https://www.archives.gov/sites/all/modules/custom/nara_document_app/js/script.js?tm9c8g

1function drawImage(document_id) {
2  const canvas = document.getElementById('canvas');
3  const ctx = canvas.getContext('2d');
4 // ctx.clearRect(0, 0, 600px, 600px);
5  
6  canvas.height = 1200;
7  canvas.width = 990;
8  const img = document.querySelector('img.active');  
9  ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
10
11 
12  var font =  document.querySelector('input[name="penmanship"]:checked').value;
13   ctx.font = "36px " + font;
14  
15  var text = document.getElementById('custom-text').value;
16   
17  if (document_id == 2) {
18   x = canvas.width/10;
19   y = canvas.height - canvas.height/3.5;
20  }
21  else if (document_id == 1) {
22   x = canvas.width/10;
23   y = canvas.height - canvas.height/8;
24  }
25  else if (document_id == 3) {
26   x = canvas.width/2.5;
27   y = canvas.height - canvas.height/16;
28   }
29   ctx.fillText(text, x, y);
30   url = canvas.toDataURL();
31   canvas.toBlob(function(blob){
32     const anchor = document.getElementById('dlink'); 
33     anchor.href = URL.createObjectURL(blob);
34   });
35
36return url;
37}
38
39(function ($) {
40  var document_id = 1;
41  $(document).ready(function() {
42    
43    
44    $(".box").on('click', function() { 
45       $(".box").removeClass("active");
46       $(".box").children("img").removeClass("active");
47       $(this).addClass("active"); 
48       $(this).children("img").addClass("active");
49       if ($("#billofrights").hasClass("active")) {
50         $(".custom-text").text("Bill of Rights");
51         document_id = 3;
52         $(".independence-text").addClass("custom-hide");
53       }
54       else if ($("#constitution").hasClass("active")) {
55         $(".custom-text").text("Constitution");
56         document_id = 2;
57         $(".independence-text").addClass("custom-hide");
58         $(".constitution-text").removeClass("custom-hide");
59       }
60       else { 
61         $(".custom-text").text("Declaration of Independence");
62         $(".independence-text").removeClass("custom-hide");
63         $(".constitution-text").addClass("custom-hide");
64         document_id = 1;  
65       }
66    });
67
68    $("button#sign-button").on('click', function() {
69       $(".download-link").html('<button><a id="dlink" download>Download this image</a></button>');
70       var img_url = drawImage(document_id);
71       $("#canvas").addClass("canvas-full-width");
72       //$(".download-link").html('<button><a href="' + img_url + '" download>Download this image</a></button>');
73    });
74
75
76  })
77}(jQuery));