```"""
Functions used to support drawing. No Pyglet/OpenGL here.
"""

import math

from typing import Tuple, cast

[docs]def get_points_for_thick_line(start_x: float, start_y: float,
end_x: float, end_y: float,
line_width: float):
"""
Function used internally for Arcade. OpenGL draws triangles only, so a think
line must be two triangles that make up a rectangle. This calculates those
points.
"""
vector_x = start_x - end_x
vector_y = start_y - end_y
perpendicular_x = vector_y
perpendicular_y = -vector_x
length = math.sqrt(vector_x * vector_x + vector_y * vector_y)
if length == 0:
normal_x = 1.0
normal_y = 1.0
else:
normal_x = perpendicular_x / length
normal_y = perpendicular_y / length
r1_x = start_x + normal_x * line_width / 2
r1_y = start_y + normal_y * line_width / 2
r2_x = start_x - normal_x * line_width / 2
r2_y = start_y - normal_y * line_width / 2
r3_x = end_x + normal_x * line_width / 2
r3_y = end_y + normal_y * line_width / 2
r4_x = end_x - normal_x * line_width / 2
r4_y = end_y - normal_y * line_width / 2
points = (r1_x, r1_y), (r2_x, r2_y), (r4_x, r4_y), (r3_x, r3_y)
return points

[docs]def get_four_byte_color(color: Color) -> RGBA:
"""
Given a RGB list, it will return RGBA.
Given a RGBA list, it will return the same RGBA.

:param Color color: Three or four byte tuple

:returns:  return: Four byte RGBA tuple
"""

if len(color) == 4:
return cast(RGBA, color)
elif len(color) == 3:
return color[0], color[1], color[2], 255
else:
raise ValueError("This isn't a 3 or 4 byte color")

[docs]def get_four_float_color(color: Color) -> Tuple[float, float, float, float]:
"""
Given a 3 or 4 RGB/RGBA color where each color goes 0-255, this
returns a RGBA tuple where each item is a scaled float from 0 to 1.

:param Color color: Three or four byte tuple
:return: Four floats as a RGBA tuple
"""
if len(color) == 4:
return color[0] / 255, color[1] / 255, color[2] / 255, color[3] / 255  # type: ignore
elif len(color) == 3:
return color[0] / 255, color[1] / 255, color[2] / 255, 1.0
else:
raise ValueError("This isn't a 3 or 4 byte color")

[docs]def get_three_float_color(color: Color) -> Tuple[float, float, float, float]:
"""
Given a 3 or 4 RGB/RGBA color where each color goes 0-255, this
returns a RGBA tuple where each item is a scaled float from 0 to 1.

:param Color color: Three or four byte tuple
:return: Three floats as a RGB tuple
"""
if len(color) == 4 or len(color) == 3:
return color[0] / 255, color[1] / 255, color[2] / 255  # type: ignore
else:
raise ValueError("This isn't a 3 or 4 byte color")

[docs]def make_transparent_color(color: Color, transparency: float):
"""
Given a RGB color, along with an alpha, returns a RGBA color tuple.

:param Color color: Three or four byte RGBA color
:param float transparency: Transparency
"""
return color[0], color[1], color[2], transparency
```