with tf.name_scope('screen'):
# linspace from 0 to N-1, to get X and Y numbers for every row and col.
x = tf.linspace(0., W-1, W)
y = tf.linspace(0., H-1, H)
with tf.name_scope('screen'):
# linspace from 0 to N-1, to get X and Y numbers for every row and col.
x = tf.linspace(0., W-1, W)
y = tf.linspace(0., H-1, H)