"""
Copyright 2008 Free Software Foundation, Inc.
This file is part of GNU Radio

GNU Radio Companion is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

GNU Radio Companion is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
"""

from Constants import POSSIBLE_ROTATIONS

def get_rotated_coordinate(coor, rotation):
	"""
	Rotate the coordinate by the given rotation.
	@param coor the coordinate x, y tuple
	@param rotation the angle in degrees
	@return the rotated coordinates
	"""
	#handles negative angles
	rotation = (rotation + 360)%360
	assert rotation in POSSIBLE_ROTATIONS
	#determine the number of degrees to rotate
	cos_r, sin_r = {
		0: (1, 0),
		90: (0, 1),
		180: (-1, 0),
		270: (0, -1),
	}[rotation]
	x, y = coor
	return (x*cos_r + y*sin_r, -x*sin_r + y*cos_r)

def get_angle_from_coordinates((x1,y1), (x2,y2)):
	"""
	Given two points, calculate the vector direction from point1 to point2, directions are multiples of 90 degrees.
	@param (x1,y1) the coordinate of point 1
	@param (x2,y2) the coordinate of point 2
	@return the direction in degrees
	"""
	if y1 == y2:#0 or 180
		if x2 > x1: return 0
		else: return 180
	else:#90 or 270
		if y2 > y1: return 270
		else: return 90

def xml_encode(string):
	"""
	Encode a string into an xml safe string by replacing special characters.
	Needed for gtk pango markup in labels.
	@param string the input string
	@return output string with safe characters
	"""
	string = str(string)
	for char, safe in (
			('&', '&'),
			('<', '&lt;'),
			('>', '&gt;'),
			('"', '&quot;'),
			("'", '&apos;'),
	): string = string.replace(char, safe)
	return string