vectise/colours.py

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Python
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2024-11-10 17:54:23 +00:00
from abc import ABC, abstractmethod
import numpy as np
# the following functions are taken from Ben Southgate:
# https://bsouthga.dev/posts/colour-gradients-with-python
def hex_to_RGB(hex):
""" "#FFFFFF" -> [255,255,255]"""
# Pass 16 to the integer function for change of base
return [int(hex[i : i + 2], 16) for i in range(1, 6, 2)]
def RGB_to_hex(RGB):
"""[255,255,255] -> "#FFFFFF" """
# Components need to be integers for hex to make sense
RGB = [int(x) for x in RGB]
return "#" + "".join(
["0{0:x}".format(v) if v < 16 else "{0:x}".format(v) for v in RGB]
)
def colour_dict(gradient):
"""Takes in a list of RGB sub-lists and returns dictionary of
colours in RGB and hex form for use in a graphing function
defined later on."""
return {
"hex": [RGB_to_hex(RGB) for RGB in gradient],
"r": [RGB[0] for RGB in gradient],
"g": [RGB[1] for RGB in gradient],
"b": [RGB[2] for RGB in gradient],
}
def linear_gradient(start_hex, finish_hex="#FFFFFF", n=10):
"""returns a gradient list of (n) colours between
two hex colours. start_hex and finish_hex
should be the full six-digit colour string,
inlcuding the number sign ("#FFFFFF")"""
# Starting and ending colours in RGB form
s = hex_to_RGB(start_hex)
f = hex_to_RGB(finish_hex)
# Initilize a list of the output colours with the starting colour
RGB_list = [s]
# Calcuate a colour at each evenly spaced value of t from 1 to n
for t in range(0, n):
# Interpolate RGB vector for colour at the current value of t
curr_vector = [
int(s[j] + (float(t) / (n - 1)) * (f[j] - s[j])) for j in range(3)
]
# Add it to our list of output colours
RGB_list.append(curr_vector)
return colour_dict(RGB_list)
def polylinear_gradient(colours, n):
"""returns a list of colours forming linear gradients between
all sequential pairs of colours. "n" specifies the total
number of desired output colours"""
# The number of colours per individual linear gradient
n_out = int(float(n) / (len(colours) - 1))
# returns dictionary defined by colour_dict()
gradient_dict = linear_gradient(colours[0], colours[1], n_out)
if len(colours) > 1:
for col in range(1, len(colours) - 1):
next = linear_gradient(colours[col], colours[col + 1], n_out)
for k in ("hex", "r", "g", "b"):
# Exclude first point to avoid duplicates
gradient_dict[k] += next[k][1:]
return gradient_dict
class ColourMap(ABC):
@abstractmethod
def __call__(self, v: float): ...
class LinearGradientColourMap(ColourMap):
def __init__(
self,
colours: list[str] | None = ["#ff0000", "#ffffff", "#0000ff"],
min_value: float | None = 0,
max_value: float | None = 1,
bins: int = 100,
):
self.colours = polylinear_gradient(colours, bins)
self.min, self.max = min_value, max_value
def __call__(self, v: float):
v = max(0, int((v - self.min) / (self.max - self.min) * 100) - 1)
if v >= len(self.colours["hex"]):
breakpoint()
return self.colours["hex"][v]
class RandomColourMap(ColourMap):
def __init__(self, random_state: int | list[int] | None = [2, 3, 4, 5, 6]):
self.rgen = np.random.default_rng(random_state)
def __call__(self, v: float):
return RGB_to_hex([x * 255 for x in self.rgen.random(3)])