Turtle Text Flashing - python

When I attempt to put text over a turtle in the python turtle module, it flashes. Any solutions?
import turtle
s = turtle.Screen()
s.setup(width=500,height=600)
c = turtle.Turtle()
c.shapesize(stretch_len=5,stretch_wid=5)
c.goto(0,0)
c.shape("square")
pen = turtle.Turtle()
pen.hideturtle()
pen.goto(0,0)
pen.color("red")
while True:
pen.write("hello!")
s.update()

Although I don't see the flashing on my screen, my guess is your problem is related to this bad idiom:
while True:
# ...
s.update()
We need neither the while True: (which has no place in an event-driven environment like turtle) nor the call to update() (which is not needed given no previous call to tracer()). Let's rewrite this as turtle code:
from turtle import Screen, Turtle
screen = Screen()
screen.setup(width=500, height=600)
turtle = Turtle()
turtle.hideturtle()
turtle.shapesize(5)
turtle.shape('square')
turtle.stamp() # stamp a square so we can reuse turtle
pen = Turtle()
pen.hideturtle()
pen.color("red")
pen.write("Hello!", align='center', font=('Arial', 16, 'normal'))
screen.exitonclick()
Does that solve your problem?

Related

Why won't my square move right? I'm trying all different methods to move it in turtle module it works for up and down but not left and right?

# Game creation
import turtle
wn = turtle.Screen()
wn.title("Pong")
wn.bgcolor("Black")
wn.setup(width=800, height=800)
wn.tracer(0)
# paddle a
paddle_a = turtle.Turtle()
paddle_a.speed(0)
paddle_a.shape("square")
paddle_a.color("white")
paddle_a.penup()
paddle_a.goto(0, 0)
# Functions
def paddle_a_right():
turtle.forward(100)
wn.onkeypress(paddle_a_right, 'd')
while True:
wn.update()
Want the square to move to the right or left using 'a' or 'd' I don't know very much about turtle, I just want to program a simple game.
There are three major issues with your code. First, you need to call wn.listen() to allow the window to receive keyboard input. Second, you do turtle.forward(100) when you mean paddle_a.forward(100). Finally, since you did tracer(0), you now need to call wn.update() anytime a change is made that you want your user to see.
Here's a simplified example:
from turtle import Screen, Turtle
def paddle_right():
paddle.forward(10)
screen.update()
screen = Screen()
screen.title("Pong")
screen.bgcolor("Black")
screen.setup(width=800, height=800)
screen.tracer(0)
paddle = Turtle()
paddle.shape("square")
paddle.color("white")
paddle.penup()
screen.onkeypress(paddle_right, 'd')
screen.listen()
screen.update()
screen.mainloop()

Why my python kept crashing when it tried to run the turtle.tracer() method in turtle module?

I was coding a Snake Game using turtle module but when I add this line into my code the turtle screen and python crashed:
turtle.tracer(0)
can somebody help me so I can complete the game? Thanks a lot
my code:
from turtle import Turtle, Screen, colormode
screen = Screen()
screen.bgcolor("black")
screen.setup(width=600, height=600)
screen.title("My Snake Game")
screen.tracer(0)
x = 0
segments = []
for turtle in range(3):
turtle = Turtle("square")
turtle.color("white")
turtle.penup()
turtle.goto(0-x, 0)
x += 20
segments.append(turtle)
game_is_on = True
screen.update()
while game_is_on:
for segment in segments:
segment.forward(20)
screen.exitonclick()
I think we need to know more about what you mean by 'crashed'. If you mean everything froze, that's the code you wrote. Once you introduce tracer() you need to provide an update() for every change you want the user to see. But you don't have any update() calls in your loop so everything visually remains as it was before the loop. If you want to see the segments move, you need to do something like:
from turtle import Turtle, Screen
screen = Screen()
screen.bgcolor('black')
screen.setup(width=600, height=600)
screen.title("My Snake Game")
screen.tracer(0)
x = 0
segments = []
for turtle in range(3):
turtle = Turtle('square')
turtle.color('white')
turtle.penup()
turtle.setx(x)
x -= 20
segments.append(turtle)
screen.update()
game_is_on = True
while game_is_on:
for segment in segments:
segment.forward(20)
screen.update()
screen.exitonclick() # never reached
If you mean by 'crashed' that Python quit back to the operating system, then you need to describe the environment under which you're running this code.

python turtle creating flickering images when using tracer(0,0)

I am trying to make a program that will repeatedly draw two lines. my code is
import turtle
screen = turtle.Screen()
t = turtle.Turtle()
t.hideturtle()
t.speed(0)
screen.tracer(0,0)
while True:
screen.clear()
t.penup()
t.goto(1,12)
t.pendown()
t.goto(4,67)
t.penup()
t.goto(50, 3)
t.pendown()
t.goto(4, 73)
screen.update()
I expect this to show two lines in turtle which do not flicker. however it is drawing one line and that line is flickering. the lines do need to be redrawn every frame so i can do some other stuff with the lines. Why is this happening?
Short answer: don't do screen.clear(), instead do t.clear().
When you clear the screen, you reset a number of its properties to the default values, including the tracer() setting. You simply want to clear whatever the turtle drew in the last iteration so clear the turtle instead.
In the long term, you don't want while True: in an event-driven environment like turtle. I would write this code more like:
from turtle import Screen, Turtle
def one_step():
turtle.clear()
turtle.penup()
turtle.goto(1, 12)
turtle.pendown()
turtle.goto(4, 67)
turtle.penup()
turtle.goto(50, 3)
turtle.pendown()
turtle.goto(4, 73)
screen.update()
screen.ontimer(one_step, 50)
screen = Screen()
screen.tracer(False)
turtle = Turtle()
turtle.hideturtle()
one_step()
screen.mainloop()

How can I make my turtle move to my cursor?

