Set/get name of an image take from canvas


Hi nobody know how to get or maybe set the name of an image in a canvas?
i use this code to save a canvas as image, but i don’t know how get the name of the image or how set .

  $scope.saveCanvas = function() {
    $scope.clearSave = false;
    $scope.FirmaBtn = true;
    $scope.canvasSi = false;

//salvo la firma

var firma = signaturePad.toDataURL(“image/jpeg”);
$timeout( function(){
$scope.signature = firma;
if ($scope.signature) {
}, 200);