Отображение разных изображений в заданный период времени - PullRequest
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Отображение разных изображений в заданный период времени

1 голос
/ 21 марта 2020

У меня есть следующие классы в CSS, которые заставляют меня отображать другое фоновое изображение на странице через некоторое время: 

.image-fader {
 width: 300px;
 height: 300px;
}

.image-fader img {
 position: absolute;
 top: 0px;
 left: 0px;
 animation-name: imagefade;
 animation-timing-function: ease-in-out;
 animation-iteration-count: infinite;
 animation-duration: 8s;
}

@keyframes imagefade {
0% {
opacity: 1;
 }
 17% {
 opacity: 1;
 }
 25% {
 opacity: 0;
 }
 92% {
 opacity: 0;
 }
 100% {
 opacity: 1;
 }
}

.image-fader img:nth-of-type(1) {
animation-delay: 6s;
}
.image-fader img:nth-of-type(2) {
animation-delay: 4s;
}
.image-fader img:nth-of-type(3) {
animation-delay: 2s;
}
.image-fader img:nth-of-type(4) {
animation-delay: 0;
}

Пока у меня есть только этот код CSS, который отображает одно изображение: 

.defaultHero,
.roomsHero {
min-height: calc(100vh - 66px);
background: url("./images/defaultBcg.jpeg") center/cover no-repeat;
display: flex;
align-items: center;
justify-content: center;
}

Компонент «Мой герой» выглядит следующим образом: 

import React from 'react'

export default function Hero({children, hero}) {
return (
<header className={hero}>
    {children}
</header>
)
}

Hero.defaultProps = {
hero: "defaultHero"
};

И я называю его на своей домашней странице следующим образом: 

import React from 'react'
import Hero from "../Components/Hero";
import Banner from "../Components/Banner";
import {Link} from 'react-router-dom';


export default function Home() {
return (
    <Hero>
        <Banner title="Affordable Apartments" subtitle="Family
    Apartments Starting At &#8364;90 per night">
    <Link to= "/rooms" className="btn-primary">
        our apartments
    </Link>
    </Banner>
    </Hero>
  );
 }

}

Как я могу сослаться на класс image-fader на моей домашней странице, чтобы вернуть много фоновых изображений, отображаемых через некоторое время. класс

1 Ответ

0 голосов
/ 21 марта 2020

Ваш код HTML должен быть похож на 

<!DOCTYPE html>
<html>
    <div class="c1" id="slideShowImages">
        <img src="Image/1.jpg">
        <img src="Image/2.jpg">
        <img src="Image/3.jpg">
    </div>
    <script src="slideShow.js"></script>
</html>

Затем создайте файл с именем: slideShow. js и вставьте следующий код: 

window.addEventListener('load', slideShow, false);

function slideShow() {

  /* GLOBALS **********************************************************************************************/

  var globals = {
    slideDelay: 6000, // The time interval between consecutive slides.
    fadeDelay: 55, // The time interval between individual opacity changes. This should always be much smaller than slideDelay.  
    wrapperID: "slideShowImages", // The ID of the <div> element that contains all of the <img> elements to be shown as a slide show.
    buttonID: "slideShowButton", // The ID of the <button> element that toggles the slide show on and off.
    buttonStartText: "Start Slides", // Text used in the slide show toggle button.
    buttonStopText: "Stop Slides", // Text used in the slide show toggle button.    
    wrapperObject: null, // Will contain a reference to the <div> element that contains all of the <img> elements to be shown as a slide show.
    buttonObject: null, // If present, will contain a reference to the <button> element that toggles the slide show on and off. The initial assumption is that there is no such button element (hence the false value).
    slideImages: [], // Will contain all of the slide image objects.
    slideShowID: null, // A setInterval() ID value used to stop the slide show.
    slideShowRunning: true, // Used to record when the slide show is running and when it's not. The slide show is always initially running.    
    slideIndex: 0 // The index of the current slide image.
  }

  /* MAIN *************************************************************************************************/

  initializeGlobals();  

  if ( insufficientSlideShowMarkup() ) {
    return; // Insufficient slide show markup - exit now.
  }

   // Assert: there's at least one slide image.

  if (globals.slideImages.length == 1) {
    return; // The solo slide image is already being displayed - exit now.
  }

  // Assert: there's at least two slide images.

  initializeSlideShowMarkup();

  globals.wrapperObject.addEventListener('click', toggleSlideShow, false); // If the user clicks a slide show image, it toggles the slide show on and off.

  if (globals.buttonObject) {
    globals.buttonObject.addEventListener('click', toggleSlideShow, false); // This callback is used to toggle the slide show on and off.
  } 

  startSlideShow();

  /* FUNCTIONS ********************************************************************************************/

  function initializeGlobals() {   
    globals.wrapperObject = (document.getElementById(globals.wrapperID) ? document.getElementById(globals.wrapperID) : null);
    globals.buttonObject = (document.getElementById(globals.buttonID) ? document.getElementById(globals.buttonID) : null);   

    if (globals.wrapperObject) {
      globals.slideImages = (globals.wrapperObject.querySelectorAll('img') ? globals.wrapperObject.querySelectorAll('img') : []);
    }
  } // initializeGlobals