I am trying to move the turtle to my cursor to draw something so that every time I click, the turtle will go there and draw something.
I have already tried onscreenclick(), onclick, and many combinations of both, I feel like I am doing something wrong, but I don't know what.
from turtle import*
import random
turtle = Turtle()
turtle.speed(0)
col = ["red","green","blue","orange","purple","pink","yellow"]
a = random.randint(0,4)
siz = random.randint(100,300)
def draw():
for i in range(75):
turtle.color(col[a])
turtle.forward(siz)
turtle.left(175)
TurtleScreen.onclick(turtle.goto)
Any help would be great, thank you for your time ( If you help me! ;)
It's not so much what method you're invoking, but on what object you're invoking it:
TurtleScreen.onclick(turtle.goto)
TurtleScreen is a class, you need to call it on a screen instance. And since you want to call draw in addition to turtle.goto you need to define your own function that calls both:
screen = Screen()
screen.onclick(my_event_handler)
Here's a rework of your code with the above fixes and other tweaks:
from turtle import Screen, Turtle, mainloop
from random import choice, randint
COLORS = ["red", "green", "blue", "orange", "purple", "pink", "yellow"]
def draw():
size = randint(100, 300)
# make turtle position center of drawing
turtle.setheading(0)
turtle.setx(turtle.xcor() - size/2)
turtle.pendown()
for _ in range(75):
turtle.color(choice(COLORS))
turtle.forward(size)
turtle.left(175)
turtle.penup()
def event_handler(x, y):
screen.onclick(None) # disable event handler inside event handler
turtle.goto(x, y)
draw()
screen.onclick(event_handler)
turtle = Turtle()
turtle.speed('fastest')
turtle.penup()
screen = Screen()
screen.onclick(event_handler)
mainloop()

Python turtle not moving on arrow press

I am trying to make my turtle (main_ship) move across the bottom of my screen according to when the user presses the left and right arrow keys but the turtle is not moving. I have used the same code before when making Pong so I'm not sure why it's not working.
import turtle
wn = turtle.Screen()
wn.title("Game")
wn.bgcolor("black")
wn.setup(width=800, height=600)
wn.tracer(0)
main_ship = turtle.Turtle()
main_ship.speed(0)
main_ship.shape("turtle")
main_ship.color("green")
main_ship.shapesize(stretch_wid=2, stretch_len=4)
main_ship.penup()
main_ship.goto(0, -290)
main_ship.left(90)
def main_ship_right():
x = main_ship.xcor()
x += 20
main_ship.setx(x)
def main_ship_left():
x = main_ship.xcor()
x -= 20
main_ship.setx(x)
while True:
wn.update()
wn.mainloop()
wn.listen()
wn.onkeypress(main_ship_right, "Right")
wn.onkeypress(main_ship_left, "Left")
When I press the arrow keys, nothing happens but the code still runs and there are no error messages.
You have to assign keys before mainloop() which runs all time till you close window.
You don't need while True because mainloop() already runs internal loop.
You may have to remove wm.tracer(0) or you will have to run wn.update() to refresh elements in window.
import turtle
# --- functions ---
def main_ship_right():
x = main_ship.xcor()
x += 20
main_ship.setx(x)
wn.update()
def main_ship_left():
x = main_ship.xcor()
x -= 20
main_ship.setx(x)
wn.update()
# --- main ---
wn = turtle.Screen()
wn.title("Game")
wn.bgcolor("black")
wn.setup(width=800, height=600)
wn.tracer(0)
main_ship = turtle.Turtle()
main_ship.speed(0)
main_ship.shape("turtle")
main_ship.color("green")
main_ship.shapesize(stretch_wid=2, stretch_len=4)
main_ship.penup()
main_ship.goto(0, -290)
main_ship.left(90)
wn.update()
wn.listen()
wn.onkeypress(main_ship_right, "Right")
wn.onkeypress(main_ship_left, "Left")
wn.mainloop()
For this style of motion, there's another way to implement it. The idea is to leave the cursor moving in it's original orientation, but use settiltangle() to make it look like it's facing upward.
This lets us use forward(20) and backward(20) to move our cursor, and not have to write:
x = main_ship.xcor()
x += 20
main_ship.setx(x)
Works great for Space Invader style games, where the player faces upwards but moves sideways:
from turtle import Screen, Turtle
from functools import partial
screen = Screen()
screen.title("Game")
screen.bgcolor('black')
screen.setup(width=800, height=600)
main_ship = Turtle('turtle')
main_ship.speed('fastest')
main_ship.color('green')
main_ship.shapesize(stretch_wid=2, stretch_len=4)
main_ship.settiltangle(90)
main_ship.penup()
main_ship.sety(-290)
screen.onkeypress(partial(main_ship.forward, 20), 'Right')
screen.onkeypress(partial(main_ship.backward, 20), 'Left')
screen.listen()
screen.mainloop()
Only works in the turtle library that comes with Python -- online Python development sites usually provide limited turtle implementations that don't include methods like settiltangle().

Categories