Javascript 使用html2canvas时不显示Google地图

我已经做了截图按钮，必须使所有身体的截图

但在这个屏幕截图上，谷歌地图并没有显示出来。 我使用html2canvas库来实现这一点。 代码如下：

HTML:

以下是我在制作截图时的情况：

---

您能告诉我出了什么问题吗？

我将这些属性添加到代码中，它可以工作：

var takeScreenShot = function() {
    var screenshot = {};
    html2canvas(document.getElementById('map'), {
        useCORS: true,
        optimized: false,
        allowTaint: false,
        onrendered: function (canvas) {
            var tempcanvas=document.createElement('canvas');
            tempcanvas.width=1350;
            tempcanvas.height=700;
            var context=tempcanvas.getContext('2d');
            context.drawImage(canvas,0,0,1350,700,0,0,1350,700);
            var link=document.createElement("a");
            link.href=tempcanvas.toDataURL('image/jpg');   //function blocks CORS
            link.download = 'screenshot.jpg';
            link.click();
        }
    });
}

var takeScreenShot = function() {
var screenshot = {};
html2canvas(document.getElementById('screenAll'), {
    onrendered: function (canvas) {
        var tempcanvas=document.createElement('canvas');
        tempcanvas.width=1350;
        tempcanvas.height=700;
        var context=tempcanvas.getContext('2d');
        context.drawImage(canvas,0,0,1350,700,0,0,1350,700);
        var link=document.createElement("a");
        link.href=tempcanvas.toDataURL('image/jpg');   //function blocks CORS
        link.download = 'screenshot.jpg';
        link.click();
    }
});

var takeScreenShot = function() {
    var screenshot = {};
    html2canvas(document.getElementById('map'), {
        useCORS: true,
        optimized: false,
        allowTaint: false,
        onrendered: function (canvas) {
            var tempcanvas=document.createElement('canvas');
            tempcanvas.width=1350;
            tempcanvas.height=700;
            var context=tempcanvas.getContext('2d');
            context.drawImage(canvas,0,0,1350,700,0,0,1350,700);
            var link=document.createElement("a");
            link.href=tempcanvas.toDataURL('image/jpg');   //function blocks CORS
            link.download = 'screenshot.jpg';
            link.click();
        }
    });
}

    var fin = document.getElementById("map");

    html2canvas(fin, {
    useCORS: true,
    onrendered: function(canvas) {
        var dataUrl= canvas.toDataURL("image/png");
        $('#map_image').attr('src',dataUrl).show();
    }
  });