CSS 伪类 - :picture-in-picture

CSS :picture-in-picture 伪类将视频弹出到一个小浮动窗口中，该窗口始终位于其他窗口之上，以便用户在执行其他操作时可以继续观看。

语法

:picture-in-picture {
   /* ... */
}

:picture-in-picture 伪类不受 Firefox 和 Safari 浏览器的支持。

CSS :picture-in-picture 示例

以下示例演示了如何为视频元素启用画中画 (PiP) 模式，并允许用户使用复选框输入打开和关闭它 -

<html>
<head>
<style>
   video {
      max-width: 50%;
      border: 1px solid;
   }
   .container {
      display: flex;
      align-items: center;
      margin-top: 20px;
   }
   .heading {
      margin-right: 10px;
   }
   .hidden {
      display: none;
   }
   :picture-in-picture {
      border: 3px solid red;
   }
</style>
</head>
<body>
   <video id="boat_video" controls src="images/boat_video.mp4"></video>
   <div class="container">
      <label class="heading">Picture-in-Picture Mode:</label>   <!-- Label for the Picture-in-Picture mode -->
      <input type="checkbox" id="pipToggle" class="hidden">    <!-- Checkbox input for toggling Picture-in-Picture mode -->
      <span id="pipStatus" class="hidden">Off</span>           <!-- Display the Picture-in-Picture status (initially hidden) -->
   </div>
   <script>
      // Get references to HTML elements
      const videoInPIP = document.getElementById('boat_video');
      const pipToggle = document.getElementById('pipToggle');
      const pipStatus = document.getElementById('pipStatus');

      // If PIP is supported, remove the 'hidden' class from the PIP toggle and status elements
      if ('pictureInPictureEnabled' in document) {
         pipToggle.classList.remove('hidden');          // Show the toggle
         pipToggle.disabled = false;                    // Enable the toggle
         pipStatus.classList.remove('hidden');          // Show the status

      // Add an event listener to the PIP toggle checkbox to handle PIP mode switching
      pipToggle.addEventListener('change', switchToPIP);
      }

      // Function to switch between Picture-in-Picture mode and normal mode
      function switchToPIP() {                   // This function will be called when the user toggles the PIP checkbox
         // Function to change the Picture-in-Picture state
         function changePictureInPictureState() {               
            if (document.pictureInPictureElement) {              // Check if the document is already in PIP mode
               document.exitPictureInPicture().catch(() => {});  // it is, exit PIP mode
            } else {
               videoInPIP.requestPictureInPicture().catch(() => {});  // If it's not, request PIP mode for the video element
            }
         }

         changePictureInPictureState(); // Call the function to change the state
      }

         // Event listener to detect when the video enters PIP mode
      videoInPIP.addEventListener('enterpictureinpicture', () => {
         pipStatus.textContent = 'On';   // Update the PIP status text to 'On'
      })

      // Event listener to detect when the video leaves PIP mode
      videoInPIP.addEventListener('leavepictureinpicture', () => {
         pipStatus.textContent = 'Off';    // Update the PIP status text to 'Off'
      });
   </script>
</body>
</html>

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