html2canvas如何实现将div保存图片高清图

这篇文章将为大家详细讲解有关html2canvas如何实现将div保存图片高清图，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。

本文介绍了html2canvas把div保存图片高清图的方法示例，分享给大家，具体如下：

选择html2canvas版本（这个版本可以放大倍数保证图片清晰）

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.class="lazy" data-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|jpeg|bmp|gif/)[0];                                    return 'image/' + r;                                };                                // 加工image data，替换mime type                                imgData = imgData.replace(_fixType(type),'image/octet-stream');                                                                var saveFile = function(data, filename){                                    var save_link = document.createElementNS('http://www.w3.org/1999/xhtml', 'a');                                    save_link.href = data;                                    save_link.download = filename;                                    var event = document.createEvent('MouseEvents');                                    event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);                                    save_link.dispatchEvent(event);                                };                                // 下载后的问题名                                var filename = aname+'肌肤检测报告' + (new Date()).getTime() + '.' + type;                                // download                                saveFile(imgData,filename);                            },                            width:1512,                            height:15000                        })                    },2500)                }                else                {                    return;                }            })

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