Share HTML5 Canvas drawing seal effect example code-H5 Tutorial-php.cn

Share HTML5 Canvas drawing seal effect example code

零下一度

Release： 2017-04-26 16:59:28

Original

4121 people have browsed it

Let’s share an example code of using HTML5 Canvas to draw a seal effect, you can take a look

<!DOCTYPE html>
<html>
<head>
 <meta charset="gbk">
 <title>HTML5 Canvas画印章</title>
</head>
<body>
    <canvas id="canvas" width="200" height="200"></canvas>
<script>
   var canvas = document.getElementById("canvas");  
   var context = canvas.getContext(&#39;2d&#39;);
   var text = "XXX专用章";
   var companyName = "浙江网络科技股份有限公司";
  
  // 绘制印章边框   
   var width = canvas.width / 2;
   var height = canvas.height / 2;
   context.lineWidth = 5;
   context.strokeStyle = "#f00";
   context.beginPath();
   context.arc(width, height, 90, 0, Math.PI * 2);//宽、高、半径
   context.stroke();

   //画五角星
   create5star(context,width,height,25,"#f00",0);

    // 绘制印章名称   
    context.font = &#39;20px 宋体&#39;;
    context.textBaseline = &#39;middle&#39;;//设置文本的垂直对齐方式
    context.textAlign = &#39;center&#39;; //设置文本的水平对对齐方式
    context.lineWidth=1;
    context.strokeStyle = &#39;#f00&#39;;
    context.strokeText(text,width,height+60);

    // 绘制印章单位   
    context.translate(width,height);// 平移到此位置,
    context.font = &#39;23px 宋体&#39;
    var  count = companyName.length;// 字数
    var  angle = 4*Math.PI/(3*(count - 1));// 字间角度   
    var chars = companyName.split("");
    var c;
   for (var i = 0; i < count; i++) {
       c = chars[i];// 需要绘制的字符   
       if (i == 0) {
           context.rotate(5 * Math.PI / 6);
       } else{
           context.rotate(angle);
       }
       context.save();
       context.translate(70, 0);// 平移到此位置,此时字和x轴垂直，公司名称和最外圈的距离
       context.rotate(Math.PI / 2);// 旋转90度,让字平行于x轴
       context.strokeText(c, 0, 0);// 此点为字的中心点
       context.restore();
   }
   //绘制五角星  
    /** 
     * 创建一个五角星形状. 该五角星的中心坐标为(sx,sy),中心到顶点的距离为radius,rotate=0时一个顶点在对称轴上 
     * rotate:绕对称轴旋转rotate弧度 
     */
    function create5star(context, sx, sy, radius, color, rotato) {
        context.save();
        context.fillStyle = color;
        context.translate(sx, sy);//移动坐标原点
        context.rotate(Math.PI + rotato);//旋转
        context.beginPath();//创建路径
        var x = Math.sin(0);
        var y = Math.cos(0);
        var dig = Math.PI / 5 * 4;
        for (var i = 0; i < 5; i++) {//画五角星的五条边
            var x = Math.sin(i * dig);
            var y = Math.cos(i * dig);
            context.lineTo(x * radius, y * radius);
        }
        context.closePath();
        context.stroke();
        context.fill();
        context.restore();
    }
</script>

Copy after login

<!DOCTYPE html>
<html>
<head>
 <meta charset="gbk">
 <title>HTML5 Canvas画印章</title>
</head>
<body>
    <canvas id="canvas" width="200" height="200"></canvas>


<script>
   var canvas = document.getElementById("canvas");  
   var context = canvas.getContext(&#39;2d&#39;);
   var text = "XXX专用章";
   var companyName = "浙江网络科技股份有限公司";
  
  // 绘制印章边框   
   var width = canvas.width / 2;
   var height = canvas.height / 2;
   context.lineWidth = 5;
   context.strokeStyle = "#f00";
   context.beginPath();
   context.arc(width, height, 90, 0, Math.PI * 2);//宽、高、半径
   context.stroke();

   //画五角星
   create5star(context,width,height,25,"#f00",0);

    // 绘制印章名称   
    context.font = &#39;20px 宋体&#39;;
    context.textBaseline = &#39;middle&#39;;//设置文本的垂直对齐方式
    context.textAlign = &#39;center&#39;; //设置文本的水平对对齐方式
    context.lineWidth=1;
    context.strokeStyle = &#39;#f00&#39;;
    context.strokeText(text,width,height+60);

    // 绘制印章单位   
    context.translate(width,height);// 平移到此位置,
    context.font = &#39;23px 宋体&#39;
    var  count = companyName.length;// 字数
    var  angle = 4*Math.PI/(3*(count - 1));// 字间角度   
    var chars = companyName.split("");
    var c;
   for (var i = 0; i < count; i++) {
       c = chars[i];// 需要绘制的字符   
       if (i == 0) {
           context.rotate(5 * Math.PI / 6);
       } else{
           context.rotate(angle);
       }
       context.save();
       context.translate(70, 0);// 平移到此位置,此时字和x轴垂直，公司名称和最外圈的距离
       context.rotate(Math.PI / 2);// 旋转90度,让字平行于x轴
       context.strokeText(c, 0, 0);// 此点为字的中心点
       context.restore();
   }

   //绘制五角星  
    /** 
     * 创建一个五角星形状. 该五角星的中心坐标为(sx,sy),中心到顶点的距离为radius,rotate=0时一个顶点在对称轴上 
     * rotate:绕对称轴旋转rotate弧度 
     */
    function create5star(context, sx, sy, radius, color, rotato) {
        context.save();
        context.fillStyle = color;
        context.translate(sx, sy);//移动坐标原点
        context.rotate(Math.PI + rotato);//旋转
        context.beginPath();//创建路径
        var x = Math.sin(0);
        var y = Math.cos(0);
        var dig = Math.PI / 5 * 4;
        for (var i = 0; i < 5; i++) {//画五角星的五条边
            var x = Math.sin(i * dig);
            var y = Math.cos(i * dig);
            context.lineTo(x * radius, y * radius);
        }
        context.closePath();
        context.stroke();
        context.fill();
        context.restore();
    }
</script>

Copy after login

The above is the detailed content of Share HTML5 Canvas drawing seal effect example code. For more information, please follow other related articles on the PHP Chinese website!