#  StarsQt.py  Copyright (c) 2010 Kari Laitinen

#  http://www.naturalprogramming.com

#  2010-09-20  File created.
#  2011-11-04  Last modification.

#  This program shows how star shapes can be drawn by using the
#  QPainterPath class

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *

class StarShape :

   def __init__( self, given_star_center_point_x,
                       given_star_center_point_y,
                       given_star_radius = 80, # radius of the bounding circle
                       given_star_color  = Qt.yellow,
                       given_hollowness  = False ) :

      self.star_center_point_x  =  given_star_center_point_x
      self.star_center_point_y  =  given_star_center_point_y
      self.star_radius          =  given_star_radius
      self.star_color           =  given_star_color
      self.star_is_hollow       =  given_hollowness


   def draw( self, painter ) :

      pass


#  The following class represents a 5-point star

class StarShape5 ( StarShape ) :

   def draw( self, painter ) :

      saved_graphics_transform  =  painter.combinedTransform()

      painter.translate( self.star_center_point_x,
                         self.star_center_point_y )

      #  By drawing an arrowhead shape several times and
      #  rotating it by 72 degrees between drawings
      #  it is possible to draw a five-point star.
      #  5 * 72 = 360

      star_5_arrowhead  = QPainterPath()

      #  The following coordinates are fixed supposing that the
      #  radius of the star is 80 pixels (points).
      #  Larger or smaller stars are drawn by adjusting the scale of
      #  the coordinate system. If you want to change the default
      #  star radius (80 points), you must modify these coordinates
      #  as well.

      star_5_arrowhead.moveTo(   0,    -80.0 ) # top middle point
      star_5_arrowhead.lineTo(  47.02,  64.72 ) # to low right point
      star_5_arrowhead.lineTo(   0,     30.56 ) # to lowish middle point
      star_5_arrowhead.lineTo( -47.02,  64.72 ) # to low left point
      star_5_arrowhead.closeSubpath()

      painter.scale( self.star_radius / 80.0, self.star_radius / 80.0 )

      if  self.star_is_hollow == True :

         saved_pen  =  painter.pen()

         painter.setPen( QPen( self.star_color, 4 ) )
         painter.drawPath( star_5_arrowhead )
         painter.rotate( 72 )  # 72 degrees clockwise
         painter.drawPath( star_5_arrowhead )
         painter.rotate( 72 )  # 72 degrees clockwise
         painter.drawPath( star_5_arrowhead )

         painter.setPen( saved_pen )

      else  :

         brush_for_filled_star = QBrush( self.star_color )

         painter.fillPath( star_5_arrowhead, brush_for_filled_star )
         painter.rotate( 72 )  # 72 degrees clockwise
         painter.fillPath( star_5_arrowhead, brush_for_filled_star )

      painter.setTransform( saved_graphics_transform )



#  The following class represents a 6-point star

class StarShape6 ( StarShape ) :


   def draw( self, painter ) :

      saved_graphics_transform  =  painter.combinedTransform()

      painter.translate( self.star_center_point_x,
                         self.star_center_point_y )

      star_6_triangle  =  QPainterPath()

      #  A six-point star will be drawn by drawing two triangles, so
      #  that the coordinate system is rotated 180 degrees between drawings.

      #  The following coordinates are fixed supposing that the
      #  radius of the star is 80 pixels (points).
      #  Larger or smaller stars are drawn by adjusting the scale of
      #  the coordinate system. If you want to change the default
      #  star radius (80 points), you must modify these coordinates
      #  as well.

      star_6_triangle.moveTo(   0,    -80.0 )  # start from the top point
      star_6_triangle.lineTo(  69.28,  40.0 )  # to lower right point
      star_6_triangle.lineTo( -69.28,  40.0 )  # to lower left point
      star_6_triangle.closeSubpath() ;           # back to top point

      painter.scale( self.star_radius / 80.0, self.star_radius / 80.0 )

      if  self.star_is_hollow == True :

         saved_pen  =  painter.pen()
         painter.setPen( QPen( self.star_color, 4 ) )

         painter.drawPath( star_6_triangle )
         painter.rotate( 180 )  # 180 degrees clockwise
         painter.drawPath( star_6_triangle )

         painter.setPen( saved_pen )

      else  :

         brush_for_filled_star = QBrush( self.star_color )

         painter.fillPath( star_6_triangle, brush_for_filled_star )
         painter.rotate( 180 ) ;  # 180 degrees clockwise
         painter.fillPath( star_6_triangle, brush_for_filled_star )


      painter.setTransform( saved_graphics_transform )




class StarsWindow ( QWidget ) :

   def __init__( self, parent=None ) :
   
      QWidget.__init__( self, parent )

      self.setGeometry( 100, 100, 850, 600 )
 
      self.setWindowTitle( "DEMONSTRATING 2D GRAPHICS OPERATIONS" )

      #  Some of the stars defined below have the same position on the screen.
      #  For example, both the large pink star and the small red star
      #  have their center point at (300,300). The small red star is thus
      #  drawn inside the larger pink star.

      self.default_star_5    =  StarShape5( 100, 300 )
      self.large_pink_star_5 =  StarShape5( 300, 300,
                                            120, QColor( "pink" ), False )
      self.small_red_star_5  =  StarShape5( 300, 300,
                                            50, Qt.red, False )
      self.hollow_star_5   =  StarShape5( 500, 300,
                                          60, Qt.white, True )

      self.larger_star_6   =  StarShape6( 700, 300,
                                          100, Qt.magenta, False )
      self.smaller_star_6  =  StarShape6( 700, 300,
                                          60, Qt.black, True )

   def paintEvent( self, event ) :
   
      painter = QPainter()

      painter.begin( self )

      painter.fillRect( 0, 0, self.width(), self.height(), Qt.darkGray )

      self.default_star_5.draw( painter )
      self.large_pink_star_5.draw( painter )
      self.small_red_star_5.draw( painter )
      self.hollow_star_5.draw( painter )

      self.larger_star_6.draw( painter )
      self.smaller_star_6.draw( painter )

      painter.end()


# Here is the "main" program:

def main( args ) :

   this_application = QApplication( args )
   application_window = StarsWindow()
   application_window.show()
   this_application.exec_()

if __name__== "__main__" :

   main( sys.argv )

# NOTES:

#  The following triangle could be used to draw a five-point star.
#  With this triangle we would not need to rotate the coordinate system.

#      star_5_triangle =  QPainterPath()

#      star_5_triangle.moveTo( -76.08, -24.72 ) # upper left point
#      star_5_triangle.lineTo(  76.08, -24.72 ) # to upper right point
#      star_5_triangle.lineTo(   0,     30.56 ) # to middle low point
#      star_5_triangle.closeSubpath()


#  The following shape is in use in the corresponding Java program.
#  It did not work properly in Qt.

#      star_shape_5  =  QPainterPath()

#      star_shape_5.moveTo(  76.08, -24.72 )  # start from upper right point
#      star_shape_5.lineTo( -47.02,  64.72 )  # to lower left point
#      star_shape_5.lineTo(   0,     -80.0  )  # to upper middle point
#      star_shape_5.lineTo(  47.02,  64.72 )  # to lower right point
#      star_shape_5.lineTo( -76.08, -24.72 )  # to upper left point
#      star_shape_5.closeSubpath()              # to upper right point