refactoring

colours.py

@@ -0,0 +1,103 @@
+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)])