path: root/graph.py

#!/usr/bin/env python
"""
 graph.py
 Activity that plots 1st and 2nd degree polynomials
 Part of the olpc.gr project
 Copyright (C) 2009 Xenofon Papadopoulos <xpapad@gmail.com>
"""

# This program 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 3 of the License, or
# (at your option) any later version.
# 
# This program 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, see <http://www.gnu.org/licenses/>.


import logging
from gettext import gettext as _
import os
import copy
import time
import math

import cairo
import pango
import gtk
import gtk.glade
import gtk.gdk
import gobject
from gobject import GObject
from math import sqrt, pow
from gtk.gdk import Color
from gtk import ListStore
from gtk import TreeViewColumn

# Check for equality between floats
SIGMA = 1e-6
def equals( x, val ):
	"""Check for equality between floats, using a Sigma of 1e-6"""
	return ( x == val or ( abs( x - val ) <= SIGMA ) )

def markup_func( column, cell, model, iter ):
	cell.props.markup = model.get_value( iter, 0 ).markup
	cell.props.foreground = model.get_value( iter, 0 ).color

def toggle_visible_func( column, cell, model, iter ):
	cell.props.active = model.get_value( iter, 0 ).visible

def toggle_info_func( column, cell, model, iter ):
	cell.props.active = model.get_value( iter, 0 ).info

def rounded_number( x, dec ):
	"""
	Return a text representation of a number with a specified number of
	decimal points.

	x	--	the number to convert to text
	dex	--	the number of decimal points
	"""
	x = float( str( x ) )
	fmt = '%%.%df' % ( dec )
	return fmt % ( x )

def translate_x( x, x_min, x_max, width ):
	return int( ( width * ( x - x_min ) ) / ( x_max - x_min ) )

def translate_y( y, y_min, y_max, height ):
	return int( height - ( height * ( y - y_min ) ) / ( y_max - y_min ) )

class Polynomial( GObject ):
	"""
	A class to handle polynomials of 1st and 2nd degree. It can be expanded
	to support polynomials of higher degree.
	It subclasses gobject.GObject so that it can be used in TreeView models,
	such as a ListStore.
	"""
	def __init__( self, degree ):
		"""Class constructor."""
		self.degree = degree
		self.coefficient = { 0: 0, 1: 0, 2: 0 }
		self.solved = False
		self.D = None
		self.x1 = None
		self.x2 = None
		self.limit = ( None, None )
		self.has_min = None
		self.cmap = gtk.gdk.colormap_get_system()
		self.fg_color = None
		self.is_visible = True
		self.show_marks = True

	def copy( self, obj ):
		"""
		Make a deep copy of the object. The copy.deepcopy() function will
		not work for GObjects.
		"""
		self.degree = obj.degree
		self.coefficient = copy.deepcopy( obj.coefficient )
		self.solved = obj.solved
		self.D = obj.D
		self.x1 = obj.x1
		self.x2 = obj.x2
		self.limit = obj.limit
		self.has_min = obj.has_min
		self.fg_color = obj.fg_color
		self.is_visible = obj.is_visible

	def equals( self, obj ):
		"""
		Check for equality between polynomials. Two polynomials are equal if
		their degree and all their coefficients are equal.
		"""
		if self.degree != obj.degree:
			return False
		degree = self.degree
		while degree >= 0:
			if not equals(self.coefficient[degree], obj.coefficient[degree]):
				return False
			degree = degree - 1
		return True

	def get_coefficient_name( self, degree ):
		"""
		Get a text representation of a coefficient's name. We assume that the
		polynomial's form is a1x^n + a2x^(n-1) + ... + a(n+1). We want to
		display a1 as 'a', a2 as 'b' etc. The exact representation is specified
		in the localization files.
		"""
		index = self.degree - degree + 1	
		name = 'a' + str( index )
		return _( name )
			
	def is_empty( self ):
		"""Check if all coefficients are zero."""
		degree = self.degree
		while degree >= 0:
			if not equals( self.coefficient[ degree ], 0 ):
				return False
			degree = degree - 1	
		return True

	def get_template_markup( self, use_f_notation = False ):
		"""
		Return a notation of the polynomial in Pango markup form. Do not
		use coefficient values; use coefficient names instead.

		use_f_notation	-- 	if True, then use f(x) = ... in the notation,
							otherwise use y = ...
		"""
		msg = ''
		if use_f_notation:
			msg = 'f( x ) = '
		else:
			msg = 'y = '
		degree = self.degree	
		while degree >= 0:
			if degree != self.degree:
				msg = msg + ' + '
			msg = msg + self.get_coefficient_name( degree )
			if degree >= 2:
				msg = msg + 'x<sup>%d</sup>' % ( degree )
			elif degree == 1:
				msg = msg + 'x'
			degree = degree - 1
		return msg

	def get_expression_markup( self, use_f_notation = False ):
		"""
		Return a notation of the polynomial in Pango markup form, by using
		coefficient values.

		use_f_notation	-- 	if True, then use f(x) = ... in the notation,
							otherwise use y = ...
		"""
		msg = ''
		added = False
		degree = self.degree	
		if use_f_notation:
			msg = 'f( x ) = '
		else:
			msg = 'y = '
		while degree >= 0:
			val = self.coefficient[ degree ]
			if equals( val, 0 ):
				degree = degree - 1
				continue

			# We do not display a coefficient of 1, unless it's last one
			if equals( abs( val ), 1.0 ) and degree > 0:
				strval = ''
			else:
				strval = '%.3g' % ( abs( val ) )

			# Display the sign seperated from the coefficient value
			# Only the first factor will be signed normally
			if not added:
				if val < 0:
					msg = msg + '-' + strval
				else:
					msg = msg + strval
			else:
				if val < 0:
					msg = msg + ' - ' + strval
				else:
					msg = msg + ' + ' + strval
			added = True

			# Add the factor notation
			if degree >= 2:
				msg = msg + 'x<sup>%d</sup>' % ( degree )
			elif degree == 1:
				msg = msg + 'x'
			degree = degree - 1

