如何使整個圖像比較滑塊居中

Question

當我設法移動圖像比較滑塊時，實際的“滑塊”留在了后面。 滑塊 JS 代碼來自https://www.w3schools.com/howto/howto_js_image_comparison.asp

並且可以在那里輕松檢查，但我也會在這里粘貼代碼。 我試圖用 Css 網格移動滑塊，但如前所述，滑塊圖標不會隨圖像移動。

 function initComparisons() { var x, i; /* Find all elements with an "overlay" class: */ x = document.getElementsByClassName("img-comp-overlay"); for (i = 0; i < x.length; i++) { /* Once for each "overlay" element: pass the "overlay" element as a parameter when executing the compareImages function: */ compareImages(x[i]); } function compareImages(img) { var slider, img, clicked = 0, w, h; /* Get the width and height of the img element */ w = img.offsetWidth; h = img.offsetHeight; /* Set the width of the img element to 50%: */ img.style.width = (w / 2) + "px"; /* Create slider: */ slider = document.createElement("DIV"); slider.setAttribute("class", "img-comp-slider"); /* Insert slider */ img.parentElement.insertBefore(slider, img); /* Position the slider in the middle: */ slider.style.top = (h / 2) - (slider.offsetHeight / 2) + "px"; slider.style.left = (w / 2) - (slider.offsetWidth / 2) + "px"; /* Execute a function when the mouse button is pressed: */ slider.addEventListener("mousedown", slideReady); /* And another function when the mouse button is released: */ window.addEventListener("mouseup", slideFinish); /* Or touched (for touch screens: */ slider.addEventListener("touchstart", slideReady); /* And released (for touch screens: */ window.addEventListener("touchstop", slideFinish); function slideReady(e) { /* Prevent any other actions that may occur when moving over the image: */ e.preventDefault(); /* The slider is now clicked and ready to move: */ clicked = 1; /* Execute a function when the slider is moved: */ window.addEventListener("mousemove", slideMove); window.addEventListener("touchmove", slideMove); } function slideFinish() { /* The slider is no longer clicked: */ clicked = 0; } function slideMove(e) { var pos; /* If the slider is no longer clicked, exit this function: */ if (clicked == 0) return false; /* Get the cursor's x position: */ pos = getCursorPos(e) /* Prevent the slider from being positioned outside the image: */ if (pos < 0) pos = 0; if (pos > w) pos = w; /* Execute a function that will resize the overlay image according to the cursor: */ slide(pos); } function getCursorPos(e) { var a, x = 0; e = e || window.event; /* Get the x positions of the image: */ a = img.getBoundingClientRect(); /* Calculate the cursor's x coordinate, relative to the image: */ x = e.pageX - a.left; /* Consider any page scrolling: */ x = x - window.pageXOffset; return x; } function slide(x) { /* Resize the image: */ img.style.width = x + "px"; /* Position the slider: */ slider.style.left = img.offsetWidth - (slider.offsetWidth / 2) + "px"; } } } initComparisons();

 .img-comp-container { margin:auto; position: relative; height: 100vh; width: 100vw } .img-comp-img { position: absolute; width: auto; height: auto; overflow:hidden; } .img-comp-img img { display: block; vertical-align: middle; } .img-comp-slider { position: absolute; z-index: 9; cursor: ew-resize; width: 0; height: 0; border-style: solid; border-width: 9px 0 9px 14px; border-color: transparent transparent transparent #ffffff; }

 <div class="img-comp-container"> <div class="img-comp-img"> <img src="img/ysl_before.jpg" width="650" height="450"> </div> <div class="img-comp-img img-comp-overlay"> <img src="img/ysl_after.jpg" width="650" height="450"> </div> </div>

Answer 1

我相信這可以解決您正在尋找的問題：

將現有容器包裝在另一個 div（img-comp-outer-container）中，從 img-comp-container 中刪除邊距並將 img-comp-container 的高度/寬度設置為 auto。

然后，您可以設置外部容器的樣式以按照您喜歡的方式對齊組件

<div class="img-comp-outer-container"> <!--new div -->
  <div class="img-comp-container">
    <div class="img-comp-img">
      <img src="img_snow.jpg" width="650" height="450">
    </div>
    <div class="img-comp-img img-comp-overlay">
      <img src="img_forest.jpg" width="650" height="450">
    </div>
  </div>
</div> <!--new div end -->

.img-comp-outer-container {
  /* add your styles to move around component */
}

.img-comp-container {
  /* margin: auto; */
  position: relative;
  height: auto; /* was 100vh */
  width: auto; /* was 100vw */
}

