Detailed explanation of the application of CSS Flex elastic layout in responsive image display

Detailed explanation of the application of CSS Flex elastic layout in responsive image display

In the past, when we displayed images on web pages, a problem we often encountered was how to use Images display well across different screen sizes. The traditional CSS layout method cannot solve this problem well, and CSS Flex elastic layout is an effective solution. This article will introduce in detail the application of CSS Flex elastic layout in responsive image display and provide specific code examples.

1. What is CSS Flex Flexible Layout

CSS Flex Flexible Layout is a new feature in CSS3, which allows elements in a container to automatically adjust their size and position under different screen sizes. . Flex layout consists of a series of containers and items. The container is the parent element and the items are the child elements. By setting different properties for containers and items, we can achieve flexible layout effects.

2. Basic principles of Flex elastic layout

When using Flex layout, we need to set the display attribute of the container to flex or inline-flex. The elements within the container will automatically become items and will be arranged according to certain rules by default.

Flex layout is based on two concepts: main axis (main axis) and cross axis (cross axis). The main axis is the main direction of the Flex container, and items are arranged along the main axis by default. The cross axis is the axis perpendicular to the main axis.

By setting different properties, you can control the position, size and arrangement of items on the main axis and cross axis. Commonly used attributes are:

1. flex-direction: Set the direction of the main axis. The default value is row (from left to right), but it can also be row-reverse (from right to left), column (from top to bottom) and column-reverse (bottom to top).
2. flex-wrap: Set whether to allow line wrapping of items. The default value is nowrap, which means no line wrapping. It can also be wrap (line wrapping) and wrap-reverse (reverse line wrapping).
3. justify-content: Controls the alignment of the item on the main axis. The default value is flex-start (starting point alignment), it can also be flex-end (end-point alignment), center (centered alignment), space-between (justified, equal spacing between items) and space-around (equal spacing on both sides of each item).
4. align-items: Control the alignment of items on the cross axis. The default value is stretch (stretch to fill the height of the container). It can also be flex-start (alignment from the starting point) or flex-end (alignment from the end point). ), center (center alignment) and baseline (baseline alignment).
5. align-self: Controls the alignment of a single item on the cross axis. The default value is auto (inherits the align-items value of the parent element), and can also be flex-start, flex-end, center and baseline. .

3. Responsive Image Display Example

The following is a simple responsive image display example, we will use Flex layout to implement it.

HTML code:

<div class="container">
  <div class="item">
    <img src="image1.jpg" alt="Image 1">
  </div>
  <div class="item">
    <img src="image2.jpg" alt="Image 2">
  </div>
  <div class="item">
    <img src="image3.jpg" alt="Image 3">
  </div>
</div>

CSS code:

.container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
}

.item {
  flex: 1 0 30%;
  margin-bottom: 20px;
}

.item img {
  width: 100%;
  height: auto;
}

In this example, we first set .container to flex layout, and then set flex-wrap to wrap, like this Items wrap automatically when they exceed the width of the container. We also set justify-content to space-between, which will equal space between items on the main axis.

.item is the style of the item. We set it to flex: 1 0 30%, so that the item will automatically adjust its size according to the remaining space, placing 3 items in each row. We also set margin-bottom to 20px to add some space between items.

Finally, we set the width of .item img to 100% and the height automatically adjusts. This way the image will automatically scale in different screen sizes.

Through this simple example, we can see that Flex layout can easily implement responsive image display. By setting different properties, we can easily control the arrangement and size of images on different screen sizes.

Conclusion:

CSS Flex elastic layout is a powerful responsive layout solution suitable for various layout needs. In responsive image display, we can easily control the arrangement and size of images by using Flex layout to achieve good display effects. I hope the introduction in this article can be helpful to readers in actual development.

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