arcade.drawing_support 源代码
"""
Functions used to support drawing. No Pyglet/OpenGL here.
"""
from __future__ import annotations
import math
from typing import Tuple
__all__ = ["get_points_for_thick_line"]
[文档]
def get_points_for_thick_line(start_x: float, start_y: float,
end_x: float, end_y: float,
line_width: float) -> Tuple[Tuple[float, float], Tuple[float, float],
Tuple[float, float], Tuple[float, float]]:
"""
Function used internally for Arcade. OpenGL draws triangles only, so a thick
line must be two triangles that make up a rectangle. This calculates and returns
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
return (r1_x, r1_y), (r2_x, r2_y), (r4_x, r4_y), (r3_x, r3_y)