		# Handle the special case where all coefficients are zero
		if not added:
			msg = msg + '0'
		return msg

	def set_expression_markup( self, txt ):
		None

	def set_coefficient( self, degree, value ):
		"""Set the value of the specified coefficient."""
		val = float( str( value ) )
		if equals( val, 0 ):
			val = 0		# For the special case of -0.0
		self.coefficient[ degree ] = float( str( value ) )
		self.solved = False

	def get_coefficients( self ):
		"""Get the values of all coefficients, in order of descending degree."""
		degree = self.degree
		ret = []
		while degree >= 0:
			ret.append( self.coefficient[ degree ] )
			degree = degree - 1
		return ret

	def calculate( self, x ):
		"""Calculate the value of the polynomial for a given x."""
		degree = 0
		y = 0
		# Add in order of increasing degree to keep precision for high x values
		while degree <= self.degree:
			coef = self.coefficient[ degree ]
			val = pow( x, degree )
			y = coef * val + y
			degree = degree + 1
		return y		

	def solve( self ):
		"""
		Solve the polynomial. When the polynomial is solved, x1 and x2 are set
		to the solutions, and D specified the number of solutions:

		D = 0 : one solution (double, in case of a 2nd degree polynomial)
		D > 0 : two solutions (only in the case of a 2nd degree polynomial)
		D < 0 : no solutions
		"""
		a = self.coefficient[ 2 ]
		b = self.coefficient[ 1 ]
		c = self.coefficient[ 0 ]

		if equals( a, 0 ):
			if equals( b, 0 ):
				self.D = -1
				self.x1 = None
				self.x2 = None
				self.solved = True
				return
			self.D = 0
			self.x1 = -c / b
			self.x2 = self.x1
			self.solved = True
			return

		# Solution
		D = b * b - 4 * a * c
		self.D = D

		if equals( D, 0 ):
			x = -b / ( 2 * a )
			self.x1 = x
			self.x2 = x
		elif D > 0:
			self.x1 = ( -b - sqrt( D ) ) / ( 2 * a )
			self.x2 = ( -b + sqrt( D ) ) / ( 2 * a )
			
		else:
			self.x1 = None
			self.x2 = None

		# Akrotata
		x = -b / ( 2 * a )
		y = -D / ( 4 * a )
		if equals( x, 0 ):
			x = 0
		if equals( y, 0 ):
			y = 0
		self.limit = ( x, y )
		if a > 0:
			self.has_min = True
		else:
			self.has_min = False

		self.solved = True

	def get_points_d1( self ):
		"""
		Return a list of points of interest for a 1st degree polynomial.
		Each list element is a tuple of point coordinations.
		Points of interest are the points of intersection of the graph with
		the axis (x=0, y=0)
		"""
		a, b = self.coefficient[ 1 ], self.coefficient[ 0 ]
		ret = []

		# x = 0
		x = 0
		y = self.calculate( x )
		ret.append( ( x, y ) )

		# y = 0
		y = 0
		if not equals( a, 0 ):
			x = -b/a
			ret.append( ( x, y ) )
		return ret	

	def get_points_d2( self ):
		"""
		Return a list of points of interest for a 2nd degree polynomial.
		Each list element is a tuple of point coordinations.
		Points of interest are the points of intersection of the graph with
		the axis (x=0, y=0)
		"""
		ret = []

		# x = 0
		x = 0
		y = self.calculate( x )
		ret.append( ( x, y ) )

		# y = 0
		self.solve()
		if equals( self.D, 0 ):
			x = self.x1
			ret.append( ( x, 0 ) )
		elif self.D > 0:
			for x in [ self.x1, self.x2 ]:
				ret.append( ( x, 0 ) )	
			
		return ret

	def get_points( self ):
		"""
		Return a list of points of interest for a polynomial.
		Each list element is a tuple of point coordinations.
		Points of interest are the points of intersection of the graph with
		the axis (x=0, y=0)
		"""
		if self.degree == 1:
			return self.get_points_d1()
		elif self.degree == 2:
			return self.get_points_d2()
		else:
			return []

	def get_second_degree( self ):
		"""
		Return a 2nd degree polynomial with the same coefficients as a 1st
		degree one. This is used to solve a system of polynomials of 1st and
		2nd degree by converting them all to 2nd degree.
		"""
		poly = Polynomial( 2 )
		if self.degree == 2:
			poly.copy( self )
		else:
			poly.coefficient[ 1 ] = self.coefficient[ 1 ]
			poly.coefficient[ 0 ] = self.coefficient[ 0 ]
			poly.solved = False
		return poly

	def get_common_points( self, poly ):
		"""
		Return a list of intersection points between self and poly. 
		Each list item is a tuple of point coordinations.
		"""
		ret = []

		# Get some 2nd degree polynomials
		if self.degree == 1:
			p1 = self.get_second_degree()
		else:
			p1 = self
		if poly.degree == 1:
			p2 = poly.get_second_degree()
		else:
			p2 = poly

		# We need the common solutions of p1, p2
		p = Polynomial( 2 )
		for i in [ 2, 1, 0 ]:
			p.coefficient[ i ] = p1.coefficient[ i ] - p2.coefficient[ i ]
		p.solve()
		if equals( p.D, 0 ):
			x = p.x1
			y = p1.calculate( x )
			ret.append( ( x, y ) )
		elif p.D > 0:
			for x in [ p.x1, p.x2 ]:
				y = p1.calculate( x )
				ret.append( ( x, y ) )	
		return ret	
	
	markup = property( get_expression_markup )
	"""The markup property."""

	def get_color( self ):
		"""color property getter."""
		return self.fg_color

	def set_color( self, val ):
		"""color property setter."""
		cmap = gtk.gdk.colormap_get_system()
		self.fg_color = cmap.alloc_color( val )

	color = property( get_color )
	"""The color property."""

	def get_visible( self ):
		"""visible property getter."""
		return self.is_visible

	def set_visible( self, state ):
		"""visible property setter."""
		self.is_visible = state

	def toggle_visible( self ):
		"""Toggles the visible property."""
		self.is_visible = not self.is_visible

	visible = property( get_visible, set_visible )	
	"""The visible property."""

