Source code for arcade.drawing_support

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

import math

from typing import Tuple, cast

from arcade import Color
from arcade import RGBA


[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