#  FlyingArrowQt.py  (c) Kari Laitinen

#  http://www.naturalprogramming.com

#  2009-11-24  File created.
#  2009-11-24  Last modification.

#  This programs shows how the coordinate system can be
#  re-positioned (i.e."translated"), rotated, and scaled.
#  In addition, you can see how to draw shapes with the
#  QPainterPath class.

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

class FlyingArrowWindow( QWidget ) :

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

      self.setGeometry( 100, 100, 800, 500 )
 
      self.setWindowTitle( "DEMONSTRATING 2D GRAPHICS OPERATIONS" )


   def paintEvent( self, event ) :
   
      #  The arrow coordinates are selected so that Point (0, 0)
      #  is at the tip of the arrow, and the arrow points upwards.

      arrow_shape_coordinates  = \
      (  QPointF(   0,   0 ), QPointF( 15,  40 ), QPointF(  5,  30 ),
         QPointF(   5, 120 ), QPointF( 15, 160 ), QPointF(  0, 130 ),
         QPointF( -15, 160 ), QPointF( -5, 120 ), QPointF( -5,  30 ),
         QPointF( -15,  40 )
      )

      flying_arrow = QPainterPath()

      flying_arrow.moveTo( arrow_shape_coordinates[ 0 ] ) 

      for point_index in range( 1, len( arrow_shape_coordinates ) ) :

         flying_arrow.lineTo( arrow_shape_coordinates[ point_index ] ) 


      flying_arrow.closeSubpath()


      painter = QPainter()
      painter.begin( self )

      brush_for_solid_arrows = QBrush( Qt.darkMagenta )

      painter.translate( 150, 250 )     # arrow tip to point (150, 250 )
      painter.fillPath( flying_arrow, brush_for_solid_arrows )

      painter.rotate( 45 )              # 45 degrees clockwise
      painter.drawPath( flying_arrow )  # draw a hollow arrow

      painter.translate( 0, -200 )      # flying "up" 200 points
      painter.fillPath( flying_arrow, brush_for_solid_arrows )

      painter.rotate( 45 )              # 45 degrees clockwise
      painter.translate( 0, -200 )      # flying "up" (i.e. to the right)
      painter.fillPath( flying_arrow, brush_for_solid_arrows )

      painter.translate( 0, -100 )      # flying "up" 100 points
      painter.rotate( 90 )              # 90 degrees clockwise
      painter.scale( 1.5, 1.5 )         # magnify everything by 1.5
      painter.drawPath( flying_arrow )  # draw a hollow arrow
      painter.translate( 0, -200 )      # flying "up" (i.e. down) 300 points
      painter.fillPath( flying_arrow, brush_for_solid_arrows )


# Here is the main program:

this_application = QApplication( sys.argv )
application_window = FlyingArrowWindow()
application_window.show()
this_application.exec_()

#  NoTES:

#  Qt color, brush, etc. definitions can be found inside the Qt class
#  which belongs to the QtCore module:

#  http://www.riverbankcomputing.co.uk/static/Docs/PyQt4/html/qt.html