How to use Layui to implement image cropping and zooming functions

How to use Layui to implement image cropping and scaling functions

Layui is a lightweight front-end framework that provides rich UI components and convenient development interfaces , allowing developers to quickly build beautiful and powerful front-end pages. The image cropping and zooming functions are one of the functions that are often needed in many projects. In this article, we will introduce how to use Layui to implement these two functions and provide specific code examples.

1. Image cropping function implementation

When implementing the image cropping function, we can use one of Layui's components - the image cropper (upload in the Layui-Extend library component attribute of the plug-in).
First, we need to introduce the necessary resource files into the page:

<link rel="stylesheet" type="text/css" href="layui/css/layui.css">
<script src="layui/layui.js"></script>

Then, we can create a clipping container:

<div class="layui-upload-drag" id="uploadContainer">
  <i class="layui-icon">&#xe67c;</i>
  <p>点击上传，或将文件拖拽到此处</p>
</div>

Next, initialize the clipper in the JavaScript code and Set relevant parameters:

layui.use('upload', function() {
  var upload = layui.upload;
  
  upload.render({
    elem: '#uploadContainer',
    url: 'upload.php',
    done: function(res) {
      // 上传成功后的回调函数
      var imageUrl = res.data.url;
      
      // 初始化图片剪裁器
      layui.use('imageCropper', function() {
        var imageCropper = layui.imageCropper;
        
        var cropper = new imageCropper('#uploadContainer', {
          saveW: 300, // 保存宽度，默认为裁剪框的宽度
          saveH: 200, // 保存高度，默认为裁剪框的高度
          areaSelect: [70, 70, 220, 220], // 默认裁剪框位置，[x, y, w, h]
          imgSrc: imageUrl, // 图片地址
          onInit: function() {
            // 初始化完成后的回调函数
            console.log('初始化完成');
          },
          onCrop: function(res) {
            // 裁剪完成后的回调函数
            console.log('裁剪完成');
            console.log(res);
          }
        });
        
        // 手动启动裁剪器
        cropper.start();
      });
    }
  });
});

In the above code, we used the upload.render method to bind the clipper to the uploadContainer container, and set the callback function. In the callback function, we initialize the imageCropper object and set parameters such as the width, height, position, and image address of the cropping box. Relevant logic can be added in the onInit and onCrop callback functions.

2. Image scaling function implementation

To implement the image scaling function, we can use Layui's image viewer (photos parameter of the layer plug-in in the Layui-Extend library).
First of all, we also need to introduce the necessary resource files into the page.

Then, we can create an image display container:

<div class="layui-carousel">
  <div carousel-item="" id="layerPhotos">
    <a href="image1.jpg" title="图片1" data-index="0"><img  src="/static/imghwm/default1.png"  data-src="image1.jpg"  class="lazy" alt="How to use Layui to implement image cropping and zooming functions" ></a>
    <a href="image2.jpg" title="图片2" data-index="1"><img  src="/static/imghwm/default1.png"  data-src="image2.jpg"  class="lazy" alt="How to use Layui to implement image cropping and zooming functions" ></a>
    <a href="image3.jpg" title="图片3" data-index="2"><img  src="/static/imghwm/default1.png"  data-src="image3.jpg"  class="lazy" alt="How to use Layui to implement image cropping and zooming functions" ></a>
  </div>
</div>

Next, initialize the image viewer in JavaScript code and set related parameters:

layui.use('layer', function() {
  var layer = layui.layer;
  
  layer.photos({
    photos: '#layerPhotos',
    anim: 5 // 弹出图片动画类型
  });
});

In the above code , the layer.photos method will add the image to the viewer based on the given container selector, and set the animation effect when the image pops up.

Through the above code examples, we can use Layui to easily implement image cropping and zooming functions. Hope this article can help you!

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