Python

Instances and loops

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Join Date: Sep 2009

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A_Dubbs

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Instances and loops

Oct 20th, 2009

Hello everyone, I need some help with instances and loops (I am a very new programmer). Basically, I have a problem where I need to make a program that has a circle move around a window every time the user clicks. This circle is suppose to have a text box inside it that states the number of times the circle has moved. When the circle gets to the end of the window, I am suppose to change the movement coordinates so it comes back. I am using graphics that an author from the book I am using wrote.

Anyways, I have written code that moves the circle when the user clicks:

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
from zellegraphics import *
 
##Write a program to animate a circle bouncing around a window. The basic idea
##is to start the circle somewhere in the interior of the window. Use variables
##dx and dy (both initalized to 10) to control the movement of the circle. Use a
##large counted loop (say 10000 iterations), and each time through the loop move
##the circle using dx and dy. When the x-value of the center of the circle gets
##too high (it hits the edge), change dx to -10. When it gets too low, change dx
##back to 10. Use a similar approach for dy.
 
def main():
    #Set up a window 400 by 400
    win = GraphWin("Circle Moving", 400, 400)
    #Set up circle that will travel around the window
    c = Circle(Point (200,200), 30)
    c.draw(win)
    x = 1
    l = Text(Point (200,200), x)
    l.draw(win)
    for i in range(100):
        win.getMouse()
        dx = 10
        dy = -10
        c.move(dx,dy)
        center = c.getCenter()
        l.move(dx,dy)
 
 
 
 
main()
from zellegraphics import *

##Write a program to animate a circle bouncing around a window. The basic idea
##is to start the circle somewhere in the interior of the window. Use variables
##dx and dy (both initalized to 10) to control the movement of the circle. Use a
##large counted loop (say 10000 iterations), and each time through the loop move
##the circle using dx and dy. When the x-value of the center of the circle gets
##too high (it hits the edge), change dx to -10. When it gets too low, change dx
##back to 10. Use a similar approach for dy.

def main():
    #Set up a window 400 by 400
    win = GraphWin("Circle Moving", 400, 400)
    #Set up circle that will travel around the window
    c = Circle(Point (200,200), 30)
    c.draw(win)
    x = 1
    l = Text(Point (200,200), x)
    l.draw(win)
    for i in range(100):
        win.getMouse()
        dx = 10
        dy = -10
        c.move(dx,dy)
        center = c.getCenter()
        l.move(dx,dy)
        
        

    
main()

I set the window to be 400 by 400. Variable c is a circle with the center point of (200,200) and a radius of 30. I made a text box which is drawn at the same place (200,200) and has a message of variable x. Variable x = 1. In the for loop I have made it so the circle will move (10,-10) every time the user clicks. Now, when I use the c.getCenter() I get back the center in the format of "Point(x,y)". The type of this is an instance.

How can I isolate point x so I can make an if statement that changes dx to -10 if x gets too high. I do not know how to work with instances. Also, I need variable x to change everytime I click. However, putting x = x+1 in the for loop won't change that. I assume this is because x in variable is outside the for loop. Can anyone help me?

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Join Date: Sep 2009

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A_Dubbs

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Newbie Poster

Oct 20th, 2009

Ok, I can't figure out how to edit my post, so I'll write my new, less confusing question here. Basically, I need to know how I can automatically change parameters in a function. Here is my code:

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
from zellegraphics import *
 
##Write a program to animate a circle bouncing around a window. The basic idea
##is to start the circle somewhere in the interior of the window. Use variables
##dx and dy (both initalized to 10) to control the movement of the circle. Use a
##large counted loop (say 10000 iterations), and each time through the loop move
##the circle using dx and dy. When the x-value of the center of the circle gets
##too high (it hits the edge), change dx to -1. When it gets too low, change dx
##back to 1. Use a similar approach for dy.
 