	def set_show_marks( self, state ):
		"""info property setter."""
		self.show_marks = state

	def get_show_marks( self ):
		"""info property getter."""
		return self.show_marks

	def toggle_info( self ):
		"""Toggles the info property."""
		self.show_marks = not self.show_marks

	info = property( get_show_marks, set_show_marks )
	"""The info property."""

	def get_x_bounds( self, axis, width, height, real_coords = False ):
		"""
		Return a tuble of x coordinates that restict the visible area of the
		polynomial on the specified screen width.

		real_coords	--	If True, then coordinates are real.
		"""
		axis_x_min, axis_x_max, axis_y_min, axis_y_max = axis
		step = ( axis_x_max - axis_x_min ) / width
		x_min = x_max = None
		xi_min = xi_max = None

		x = axis_x_min
		while x <= axis_x_max:
			y = self.calculate( x )
			xi = translate_x( x, axis_x_min, axis_x_max, width )
			yi = translate_y( y, axis_y_min, axis_y_max, height )
			if ( xi >= 0 and xi <= width and yi >= 0 and yi <= height ):
				if xi_min == None:
					xi_min = xi_max = xi
					x_min = x_max = x
					x = x + step
					continue
				if xi_max < xi:
					xi_max = xi
					x_max = x
			x = x + step

		if real_coords:
			return ( xi_min, xi_max )
		else:
			return ( x_min, x_max )	
		
	def get_animator( self, wnd, gc, pixmap, axis ):
		"""Get the polygon's animator"""		
		if self.degree == 1:
			ani = Animator_Degree_1( self, wnd, gc, pixmap, axis )
		else:
			ani = None
		return ani

class Point:
	"""
	A helper class to handle points of interest of polynomials on the x-y
	axis. It contains the coordinates, and some text to display when the user
	clicks on (or near) them.
	Each point has an associated rectangle of specified size that constitutes
	the 'active' area around the point. The user may click on the rectangle
	to get info about the point.
	Point.x and Point.y are REAL, screen coordinates.
	"""
	def __init__(self, x, y, size = 8):
		"""Class constructor."""
		self.x = x
		self.y = y
		self.size = size
		self.txt = ''
		self.color = None

	def set_text( self, txt ):
		"""Set the text displayed when the user clicks near the points."""	
		self.txt = txt

	def set_poly_coords( self, x, y ):
		"""Set the coordinates of the rectangle displayed at this point."""
		self.poly_x = x
		self.poly_y = y

	def draw( self, wnd, gc, size = 8 ):
		"""Draw a rectangle around this point, with te specified size."""
		old_fg = None
		if size != self.size:
			self.size = size
		if self.color != None:
			old_fg = gc.foreground
			gc.set_foreground( self.color )
		s = self.size
		x,y = self.x,self.y
		wnd.draw_rectangle( gc, True, x - s / 2, y - s / 2, s + 1, s + 1 )
		if old_fg != None:
			gc.set_foreground( old_fg )

	def set_color( self, color ):
		"""Set the color of this point."""
		self.color = color

	def in_window( self, xi, yi ):
		"""Return True if xi, yi reside inside the rectangle of this point."""
		s = self.size
		x,y = self.x, self.y
		if xi < x - s/2 or xi > x + s/2:
			return False
		if yi < y - s/2 or yi > y + s/2:
			return False
		return True

	def get_markup( self ):
		"""Return a formatted string of the point's text."""
		x,y = self.poly_x, self.poly_y
		msg = "x=%s\ny=%s" % ( rounded_number( x, 2 ), rounded_number( y, 2 ) )
		return msg

class Animator:
	"""A helper class to handle animation effects."""
	def __init__(self, poly, wnd, gc, pixmap, axis ):
		self.round = 0
		self.poly = poly
		self.wnd = wnd
		self.gc = gc
		self.pixmap = pixmap
		self.axis = axis
		self.width, self.height = pixmap.get_size()
		self.x_min, self.x_max = poly.get_x_bounds( axis, self.width, self.height )
		self.xi_min = self.translate_x( self.x_min )
		self.xi_max = self.translate_x( self.x_max )

	def translate_x( self, x ):
		axis_x_min, axis_x_max, axis_y_min, axis_y_max = self.axis
		return translate_x( x, axis_x_min, axis_x_max, self.width )

	def translate_y( self, y ):
		axis_x_min, axis_x_max, axis_y_min, axis_y_max = self.axis
		return translate_y( y, axis_y_min, axis_y_max, self.height )

	def animate(self):
		"""
		This is called whenever pixmap needs an update. The method should just
		draw on the pixmap, updates are handled elsewhere.
		
		Return False to end the animation.
		"""
		self.round = self.round + 1
		return self.round != 5
	
	def next_round(self):
		"""Next animator round."""
		self.round = self.round + 1

class Animator_Degree_1( Animator ):
	def __init__(self, poly, wnd, gc, pixmap, axis ):
		Animator.__init__(self, poly, wnd, gc, pixmap, axis)
		self.a = poly.coefficient[ 1 ]
		
		self.pixbufs = [
			self.pixbuf_from_img( "images/bike_rider_1.png", self.a ),
			self.pixbuf_from_img( "images/bike_rider_2.png", self.a ),
			self.pixbuf_from_img( "images/bike_rider_3.png", self.a ) ]

	def pixbuf_from_img( self, img, theta ):
		# Read the bike image
		image = cairo.ImageSurface.create_from_png( img )
		# Calculate the size of the rotated image
		w, h = image.get_width(), image.get_height()
		r = abs( math.atan( theta ) )
		sinf = math.sin( r )
		cosf = math.cos( r )
		new_w = int( w * cosf + h * sinf )
		new_h = int( w * sinf + h * cosf )

		# Create a rotated image of the appropriate size
		surface = cairo.ImageSurface( cairo.FORMAT_ARGB32, new_w, new_h )
		context = cairo.Context( surface )

