canvas合成图片

<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no" />
    <meta name="viewport" content="width=640, user-scalable=no, target-densitydpi=device-dpi">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <style>
    *{
        margin: 0;
        padding: 0;
    }
    button{
        width: 100px;
        height: 60px;
    }
    #code{
        position: relative;
    }
    </style>
</head>
<body>
    <div id="code">
    </div>
    <canvas id="main" height="700" width="420" style="border:1px solid #d3d3d3;"></canvas>
    <!--saveImageInfo()生成照片并显示到另个网页-->
    <button onclick="saveImageInfo()">生成图片</button>
<script src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
<script src="https://cdn.bootcss.com/jquery.qrcode/1.0/jquery.qrcode.min.js"></script>
<script>
    //预加载将图片绘制到画布
    $(function(){
        drawImg();
    });

    function drawImg(){
        $("#code").qrcode({
            render: "canvas", //table方式
             120, //宽度
            height:145, //高度
            text: "www.helloweba.com" //任意内容
        });
        //获取画布对象
        var mainCtx = getCanvasContext('main');
        var maxWidth = mainCtx.width;
        var maxHeight = mainCtx.height;
        var qrcode=$('#code').find('canvas')[0];
        mainCtx.clearRect(0,0,1000,1000);
        //获取图片的实际路径
        var starImg = new Image();
        var starImg1 = new Image();
        var starImg2 = new Image();
        starImg.src='bg-alert.png';
        starImg1.src='myorder_03.png';
        starImg2.src='myorder_03.png';
        //背景图
        starImg.onload=function(){
            //先把图片绘制在这里
            mainCtx.drawImage(starImg,0,0,420,730);
            //绘制二维码
            mainCtx.drawImage(qrcode,150,500)
            //设置用户文本的大小字体等属性
            mainCtx.font = "small-caps bold 18px STXinwei";
            //设置用户文本填充颜色
            mainCtx.fillStyle = "white";
            //绘制文字
            mainCtx.fillText('阿瑟发',120,110);
        };
        // 商品图
        starImg1.onload=function(){
            //先把图片绘制在这里
            mainCtx.drawImage(starImg1,150,280,120,120);
        };
        starImg2.onload=function(){
            //先把图片绘制在这里
            mainCtx.drawImage(starImg2,200,560,30,30);
        };
    }
    //通过id获取canvas对象
    function getCanvasContext(id){
        return document.getElementById(id).getContext("2d");
    }
    //将画布生成图片
    function saveImageInfo() {
        var mycanvas = document.getElementById("main");
        var image = mycanvas.toDataURL("image/jpg");
        var w=window.open('about:blank','image from canvas');
        w.document.write("<img src='"+image+"' alt='from canvas'/>");
    }
    //下载图片
    function saveAsLocalImage(){
        var myCanvas = document.getElementById("main");
        var image = myCanvas.toDataURL("image/jpg").replace("image/jpg", "image/octet-stream");
        window.location.href=image;
    }

</script>

</body>
</html>
原文地址:https://www.cnblogs.com/vhen/p/7687275.html