Canvas矩阵动画JS

Question

我在 codePen 上找到了这个例子，
并且当字母在一行中移动时的第一次迭代看起来很糟糕，
是否可以从一开始就从不同的位置开始移动列？（不是来自第二次迭代）
我的解决方案也很糟糕：
我添加了不透明度为 0 到 100 的 @keyframes
并添加了持续时间为 3s 和动画计时功能的动画：step-end;

// geting canvas by Boujjou Achraf
        var c = document.getElementById("c");
        var ctx = c.getContext("2d");

        //making the canvas full screen
        c.height = window.innerHeight;
        c.width = window.innerWidth;

        //chinese characters - taken from the unicode charset
        var matrix = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789@#$%^&*()*&^%+-/~{[|`]}";
        //converting the string into an array of single characters
        matrix = matrix.split("");

        var font_size = 10;
        var columns = c.width/font_size; //number of columns for the rain
        //an array of drops - one per column
        var drops = [];
        //x below is the x coordinate
        //1 = y co-ordinate of the drop(same for every drop initially)
        for(var x = 0; x < columns; x++)
            drops[x] = 1; 

        //drawing the characters
        function draw()
        {
            //Black BG for the canvas
            //translucent BG to show trail
            ctx.fillStyle = "rgba(0, 0, 0, 0.04)";
            ctx.fillRect(0, 0, c.width, c.height);

            ctx.fillStyle = "#f4427d";//green text
            ctx.font = font_size + "px arial";
            //looping over drops
            for(var i = 0; i < drops.length; i++)
            {
                //a random chinese character to print
                var text = matrix[Math.floor(Math.random()*matrix.length)];
                //x = i*font_size, y = value of drops[i]*font_size
                ctx.fillText(text, i*font_size, drops[i]*font_size);

                //sending the drop back to the top randomly after it has crossed the screen
                //adding a randomness to the reset to make the drops scattered on the Y axis
                if(drops[i]*font_size > c.height && Math.random() > 0.975)
                    drops[i] = 0;

                //incrementing Y coordinate
                drops[i]++;
            }
        }

        setInterval(draw, 35);

/* By Boujjou Achraf*/

/*basic reset */
            
            *{
                margin: 0;
                padding: 0;
            }
            
            body {background: black;}
            canvas {display:block;}

/* By Boujjou Achraf*/

<html>
 
    <head>
        
    </head>
    <body>
    
        <canvas id="c"></canvas>
        
    </body>
</html>

Answer 1

每个动画字母的垂直屏幕位置存储在一个名为 drops 的数组中。

在启动时，每个字母通过以下两行获得相同的初始位置：

for (var x = 0; x < columns; x++)
    drops[x] = 1;

您可以将每个字母的位置设为从 0 到 canvas 元素高度的随机数，方法是将上面的内容更改为：

for (var x = 0; x < columns; x++)
    drops[x] = parseInt(Math.random() * c.height);

Math.random() returns 介于 0 和 1 之间的浮点数和 c.height returns <canvas> 元素的高度。通过将这两个值相乘，我们得到一个介于 0 和 canvas' 高度之间的随机数。

这是您修改后的示例：

var c = document.getElementById("c");
var ctx = c.getContext("2d");

//making the canvas full screen
c.height = window.innerHeight;
c.width = window.innerWidth;

//chinese characters - taken from the unicode charset
var matrix = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789@#$%^&*()*&^%+-/~{[|`]}";
//converting the string into an array of single characters
matrix = matrix.split("");

var font_size = 10;
var columns = c.width / font_size; //number of columns for the rain
//an array of drops - one per column
var drops = [];
//x below is the x coordinate
//1 = y co-ordinate of the drop(same for every drop initially)
for (var x = 0; x < columns; x++)
  drops[x] = parseInt(Math.random() * c.height);

//drawing the characters
function draw() {
  //Black BG for the canvas
  //translucent BG to show trail
  ctx.fillStyle = "rgba(0, 0, 0, 0.04)";
  ctx.fillRect(0, 0, c.width, c.height);

  ctx.fillStyle = "#f4427d"; //green text
  ctx.font = font_size + "px arial";
  //looping over drops
  for (var i = 0; i < drops.length; i++) {
    //a random chinese character to print
    var text = matrix[Math.floor(Math.random() * matrix.length)];
    //x = i*font_size, y = value of drops[i]*font_size
    ctx.fillText(text, i * font_size, drops[i] * font_size);

    //sending the drop back to the top randomly after it has crossed the screen
    //adding a randomness to the reset to make the drops scattered on the Y axis
    if (drops[i] * font_size > c.height && Math.random() > 0.975)
      drops[i] = 0;

    //incrementing Y coordinate
    drops[i]++;
  }
}

setInterval(draw, 35);

* {
  margin: 0;
  padding: 0;
}

body {
  background: black;
}

canvas {
  display: block;
}

<canvas id="c"></canvas>

Canvas矩阵动画JS

Canvas Matrix Animation JS

javascript

css

canvas