Answer 2

我想把我使用圖像比較滑塊比較的兩個圖像帶到頁面的中心。 W3Schools 上可用的代碼使用滑塊比較圖像，但沒有建議將其居中。 所以我所做的是我放置 div id 框並將所有其他類添加到其中，並將框設置為具有高度和寬度的白色，並將浮動右側添加到 img-comp-container。 您可以相應地更改框的寬度和高度以使滑塊居中。

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
* {box-sizing: border-box;}

.img-comp-container {
  float: right; /*new change*/
  position: relative;
  height: 200px; /*should be the same height as the images*/
}

.img-comp-img {
  position: absolute;
  width: auto;
  height: auto;
  overflow:hidden;
}

.img-comp-img img {
  display:block;
  vertical-align:middle;
}

.img-comp-slider {
  position: absolute;
  z-index:9;
  cursor: ew-resize;
  /*set the appearance of the slider:*/
  width: 40px;
  height: 40px;
  background-color: #2196F3;
  opacity: 0.7;
  border-radius: 50%;
}
/*new change*/
#box{ 
background: white;
width: 150px;
height: 200px;
}
</style>
<script>
function initComparisons() {
  var x, i;
  /*find all elements with an "overlay" class:*/
  x = document.getElementsByClassName("img-comp-overlay");
  for (i = 0; i < x.length; i++) {
    /*once for each "overlay" element:
    pass the "overlay" element as a parameter when executing the compareImages function:*/
    compareImages(x[i]);
  }
  function compareImages(img) {
    var slider, img, clicked = 0, w, h;
    /*get the width and height of the img element*/
    w = img.offsetWidth;
    h = img.offsetHeight;
    /*set the width of the img element to 50%:*/
    img.style.width = (w / 2) + "px";
    /*create slider:*/
    slider = document.createElement("DIV");
    slider.setAttribute("class", "img-comp-slider");
    /*insert slider*/
    img.parentElement.insertBefore(slider, img);
    /*position the slider in the middle:*/
    slider.style.top = (h / 2) - (slider.offsetHeight / 2) + "px";
    slider.style.left = (w / 2) - (slider.offsetWidth / 2) + "px";
    /*execute a function when the mouse button is pressed:*/
    slider.addEventListener("mousedown", slideReady);
    /*and another function when the mouse button is released:*/
    window.addEventListener("mouseup", slideFinish);
    /*or touched (for touch screens:*/
    slider.addEventListener("touchstart", slideReady);
    /*and released (for touch screens:*/
    window.addEventListener("touchend", slideFinish);
    function slideReady(e) {
      /*prevent any other actions that may occur when moving over the image:*/
      e.preventDefault();
      /*the slider is now clicked and ready to move:*/
      clicked = 1;
      /*execute a function when the slider is moved:*/
      window.addEventListener("mousemove", slideMove);
      window.addEventListener("touchmove", slideMove);
    }
    function slideFinish() {
      /*the slider is no longer clicked:*/
      clicked = 0;
    }
    function slideMove(e) {
      var pos;
      /*if the slider is no longer clicked, exit this function:*/
      if (clicked == 0) return false;
      /*get the cursor's x position:*/
      pos = getCursorPos(e)
      /*prevent the slider from being positioned outside the image:*/
      if (pos < 0) pos = 0;
      if (pos > w) pos = w;
      /*execute a function that will resize the overlay image according to the cursor:*/
      slide(pos);
    }
    function getCursorPos(e) {
      var a, x = 0;
      e = e || window.event;
      /*get the x positions of the image:*/
      a = img.getBoundingClientRect();
      /*calculate the cursor's x coordinate, relative to the image:*/
      x = e.pageX - a.left;
      /*consider any page scrolling:*/
      x = x - window.pageXOffset;
      return x;
    }
    function slide(x) {
      /*resize the image:*/
      img.style.width = x + "px";
      /*position the slider:*/
      slider.style.left = img.offsetWidth - (slider.offsetWidth / 2) + "px";
    }
  }
}
</script>
</head>
<body>

<h1>Compare Two Images</h1>

<p>Click and slide the blue slider to compare two images:</p>
<div id="box">/*new change*/
<div class="img-comp-container">
  <div class="img-comp-img">
    <img src="img_snow.jpg" width="300" height="200">
  </div>
  <div class="img-comp-img img-comp-overlay">
    <img src="img_forest.jpg" width="300" height="200">
  </div>
</div>
</div>
<script>
/*Execute a function that will execute an image compare function for each element with the img-comp-overlay class:*/
initComparisons();
</script>

</body>
</html>