Added function for downloading spectrum img

Author: waridrox

examples/capture/capture.js

@@ -161,6 +161,27 @@ $W = {
     this_.getRecentCalibrations("#calibration_id");
   },
 
+  downloadSpectrum: function() {
+    function getFormattedTime() {
+      let current_date = new Date();
+      let year = current_date.getFullYear();
+      let month = current_date.getMonth() + 1;
+      let day = current_date.getDate();
+      let hours = current_date.getHours();
+      let minutes = current_date.getMinutes();
+      let seconds = current_date.getSeconds();
+      return (year + '-' + month + '-' + day + '-' + hours + '-' + minutes + '-' + seconds);
+    }
+
+  let base64_imgdata = $('#dataurl').val($W.canvas.toDataURL())[0].defaultValue;
+  console.log(base64_imgdata);
+
+  let a = document.createElement('a');
+  a.href = base64_imgdata;
+  a.download = ('spectrum_img-' + getFormattedTime() + '.png');
+  a.click();
+  },
+
   getRecentCalibrations: function(selector) {
     $.ajax({
       url: "/capture/recent_calibrations.json?calibration_id=" + $W.calibration_id,