def scrolling_text(text, start_from_right=True, scroll_length=1):
"""
take in a string, output a generator that is a series of
frames (5x7 matrices)
"""
if start_from_right:
matrix = [[0 for _ in range(6)] for __ in range(5)]
else:
matrix = [[] for _ in range(5)]
for char in list(text):
trimmed_char = _trim_frame(Characters.string_to_matrices(char)[0])
for i in range(5):
matrix[i] += trimmed_char[i] + [0]
while len(matrix[0]) >= 7:
yield [col[:7] for col in matrix]
matrix = [col[scroll_length:] for col in matrix]
while (len(matrix[0]) > 0):
padding = [0 for _ in range(7 - len(matrix[0]))]
yield [matrix[i] + padding for i in range(5)]
matrix = [col[scroll_length:] for col in matrix]
