			{
				'link': '',
				'external': false,
				'html': '<picture><source srcset="./image/panel06b.webp" media="(width < 700px)"><img src="./image/panel06.webp" draggable="false"></picture>',
				'thumbnail': '<picture><img src="./image/thumb06.webp" draggable="false"></picture>',
			},
		]
	);
})();