		# Test rectangle
		"""
		context.set_line_width( 1 )
		context.set_source_rgba( 1, 0, 0 )
		context.rectangle( 0, 0, new_w, new_h )
		context.stroke()
		"""

		if theta >= 0:
			context.translate( 0, w * sinf )
			context.rotate( -r )
		else:
			context.translate( h * sinf, 0 )
			context.rotate( r )
		context.set_source_surface( image )
		context.paint()

		if theta >= 0:
			hypo = h + w * sinf * cosf
			dx = - int( sinf * hypo )
			dy = - int( cosf * hypo )
		else:
			hypo = h * cosf * cosf
			dx = int( sinf * hypo )
			dy = - int( cosf * hypo )
			
		data = surface.get_data()
		width, height = surface.get_width(), surface.get_height()
		stride = surface.get_stride()

		pixbuf = gtk.gdk.pixbuf_new_from_data( data, gtk.gdk.COLORSPACE_RGB, True, 8, width, height, stride )
		return ( pixbuf, dx, dy )

	def animate(self):
		# Get image info
		width, height = self.pixmap.get_size()
		pb, dx, dy = self.pixbufs[ self.round % len( self.pixbufs ) ]
		iw,ih = pb.get_width(), pb.get_height()

		axis_x_min, axis_x_max, axis_y_min, axis_y_max = self.axis
		x_start = axis_x_min
		x_end = axis_x_max

		if self.x_min == None:
			return False

		step = ( self.x_max - self.x_min ) / 45
		x = self.x_min + step * self.round
		self.round = self.round + 1
		if x >= self.x_max:
			return False

		y = self.poly.calculate( x )
		xi, yi = self.translate_x( x ), self.translate_y( y )

		posx = xi + dx
		posy = yi + dy
		self.pixmap.draw_pixbuf( self.gc, pb, 0, 0, posx, posy, iw, ih )
		return True

class Animator_Degree_2( Animator ):
	def __init__(self, poly, wnd, gc, pixmap, axis ):
		Animator.__init__(self, poly, wnd, gc, pixmap, axis)
		self.a = poly.coefficient[ 1 ]
		
		self.pixbufs = [
			self.pixbuf_from_img( "images/bike_rider_1.png", self.a ),
			self.pixbuf_from_img( "images/bike_rider_2.png", self.a ),
			self.pixbuf_from_img( "images/bike_rider_3.png", self.a ) ]

	def pixbuf_from_img( self, img, theta ):
		# Read the bike image
		image = cairo.ImageSurface.create_from_png( img )
		# Calculate the size of the rotated image
		w, h = image.get_width(), image.get_height()
		r = abs( math.atan( theta ) )
		sinf = math.sin( r )
		cosf = math.cos( r )
		new_w = int( w * cosf + h * sinf )
		new_h = int( w * sinf + h * cosf )

		# Create a rotated image of the appropriate size
		surface = cairo.ImageSurface( cairo.FORMAT_ARGB32, new_w, new_h )
		context = cairo.Context( surface )

		# Test rectangle
		"""
		context.set_line_width( 1 )
		context.set_source_rgba( 1, 0, 0 )
		context.rectangle( 0, 0, new_w, new_h )
		context.stroke()
		"""

		if theta >= 0:
			context.translate( 0, w * sinf )
			context.rotate( -r )
		else:
			context.translate( h * sinf, 0 )
			context.rotate( r )
		context.set_source_surface( image )
		context.paint()

		if theta >= 0:
			hypo = h + w * sinf * cosf
			dx = - int( sinf * hypo )
			dy = - int( cosf * hypo )
		else:
			hypo = h * cosf * cosf
			dx = int( sinf * hypo )
			dy = - int( cosf * hypo )
			
		data = surface.get_data()
		width, height = surface.get_width(), surface.get_height()
		stride = surface.get_stride()

		pixbuf = gtk.gdk.pixbuf_new_from_data( data, gtk.gdk.COLORSPACE_RGB, True, 8, width, height, stride )
		return ( pixbuf, dx, dy )

	def animate(self):
		# Get image info
		width, height = self.pixmap.get_size()
		pb, dx, dy = self.pixbufs[ self.round % len( self.pixbufs ) ]
		iw,ih = pb.get_width(), pb.get_height()

		axis_x_min, axis_x_max, axis_y_min, axis_y_max = self.axis
		x_start = axis_x_min
		x_end = axis_x_max

		if self.x_min == None:
			return False

		step = ( self.x_max - self.x_min ) / 45
		x = self.x_min + step * self.round
		self.round = self.round + 1
		if x >= self.x_max:
			return False

		y = self.poly.calculate( x )
		xi, yi = self.translate_x( x ), self.translate_y( y )

		posx = xi + dx
		posy = yi + dy
		self.pixmap.draw_pixbuf( self.gc, pb, 0, 0, posx, posy, iw, ih )
		return True

# The main module class
class Graph:
	"""
	The main application class.
	"""
	def __init__(self, runaslib=True):
		"""Class constructor."""
		# Load Glade XML
		self.xml = gtk.glade.XML( "graph.glade" )

		# Make sure application shuts down if main window closes
		self.w = self.xml.get_widget( 'window_graph' )
		self.w.connect( 'delete_event', gtk.main_quit )

		# Get Windows child
		self.w_child = self.w.get_child()

		# Get a 2nd degree polynomial
		self.poly = None

		# Get widgets
		self.label_info = self.xml.get_widget( 'label_info' )
		self.txt_func_a_1 = self.xml.get_widget( 'txt_func_a_1' )
		self.txt_func_b_1 = self.xml.get_widget( 'txt_func_b_1' )
		self.txt_func_a_2 = self.xml.get_widget( 'txt_func_a_2' )
		self.txt_func_b_2 = self.xml.get_widget( 'txt_func_b_2' )
		self.txt_func_c_2 = self.xml.get_widget( 'txt_func_c_2' )

