HighChart - Best Label Angle

gistfile1.txt

from datetime import timedelta
from math import ceil, fabs, acos, sqrt, degrees
import Tkinter as tk
import tkFont
import datetime
import time
from random import randint

def get_chart_segments_from_total_of_days(date_days):
	if (date_days <= 31): # format x-axis daily
		return date_days

	elif (date_days < 217): # format x-axis weekly	
		return ceil(date_days / 7)

	elif (date_days <= 365): # format x-axis as monthly
		return ceil(date_days / 31)

def get_string_width_in_pixels(str):
	font = tkFont.Font(family="Lucida Grande", size=8)

	return (font.measure(str), font.metrics("linespace")) # string width and height in pixels

def calc_vector_module(x, y):
	return sqrt(x**2 + y**2)

def get_best_label_angle(date_from, date_to, chart_x_axis_width, chart_x_axis_labels = []):
	date_days = timedelta(seconds=(date_to - date_from)).days
	chart_x_axis_segments = get_chart_segments_from_total_of_days(date_days)

	chart_x_axis_segment_width_in_pixel = chart_x_axis_width / chart_x_axis_segments

	label_x_axis_pixel_size = 0

	for chart_x_axis_label in chart_x_axis_labels:
		chart_label_pixel_size = get_string_width_in_pixels(chart_x_axis_label)
		chart_x_axis_label_pixel_size = chart_label_pixel_size[0] # label x-axis lenght

		if (chart_x_axis_label_pixel_size > label_x_axis_pixel_size):
			label_x_axis_pixel_size = chart_x_axis_label_pixel_size

	x_axis_over_segment = (label_x_axis_pixel_size**2) - (chart_x_axis_segment_width_in_pixel**2)
	if (x_axis_over_segment <= 0):
		return 0.0

	(x, y) = (chart_x_axis_segment_width_in_pixel, sqrt(x_axis_over_segment))

	scalar_product = chart_x_axis_segment_width_in_pixel**2

	angle = degrees(acos(scalar_product/(chart_x_axis_segment_width_in_pixel*calc_vector_module(chart_x_axis_segment_width_in_pixel, x_axis_over_segment))))

	return round(angle, 1)

if __name__ == "__main__":
	root = tk.Tk()

	from_datetime = datetime.datetime.strptime('06-10-2012', '%d-%m-%Y')
	from_timestamp = time.mktime(from_datetime.timetuple())
	to_datetime = datetime.datetime.strptime('10-10-2012', '%d-%m-%Y')
	to_timestamp = time.mktime(to_datetime.timetuple())

	chart_labels = []

	for x in xrange(1, 2):
		day = randint(1, 31)
		month = randint(1, 12)
		year = randint(2012, 2020)

		chart_labels.append('14/1/2020')

	print get_best_label_angle(from_timestamp, to_timestamp, 30*4, chart_labels)