Bootstrap 4 - 影像



描述

Bootstrap 4 使用<img>標籤提供對影像的支援。它提供了三個類,可用於對影像應用一些簡單的樣式。

  • .img-rounded - 使用.rounded類可以使影像具有圓角。

  • .img-circle - 使用.rounded-circle類可以使影像成為圓形。

  • .img-thumbnail - 使用.img-thumbnail類可以使影像成為縮圖(帶1畫素圓角邊框)。

以下示例演示了上述類對影像進行樣式設定的使用方法:

示例

<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = "stylesheet" 
         href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" 
         crossorigin = "anonymous">
      
      <title>Bootstrap 4 Example</title>
   </head>
   
   <body>
      <div class = "container">
         <h2>Rounded Corners Image</h2>
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg" 
            class = "rounded" alt = "Rounded Image" width = "200" height = "200"> 
         
         <p></p>
         <h2>Circle Image</h2>
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg" 
            class = "rounded-circle" alt = "Rounded Image" width = "200" height = "200">
         
         <p></p>
         <h2>Thumbnail Image</h2>
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg"
            class = "img-thumbnail" alt = "Rounded Image" width = "200" height = "200">
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js" 
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它將產生以下結果:

輸出

對齊影像

可以使用.float-left類將影像移動到左側,使用.float-right類將影像移動到右側。

以下示例演示了影像的對齊方式:

示例

<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = "stylesheet" 
         href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" 
         crossorigin = "anonymous">
      
      <title>Bootstrap 4 Example</title>
   </head>
   
   <body>
      <div class = "container">
         <h2>Aligning Images</h2>
         <br>
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg" 
            class = "float-left" alt = "Left Image" width = "200" height = "200"> 
         
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg" 
            class = "float-right" alt = "Right Image" width = "200" height = "200">
            
         <p></p>
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js" 
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它將產生以下結果:

輸出

居中影像

您可以使用.mx-auto(margin:auto)和.d-block(display:block)類將影像置於中心。

以下示例顯示了將影像置於中心:

示例

<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = "stylesheet" 
         href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" 
         crossorigin = "anonymous">
      
      <title>Bootstrap 4 Example</title>
   </head>
   
   <body>
      <div class = "container">
         <h2>Centered Image</h2>
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg" 
            class = "mx-auto d-block" alt = "Center Image" width = "200" height = "200">
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js" 
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它將產生以下結果:

輸出

響應式影像

您可以使用.img-fluid類(為影像提供max-width: 100%;height: auto;)建立響應式影像(自動調整以適應跨裝置螢幕的大小)。

以下示例演示了在文件中顯示響應式影像:

示例

<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = "stylesheet" 
         href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" 
         crossorigin = "anonymous">
      
      <title>Bootstrap 4 Example</title>
   </head>
   <body>
      <div class="container">
         <h2>Responsive Image</h2>
         <img src = "https://tutorialspoint.tw/bootstrap/images/64.jpg" 
            class = "img-fluid" alt = "Responsive Image" width = "200" height = "200">
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js" 
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它將產生以下結果:

輸出

bootstrap4_content.htm
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