		# Axis widgets
		self.txt_axis_x_min = self.xml.get_widget( 'txt_axis_x_min' )
		self.txt_axis_x_max = self.xml.get_widget( 'txt_axis_x_max' )
		self.txt_axis_x_step = self.xml.get_widget( 'txt_axis_x_step' )
		self.txt_axis_y_min = self.xml.get_widget( 'txt_axis_y_min' )
		self.txt_axis_y_max = self.xml.get_widget( 'txt_axis_y_max' )
		self.txt_axis_y_step = self.xml.get_widget( 'txt_axis_y_step' )

		# Main tab buttons
		btn_draw = self.xml.get_widget( 'btn_draw' )
		btn_draw.connect( 'clicked', self.on_draw_clicked )
		self.set_button_icon( btn_draw, 'draw.svg' )

		btn_store = self.xml.get_widget( 'btn_store' )
		btn_store.connect( 'clicked', self.on_store_clicked )
		self.set_button_icon( btn_store, 'archive.svg' )

		self.btn_delete = self.xml.get_widget( 'btn_delete' )
		self.btn_delete.connect( 'clicked', self.on_delete_clicked )
		self.set_button_icon( self.btn_delete, 'delete.svg' )

		self.btn_color = self.xml.get_widget( 'btn_color' )
		self.btn_color.connect( 'clicked', self.on_color_clicked )
		self.set_button_icon( self.btn_color, 'color.svg' )
		self.color_dlg = None

		self.btn_animate = self.xml.get_widget( 'btn_animate' )
		self.btn_animate.connect( 'clicked', self.on_animate_clicked )
		self.set_button_icon( self.btn_animate, 'animate.svg' )

		# Config tab buttons
		btn_reset = self.xml.get_widget( 'btn_reset' )
		btn_reset.connect( 'clicked', self.on_reset_clicked )
		self.set_button_icon( btn_reset, 'undo.svg' )

		self.toggle_show_axis_numbers = self.xml.get_widget( "toggle_show_axis_numbers" )
		self.set_button_icon( self.toggle_show_axis_numbers, 'ruller.svg' )

		self.toggle_show_grid = self.xml.get_widget( "toggle_show_grid" )
		self.set_button_icon( self.toggle_show_grid, 'grid.svg' )

		# Setup draw area
		self.draw = self.xml.get_widget( 'drawing_area' )
		self.draw.connect( 'motion_notify_event', self.update_coords )
		self.draw.connect( 'button_press_event', self.on_draw_button_pressed )
		self.draw.connect( 'configure_event', self.on_draw_configure )
		self.draw.connect( "expose_event", self.on_draw_expose )
		self.draw.get_pango_context().set_font_description( pango.FontDescription( "fixed 6" ) )
		self.pixmap = None
		self.old_pixmap = None
		self.gc = None
		self.width = self.height = 0

		# More event handlers
		self.notebook = self.xml.get_widget( 'notebook_app' )
		self.notebook.connect( 'switch_page', self.on_tab_switched )

		# Template labels
		self.notebook_degree = self.xml.get_widget( 'notebook_degree' )
		self.list_functions = self.xml.get_widget( 'list_functions' )
		self.list_functions.connect( "cursor-changed", self.on_functions_updated )
		# setup the view ...
		cellr = gtk.CellRendererText()
		col = TreeViewColumn( _( 'Functions' ), cellr )
		col.set_cell_data_func( cellr, markup_func )
		col.set_expand( True )
		self.list_functions.append_column( col )

		cellr = gtk.CellRendererToggle()
		cellr.connect( "toggled", self.on_visible_toggled )
		pb = gtk.gdk.pixbuf_new_from_file( "icons/eye.png" )
		img = gtk.Image()
		img.set_from_pixbuf( pb )
		img.show()
		col = TreeViewColumn( None, cellr )
		col.set_widget( img )
		col.set_cell_data_func( cellr, toggle_visible_func )
		col.set_expand( False )
		self.list_functions.append_column( col )

		cellr = gtk.CellRendererToggle()
		cellr.connect( "toggled", self.on_info_toggled )
		pb = gtk.gdk.pixbuf_new_from_file( "icons/information.png" )
		img = gtk.Image()
		img.set_from_pixbuf( pb )
		img.show()
		col = TreeViewColumn( None, cellr )
		col.set_widget( img )
		col.set_cell_data_func( cellr, toggle_info_func )
		col.set_expand( False )
		self.list_functions.append_column( col )

		# ... and the model
		self.list_functions.set_model( ListStore( gobject.TYPE_PYOBJECT ) )

		# Labels
		self.label_function_1_template = self.xml.get_widget( 'label_function_1_template' )
		self.label_function_1_template.set_markup( Polynomial( 1 ).get_template_markup() )
		self.label_function_2_template = self.xml.get_widget( 'label_function_2_template' )
		self.label_function_2_template.set_markup( Polynomial( 2 ).get_template_markup() )

		# Info label
		self.label_info = self.xml.get_widget( 'label_info' )
		self.label_info.set_text( '' )
		#self.label_info.modify_font( pango.FontDescription( "sans 14" ) )

		self.label_coords = self.xml.get_widget( 'label_coords' )
		self.label_coords.set_text( '' )

		# a[n] labels
		self.xml.get_widget( "label_a_1" ).set_text( _( 'a1' ) + ' = ' ) 
		self.xml.get_widget( "label_b_1" ).set_text( _( 'a2' ) + ' = ' ) 
		self.xml.get_widget( "label_a_2" ).set_text( _( 'a1' ) + ' = ' ) 
		self.xml.get_widget( "label_b_2" ).set_text( _( 'a2' ) + ' = ' ) 
		self.xml.get_widget( "label_c_2" ).set_text( _( 'a3' ) + ' = ' ) 

