将 div 元素调整为其背景图像大小 [英] Resize a div element to its background image size

问题描述

是否可以使 <div> 适应其背景图像?我的意思是保持宽度和高度的比例.

Is it possible to make a <div> adapt to its background image? I mean to maintain the proportions width and height.

澄清:

• div 改变宽度.(这是一种响应式设计)

• The div change the width. (it is a responsive design)

我不是说让背景适应div.这可以通过 background-size 实现.但我要问的是方法:在背景中有一个图像，让 div 父级适应该图像，无论其大小是多少.

I do not mean to make the background adapt to the div. This is possible with background-size. But what I am asking is the way round: to have a image in the background and make the div parent adapt to that image whatever its size is.

我知道如果我将图像放在 html 中，而不是放在背景中，我可以做类似的事情.但在这种情况下，我无法更改不同设备尺寸的图像.所以我要求将图像放在背景中以便能够使用 CSS 更改它.

I know that I can do something similar if I put the image in the html, and not in the background. But in this case, I could not change the image for different device sizes. So I am asking to put the image in background to be able to change it with CSS.

在我给出的示例中，我可以使图像适应宽度，但与高度存在差距.当图像改变它的大小时，我可以让 div 也适应图像的高度吗?换一种方式问:在响应式环境中，带图片背景的div能否在不留空白的情况下改变大小?

In the example I give, I can make the image adapt to the width but I get a gap with the height. Can I make the div adapt to the height too of the image , as the image changes its size? Asked in another way: In a responsive environment, can a div with an image background, change in size without leaving empty spaces ?

这里是示例.

CSS:

#image {
    margin:0px auto; 
    width:90%;
    max-width:512px;
    height:512px; /* I need to give heigt to make it visible? */

    background-image:url('http://www.w3.org/html/logo/downloads/HTML5_Logo_512.png');
    background-repeat:no-repeat;
    background-size:100%;
    background-color:yellow;/*just to make visible the gap in the height*/
}

HTML:

<div id="image"></div>

推荐答案

不，不可能让 div 适应它的背景图像.

No it is NOT possible to adapt a div to it's background image.

因为它是无意义的"

是这样的:

一个 div 的大小是由它的内容"决定的，或者它的尺寸是专门设置的.由于 background-image 不属于这些类别中的任何一个，您可以看到这是不可能的.

A div's size is determined by its "content", or if its dimensions are SPECIFICALLY set. Since the background-image does not fall into any of these categories, you can see that it's impossible.

你可以这样做:

<div class="image-controlled">
  <img>...</img>
  <div class="content">...</div>
</div>

CSS

 .image-controlled {
   position: relative; 
   overflow: hidden <-- optional, if you want to cut off .content which overflows the image boundaries
 }
 .content {
   position: absolute;
   top: 0; left: 0; <-- position of the content as it should be (normally)
 }

div 现在将是图像的大小，并且 .content 将显示在它上面.

The div will now be the size of the image, and the .content will be shown over it.

另请注意，.content div 可以按出现顺序位于 的上方或下方，但效果相同.但是，如果你也对 img 元素应用 position 属性，那么你需要设置 的 z-index.content 大于 <img>

Also note that the .content div can come above or below the <img> in order of appearance, but the effect would be the same. But, if you apply a position property on the img element too, then you'll need to set the z-index of .content greater than that of <img>

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