JS simple drawing board effect code based on ocanvas plug-in (with demo source code download)

JS simple drawing board effect code based on ocanvas plug-in (with demo source code download)_javascript skills

WBOY

Release： 2016-05-16 15:06:49

Original

1648 people have browsed it

The example in this article describes the simple drawing board effect implemented by JS based on the ocanvas plug-in. Share it with everyone for your reference, the details are as follows:

Using ocanvas to create a simple online drawing board.

ocanvas reference: http://ocanvas.org/

The effect is as follows:

The main code is as follows:

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8" />
  <title>oCanvas Example</title>
  <meta name="robots" content="noindex, nofollow">
  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
  <meta name="apple-mobile-web-app-capable" content="yes" />
  <meta name="apple-mobile-web-app-status-bar-style" content="black" />
  <script src="http://libs.useso.com/js/zepto/1.1.3/zepto.min.js"></script>
  <script>
  var line_color = '#000';
  var line_size = 3;
  $(function(){
    $('.tool .color div').click(function(){
      $('.tool .color div').removeClass('active');
      $(this).addClass('active');
      line_color = $(this).data('color');
      mouseDot.fill = line_color;
    });
    $('.tool .size div').click(function(){
      $('.tool .size div').removeClass('active');
      $(this).addClass('active');
      line_size = $(this).data('size');
      mouseDot.radius = Math.max(line_size / 2, 3);
    });
  });
  </script>
  <style>
  body, html {padding:0; margin:0; overflow:hidden;}
  .tool{position:absolute; top:10px; left:10px; border:solid 1px #aaa; background-color:#eee; border-radius:5px; padding-right:5px;}
  .tool .color {float:left; margin:5px; width:30px;}
  .tool .color div{width:24px; height:24px; border:solid 2px #aaa; margin-bottom:5px; opacity:0.5;}
  .tool .color div:hover{opacity:1; cursor:pointer;}
  .tool .color .active{opacity:1; border:solid 2px #000;}
  .tool .size {float:left; margin:5px; width:30px; margin-left:0;}
  .tool .size div{width:30px; height:30px; border:solid 2px #aaa; margin-bottom:5px; opacity:0.5;}
  .tool .size div:hover{opacity:1; cursor:pointer;}
  .tool .size .active{opacity:1; border:solid 2px #000;}
  .tool .size span{display:block; margin:3px auto; height:24px; background-color:black;}
  .btn {clear:both; margin-bottom:5px; text-align:center;}
  .btn input {padding:3px 15px;}
  </style>
</head>
<body>
  <canvas id="canvas" width="200" height="100"></canvas>
  <div class="tool">
    <div class="color">
      <div style="background:#000;" data-color="#000" class="active"></div>
      <div style="background:#f00;" data-color="#f00"></div>
      <div style="background:#0f0;" data-color="#0f0"></div>
      <div style="background:#00f;" data-color="#00f"></div>
      <div style="background:#ff0;" data-color="#ff0"></div>
      <div style="background:#0ff;" data-color="#0ff"></div>
      <div style="background:#f0f;" data-color="#f0f"></div>
      <div style="background:#fff;" data-color="#fff"></div>
    </div>
    <div class="size">
      <div class="active" data-size="3" ><span style="width:3px;" ></span></div>
      <div data-size="6" ><span style="width:6px;" ></span></div>
      <div data-size="9" ><span style="width:9px;" ></span></div>
      <div data-size="12"><span style="width:12px;"></span></div>
      <div data-size="15"><span style="width:15px;"></span></div>
      <div data-size="20"><span style="width:20px;"></span></div>
      <div data-size="25"><span style="width:25px;"></span></div>
    </div>
    <div class="btn">
      <input type="button" value="清 空" onclick="clearAll();" />
    </div>
  </div>
  <script src="js/ocanvas-2.7.3.min.js"></script>
  <script>
  var c = document.querySelector("#canvas"),
  ctx = c.getContext("2d");
  c.width = window.innerWidth;
  c.height = window.innerHeight;
  c.addEventListener("touchmove", function (e) { e.preventDefault(); }, false);
  var cs = oCanvas.create({
    canvas: "#canvas",
    background: "#fff",
    fps: 30,
    disableScrolling: true
  });
  var isDraw = false;
  var xx = 0;
  var yy = 0;
  var mouseDot;
  clearAll();
  cs.bind('mousedown', function(){
    drawBegin(cs.mouse.x, cs.mouse.y);
  }).bind('touchstart tap', function(){
    drawBegin(cs.touch.x, cs.touch.y);
  }).bind('mouseup touchend', function(){
    isDraw = false;
  }).bind('mousemove', function(){
    drawMove(cs.mouse.x, cs.mouse.y);
  }).bind('touchmove', function(){
    drawMove(cs.touch.x, cs.touch.y);
  });
  /*
  cs.setLoop(function () {
    mouseDot.x = cs.mouse.x;
    mouseDot.y = cs.mouse.y;
  }).start();
  */
  function drawBegin(x, y)
  {
    isDraw = true;
    xx = x;
    yy = y;
    var dot = cs.display.arc({
      x: x,
      y: y,
      radius: line_size / 2,
      start: 0,
      end: 360,
      fill: line_color
    });
    cs.addChild(dot);
  }
  function drawMove(x, y)
  {
    if (isDraw)
    {
      var line = cs.display.line({
        start: { x: xx, y: yy },
        end: { x: x, y: y },
        stroke: '' + line_size + 'px ' + line_color,
        cap: "round"
      });
      cs.addChild(line);
      xx = x;
      yy = y;
    }
    else
    {
      mouseDot.moveTo(x, y);
      cs.addChild(mouseDot);
      cs.draw.redraw();
    }
  }
  function clearAll()
  {
    cs.reset();
    // 处理鼠标
    cs.mouse.hide();
    mouseDot = cs.display.arc({
      x: -100,
      y: -100,
      radius: Math.max(line_size / 2, 3),
      start: 0,
      end: 360,
      fill: line_color,
      shadow: '0 0 5px #333'
    });
    cs.addChild(mouseDot);
  }
  </script>
</body>
</html>

Copy after login

Readers who are interested in more JavaScript-related content can check out the special topics on this site: "Summary of JavaScript switching effects and techniques", "Summary of JavaScript search algorithm techniques", "Summary of JavaScript animation special effects and techniques", "Summary of JavaScript errors and debugging skills", "Summary of JavaScript data structures and algorithm techniques", "JavaScript traversal Summary of Algorithms and Techniques" and "Summary of JavaScript Mathematical Operation Usage"

Click here for the complete example codeDownload from this site.

I hope this article will be helpful to everyone in JavaScript programming.