		# More labels
		self.xml.get_widget( "label_from_1" ).set_text( _( 'From' ) )
		self.xml.get_widget( "label_from_2" ).set_text( _( 'From' ) )
		self.xml.get_widget( "label_until_1" ).set_text( _( 'To' ) )
		self.xml.get_widget( "label_until_2" ).set_text( _( 'To' ) )
		self.xml.get_widget( "label_step_1" ).set_text( _( 'Step' ) )
		self.xml.get_widget( "label_step_2" ).set_text( _( 'Step' ) )
		self.xml.get_widget( "label_axis" ).set_text( _( 'Axis' ) )
		self.xml.get_widget( "label_dec_1" ).set_text( _( 'Decimals' ) )
		self.xml.get_widget( "label_dec_2" ).set_text( _( 'Decimals' ) )

		# Spin
		self.spin_axis_x_dec = self.xml.get_widget( "spin_axis_x_dec" )
		self.spin_axis_y_dec = self.xml.get_widget( "spin_axis_y_dec" )
		self.spin_axis_x_dec.set_editable( False )
		self.spin_axis_y_dec.set_editable( False )

		# Tab labels
		self.xml.get_widget( "label_tab_graph" ).set_text( _( 'Graph Tab' ) )
		self.xml.get_widget( "label_tab_config" ).set_text( _( 'Config Tab' ) )

		# Get parameters
		self.txt_func_a_1 = self.xml.get_widget( 'txt_func_a_1' )
		self.txt_func_b_1 = self.xml.get_widget( 'txt_func_b_1' )
		self.txt_func_a_2 = self.xml.get_widget( 'txt_func_a_2' )
		self.txt_func_b_2 = self.xml.get_widget( 'txt_func_b_2' )
		self.txt_func_c_2 = self.xml.get_widget( 'txt_func_c_2' )

		# Setup colors
		cmap = gtk.gdk.colormap_get_system()
		self.color_bg = cmap.alloc_color( '#FFFFCC' )
		self.marked_point_color = cmap.alloc_color( '#00FF00' )

		# Setup initial axis values etc
		self.validate_parameters( None )
		self.update_buttons_status()

		# self.widget will be attached to the Activity
		# This can be any GTK widget except a window
		self.widget = self.w_child
		if not runaslib:
			self.w.show_all()
			gtk.main()	

	def set_button_icon( self, btn, file, width = 40, height = 40 ):
		fname = "icons/" + file
		pb = gtk.gdk.pixbuf_new_from_file( fname )
		pb = pb.scale_simple( width, height, gtk.gdk.INTERP_BILINEAR )
		img = gtk.Image()
		img.set_from_pixbuf( pb )
		btn.set_label( '' )
		btn.set_image( img )

	def validate_parameters( self, poly ):
		# Set default function factors
		for txt in ( self.txt_func_a_1, self.txt_func_b_1, self.txt_func_a_2, self.txt_func_b_2, self.txt_func_c_2  ):
			if ( txt.get_text() == '' ):
				txt.set_text( '0' )

		# Override function factors
		try:
			a1 = float( self.txt_func_a_1.get_text() )
			b1 = float( self.txt_func_b_1.get_text() )
			a2 = float( self.txt_func_a_2.get_text() )
			b2 = float( self.txt_func_b_2.get_text() )
			c2 = float( self.txt_func_c_2.get_text() )
		except:
			return False

		# Set default axis values
		if self.txt_axis_x_min.get_text() == '':
			self.txt_axis_x_min.set_text( '-10' )
		if self.txt_axis_x_max.get_text() == '':
			self.txt_axis_x_max.set_text( '10' )
		if self.txt_axis_x_step.get_text() == '':
			self.txt_axis_x_step.set_text( '1' )

		if self.txt_axis_y_min.get_text() == '':
			self.txt_axis_y_min.set_text( '-10' )
		if self.txt_axis_y_max.get_text() == '':
			self.txt_axis_y_max.set_text( '10' )
		if self.txt_axis_y_step.get_text() == '':
			self.txt_axis_y_step.set_text( '1' )

		# Override axis values
		try:
			self.axis_x_min = float( self.txt_axis_x_min.get_text() );
			self.axis_x_max = float( self.txt_axis_x_max.get_text() );
			self.axis_x_step = float( self.txt_axis_x_step.get_text() );

			self.axis_y_min = float( self.txt_axis_y_min.get_text() );
			self.axis_y_max = float( self.txt_axis_y_max.get_text() );
			self.axis_y_step = float( self.txt_axis_y_step.get_text() );
		except:
			return False

		# Update the poly coefficients
		if poly != None:
			if poly.degree == 2:
				poly.set_coefficient( 2, a2 )
				poly.set_coefficient( 1, b2 )
				poly.set_coefficient( 0, c2 )
			elif poly.degree == 1:
				poly.set_coefficient( 1, a1 )
				poly.set_coefficient( 0, b1 )
			else:
				return False

		# Eveything is fine
		return True

	def get_selected_function_iter( self ):
		tree = self.list_functions
		select = tree.get_selection()
		if select == None:
			return
		tree, iter = select.get_selected()
		return iter

	def on_visible_toggled( self, renderer, path, *args ):
		model = self.list_functions.get_model()
		iter = model.get_iter( path )
		if iter == None:
			return		
		poly = model.get_value( iter, 0 )
		poly.toggle_visible()
		self.refresh()

	def on_info_toggled( self, renderer, path, *args ):
		model = self.list_functions.get_model()
		iter = model.get_iter( path )
		if iter == None:
			return		
		poly = model.get_value( iter, 0 )
		poly.toggle_info()
		self.refresh()

	def update_buttons_status( self ):
		iter = self.get_selected_function_iter()
		if iter == None:
			self.btn_delete.set_sensitive( False )
			self.btn_color.set_sensitive( False )
			self.btn_animate.set_sensitive( False )
		else:
			self.btn_delete.set_sensitive( True )
			self.btn_color.set_sensitive( True )
			self.btn_animate.set_sensitive( True )

	def update_all_buttons( self, state ):
		self.notebook.set_sensitive( state )	

	def on_functions_updated( self, tree, *args ):
		self.update_buttons_status( )
	
	def on_animate_clicked( self, *args ):
		self.animate_selected_function()
		return
		
