def computeColor()

in flow_color.py [0:0]

• 30 lines of code
• 1 McCabe index (conditional complexity)

def computeColor(u, v):

	colorwheel = makeColorwheel();
	nan_u = np.isnan(u)
	nan_v = np.isnan(v)
	nan_u = np.where(nan_u)
	nan_v = np.where(nan_v) 

	u[nan_u] = 0
	u[nan_v] = 0
	v[nan_u] = 0 
	v[nan_v] = 0

	ncols = colorwheel.shape[0]
	radius = np.sqrt(u**2 + v**2)
	a = np.arctan2(-v, -u) / np.pi
	fk = (a+1) /2 * (ncols-1) # -1~1 maped to 1~ncols
	k0 = fk.astype(np.uint8)	 # 1, 2, ..., ncols
	k1 = k0+1;
	k1[k1 == ncols] = 0
	f = fk - k0

	img = np.empty([k1.shape[0], k1.shape[1],3])
	ncolors = colorwheel.shape[1]
	for i in range(ncolors):
		tmp = colorwheel[:,i]
		col0 = tmp[k0]/255
		col1 = tmp[k1]/255
		col = (1-f)*col0 + f*col1
		idx = radius <= 1
		col[idx] = 1 - radius[idx]*(1-col[idx]) # increase saturation with radius    
		col[~idx] *= 0.75 # out of range
		img[:,:,2-i] = np.floor(255*col).astype(np.uint8)

	return img.astype(np.uint8)