#Set up a window 400 by 400
win = GraphWin("Circle Moving", 400, 400)
#Set up circle that will travel around the window
c = Circle(Point (200,200), 30)
c.draw(win)
x = 1
l = Text(Point (200,200), x)
l.draw(win)
 
 
def move(x,y):
    win.getMouse()
    dx = x
    dy = y
    c.move(dx,dy)
    l.move(dx,dy)
    center = c.getCenter()
    center = center.getX()
    print center
    if center == 400.0:
        dx = -10
        return dx
 
 
def main():
    for i in range(100):
        move(10,-10)
 
 
 
main()
from zellegraphics import *

##Write a program to animate a circle bouncing around a window. The basic idea
##is to start the circle somewhere in the interior of the window. Use variables
##dx and dy (both initalized to 10) to control the movement of the circle. Use a
##large counted loop (say 10000 iterations), and each time through the loop move
##the circle using dx and dy. When the x-value of the center of the circle gets
##too high (it hits the edge), change dx to -1. When it gets too low, change dx
##back to 1. Use a similar approach for dy.

#Set up a window 400 by 400
win = GraphWin("Circle Moving", 400, 400)
#Set up circle that will travel around the window
c = Circle(Point (200,200), 30)
c.draw(win)
x = 1
l = Text(Point (200,200), x)
l.draw(win)

        
def move(x,y):
    win.getMouse()
    dx = x
    dy = y
    c.move(dx,dy)
    l.move(dx,dy)
    center = c.getCenter()
    center = center.getX()
    print center
    if center == 400.0:
        dx = -10
        return dx


def main():
    for i in range(100):
        move(10,-10)
        
        

main()

What I would like to do is have dx change to -10 when center = 400.0 . So function move(10,-10) will go until center = 400, then it would change to function move (-10,-10). Can anyone help with this? Thanks!

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Join Date: Jul 2008

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Gribouillis Gribouillis is offline

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Posting Shark

Oct 20th, 2009

Your move function should return the next dx and dy. You could write this

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
from zellegraphics import *
 
##Write a program to animate a circle bouncing around a window. The basic idea
##is to start the circle somewhere in the interior of the window. Use variables
##dx and dy (both initalized to 10) to control the movement of the circle. Use a
##large counted loop (say 10000 iterations), and each time through the loop move
##the circle using dx and dy. When the x-value of the center of the circle gets
##too high (it hits the edge), change dx to -1. When it gets too low, change dx
##back to 1. Use a similar approach for dy.
 
#Set up a window 400 by 400
win = GraphWin("Circle Moving", 400, 400)
#Set up circle that will travel around the window
c = Circle(Point (200,200), 30)
c.draw(win)
x = 1
l = Text(Point (200,200), x)
l.draw(win)
 
 
def move(x,y):
    win.getMouse()
    dx = x
    dy = y
    c.move(dx,dy)
    l.move(dx,dy)
    center = c.getCenter()
    center = center.getX()
    print center
    if center == 400.0:
        dx = -10
    return dx, dy
 
 
def main():
    dx, dy = 10, -10
    for i in range(100):
        dx, dy = move(dx, dy)
 
main()
from zellegraphics import *

##Write a program to animate a circle bouncing around a window. The basic idea
##is to start the circle somewhere in the interior of the window. Use variables
##dx and dy (both initalized to 10) to control the movement of the circle. Use a
##large counted loop (say 10000 iterations), and each time through the loop move
##the circle using dx and dy. When the x-value of the center of the circle gets
##too high (it hits the edge), change dx to -1. When it gets too low, change dx
##back to 1. Use a similar approach for dy.

#Set up a window 400 by 400
win = GraphWin("Circle Moving", 400, 400)
#Set up circle that will travel around the window
c = Circle(Point (200,200), 30)
c.draw(win)
x = 1
l = Text(Point (200,200), x)
l.draw(win)

        
def move(x,y):
    win.getMouse()
    dx = x
    dy = y
    c.move(dx,dy)
    l.move(dx,dy)
    center = c.getCenter()
    center = center.getX()
    print center
    if center == 400.0:
        dx = -10
    return dx, dy


def main():
    dx, dy = 10, -10
    for i in range(100):
        dx, dy = move(dx, dy)
        
main()

To change the text, we need to have some documentation about Text. Can you run the following code ?

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
from zellegraphics import *
from pydoc import TextDoc
textdoc = TextDoc()
out = open("mydoc.txt", "w")
out.write(textdoc.document(Text))
from zellegraphics import *
from pydoc import TextDoc
textdoc = TextDoc()
out = open("mydoc.txt", "w")
out.write(textdoc.document(Text))

If it works, please put the content of the file mydoc.txt in a post between code tags.

