欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  web前端

JavaScript、html5、canvas实现图片上画超链接

程序员文章站 2022-05-31 13:05:05
...
本文主要为大家详细介绍了JavaScript html5 canvas实现图片上画超链接,具有一定的参考价值,感兴趣的小伙伴们可以参考一下,希望能帮助到大家。

1. html


<canvas id="canvasFile" style="margin-top:15px;" width="500" height="400"></canvas> 
<input type="button" id="btnRedo" value="Re-Draw" class="btn btn-warning"/>

2. javascript


var photoW = 400; 
    var photoH = 300; 
    var photo; 
     
     
    // logic load image into canvas 
    // ... 
    // e.g.  
    // photo = new Image(); 
    // photo.onload = function() { 
    // draw photo into canvas when ready 
    // ctx.drawImage(photo, 0, 0, photoW, photoH); 
    // }; 
    // load photo into canvas 
    // photo.src = picURL; 
   
     
 // canvas highlight 
    var canvas = document.getElementById('canvasFile'), 
      ctx = canvas.getContext('2d'), 
      img = new Image; 
    var btnDone = document.getElementById('btnDone'); 
    var btnRedo = document.getElementById('btnRedo'); 
 
 
    ctx.strokeStyle = '#FF0000'; 
 
    function DrawDot(x, y) { 
      var centerX = x; 
      var centerY = y; 
      var radius = 2; 
 
 
      ctx.beginPath(); 
      ctx.arc(centerX, centerY, radius, 0, 2 * Math.PI, false); 
      ctx.fillStyle = 'red'; 
      ctx.fill(); 
      ctx.lineWidth = 2; 
      ctx.strokeStyle = '#FF0000'; 
      ctx.stroke(); 
    } 
 
 
    function startDrawing() { 
      ctx.drawImage(img, 0, 0, photoW, photoH); 
      canvas.onmousemove = mousemoving; 
      canvas.onmousedown = mousedownhandle; 
      canvas.onmouseup = mouseuphandle; 
      // ## mobile events 
      //touchstart – to toggle drawing mode “on” 
      //touchend – to toggle drawing mode “off” 
      //touchmove – to track finger position, used in drawing 
      canvas.addEventListener('touchmove', touchmove, false); 
      canvas.addEventListener('touchend', mouseuphandle, false); 
 
 
      btnRedo.onclick = function (e) { 
        ctx.clearRect(0, 0, ctx.width, ctx.height); 
        ctx.drawImage(photo, 0, 0, photoW, photoH); 
        savedrawing(); 
      } 
    } 
    function savedrawing(e) { 
      var image = document.getElementById('canvasFile').toDataURL("image/jpeg"); 
      image = image.replace('data:image/jpeg;base64,', ''); 
      $("#imgNric1").val(image); 
    }; 
 

    function mousemoving(e) { 
      if (drawing) { 
        mousedownhandle(e); 
      } 
    } 
 
 
    var drawing = false; 
 
 
    function mousedownhandle(e) { 
      drawing = true; 
      var r = canvas.getBoundingClientRect(), 
        x = e.clientX - r.left, 
        y = e.clientY - r.top; 
 
 
      DrawDot(x, y); 
    }  
 
    function mouseuphandle(e) { 
      savedrawing(); 
      e.preventDefault(); 
      drawing = false; 
       
    } 
  
 
    //// mobile touch events 
    function touchmove(e) { 
      if (e.clientX > 800) { 
        mousedownhandle(e); 
        return; 
      } 
 
      var r = canvas.getBoundingClientRect(), 
        //event.changedTouches[0].pageX + ":" + event.changedTouches[0].pageY; 
        x = e.changedTouches[0].pageX - r.left, 
        y = e.changedTouches[0].pageY - r.top; 
 
 
      DrawDot(x, y); 
      e.preventDefault(); 
    }

相关推荐:

html里的超链接标签

css怎么去掉超链接下划线

js实现页面加载时自动触发超链接实例详解

以上就是JavaScript、html5、canvas实现图片上画超链接的详细内容,更多请关注其它相关文章!