Develop Reference

Trying to find the screensize and make an object go to the screensize over 2 with turtle

So I'm writing a tron game in python turtle and I want to make the two bikes start at whatever the screen width is/2, and height/2. (Same thing for the other but negative width). Sadly this doesn't seem to work because you can't divide a function by an int. Does anyone know how to do it?
This is what I tried:
width = turtle.window_width
height = turtle.window_height
def tron():
#Drawing the starting turtles
blueplayer = turtle.Turtle()
redplayer = turtle.Turtle()
screen = turtle.Screen()
screen.setup(width, height)
screen.bgpic('TronBg.png')
screen.bgcolor('black')
screen.addshape('BlueBike.gif')
screen.addshape('RedBike.gif')
blueplayer.shape('BlueBike.gif')
redplayer.shape('RedBike.gif')
redplayer.pencolor("red")
redplayer.pensize(3)
blueplayer.pencolor("blue")
blueplayer.pensize(3)
redplayer.pu()
blueplayer.pu()
-> blueplayer.goto(width/2, height/2)
-> redplayer.goto(-1*(width)/2, height/2)**
redplayer.pd()
blueplayer.pd()
#Box border
#Border
box = Turtle()
box.ht()
box.color('purple')
box.speed('fastest')
box.pensize(10)
box.pu()
box.setpos(-355, -345)
box.pd()
for i in range(5):
box.forward(700)
box.left(90)
tron()

Change your code as follows and the problem will go away:
import turtle
width = turtle.window_width()
height = turtle.window_height()
P.S. to obtain window width you call in case of the turtle module a function. To call a function it is necessary to provide () after the function name, else width will become just another name for turtle.window_width function.
If you don't put the brackets after turtle.window_width in width = turtle.window_width you can solve the problem by adding width = width() in the next line. Try this out to see that it works in order to gain better understanding of what an assignment operator = does.
By the way: you can check which type and which value the variable width has with print(type(width), width). Such print debugging is often helpful because sometimes it is necessary to use value = module.some_name and sometimes value = module.some_name() to get the right value.

how to upside down a text in python turtle.write() method?

nowadays I'm writing a program to fetch 4 poker cards from 52 poker cards randomly and I have to draw these pokers by python turtle module. Now here's my question: cause there's an upside-down number in pokers, just like this(the bottom right corner number)
at first I want to use this code to generate the numbers:
import turtle as do
def generate_digital(number, x, y, start_angle, size):
'''
this function generate '2-10'
parameters:
number: this is number you want to write
x and y: this is the pen's initial location
start_angle: the pen's initial direction
size: the number's size
'''
do.penup()
do.goto(x, y)
do.pensize(30)
do.setheading(start_angle)
do.write(number, font=("Arial", size, "normal"))
I want to use
do.settheading() to set the angle of the number, but I found that it didn't work! I can get a 5 but I can't get a upside-down 5 using the do.write() method......
Now, the only way myself can think of is to use this
def generate_photo_2(x, y, start_angle, size):
'''
this function generate a '2'
parameters:
just like last function
'''
do.penup()
do.goto(x, y)
do.pensize(3)
do.setheading(start_angle)
do.pendown()
do.circle(-size, 200)
do.fd(2 * size)
do.left(45)
do.fd(0.6 * size)
do.left(90)
do.fd(2 * size)
code to 'draw' a number, and by setting the start angle, I can 'draw' a upside-side number 2, but it causes a lot of trouble, isn't it?
Could anybody tells me how to write() a upside-down number?
Thank you very much!!!

turtle doesn't have function to display text upside down.
But turtle is built on top of tkinter module and Canvas widget which has method
create_text(x, y, text=.., angle=..., ...)
Working example
import turtle
c = turtle.getcanvas()
item_id = c.create_text(0, 0, text='5', angle=180, font=("Arial", 30, "normal"))
turtle.mainloop() # run tkinter event loop
Later you can change angle using item_id
c.itemconfig(item_id, angle=45)
Effbot.org: Canvas in tkinter.
BTW: I found information that only the newest tkinter with Tk 8.6 has angle=.
You can check version
import tkinter
print(tkinter.TkVersion)

