Vision: Single feature functions generated by cloud vision client library does not support parameter max_results

[michaelawyu]

As specified in the gRPC reference, AnnotateImageRequest message have three fields, image, features[] and image_context, in which the features[] field determines what feature user is request (type) and max number of returned results (max_results). The code for generating single-feature functions (for example, face_detection()), however, does not allow user to specify max_results:

feature_value = {'type': enum.__dict__[feature]}
def inner(self, image, options=None, **kwargs):
        request = dict(
            image=image,
            features=[feature_value],
            **kwargs
        )
        return self.annotate_image(request, options=options)

Reported in GoogleCloudPlatform/python-docs-samples#1173

[chemelnucfin]

See PR #4817

Tracking this in Feature Requests