	def on_color_clicked( self, *args ):
		iter = self.get_selected_function_iter()
		if iter == None:
			return
		poly = self.list_functions.get_model().get_value( iter, 0 )
		old_color = poly.get_color()
		dlg  = gtk.ColorSelectionDialog( _( 'Select a color' ) )
		ret = dlg.run()
		if ret == gtk.RESPONSE_OK:
			color = dlg.colorsel.get_current_color()
			if color != old_color:
				poly.set_color( color )
				self.refresh()
		dlg.destroy()

	def on_tab_switched( self, notebook, page, page_num ):
		if page_num == 0:
			self.refresh()

	def on_delete_clicked( self, *args ):
		iter = self.get_selected_function_iter()
		if iter == None:
			return
		model = self.list_functions.get_model()
		model.remove( iter )
		self.update_buttons_status()
		self.refresh()	
	
	def on_draw_button_pressed( self, widget, event ):
		if ( event.button != 1 ):
			return
		wnd = self.pixmap
		gc = self.gc
		for pt in self.points:
			if pt.in_window( event.x, event.y ):
				self.label_info.set_markup( pt.get_markup() )
				for pto in self.points:
					pto.set_color( None )
					pto.draw( wnd, self.gc )
				pt.set_color( self.marked_point_color )
				pt.draw( wnd, gc )
				self.draw.queue_draw()
				return				
	
	def on_reset_clicked( self, *args ):
		self.txt_axis_x_min.set_text( '-10' )
		self.txt_axis_x_max.set_text( '10' )
		self.txt_axis_x_step.set_text( '1' )
		self.txt_axis_y_min.set_text( '-10' )
		self.txt_axis_y_max.set_text( '10' )
		self.txt_axis_y_step.set_text( '1' )

	def refresh( self ):
		wnd = self.pixmap
		gc = self.gc
		visible_polys = []
		points = []
		
		# Get current window dimensions
		self.width, self.height = self.pixmap.get_size()
		self.draw.set_size_request( self.width, self.height )

		wnd.draw_rectangle( self.draw.get_style().white_gc, True, 0, 0, self.width, self.height )
		gc.set_background( self.color_bg )
		self.points = [ ]
		self.draw_axis( wnd, gc )

		# Get a list of all visible polynomials
		model = self.list_functions.get_model()
		iter = model.get_iter_first()
		while iter != None:
			poly = model.get_value( iter, 0 )
			if poly.get_visible():
				visible_polys.append( poly )		
			iter = model.iter_next( iter )
		if self.poly != None:
			visible_polys.append( self.poly )

		# Get a list of points of interest
		m = len( visible_polys )
		i = 0
		for poly in visible_polys:
			self.draw_function( wnd, gc, poly )
			if not poly.info:
				continue

			points = points +  poly.get_points()
			t = i + 1
			while t < m:
				p2 = visible_polys[ t ]
				if not p2.info:
					t = t + 1
					continue
				points = points + poly.get_common_points( p2 )
				t = t + 1
			i = i + 1

		# Now we have the points. Create the data
		for p in points:
			x,y = p
			xi, yi = self.translate_x( x ), self.translate_y( y )
			pt = Point( xi, yi )
			pt.set_poly_coords( x, y )
			pt.draw( wnd, gc )
			self.points.append( pt )

		self.draw.queue_draw()
		
	def copy_pixmap( self, pixmap ):
		width, height = pixmap.get_size()
		cp = gtk.gdk.Pixmap( pixmap, width, height, -1 )
		cp.draw_drawable( self.gc, pixmap, 0, 0, 0, 0, width, height )
		return cp

	def animate( self, animator ):
		w, h = self.pixmap.get_size()
		self.pixmap.draw_drawable( self.gc, self.old_pixmap, 0, 0, 0, 0, w, h ) 
		self.draw.queue_draw()
		ret = animator.animate()
		self.draw.queue_draw()
		if ret == False:
			self.pixmap.draw_drawable( self.gc, self.old_pixmap, 0, 0, 0, 0, w, h ) 
			self.old_pixmap = None
			return False
		return True
		
	# Some animations
	def animate_selected_function( self ):
		# Get the selected polynomial
		iter = self.get_selected_function_iter()
		if iter == None:
			return
		poly = self.list_functions.get_model().get_value( iter, 0 )

		# Store the pixmap
		self.old_pixmap = self.copy_pixmap( self.pixmap )

		# Queue the animation
		axis = ( self.axis_x_min, self.axis_x_max, self.axis_y_min, self.axis_y_max )
		ani = poly.get_animator( self.draw.window, self.gc, self.pixmap, axis )
		if ani != None:
			gobject.timeout_add( 100, self.animate, ani )

	# This is called when the drawing area is created, and every time its
	# size changes
	def on_draw_configure( self, widget, event ):
		x,y,width,height = widget.get_allocation()
		self.pixmap = gtk.gdk.Pixmap( widget.get_window(), width, height, -1 )
		self.pixmap.draw_rectangle( widget.get_style().white_gc, True, 0, 0, width, height )
		if self.gc == None:
			self.gc = self.pixmap.new_gc( )
		self.refresh()

	def on_draw_expose( self, widget, event ):
		x, y, width, height = event.area
		wnd = widget.window
		wnd.draw_drawable( self.gc, self.pixmap, x, y, x, y, width, height )
		return False

	def poly_is_stored( self, poly ):
		model = self.list_functions.get_model()
		iter = model.get_iter_first()
		while iter != None:
			p = model.get_value( iter, 0 )	
			if p.equals( poly ):
				return True
			iter = model.iter_next( iter )
		return False

	def on_store_clicked( self, *args ):
		if self.notebook_degree.get_current_page() == 0:
			poly = Polynomial( 1 )
		else:
			poly = Polynomial( 2 )
		if not self.validate_parameters( poly ):
			# TODO: Warn about error
			return

		# Ignore stored polynomials
		if poly.is_empty() or self.poly_is_stored( poly ):
			return
		self.poly = None

		# add to model
		model = self.list_functions.get_model()
		model.append( [ poly ] )
		self.refresh()
		
	def on_draw_clicked( self, *args ):
		if self.notebook_degree.get_current_page() == 0:
			poly = Polynomial( 1 )
		else:
			poly = Polynomial( 2 )