Using turtle in Python to draw six-pointed stars with different side lengths

Hopefully I'll be able to explain this well. I'm currently using helper functions to draw a six-pointed star in the turtle graphics window of python. First, we had to create a function to draw a triangle. Here is my code:
import turtle
wn = turtle.Screen()
tess = turtle.Turtle()
tess.speed(30)
def triangle(sz):
for i in range(3):
tess.fd(sz)
tess.lt(120)
Then, we had to use the triangle function to draw a six-pointed star. Here is my code:
def sixPtdStar(sz):
triangle(sz)
tess.lt(90)
tess.pu()
tess.fd(80)
tess.rt(90)
tess.fd(120)
tess.pd()
tess.rt(180)
triangle(sz)
Now, for me, this all runs smoothly. But the parameters for our test run of those two functions was that sz = 120 (so in the shell we'd type sixPtdStar(120) and it would run. But then we had to draw a row of stars with a new function, and then a BOX outline by those rows of stars, in another function. Here is my code:
def rowOfStars(numInRow,sz):
for i in range(numInRow):
sixPtdStar(sz)
tess.pu()
tess.lt(90)
tess.fd(80)
tess.lt(90)
def sqrOfRows(numInRow, sz):
for i in range(4):
rowOfStars(numInRow, sz)
tess.rt(90)
While this accomplishes the task, it only does so if the sz = 120. And for our test run on the rowOfStars function, the parameters are supposed to be (6, 72) and for the test run on the sqrOfRows function, our parameters are supposed to be (6, 36).
So my issue is this. How can I make this work no matter what sz equals? When I run it as is (with (6, 72) for rowOfStars or (6, 36) for sqrOfRows), the pen moves too far because the triangles aren't as big anymore.
Please let me know if more info is needed! Thanks! (I'm using Python 3.5.2)

Anywhere you use a unit that has a dimension:
tess.fd(80)
tess.fd(120) # probably should be tess.fd(sz)
tess.fd(80)
you need to scale it by what ever logic you used to get from 120 (sz) to 80. However, as #wptreanor mentioned, that logic is slightly flawed as the points on your star are uneven:
Also, your rowOfStars() routine doesn't really draw a row of stars (math is off and the pen is in the wrong state at times.) Simply fixing the scaling won't fix this. Finally, your sqrOfRows() routine won't work until rowOfStars() is fixed, and to make it useful, you need to adjust the starting position on the screen to make room for the drawing.
Below is my rework of your code to address some of these issues. It uses a slightly different calculation of how to position from finishing the lower to starting the upper triangle so the numbers are slightly different:
from turtle import Turtle, Screen
WIDTH_RATIO = 2 * 3**0.5 / 3 # ratio of widest point in star to edge of triangle
def triangle(size):
for i in range(3):
tess.fd(size)
tess.lt(120)
def sixPtdStar(size):
triangle(size)
tess.lt(30)
tess.pu()
tess.fd(size * WIDTH_RATIO)
tess.lt(150)
tess.pd()
triangle(size)
def rowOfStars(numInRow, size):
for i in range(numInRow):
sixPtdStar(size)
tess.pu()
tess.lt(90)
tess.fd(size * WIDTH_RATIO / 2)
tess.lt(90)
tess.pd()
def sqrOfRows(numInRow, size):
tess.pu()
halfSize = numInRow * size / 2
tess.goto(-halfSize, halfSize) # center on screen
tess.pd()
for i in range(4):
rowOfStars(numInRow, size)
tess.rt(90)
screen = Screen()
tess = Turtle()
tess.speed("fastest") # numbers > 10 are all equivalent, safer to use symbols
sqrOfRows(6, 36)
screen.exitonclick()

The problem is in your sixPtdStar() function.
def sixPtdStar(sz):
triangle(sz)
tess.lt(90)
tess.pu()
tess.fd(80) # here
tess.rt(90)
tess.fd(120) # and here
tess.pd()
tess.rt(180)
triangle(sz)
If your function takes a size as a parameter, all functions involving movement (such as forward() or goto()) need to be scaled by the size as well. The following code should work:
def sixPtdStar(sz):
triangle(sz)
tess.lt(90)
tess.pu()
tess.fd((2.0/3.0)*sz) #formerly 80
tess.rt(90)
tess.fd(sz) #formerly 120
tess.pd()
tess.rt(180)
triangle(sz)
This will ensure that all forward movements are proportional to the size of the object you create. You will need to make similar tweaks to your rowOfStars() function. I've also noticed that your six pointed star isn't fully symmetrical. You could resolve that by replacing tess.fd((2.0/3.0)*sz) with tess.fd((7.0/12.0)*sz).

