# vim: expandtab:ts=4:sw=4
import colorsys
import numpy as np
import cv2
def create_unique_color_float(tag, hue_step=0.41):
"""Create a unique RGB color code for a given track id (tag).
The color code is generated in HSV color space by moving along the
hue angle and gradually changing the saturation.
Parameters
----------
tag : int
The unique target identifying tag.
hue_step : float
Difference between two neighboring color codes in HSV space (more
specifically, the distance in hue channel).
Returns
-------
(float, float, float)
RGB color code in range [0, 1]
"""
h, v = (tag * hue_step) % 1, 1. - (int(tag * hue_step) % 4) / 5.
r, g, b = colorsys.hsv_to_rgb(h, 1., v)
return r, g, b
def create_unique_color_uchar(tag, hue_step=0.41):
"""Create a unique RGB color code for a given track id (tag).
The color code is generated in HSV color space by moving along the
hue angle and gradually changing the saturation.
Parameters
----------
tag : int
The unique target identifying tag.
hue_step : float
Difference between two neighboring color codes in HSV space (more
specifically, the distance in hue channel).
Returns
-------
(int, int, int)
RGB color code in range [0, 255]
"""
r, g, b = create_unique_color_float(tag, hue_step)
return int(255 * r), int(255 * g), int(255 * b)
def apply_heat_map_uchar(values, mini=None, maxi=None):
"""Color values by their intensity.
Applies an HSV color map.
Parameters
----------
values: ndarray
The N dimensional array of intensities (ndim=1).
mini : Optional[float]
The intensity value of minimum saturation (lower bound of color map).
maxi : Optional[float]
The intensity value of maximum saturation (upper bound of color map).
Returns
-------
ndarray
The Nx3 shaped array of color codes in range [0, 255]. The dtype is
np.int.
"""
if len(values) == 0:
return np.zeros((0, ), dtype=np.uint8)
mini, maxi = mini or np.min(values), maxi or np.max(values)
valrange = maxi - mini
if valrange < np.finfo(valrange).eps:
valrange = np.inf
normalized = (255. * (values - mini) / valrange).astype(np.uint8)
colors = cv2.applyColorMap(normalized, cv2.COLORMAP_HSV)
return colors.astype(np.int).reshape(-1, 3)
def apply_heat_map_float(values, mini=None, maxi=None, dtype=np.float):
"""Color values by their intensity.
Applies an HSV color map.
Parameters
----------
values: ndarray
The N dimensional array of intensities (ndim=1).
mini : Optional[float]
The intensity value of minimum saturation (lower bound of color map).
maxi : Optional[float]
The intensity value of maximum saturation (upper bound of color map).
dtype: Optional[nd.dtype]
Target numeric type for output array.
Returns
-------
ndarray
The Nx3 shaped array of color codes in range [0, 1].
"""
if len(values) == 0:
return np.zeros((0, ), dtype=np.float)
heat_map_uchar = apply_heat_map_uchar(values, mini, maxi)
return heat_map_uchar.astype(dtype) / 255.
