A brief analysis of several methods of setting centered images in css

In web design, pictures are a very important element and are often used as an important part of page layout. So, when setting the position of the image display, how to achieve the centered display of the image through CSS? This article will introduce you to the method of setting a centered image in CSS.

1. Set background-image in div

Through background-image, we can achieve the simplest image background setting. First, in HTML, we define a div element and set a unique ID for it:

<div id="img_div"></div>

Then, in CSS, we use the following code to set the background image and set the background-position attribute to center , you can achieve centered display:

#img_div {
  background-image: url("image.jpg");
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
}

Among them, the background-size attribute is set to cover to ensure that the image can be scaled proportionally to the same width and height as the container when displayed.

2. Use position and margin to center the image

For the image element itself, we can achieve centered display by setting its position attribute and margin attribute. First, in HTML, we define an img element and set a unique ID:

<img id="img_elem" src="image.jpg" />

Then, in CSS, we can set its position to absolute, and then adjust its margin value to achieve Centered display:

#img_elem {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

Among them, set the left and top attributes to 50% to position the element to the center of the parent container, and the translate() function of the transform attribute can move the element to its own width and height. Half position to achieve centered display.

3. Use flex layout to center the image

Flex layout is one of the important features in CSS3, which can easily implement the layout of elements. Among them, you can achieve horizontal and vertical center alignment of child elements in the container by setting the justify-content and align-items properties of the flex container. Next, let’s take a look at how to center the image.

First, in HTML, we define a div element and set a unique ID:

<div id="img_div">
  <img src="image.jpg" />
</div>

Then, in CSS, we set the div element as a flex container and set justify If the -content and align-items attributes are set to center, the image can be displayed in the center:

#img_div {
  display: flex;
  justify-content: center; /* 水平居中对齐 */
  align-items: center; /* 垂直居中对齐 */
}

In this way, after setting these attributes of the div element where the image is located, its sub-element img can automatically be displayed in the center.

Summary

The above are several ways to set a centered image in CSS. Among them, the methods of using background-image and position margin are relatively simple, while using flex layout can handle the layout of child elements more conveniently. Different methods are suitable for different scenarios. Developers can choose the method that suits them according to the actual situation and use it flexibly.

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