Question

我尝试过使用同样的方法：
https://www.w3schools.com/css/tryit.asp?filename=tryresponsive_image2

我看到当w3schools我调整大小时，图片也将调整宽度和高度。

就我而言，当我调整相同的代码时。我的图像裁剪到左上角。不是整个图像：

我错过了哪些东西？

JsBIN： http://jsbin.com/doyaseyabu/edit?html,css,output

HTML：

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>About Page template By Adobe Dreamweaver CC</title>
<link href="AboutPageAssets/styles/aboutPageStyle.css" rel="stylesheet" type="text/css">

<!--The following script tag downloads a font from the Adobe Edge Web Fonts server for use within the web page. We recommend that you do not modify it.-->
<script>var __adobewebfontsappname__="dreamweaver"</script><script src="http://use.edgefonts.net/montserrat:n4:default;source-sans-pro:n2:default.js" type="text/javascript"></script>

<script>


function load() {
 var context = document.getElementById('main').getContext("2d");

var img = new Image();
img.src = "http://via.placeholder.com/75x150";
img.onload = function () {

    context.drawImage(img, 250, 0);
}

}
</script>

</head>

<body onload="load();">
<!-- Header content -->
<header>
  <div class="profileLogo"> 
    <!-- Profile logo. Add a img tag in place of <span>. -->
    <p class="logoPlaceholder"><!-- <img src="logoImage.png" alt="sample logo"> --><span>Name :</span></p>
    <p class="logoPlaceholder"><!-- <img src="logoImage.png" alt="sample logo"> --><span>Attempts :</span></p>
    <p class="logoPlaceholder"><!-- <img src="logoImage.png" alt="sample logo"> --><span>Score :</span></p>
  </div>
  <section>
<div class="wrapper">
  <div class="container">
    <div class="canvas-container">

      <canvas id="main" width="500px" height="250px"></canvas>
    </div>
  </div>
</div>
  </section>
  <!-- Links to Social network accounts -->
  <aside class="socialNetworkNavBar">
    <div style="margin-right: 50px;" class="socialNetworkNav"> 
      <!-- Add a Anchor tag with nested img tag here --> 
      <input type="image" src="http://via.placeholder.com/75x75" >

      </div>
    <div id="left" style="margin-right: 50px;" class="socialNetworkNav"> 
      <!-- Add a Anchor tag with nested img tag here --> 
      <input type="image" src="http://via.placeholder.com/75x75" > </div>
    <div id="down" style="margin-right: 50px;" class="socialNetworkNav"> 
      <!-- Add a Anchor tag with nested img tag here --> 
      <input id="right"  type="image" src="http://via.placeholder.com/75x75" >
 </div>

  </aside>
</header>
<!-- content -->

</body>
</html>

CSS：

@charset "utf-8";
/* Global Styles */
#main {
    width:100%;
    background-image:url('http://www.desktopwarehouse.com/wallpapers/christmas-tree-background-852x480.jpg');
}   
body {
    margin-left: auto;
    margin-right: auto;
    width: 92%;
    max-width: 960px;
    padding-left: 2.275%;
    padding-right: 2.275%;
}
/* Header */
header {
    text-align: center;
    display: block;
}
header .profileLogo .logoPlaceholder {
    background-color: white;
    color:black;
    width: 300px;
    text-align: center;
}
header .logoPlaceholder span {
    width: 180px;
    height: 22px;
    font-family: 'Montserrat', sans-serif;
    color: black;
    font-size: 30px;
    font-weight: 700;
    line-height: 53px;
}
header .logoPlaceholder2 span {
    width: 180px;
    height: 22px;
    font-family: 'Montserrat', sans-serif;
    color: black;
    font-size: 30px;
    font-weight: 700;
    line-height: 53px;
}
header .profilePhoto {
    background-color: rgba(237,237,237,1.00);
    width: 259px;
    border-radius: 50%;
    height: 259px;
    clear: both;
}
header .profileHeader h1 {
    font-family: 'Montserrat', sans-serif;
    color: rgba(146,146,146,1.00);
    font-size: 30px;
    font-weight: 700;
    line-height: 24px;
}
header .profileHeader h3 {
    font-family: sans-serif;
    color: rgba(146,146,146,1.00);
    font-size: 16px;
    font-weight: 700;
    line-height: 24px;
}
hr {
    background-color: rgba(208,207,207,1.00);
    height: 1px;
}
header .profileHeader p {
    font-family: sans-serif;
    color: rgba(146,146,146,1.00);
    font-size: 14px;
    font-weight: 400;
    line-height: 1.8;
    overflow-y: auto;
}
header .socialNetworkNavBar {
    text-align: center;
    display: block;
    margin-top: 60px;
    clear: both;
}
header .socialNetworkNavBar .socialNetworkNav {
    border-radius: 50%;
    cursor: pointer;
}
header .socialNetworkNavBar .socialNetworkNav img:hover {
    opacity: 0.5;
}


/* Media query for Mobile devices*/
@media only screen and (min-width : 285px) and (max-width : 480px) {
/* Header */
#main {

width:100%;

}   
header {
    width: 100%;
    float: left;
}
.wrapper {
   display: inline-block;
   width: 100%;
   height: 100%;
}   
header .profileLogo .logoPlaceholder {
    display: inline-block;
    text-align: left;
}
header .profilePhoto {
    display: inline-block;
}
header .profileHeader {
    text-align: center;
    margin-top: 10%;
}
header .profileHeader p {
    text-align: justify;
}
header .socialNetworkNavBar {
    text-align: center;
    display: block;
    margin-top: 60px;

    clear: both;
    margin-bottom: 15%;
}
header .socialNetworkNavBar .socialNetworkNav {
    width: 60px;
    height: 60px;
    display: inline-block;
    margin-right: 23px;
}

}

/* Media Query for Tablets */
@media only screen and (min-width : 481px) and (max-width : 1024px) {
/* Header */
header {
    width: 100%;
    float: none;
}
header .profileLogo .logoPlaceholder {
    display: inline-block;
    font-family: 'Montserrat', sans-serif;
}
header .profilePhoto {
    float: left;
    clear: both;
    margin-right: 3%;
    margin-top: 5%;
}
header .profileHeader {
    text-align: left;
    margin-top: 7%;
}
header .socialNetworkNavBar .socialNetworkNav {
    width: 74px;
    height: 74px;
    display: inline-block;
    margin-right: 23px;
}

}

/* Desktops and laptops  */
@media only screen and (min-width:1025px) {
/* Header */
header .profileLogo .logoPlaceholder {
    float: left;
    margin-bottom: 50px;
}
header .profilePhoto {
    float: left;
    clear: both;
    margin-right: 3%;
}
header .profileHeader {
    text-align: left;
    padding-top: 10%;
}
header .socialNetworkNavBar .socialNetworkNav {
    width: 74px;
    height: 74px;
    display: inline-block;
    margin-right: 23px;
}



.wrapper {
   display: table;
   padding: 0;
   width: 100%;
   height: 100%;
}
.container {
   display: table-cell;
   vertical-align: middle;
}
.canvas-container {
   position: relative;
   max-width: 1024px;
   min-width: 120px;
   margin: 0 auto;
}



}

图片问题： -

在网站上：

在手机上：

Answer 1

您需要为canvas元素（background-size: cover）设置样式#main，因为您没有使用实际的图像元素，但为此设置了背景图像画布。

#main {
    width: 100%;
    background-image: url('http://www.desktopwarehouse.com/wallpapers/christmas-tree-background-852x480.jpg');
    background-size: cover;
}

HTML调整大小问题

1 个答案: