swiper/modules/effect-coverflow/effect-coverflow.js

import createShadow from '../../shared/create-shadow.js';
import effectInit from '../../shared/effect-init.js';
import effectTarget from '../../shared/effect-target.js';
export default function EffectCoverflow({
  swiper,
  extendParams,
  on
}) {
  extendParams({
    coverflowEffect: {
      rotate: 50,
      stretch: 0,
      depth: 100,
      scale: 1,
      modifier: 1,
      slideShadows: true,
      transformEl: null
    }
  });

  const setTranslate = () => {
    const {
      width: swiperWidth,
      height: swiperHeight,
      slides,
      slidesSizesGrid
    } = swiper;
    const params = swiper.params.coverflowEffect;
    const isHorizontal = swiper.isHorizontal();
    const transform = swiper.translate;
    const center = isHorizontal ? -transform + swiperWidth / 2 : -transform + swiperHeight / 2;
    const rotate = isHorizontal ? params.rotate : -params.rotate;
    const translate = params.depth; // Each slide offset from center

    for (let i = 0, length = slides.length; i < length; i += 1) {
      const $slideEl = slides.eq(i);
      const slideSize = slidesSizesGrid[i];
      const slideOffset = $slideEl[0].swiperSlideOffset;
      const centerOffset = (center - slideOffset - slideSize / 2) / slideSize;
      const offsetMultiplier = typeof params.modifier === 'function' ? params.modifier(centerOffset) : centerOffset * params.modifier;
      let rotateY = isHorizontal ? rotate * offsetMultiplier : 0;
      let rotateX = isHorizontal ? 0 : rotate * offsetMultiplier; // var rotateZ = 0

      let translateZ = -translate * Math.abs(offsetMultiplier);
      let stretch = params.stretch; // Allow percentage to make a relative stretch for responsive sliders

      if (typeof stretch === 'string' && stretch.indexOf('%') !== -1) {
        stretch = parseFloat(params.stretch) / 100 * slideSize;
      }

      let translateY = isHorizontal ? 0 : stretch * offsetMultiplier;
      let translateX = isHorizontal ? stretch * offsetMultiplier : 0;
      let scale = 1 - (1 - params.scale) * Math.abs(offsetMultiplier); // Fix for ultra small values

      if (Math.abs(translateX) < 0.001) translateX = 0;
      if (Math.abs(translateY) < 0.001) translateY = 0;
      if (Math.abs(translateZ) < 0.001) translateZ = 0;
      if (Math.abs(rotateY) < 0.001) rotateY = 0;
      if (Math.abs(rotateX) < 0.001) rotateX = 0;
      if (Math.abs(scale) < 0.001) scale = 0;
      const slideTransform = `translate3d(${translateX}px,${translateY}px,${translateZ}px)  rotateX(${rotateX}deg) rotateY(${rotateY}deg) scale(${scale})`;
      const $targetEl = effectTarget(params, $slideEl);
      $targetEl.transform(slideTransform);
      $slideEl[0].style.zIndex = -Math.abs(Math.round(offsetMultiplier)) + 1;

      if (params.slideShadows) {
        // Set shadows
        let $shadowBeforeEl = isHorizontal ? $slideEl.find('.swiper-slide-shadow-left') : $slideEl.find('.swiper-slide-shadow-top');
        let $shadowAfterEl = isHorizontal ? $slideEl.find('.swiper-slide-shadow-right') : $slideEl.find('.swiper-slide-shadow-bottom');

        if ($shadowBeforeEl.length === 0) {
          $shadowBeforeEl = createShadow(params, $slideEl, isHorizontal ? 'left' : 'top');
        }

        if ($shadowAfterEl.length === 0) {
          $shadowAfterEl = createShadow(params, $slideEl, isHorizontal ? 'right' : 'bottom');
        }

        if ($shadowBeforeEl.length) $shadowBeforeEl[0].style.opacity = offsetMultiplier > 0 ? offsetMultiplier : 0;
        if ($shadowAfterEl.length) $shadowAfterEl[0].style.opacity = -offsetMultiplier > 0 ? -offsetMultiplier : 0;
      }
    }
  };

  const setTransition = duration => {
    const {
      transformEl
    } = swiper.params.coverflowEffect;
    const $transitionElements = transformEl ? swiper.slides.find(transformEl) : swiper.slides;
    $transitionElements.transition(duration).find('.swiper-slide-shadow-top, .swiper-slide-shadow-right, .swiper-slide-shadow-bottom, .swiper-slide-shadow-left').transition(duration);
  };

  effectInit({
    effect: 'coverflow',
    swiper,
    on,
    setTranslate,
    setTransition,
    perspective: () => true,
    overwriteParams: () => ({
      watchSlidesProgress: true
    })
  });
}