jquery modify transform

When we need to modify the style of page elements, jQuery is a common solution. As for the modification of the transform attribute, it is somewhat different from other style attributes and requires special processing. This article will introduce how to use jQuery to modify the transform attribute.

First, we need to understand the transform attribute. The transform attribute is used to perform rotation, scaling, translation and other transformations on elements. Common transformation functions include translate, rotate, scale, etc. You can use combination methods to achieve more complex transformation effects.

We can define the transform attribute of the element through CSS, for example, to rotate an element 45 degrees:

div {
  transform: rotate(45deg);
}

In this way, the element can be rotated 45 degrees. Of course, we can also use jQuery to modify this property. First, we need to know how to use jQuery to get the transform attribute value of the element:

// 获取transform属性值
var transformValue = $('div').css('transform');

Here we will get a string representing the transform attribute value of the element. For example, when we use the previous CSS code to rotate a div element 45 degrees, calling the above code will get the following result:

matrix(0.7071, 0.7071, -0.7071, 0.7071, 0, 0)

This string represents a matrix used to describe the transformation effect of the element. But it is difficult for us to understand the transformation effect of elements directly through this matrix, so we need a more friendly way to express it. Below, we'll cover how to transform a matrix into a more readable way.

First, we need to decompose the matrix into a single transformation function to describe the transformation effect of the elements. We can use a JavaScript library [1] to implement this function:

// 分解矩阵成变换函数
function decomposeMatrix(matrix) {
  // 用来存储变换函数
  var transform = {};
  // 计算平移和旋转
  var a = matrix[0], b = matrix[1], c = matrix[2], d = matrix[3];
  var scaleX = Math.sqrt(a*a + b*b);
  var scaleY = Math.sqrt(c*c + d*d);
  transform.translateX = a > 0 ? matrix[4] : matrix[4] + scaleX;
  transform.translateY = d > 0 ? matrix[5] : matrix[5] + scaleY;
  transform.rotate = Math.atan2(b, a) * (180/Math.PI);
  // 计算缩放
  transform.scaleX = scaleX;
  transform.scaleY = scaleY;
  // 返回变换函数对象
  return transform;
}

// 示例：
var matrix = [0.7071, 0.7071, -0.7071, 0.7071, 0, 0];
var transform = decomposeMatrix(matrix);
console.log(transform);
// 输出：{translateX: 0, translateY: 0, rotate: 45, scaleX: 1, scaleY: 1}

This function decomposes the matrix into a set of transformation functions, which is easier to understand. For example, translateX and translateY represent the translation distance of the element, while rotate represents the rotation angle of the element.

At the same time, we can also combine these transformation functions to generate a new transform attribute value. Below, we will introduce how to use jQuery to achieve this function.

First of all, in order to easily modify the transform attribute, we can encapsulate it into a jQuery plug-in:

// 封装transform函数
$.fn.transform = function(transforms) {
  var props = '';
  $.each(transforms, function(key, value) {
    props += key + '(' + value + ') ';
  });
  return this.css('transform', props.trim());
};

The function of this plug-in is to combine the incoming transformation function objects into a new transform attribute value and set to the current element. For example, to translate an element 20 pixels to the right, you can call it like this:

$('div').transform({translateX: '20px'});

This will translate the element 20 pixels. Similarly, we can also achieve other effects on elements by modifying other transformation functions.

In addition, we can also use this plug-in to get the transform attribute value of the element, for example:

var transforms = $('div').transform();
console.log(transforms);
// 输出：{translateX: 20, translateY: 0, rotate: 45, scaleX: 1, scaleY: 1}

In this way, we can get a transformation function object that contains all the transformation effects of the element.

In summary, by using the transform attribute of jQuery and CSS, we can achieve transformation effects such as rotation, scaling, and translation of page elements. When you need to modify the transform attribute, you can use the above techniques to achieve more convenient and flexible operations by encapsulating plug-ins.

The above is the detailed content of jquery modify transform. For more information, please follow other related articles on the PHP Chinese website!