用canvas实现简易的画布效果

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
        canvas{
            border:1px solid #ccc;
        }
        #box{
            display: inline-block;
            width: 20px;
            height: 20px;
            background: yellow;
        }
        #nul{
            display: inline-block;
            margin-left: 10px;
            font-size: 12px;
            text-align: center;
            width: 40px;
            height: 20px;
            background: pink;
        }
    </style>
</head>
<body>
    <div id="box"></div>
    <div id="nul">清除</div><br>
    <canvas id="mycanvas">您的破浏览器不兼容
    </canvas>
            
    <script>
        
        var canvas = document.getElementById("mycanvas");
        var box = document.getElementById("box");
        var nul = document.getElementById("nul");

        //设置宽高
        canvas.width = 500;
        canvas.height = 500;

        //获取绘图环境
        var cxt = canvas.getContext("2d");

        //鼠标按下
        canvas.onmousedown = function(e){
            //鼠标在 画布上的位置
            var x = e.clientX - canvas.offsetLeft;
            var y = e.clientY - canvas.offsetTop;
            cxt.beginPath();
            cxt.moveTo(x, y);
            console.log("mousedown");

            //鼠标移动
            canvas.onmousemove = function(e){
                var x = e.clientX - canvas.offsetLeft;
                var y = e.clientY - canvas.offsetTop;
                cxt.lineTo(x, y);
                cxt.stroke();
            }
                        //点击box改变画笔颜色 
            box.onclick=function(){
                cxt.strokeStyle = "yellow";
            }
                        //点击nul清空画布
            nul.onclick=function(){
                    cxt.clearRect(0,0,500,500);
                }

            //鼠标抬起事件
            canvas.onmouseup = function(){
                canvas.onmousemove = null;
            }

            
        }


    </script>
</body>
</html>
最后编辑于 ：
©著作权归作者所有,转载或内容合作请联系作者
平台声明：文章内容（如有图片或视频亦包括在内）由作者上传并发布，文章内容仅代表作者本人观点，简书系信息发布平台，仅提供信息存储服务。

推荐阅读更多精彩内容