html2canvas 如何生成高清圖片

需求
個人需求是在手機頁面講一段html轉成圖片讓用戶能夠保存,因此以前那段html則不須要顯示了。css

正常渲染
使用html2canvas正常渲染出來在手機上顯示很是的模糊。代碼以下:html

var dom = $("#id");

html2canvas(dom[0], {

canvas: canvas,

onrendered: function (canvas) {

$(dom).css("display", "none");

$(".img-container").append(Canvas2Image.convertToImage(canvas, width * scaleBy, height * scaleBy, type));

}

});

例子中還用了插件canvas2image.js將canvas轉成了圖片canvas

優化app

var dom = $(".content-container .show-content");

var width = dom.width();

var height = dom.height();

var type = "png";

var scaleBy = 3;

var canvas = document.createElement('canvas');

canvas.width = width * scaleBy;

canvas.height = height * scaleBy + 35;

canvas.style.width = width * scaleBy + 'px';

canvas.style.height = height * scaleBy + 'px';

var context = canvas.getContext('2d');

context.scale(scaleBy, scaleBy);

context.font = 'Microsoft YaHei';

html2canvas(dom[0], {

canvas: canvas,

onrendered: function (canvas) {

var all_width = $(window).width();

$("#content-container").css("display", "none");

$(".img-container").append(Canvas2Image.convertToImage(canvas, width * scaleBy, height * scaleBy, type));

$(".img-container img").css("width", all_width + "px").css("height", "aotu");

}

});

這樣清晰度幾乎和原dom清晰度同樣,這裏有個坑就是dom的位置須要在左上角開始位置,否則渲染的canvas會把間距也渲染出來就很難處理了。dom

若是對你有幫助。或者想關注更多能夠看看博客優化

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