		# Get and validate function arguments
		if not self.validate_parameters( poly ):
			# TODO: Warn about error
			return

		if poly.is_empty():
			return
		self.poly = poly
		self.refresh()

	# Draw the axes of the graph
	def draw_axis( self, wnd, gc ):
		width = self.width
		height = self.height
		x0 = self.translate_x( 0 )
		y0 = self.translate_y( 0 )
		w = gc.line_width
		gc.line_width = 2
		# y-axis (x=0)
		wnd.draw_line( gc, x0, 0, x0, height ) 
		# x-axis (y=0)
		wnd.draw_line( gc, 0, y0, width, y0 )
		gc.line_width = w
		self.draw_marks( wnd, gc )

	def draw_marks( self, wnd, gc ):
		x0 = self.translate_x( 0 )
		y0 = self.translate_y( 0 )
		width = self.width
		height = self.height
		show_numbers = self.toggle_show_axis_numbers.get_active()
		show_grid = self.toggle_show_grid.get_active()
		x = 0
		dec_x = self.spin_axis_x_dec.get_value_as_int()
		dec_y = self.spin_axis_y_dec.get_value_as_int()

		while x < self.axis_x_max:
			x = x + self.axis_x_step
			if x >= self.axis_x_max:
				break
			tx = self.translate_x( x )
			wnd.draw_line( gc, tx, y0 - 2, tx, y0 + 2 )
			if show_numbers:
				self.add_axis_number( wnd, gc, x, dec_x, tx - 6, y0 + 4 )
			if show_grid:
				wnd.draw_line( gc, tx, 0, tx, height )
		x = 0
		while x > self.axis_x_min:
			x = x - self.axis_x_step
			if x <= self.axis_x_min:
				break
			tx = self.translate_x( x )
			wnd.draw_line( gc, tx, y0 - 2, tx, y0 + 2 )
			if show_numbers:
				self.add_axis_number( wnd, gc, x, dec_x, tx - 6, y0 + 4 )
			if show_grid:
				wnd.draw_line( gc, tx, 0, tx, height )
		y = 0
		while y < self.axis_y_max:
			y = y + self.axis_y_step
			if y >= self.axis_y_max:
				break
			ty = self.translate_y( y )
			wnd.draw_line( gc, x0 - 2, ty, x0 + 2, ty )
			if show_numbers:
				self.add_axis_number( wnd, gc, y, dec_y, x0 - 25, ty - 6 )
			if show_grid:
				wnd.draw_line( gc, 0, ty, width, ty )
		y = 0
		while y > self.axis_y_min:
			y = y - self.axis_y_step
			if y <= self.axis_y_min:
				break
			ty = self.translate_y( y )
			wnd.draw_line( gc, x0 - 2, ty, x0 + 2, ty )
			if show_numbers:
				self.add_axis_number( wnd, gc, y, dec_y, x0 - 25, ty - 6 )
			if show_grid:
				wnd.draw_line( gc, 0, ty, width, ty )

	def add_axis_number( self, wnd, gc, val, dec, x, y ):
		pl = pango.Layout( self.draw.get_pango_context() )
		msg = rounded_number( val, dec )
		pl.set_text( msg )
		wnd.draw_layout( gc, x, y, pl )

	# Draw the graph of the function
	def draw_function( self, wnd, gc, poly ):
		# Setup some graph parameters
		width = self.width
		height = self.height
		x_start = self.axis_x_min
		x_end = self.axis_x_max
		step = ( x_end - x_start ) / width

		# Set the line color
		old_fg = gc.foreground
		fg = poly.get_color()
		if fg != None:
			gc.set_foreground( fg )

		# Erase old point
		old_x, old_y = ( None, None )

		x = x_start
		while x < x_end:
			y = poly.calculate( x )
			x = x + step
			self.draw_line( wnd, gc, old_x, old_y, x, y )
			old_x = x
			old_y = y

		gc.set_foreground( old_fg )

	def translate_x( self, x ):
		width = self.width
		x_min = self.axis_x_min
		x_max = self.axis_x_max
		return int( ( width * ( x - x_min ) ) / ( x_max - x_min ) )

	def rev_translate_x( self, x ):
		width = self.width
		x_min = self.axis_x_min
		x_max = self.axis_x_max
		return x_min + ( x * ( x_max - x_min ) ) / width

	def translate_y( self, y ):
		height = self.height
		y_min = self.axis_y_min
		y_max = self.axis_y_max
		return int( height - ( height * ( y - y_min ) ) / ( y_max - y_min ) )

	def rev_translate_y( self, y ):
		height = self.height
		y_min = self.axis_y_min
		y_max = self.axis_y_max
		return y_min + ( ( height - y ) * ( y_max - y_min ) ) / height 
	
	def draw_line( self, wnd, gc, old_x, old_y, x, y ):
		if old_x == None:
			wnd.draw_point( gc, self.translate_x( x), self.translate_y( y ) )
			return

		x0 = self.translate_x( old_x )
		y0 = self.translate_y( old_y )
		x1 = self.translate_x( x )
		y1 = self.translate_y( y )
		if ( x0 < 0 or x0 > self.width ):
			return
		if ( x1 < 0 or x1 > self.width ):
			return
		if ( y0 < 0 or y0 > self.height ):
			return
		if ( y1 < 0 or y1 > self.height ):
			return

		wnd.draw_line( gc, x0, y0, x1, y1 )

	def update_coords( self, widget, event ):
		if self.width == 0 or self.height == 0:
			return
		if event.is_hint:
			x, y, = event.window.pointer
			state = event.window.pointer_state
		else:
			x = event.x
			y = event.y
			state = event.state
		self.draw.get_pointer()
		x = self.rev_translate_x( x )
		y = self.rev_translate_y( y )
		msg = '(%4.2f,%4.2f)' % ( x, y )
		self.label_coords.set_text( msg )

# Uncomment the following line for stand-alone application
#Graph( False )