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function insufficientSlideShowMarkup() {
    if (!globals.wrapperObject) { // There is no wrapper element whose ID is globals.wrapperID - fatal error.
      if (globals.buttonObject) {
        globals.buttonObject.style.display = "none"; // Hide the not needed slide show button element when present.
      }
      return true;
    }

    if (!globals.slideImages.length) { // There needs to be at least one slide <img> element - fatal error.
      if (globals.wrapperObject) {
        globals.wrapperObject.style.display = "none"; // Hide the not needed <div> wrapper element.
      }

      if (globals.buttonObject) {
        globals.buttonObject.style.display = "none"; // Hide the not needed slide show button element.
      }

      return true;
    }

    return false; // The markup expected by this library seems to be present.
  } // insufficientSlideShowMarkup

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function initializeSlideShowMarkup() {  
    var slideWidthMax = maxSlideWidth(); // Returns a value that is always in pixel units.
    var slideHeightMax = maxSlideHeight(); // Returns a value that is always in pixel units.

    globals.wrapperObject.style.position = "relative";
    globals.wrapperObject.style.overflow = "hidden"; // This is just a safety thing.
    globals.wrapperObject.style.width = slideWidthMax + "px";
    globals.wrapperObject.style.height = slideHeightMax + "px";

    var slideCount = globals.slideImages.length;
    for (var i = 0; i < slideCount; i++) { 
      globals.slideImages[i].style.opacity = 0;
      globals.slideImages[i].style.position = "absolute";
      globals.slideImages[i].style.top = (slideHeightMax - globals.slideImages[i].getBoundingClientRect().height) / 2 + "px";   
      globals.slideImages[i].style.left = (slideWidthMax - globals.slideImages[i].getBoundingClientRect().width) / 2 + "px";               
    }

    globals.slideImages[0].style.opacity = 1; // Make the first slide visible.

    if (globals.buttonObject) {
      globals.buttonObject.textContent = globals.buttonStopText;
    }
  } // initializeSlideShowMarkup

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function maxSlideWidth() {
    var maxWidth = 0;
    var maxSlideIndex = 0;
    var slideCount = globals.slideImages.length;

    for (var i = 0; i < slideCount; i++) {
      if (globals.slideImages[i].width > maxWidth) {
        maxWidth = globals.slideImages[i].width; // The width of the widest slide so far.
        maxSlideIndex = i; // The slide with the widest width so far.
      }
    }

    return globals.slideImages[maxSlideIndex].getBoundingClientRect().width; // Account for the image's border, padding, and margin values. Note that getBoundingClientRect() is always in units of pixels.
  } // maxSlideWidth

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function maxSlideHeight() {
    var maxHeight = 0;
    var maxSlideIndex = 0;    
    var slideCount = globals.slideImages.length;

    for (var i = 0; i < slideCount; i++) {
      if (globals.slideImages[i].height > maxHeight) {
        maxHeight = globals.slideImages[i].height; // The height of the tallest slide so far.
        maxSlideIndex = i; // The slide with the tallest height so far.
      }
    }

    return globals.slideImages[maxSlideIndex].getBoundingClientRect().height; // Account for the image's border, padding, and margin values. Note that getBoundingClientRect() is always in units of pixels.
  } // maxSlideHeight

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function startSlideShow() {
    globals.slideShowID = setInterval(transitionSlides, globals.slideDelay);                
  } // startSlideShow

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function haltSlideShow() {
    clearInterval(globals.slideShowID);   
  } // haltSlideShow

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function toggleSlideShow() {
    if (globals.slideShowRunning) {
      haltSlideShow();
      if (globals.buttonObject) { 
        globals.buttonObject.textContent = globals.buttonStartText; 
      }
    }
    else {
      startSlideShow();
      if (globals.buttonObject) { 
        globals.buttonObject.textContent = globals.buttonStopText; 
      }            
    }
    globals.slideShowRunning = !(globals.slideShowRunning);
  } // toggleSlideShow

  // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  function transitionSlides() {
    var currentSlide = globals.slideImages[globals.slideIndex];

    ++(globals.slideIndex);
    if (globals.slideIndex >= globals.slideImages.length) {
      globals.slideIndex = 0;
    }

    var nextSlide = globals.slideImages[globals.slideIndex];

    var currentSlideOpacity = 1; // Fade the current slide out.
    var nextSlideOpacity = 0; // Fade the next slide in.
    var opacityLevelIncrement = 1 / globals.fadeDelay;
    var fadeActiveSlidesID = setInterval(fadeActiveSlides, globals.fadeDelay);

    function fadeActiveSlides() {
      currentSlideOpacity -= opacityLevelIncrement;
      nextSlideOpacity += opacityLevelIncrement;

      // console.log(currentSlideOpacity + nextSlideOpacity); // This should always be very close to 1.

      if (currentSlideOpacity >= 0 && nextSlideOpacity <= 1) {
        currentSlide.style.opacity = currentSlideOpacity;
        nextSlide.style.opacity = nextSlideOpacity; 
      }
      else {
        currentSlide.style.opacity = 0;
        nextSlide.style.opacity = 1; 
        clearInterval(fadeActiveSlidesID);
      }        
    } // fadeActiveSlides
  } // transitionSlides

} // slideShow
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