How to change size of turtle?

I am trying to double the size of the turtle in the window every time I press x on my keyboard. I tried using .turtlesize(2,2,2), but that's not right. I need to double every time the key is pressed so if the turtle size is (1,1,1), it will become (2,2,2) then (4,4,4) and so on each time I press x.
This is what I have so far:
import turtle
turtle.setup(500,500)
wn = turtle.Screen()
wn.title("Commands")
wn.bgcolor("black")
tess = turtle.Turtle()
tess.shape("triangle")
tess.color("red")
tess.left(90)
def increaseSize():
size = tess.turtlesize()
increase = tuple([2 * num for num in size])
tess.turtlesize(increase) #this is where the error occurs
wn.onkey(increaseSize, "x")
wn.listen()

Change this line:
tess.turtlesize(increase)
to instead be:
tess.turtlesize(*increase)
turtlesize() wants three separate values but you were passing one tuple of three values so we need to spread that tuple across the argument list.

The default size of a Turtle object is 20 pixels, which is the equivalent of the ratio 1 when resizing the Turtle.
For example:
import turtle
tess = turtle.Turtle()
print(tess.shapesize())
Output:
(1.0, 1.0, 1)
The first two 1.0s in the tuple represents how many units 20 pixels the Turtle's width and height are, and the last 1 represents the width of the Turtle's outline.
You won't be able to see the outline if you only pass one argument into the tess.color() brackets, because by default, there is no outline.
To increase the Turtle's size, simply pass in the number of 20 pixels you want each of the Turtle's dimensions to be into tess.shapesize() or tess.turtesize():
import turtle
tess = turtle.Turtle()
tess.shapesize(2, 3, 1) # Sets the turtle's width to 60px and height to 90px
The other answer points out that the turtlesize function does not take in an
array; it takes in ints or floats, so you'll need to unpack the tuple with a *
when you pass the tuple into the function.
In your increaseSize function, the tuple and [] wrappers aren't necessary,
and only wastes efficiency. Simply use ():
def increaseSize():
size = tess.turtlesize()
increase = (2 * num for num in size)
tess.turtlesize(*increase)
On top of your code there is
turtle.setup(500,500)
wn = turtle.Screen()
Since you defined a Screen object, wn, it's cleaner to use wn.setup() instead of turtle.setup():
wn = turtle.Screen()
wn.setup(500,500)
All together:
import turtle
wn = turtle.Screen()
wn.setup(500,500)
tess = turtle.Turtle("triangle")
tess.color("red")
tess.left(90)
def increaseSize():
size = tess.turtlesize()
increase = (2 * num for num in size)
tess.turtlesize(*increase)
wn.onkey(increaseSize, "x")
wn.listen()
Output:

(Instantiating an array of Buttons, but only one works

I'm trying to create a GUI for a virtual board for the game Go. There should be an nxn grid of tiles where a player can place a stone, either black or white. Clicking on a tile will make it change from tan(the default) to black, click again to white, and click a third time to go back to tan. Player one can click once on a spot to place a stone there, and player two can click twice (you need to remove stones later, so three clicks resets it). I created a tile object and then used a nested for loop to instantiate 9 by 9 of them. Unfortunately, running the code only seems to produce 1 functional tile, not 81. This code should work on any python machine (I'm using Python 3.4), so you can try to run it and see for yourself. Can anyone point out the reason the loop is only running once?
from tkinter import *
window = Tk()
n = 9
"""
A tile is a point on a game board where black or white pieces can be placed. If there are no pieces, it remains tan.
The basic feature is the "core" field which is a tkinter button. when the color is changed, the button is configured to represent this.
"""
class tile(object):
core = Button(window, height = 2, width = 3, bg = "#F4C364")
def __init__(self):
pass
"""the cycle function makes the tile object actually change color, going between three options: black, white, or tan."""
def cycle(self):
color = self.core.cget("bg")
if(color == "#F4C364"): #tan, the inital value.
self.core.config(bg = "#111111")#white.
elif (color == "#111111"):
self.core.config(bg = "#DDDDDD")#black.
else:
self.core.config(bg = "#F4C364")#back to tan.
board = [] #create overall array
for x in range(n):
board.append([])#add subarrays inside it
for y in range(n):
board[x].append(tile())#add a tile n times in each of the n subarrays
T = board[x][y] #for clarity, T means tile
T.core.config(command = lambda: T.cycle()) #I do this now because cycle hadn't been defined yet when I created the "core" field
T.core.grid(row = x, column = y) #put them into tkinter.
window.mainloop()

