CSC111 Lab 11 2014

--D. Thiebaut (talk) 17:42, 13 April 2014 (EDT)

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Creating the Graphics Library

The graphics library written by Horstmann, the author of our textbook is available here. Download it and create a file called graphics.py in your current directory.

Simple Test

Verify that your library is correctly installed by running the python program below. Call it lab10.py. Make sure to save it in the same directory where you saved graphics.py.

from graphicsH import GraphicsWindow

MAXWIDTH = 800
MAXHEIGHT = 600


def main():
    win = GraphicsWindow(MAXWIDTH, MAXHEIGHT)
    canvas = win.canvas()

    canvas.setFill( 255, 0, 0  )    # full red
    canvas.drawRect( 100, 100, 300, 200 )

    win.wait()
    win.close()

main()

Challenge 1: Two rectangle, random colors

• Change the color of the rectangle.
• Add a second rectangle with a different color
• Make the color of the two rectangles random.

Hints: to generate a random number between 0 and 255, you can do this:

# at the top of the program
from random import seed
from random import randrange

# at the beginning of main()
seed()

# where you need a random number between 0 and 255 (included):
x = randrange( 256 ):

Challenge 2: 500 random rects

• Generate 500 random rectangles of random colors at random locations, and with random width and height.

Drawing circles

The graphics library also supports circles with the method drawOval( x, y, w, h ), where x, and y represent to top corner of the invisible rectangle that contains the oval, and w and h represent the width and height of the invisible rectangle.

            canvas.drawOval( x, y, w, h )

Create a Rectangle Class

from graphics import GraphicsWindow
from random   import randrange
from random   import seed
from time     import sleep

MAXWIDTH = 800
MAXHEIGHT= 600


class Rectangle:
    def __init__( self, x, y, width, height, color ):
        self._x      = x
        self._y      = y
        self._width  = width
        self._height = height
        self._color  = color   # list of 3 ints between 0 and 255

    def draw( self, canvas ):
        canvas.setFill( self._color[0], self._color[1], self._color[2] )            
        canvas.drawRect( self._x, self._y, self._width, self._height )

def twoRects( canvas ):
    rect1 = Rectangle( 100, 100, 500, 20, (255, 0, 0 ) )
    rect1.draw( canvas )
    
    rect2 = Rectangle( 200, 200, 50, 200, (165, 76, 89 ) )
    rect2.draw( canvas )

def fiveHundredRects( canvas ):
    for i in range( 500 ):
        x = randrange( MAXWIDTH*3//4 )
        y = randrange( MAXHEIGHT *3//4 )
        w = randrange( MAXWIDTH // 2 )
        h = randrange( MAXHEIGHT // 2 )
        red   = randrange( 256 )
        green = randrange( 256 )
        blue  = randrange( 256 )
        rect = Rectangle( x, y, w, h, (red, green, blue ) )
        rect.draw( canvas )
        
            
def main():
    seed()
    win = GraphicsWindow(MAXWIDTH, MAXHEIGHT)
    canvas = win.canvas()

    #twoRects( canvas )

    fiveHundredRects( canvas )

    win.wait()
    win.close()    
    
        
main()

Create a Circle Class

Use the example of Rectangle

Create a Circle Class with a Center

Modify the class so that the x and y passed are the x and y of the center of the circle.

Create a class Wheel that contains two concentric circles

The inside circle will be concentric with the outside one, and will always have a radius half the radius of the large one.

Create a new Class that is a car

• one rectangle
• two wheels
• x, y of top left corner of rectangle
• width and height of rectangle.
• center of 1st wheel 1/4 width from left of car
• center of 2nd wheel 1/4 width from right of car
• radius of wheel = 1/8 of car width