html2canvas把div保存图片高清图（图文说明教程）

默认生成的 canvas 图片在 retina 设备上显示很模糊，处理成 2 倍图能解决这个问题：

var w = $("#code").width();
var h = $("#code").height();
//要将 canvas 的宽高设置成容器宽高的 2 倍
var canvas = document.createElement("canvas");
canvas.width = w * 2;
canvas.height = h * 2;
canvas.style.width = w + "px";
canvas.style.height = h + "px";
var context = canvas.getContext("2d");
//然后将画布缩放，将图像放大两倍画到画布上
context.scale(2,2);
html2canvas(document.querySelector("#code"), {
    canvas: canvas,
    onrendered: function(canvas) {
        ...
    }
});

下载方法：

.on('click','.download',function(){
                $('#mycanvas').remove();
                var _height=$('.skinReport').height();
                //滚到顶部
                $('html, body').animate({scrollTop:0});
                if(confirm('是否下载肌肤检测报告？'))
                {
                    setTimeout(function(){
                        var canvas = document.createElement("canvas"),
                            w=$('#skinReport').width(),
                            h=$('#skinReport').height();
                        canvas.width = w * 2;
                        canvas.height = h * 2;
                        canvas.style.width = w + "px";
                        canvas.style.height = h + "px";
                        var context = canvas.getContext("2d");
//然后将画布缩放，将图像放大两倍画到画布上
                        context.scale(2,2);
                        html2canvas(document.getElementById('skinReport'), {
                            allowTaint: false,
                            taintTest: true,
                            canvas: canvas,
                            onrendered: function(canvas) {
                                canvas.id = "mycanvas";
                                canvas.style.display = 'none';
                                document.body.appendChild(canvas);
                                //生成base64图片数据
                                imgData = canvas.toDataURL(type);
                                //var newImg = document.createElement("img");
                                //newImg.src =  dataUrl;
                                //document.body.appendChild(newImg);
                                //console.log(imgData);
                                var _fixType = function(type) {
                                    type = type.toLowerCase().replace(/jpg/i, 'jpeg');
                                    var r = type.match(/png

关键词：html2canvas把div保存图片高清图（图文详细教程）