As mhawke points out in his answer you need to make the core an instance variable, so that each Tile gets its own core.
And as I mention in my comment above, you also need to fix the Button's command callback function. The code you use in your question will call the .cycle() method of the current value of T, which happens to be the last tile created. So no matter where you click only the last tile changes color. One way to fix that is to pass the current tile as a default argument of the lambda function when you create it. But because you are using OOP to create your Tile there's a better way, which you can see below.
I've made a few modifications to your code.
Although many Tkinter examples use from tkinter import * it's not a good practice. When you do from some_module import * it brings all of the names from some_module into the current module (your script), which means you could accidentally override those names with your own names. Even worse, if you do import * with multiple modules each new module's names can clash with the previous module's names, and you have no way of knowing that's happened until you start getting mysterious bugs. Using import tkinter as tk means you need to do a little more typing, but it makes the resulting program less bug-prone and easier to read.
I've modified the __init__ method so that it is called with the window and the (x, y) location of the tile (it's customary to use x for the horizontal coordinate and y for the vertical coordinate). Each Tile object now keeps track of its current state, where 0=empty, 1=black, 2=white. This makes it easier to update the colors. And because we've passed in the window and (x, y) we can use that info to add the tile to the grid. The tile also remembers the location (in self.location), which may come in handy.
I've modified the cycle method so that it updates both the background color and the activebackground of the tile. So when the mouse hovers over the tile it changes to a color that's (roughly) halfway between its current color and the color it will turn if you click it. IMO, this is nicer than the tile always turning pale grey when the mouse hovers over it.
I've also optimized the code that creates all the tiles and stores them in the board list of lists.
import tkinter as tk
colors = (
#background, #activebackground
("#F4C364", "#826232"), #tan
("#111111", "#777777"), #black
("#DDDDDD", "#E8C8A8"), #white
)
class Tile(object):
""" A tile is a point on a game board where black or white pieces can be placed.
If there are no pieces, it remains tan.
The basic feature is the "core" field which is a tkinter button.
when the color is changed, the button is configured to represent this.
"""
def __init__(self, win, x, y):
#States: 0=empty, 1=black, 2=white
self.state = 0
bg, abg = colors[self.state]
self.core = tk.Button(win, height=2, width=3,
bg=bg, activebackground=abg,
command=self.cycle)
self.core.grid(row=y, column=x)
#self.location = x, y
def cycle(self):
""" the cycle function makes the tile object actually change color,
going between three options: black, white, or tan.
"""
#cycle to the next state. 0 -> 1 -> 2 -> 0
self.state = (self.state + 1) % 3
bg, abg = colors[self.state]
self.core.config(bg=bg, activebackground=abg)
#print(self.location)
window = tk.Tk()
n = 9
board = []
for y in range(n):
row = [Tile(window, x, y) for x in range(n)]
board.append(row)
window.mainloop()

The problem is that core is a class variable which is created once and shared by all instances of class tile. It should be an instance variable for each tile instance.
Move core = Button(window, height = 2, width = 3, bg = "#F4C364") into tile.__init__() like this:
class Tile(object):
def __init__(self):
self.core = Button(window, height = 2, width = 3, bg = "#F4C364")

The root of the problem is that core is shared by all instances of the class by virtue of how you've defined it. You need to move creation of the button into the initializer.
I also suggest moving the configuration of the command into the button itself. The caller shouldn't need (nor care) how the button works internally. Personally I'd have the tile inherit from Button, but if you favor composition over inheritance I'll stick with that.
Example:
class tile(object):
def __init__(self):
self.core = Button(window, height = 2, width = 3, bg = "#F4C364"
command=self.cycle)