a way to know when Angular $http is "requesting"

I make an $http request when a user clicks a <button> and I disable/hide/show several elements on screen until the request comes back with either success or error

Is there a way to know that $http hasn't had a response yet? The way I am doing it right now is I have a var in my controller called $scope.requesting which I then use in my HTML page like so:

<img src="img/loader.gif" ng-show="requesting" />

so basically when $scope.requesting is true, show the spinning ajaxyish loader.

I'd like to ditch the $scope.requesting if possible and use whatever $http has to offer, if any at all.

Login Controller

function LoginForm($scope, $http)
{
    $scope.requesting = false;

    $scope.login = function()
    {
        $scope.requesting = true;

        $http.post('resources/request.php', data, {timeout:20000})
            .success(function(data, status, headers, config)
            {
                $scope.requesting = false;
            })
            .error(function(data, status, headers, config)
            {
                $scope.requesting = false;
            }
        );
    }
}