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Implementing moving animation effects based on HTML5 gyroscope

php中世界最好的语言Original: 2018-03-26 17:37:418776browse

This time I will bring you the moving animation effect based on the HTML5 gyroscope. What are the precautions for realizing the moving animation effect based on the HTML5 gyroscope. The following is a practical case, let's take a look.

When I was using the Ofo Little Yellow Car App recently, I found that when I swiped the swipe below, it turned into a little yellow man with moving eyes. I thought it was quite interesting. Here I use HTML5 to imitate the effect.

ofo eye effect

##Effect analysis

It is not difficult to see from the effect that it is achieved using gyroscope events.

Let’s first look at some concepts of gyroscope events in HTML5.

The gyroscope event is

deviceorientation. Here we mainly get the alpha, beta, gamma in the event.

aplha

The angle of rotation around the Z-axis when the mobile device is placed horizontally, ranging from 0 to 360 degrees.

beta

The angle of rotation around the X-axis when the mobile device is placed horizontally, ranging from -180 degrees to 180 degrees.

gamma

The angle of rotation around the Z-axis when the mobile device is placed horizontally, the value is -90 degrees to 90 degrees.

Here, only beta and gamma need to be used.

Unzip the apk and get the eye material:

Code implementation

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
  <title>Document</title>
  <style>
    #box{
      position: relative;
      width: 300px;
      margin: 0 auto;
    }
    #face{
      background-image: url(images/face.png);
      background-size: cover;
      width: 300px;
      height: 300px;
      position: absolute;
    }
    #eyeLeft{
      background-image: url(images/eye.png);
      background-size: cover;
      width: 40px;
      height: 40px;
      position: absolute;
      top: 90px;
      left: 100px;
    }
    #eyeRight{
      background-image: url(images/eye.png);
      background-size: cover;
      width: 40px;
      height: 40px;
      position: absolute;
      top: 90px;
      left: 190px;
    }
    #glass{
      background-image: url(images/glass.png);
      background-size: cover;
      width: 300px;
      height: 300px;
      position: absolute;
    }
  </style>
</head>
<body>
  <p id="box">
    <p id="face"></p>
    <p id="eyeLeft"></p>
    <p id="eyeRight"></p>
    <p id="glass"></p>
    <p id="log"></p>
  </p>
<script>
'use strict';
/*
* author: 王乐平
* date:2017.7.17
*/
var eyeLeftPosition = {
  start: [70, 78],
  end: [100, 110]
};
var eyeRightPosition = {
  start: [150, 78],
  end: [190, 110]
};
var eyeLeftCenterPosition = {
  x: (eyeLeftPosition.end[0] - eyeLeftPosition.start[0]) / 2 + eyeLeftPosition.start[0],
  y: (eyeLeftPosition.end[1] - eyeLeftPosition.start[1]) / 2 + eyeLeftPosition.start[1]
};
var eyeRightCenterPosition = {
  x: (eyeRightPosition.end[0] - eyeRightPosition.start[0]) / 2 + eyeRightPosition.start[0],
  y: (eyeRightPosition.end[1] - eyeRightPosition.start[1]) / 2 + eyeRightPosition.start[1]
};
var r = 20;
var eyeLeft = document.querySelector('#eyeLeft');
var eyeRight = document.querySelector('#eyeRight');
if (window.DeviceOrientationEvent) {
  window.addEventListener('deviceorientation', function (event) {
    let {alpha, beta, gamma} = event;
    eyeLeft.style.left = eyeLeftCenterPosition.x + gamma / 90 * r + 'px';
    eyeRight.style.left = eyeRightCenterPosition.x + gamma / 90 * r + 'px';
    eyeLeft.style.top = eyeRight.style.top 
                      = eyeLeftCenterPosition.y + beta / 180 * r + 'px';
    eyeRight.style.transform = eyeLeft.style.transform 
                         = eyeRight.style.WebkitTransform 
                         = eyeLeft.style.WebkitTransform 
                         = 'rotate(' + beta + 'deg)';
  }, false);
} else {
  document.querySelector('body').innerHTML = '浏览器不支持DeviceOrientationEvent';
}
</script>
</body>
</html>

Final effect

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Implementing moving animation effects based on HTML5 gyroscope

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