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Join Date: Sep 2009

Posts: 12

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A_Dubbs

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Newbie Poster

Oct 20th, 2009

Thanks, the first part ended up working great.

Here is the contents of that file, hard to read:

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
class TTeexxtt(GraphicsObject)
 |  Methods defined here:
 |  
 |  ____iinniitt____(self, p, text)
 |  
 |  ____rreepprr____(self)
 |  
 |  cclloonnee(self)
 |  
 |  ggeettAAnncchhoorr(self)
 |  
 |  ggeettTTeexxtt(self)
 |  
 |  sseettFFaaccee(self, face)
 |  
 |  sseettSSiizzee(self, size)
 |  
 |  sseettSSttyyllee(self, style)
 |  
 |  sseettTTeexxtt(self, text)
 |  
 |  sseettTTeexxttCCoolloorr(self, color)
 |  
 |  ----------------------------------------------------------------------
 |  Methods inherited from GraphicsObject:
 |  
 |  ddrraaww(self, graphwin)
 |      Draw the object in graphwin, which should be a GraphWin
 |      object.  A GraphicsObject may only be drawn into one
 |      window. Raises an error if attempt made to draw an object that
 |      is already visible.
 |  
 |  mmoovvee(self, dx, dy)
 |      move object dx units in x direction and dy units in y
 |      direction
 |  
 |  sseettFFiillll(self, color)
 |      Set interior color to color
 |  
 |  sseettOOuuttlliinnee(self, color)
 |      Set outline color to color
 |  
 |  sseettWWiiddtthh(self, width)
 |      Set line weight to width
 |  
 |  uunnddrraaww(self)
 |      Undraw the object (i.e. hide it). Returns silently if the
 |      object is not currently drawn.
class TTeexxtt(GraphicsObject)
 |  Methods defined here:
 |  
 |  ____iinniitt____(self, p, text)
 |  
 |  ____rreepprr____(self)
 |  
 |  cclloonnee(self)
 |  
 |  ggeettAAnncchhoorr(self)
 |  
 |  ggeettTTeexxtt(self)
 |  
 |  sseettFFaaccee(self, face)
 |  
 |  sseettSSiizzee(self, size)
 |  
 |  sseettSSttyyllee(self, style)
 |  
 |  sseettTTeexxtt(self, text)
 |  
 |  sseettTTeexxttCCoolloorr(self, color)
 |  
 |  ----------------------------------------------------------------------
 |  Methods inherited from GraphicsObject:
 |  
 |  ddrraaww(self, graphwin)
 |      Draw the object in graphwin, which should be a GraphWin
 |      object.  A GraphicsObject may only be drawn into one
 |      window. Raises an error if attempt made to draw an object that
 |      is already visible.
 |  
 |  mmoovvee(self, dx, dy)
 |      move object dx units in x direction and dy units in y
 |      direction
 |  
 |  sseettFFiillll(self, color)
 |      Set interior color to color
 |  
 |  sseettOOuuttlliinnee(self, color)
 |      Set outline color to color
 |  
 |  sseettWWiiddtthh(self, width)
 |      Set line weight to width
 |  
 |  uunnddrraaww(self)
 |      Undraw the object (i.e. hide it). Returns silently if the
 |      object is not currently drawn.

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Join Date: Jul 2008

Posts: 963

Reputation: Gribouillis is a jewel in the rough

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Gribouillis Gribouillis is offline

Offline

Posting Shark

Oct 20th, 2009

Ok, you can change the text with

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
l.setText(str(300)) # the text now shows 300
l.setText(str(300)) # the text now shows 300

note that the letter 'l' is a bad variable name. Good variable names have at least 3 characters (except for loop variables like i, j, ...)
For the doc, you could use

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
from zellegraphics import *
from pydoc import HTMLDoc
textdoc = HTMLDoc()
out = open("mydoc.html", "w")
out.write(textdoc.document(Text))
from zellegraphics import *
from pydoc import HTMLDoc
textdoc = HTMLDoc()
out = open("mydoc.html", "w")
out.write(textdoc.document(Text))

to get a file mydoc.html to view in your browser.

About the floating point test, you should use if center >= 400.0 rather that == because floating point numbers seldom happen to be equal. If the value is 400.00000001, dx should be set to -10 for example.

Last edited by Gribouillis; Oct 20th, 2009 at 6:27 am.