# Copyright (c) Facebook, Inc. and its affiliates.
"""
An awesome colormap for really neat visualizations.
Copied from Detectron, and removed gray colors.
"""
import numpy as np
__all__ = ["colormap", "random_color"]
# fmt: off
# RGB:
_COLORS = np.array(
[
0.000, 0.447, 0.741,
0.850, 0.325, 0.098,
0.929, 0.694, 0.125,
0.494, 0.184, 0.556,
0.466, 0.674, 0.188,
0.301, 0.745, 0.933,
0.635, 0.078, 0.184,
0.300, 0.300, 0.300,
0.600, 0.600, 0.600,
1.000, 0.000, 0.000,
1.000, 0.500, 0.000,
0.749, 0.749, 0.000,
0.000, 1.000, 0.000,
0.000, 0.000, 1.000,
0.667, 0.000, 1.000,
0.333, 0.333, 0.000,
0.333, 0.667, 0.000,
0.333, 1.000, 0.000,
0.667, 0.333, 0.000,
0.667, 0.667, 0.000,
0.667, 1.000, 0.000,
1.000, 0.333, 0.000,
1.000, 0.667, 0.000,
1.000, 1.000, 0.000,
0.000, 0.333, 0.500,
0.000, 0.667, 0.500,
0.000, 1.000, 0.500,
0.333, 0.000, 0.500,
0.333, 0.333, 0.500,
0.333, 0.667, 0.500,
0.333, 1.000, 0.500,
0.667, 0.000, 0.500,
0.667, 0.333, 0.500,
0.667, 0.667, 0.500,
0.667, 1.000, 0.500,
1.000, 0.000, 0.500,
1.000, 0.333, 0.500,
1.000, 0.667, 0.500,
1.000, 1.000, 0.500,
0.000, 0.333, 1.000,
0.000, 0.667, 1.000,
0.000, 1.000, 1.000,
0.333, 0.000, 1.000,
0.333, 0.333, 1.000,
0.333, 0.667, 1.000,
0.333, 1.000, 1.000,
0.667, 0.000, 1.000,
0.667, 0.333, 1.000,
0.667, 0.667, 1.000,
0.667, 1.000, 1.000,
1.000, 0.000, 1.000,
1.000, 0.333, 1.000,
1.000, 0.667, 1.000,
0.333, 0.000, 0.000,
0.500, 0.000, 0.000,
0.667, 0.000, 0.000,
0.833, 0.000, 0.000,
1.000, 0.000, 0.000,
0.000, 0.167, 0.000,
0.000, 0.333, 0.000,
0.000, 0.500, 0.000,
0.000, 0.667, 0.000,
0.000, 0.833, 0.000,
0.000, 1.000, 0.000,
0.000, 0.000, 0.167,
0.000, 0.000, 0.333,
0.000, 0.000, 0.500,
0.000, 0.000, 0.667,
0.000, 0.000, 0.833,
0.000, 0.000, 1.000,
0.000, 0.000, 0.000,
0.143, 0.143, 0.143,
0.857, 0.857, 0.857,
1.000, 1.000, 1.000
]
).astype(np.float32).reshape(-1, 3)
# fmt: on
[docs]def colormap(rgb=False, maximum=255):
"""
Args:
rgb (bool): whether to return RGB colors or BGR colors.
maximum (int): either 255 or 1
Returns:
ndarray: a float32 array of Nx3 colors, in range [0, 255] or [0, 1]
"""
assert maximum in [255, 1], maximum
c = _COLORS * maximum
if not rgb:
c = c[:, ::-1]
return c
[docs]def random_color(rgb=False, maximum=255):
"""
Args:
rgb (bool): whether to return RGB colors or BGR colors.
maximum (int): either 255 or 1
Returns:
ndarray: a vector of 3 numbers
"""
idx = np.random.randint(0, len(_COLORS))
ret = _COLORS[idx] * maximum
if not rgb:
ret = ret[::-1]
return ret
if __name__ == "__main__":
import cv2
size = 100
H, W = 10, 10
canvas = np.random.rand(H * size, W * size, 3).astype("float32")
for h in range(H):
for w in range(W):
idx = h * W + w
if idx >= len(_COLORS):
break
canvas[h * size : (h + 1) * size, w * size : (w + 1) * size] = _COLORS[idx]
cv2.imshow("a", canvas)
cv2.waitKey(0)