swiper/modules/parallax/parallax.js

import $ from '../../shared/dom.js';
export default function Parallax({
  swiper,
  extendParams,
  on
}) {
  extendParams({
    parallax: {
      enabled: false
    }
  });

  const setTransform = (el, progress) => {
    const {
      rtl
    } = swiper;
    const $el = $(el);
    const rtlFactor = rtl ? -1 : 1;
    const p = $el.attr('data-swiper-parallax') || '0';
    let x = $el.attr('data-swiper-parallax-x');
    let y = $el.attr('data-swiper-parallax-y');
    const scale = $el.attr('data-swiper-parallax-scale');
    const opacity = $el.attr('data-swiper-parallax-opacity');

    if (x || y) {
      x = x || '0';
      y = y || '0';
    } else if (swiper.isHorizontal()) {
      x = p;
      y = '0';
    } else {
      y = p;
      x = '0';
    }

    if (x.indexOf('%') >= 0) {
      x = `${parseInt(x, 10) * progress * rtlFactor}%`;
    } else {
      x = `${x * progress * rtlFactor}px`;
    }

    if (y.indexOf('%') >= 0) {
      y = `${parseInt(y, 10) * progress}%`;
    } else {
      y = `${y * progress}px`;
    }

    if (typeof opacity !== 'undefined' && opacity !== null) {
      const currentOpacity = opacity - (opacity - 1) * (1 - Math.abs(progress));
      $el[0].style.opacity = currentOpacity;
    }

    if (typeof scale === 'undefined' || scale === null) {
      $el.transform(`translate3d(${x}, ${y}, 0px)`);
    } else {
      const currentScale = scale - (scale - 1) * (1 - Math.abs(progress));
      $el.transform(`translate3d(${x}, ${y}, 0px) scale(${currentScale})`);
    }
  };

  const setTranslate = () => {
    const {
      $el,
      slides,
      progress,
      snapGrid
    } = swiper;
    $el.children('[data-swiper-parallax], [data-swiper-parallax-x], [data-swiper-parallax-y], [data-swiper-parallax-opacity], [data-swiper-parallax-scale]').each(el => {
      setTransform(el, progress);
    });
    slides.each((slideEl, slideIndex) => {
      let slideProgress = slideEl.progress;

      if (swiper.params.slidesPerGroup > 1 && swiper.params.slidesPerView !== 'auto') {
        slideProgress += Math.ceil(slideIndex / 2) - progress * (snapGrid.length - 1);
      }

      slideProgress = Math.min(Math.max(slideProgress, -1), 1);
      $(slideEl).find('[data-swiper-parallax], [data-swiper-parallax-x], [data-swiper-parallax-y], [data-swiper-parallax-opacity], [data-swiper-parallax-scale]').each(el => {
        setTransform(el, slideProgress);
      });
    });
  };

  const setTransition = (duration = swiper.params.speed) => {
    const {
      $el
    } = swiper;
    $el.find('[data-swiper-parallax], [data-swiper-parallax-x], [data-swiper-parallax-y], [data-swiper-parallax-opacity], [data-swiper-parallax-scale]').each(parallaxEl => {
      const $parallaxEl = $(parallaxEl);
      let parallaxDuration = parseInt($parallaxEl.attr('data-swiper-parallax-duration'), 10) || duration;
      if (duration === 0) parallaxDuration = 0;
      $parallaxEl.transition(parallaxDuration);
    });
  };

  on('beforeInit', () => {
    if (!swiper.params.parallax.enabled) return;
    swiper.params.watchSlidesProgress = true;
    swiper.originalParams.watchSlidesProgress = true;
  });
  on('init', () => {
    if (!swiper.params.parallax.enabled) return;
    setTranslate();
  });
  on('setTranslate', () => {
    if (!swiper.params.parallax.enabled) return;
    setTranslate();
  });
  on('setTransition', (_swiper, duration) => {
    if (!swiper.params.parallax.enabled) return;
    setTransition(duration);
  });
}