python turtle graphic doesn't draw - python

When I run the following code it only pops up a window and doesn't draw any graphic.
I tried a few examples from references but in all cases, it happened. Can someone help me to fix the problem?
import turtle
turtle.mainloop()
t = turtle.Turtle()
t.color('red')
t.pensize(10)
t.shape('turtle')

See here:
https://docs.python.org/3.1/library/turtle.html#turtle.mainloop
Starts event loop - calling Tkinter’s mainloop function. Must be the last statement in a turtle graphics program. Must not be used if a script is run from within IDLE in -n mode (No subprocess) - for interactive use of turtle graphics.
So you have the second line to the end of your program
Also without mainloop i can see an red Turtle drawn when run in repl.it:
https://repl.it/#CarstenEggers/Raphael

The reason it's not doing anything is because you haven't actually told the "draw-er" t to draw anything. All the stuff you've told it to do is just set-up instructions: what color to use, what size to draw at, etc.
Try running this code instead. Explanations in comments:
import turtle
# turtle.mainloop() # Generally not necessary to run mainloop; can just delete
t = turtle.Turtle() # Creating a turtle to do drawing
t.color('red') # Telling it what color to draw
t.pensize(10) # Telling it what size to draw at
t.shape('turtle') # What shape turtle draw-er should be: "arrow", "turtle", etc
# Now let's draw something!
t.forward(50) # Tell turtle to draw in forward direction 50 pixels
t.left(80) # Tell turtle to turn in-place 80 degrees to left
t.forward(100) # Draw 100 pixels forward
t.right(90) # Turn in-place 90 degrees right
t.forward(170) # Draw 170 pixels forward
# Done drawing!
turtle.exitonclick() # Tell program to keep picture on screen, exit on click
# Note: See how that's `turtle` and not `t`? That's because we don't want to
# tell our draw-er `t` anything: `t` is just for drawing, it doesn't control
# the larger scope of starting and exiting. If we said `t.exitonclick()`, the
# program would just break at the end, because the draw-er does not know how
# to exit or anything.
# On the the other hand, the module `turtle` (where we get the draw-er and
# everything else from) does know how to handle starting and exiting, so that's
# why we make the call to the module itself instead of the draw-er `t`.

Related

Turtle Screen.tracer(0) doesn't stop all animation

I thought using Screen.tracer(0) disabled animation in Python Turtle Graphics. However in the following program, if you comment out screen.update(), there is still some animation happening - the turtle trail gets drawn although the turtle doesn't "move" (or get updated). What is happening here please? Is there way to make updating the screen completely manual?
import turtle
def move():
my_turtle.forward(1)
my_turtle.right(1)
screen.update() # Comment out this line to see issue.
screen.ontimer(move, 10)
screen = turtle.Screen()
my_turtle = turtle.Turtle()
my_turtle.shape("turtle")
screen.tracer(0)
move()
turtle.done()
No, screen.tracer(0) doesn't stop all animation. Some turtle commands like end_fill() invoke screen.update() directly, some like dot() invoke it due to other methods that they in turn invoke. You only advise the system when you call update(), not control it completely.
Put your update() calls where you believe you need them, and don't assume certain methods force an update, otherwise future updates of turtle might break your code. (I.e. someone might actually fix turtle.)
For potentially helpful details, see my tracer() rules of thumb and information about the first argument's numeric value
In turtle.py, forward() calls _go() which sets an endpoint, then calls _goto()
_goto() creates a newline if line segments get above 42
if len(self.currentLine) > 42: # 42! answer to the ultimate question
# of life, the universe and everything
self._newLine()
The value appears to be arbitrary; you could set it to something higher, but then there are pauses where nothing appears to be happening.
def _newLine(self, usePos=True):
"""Closes current line item and starts a new one.
Remark: if current line became too long, animation
performance (via _drawline) slowed down considerably.
"""

How do I change the Hitbox size of a turtle in python turtle graphics?

I dont know how to change the size of a turtle hitbox in python turtle graphics
I haven't tried anything yet because I'm new, and know very little about this. I've tried googling it, though, but nothing popped up.
from turtle import *
import turtle
from random import randint
import time
screen = turtle.Screen()
screen.setup(1920, 1080)
player = turtle.Turtle()
I want to add a button that you have to click to start right here
The game starts right here :
wn = turtle.Screen()
last_pressed = 'up'
def setup(col, x, y, w, s, shape):
player.penup()
player.up()
player.goto(x,y)
player.width(w)
player.turtlesize(s)
player.color(col)
player.lt(90)
player.down()
wn.onkey(up, "s")
wn.onkey(left, "d")
wn.onkey(right, "a")
wn.onkey(back, "w")
wn.onkey(quitTurtles, "Escape")
wn.listen()
wn.mainloop()
This may not be exactly what you are looking for, but this might work in your situation.
Detecting collision in Python turtle game
This is a thread on collision detection between objects and with some tweaking of numbers you could increase the hitbox of the turtle using the abs() function
I dont know how to change the size of a turtle hitbox in python turtle graphics
What do you mean by "hitbox"? I'm not sure what you mean by that (and neither does Google, apparently).
Do you mean that you want a rectangular button to click on? If that's the case, you could use the tkinter module together with the turtle module to create a button to click. (But be aware that it's not always easy to get the tkinter and turtle modules to work together to do what you want.)
If you want a button to click on, but don't need a Tkinter button, you could just try creating a new turtle in the shape of a rectangle that intercepts mouse clicks with onclick(). You can see an example of this if you run:
python3 -m turtledemo
and select Examples >> colormixer from the main menubar.
Or, if by "hitbox" you mean how to detect when one turtle has intercepted another turtle (as in, one has come close enough to the other to be considered a "hit"), I suggest querying each turtle's location, then using the Pythagorean Theorem to calculate the distance from each other. If this distance is within a predetermined threshold, consider the hitbox as being "hit."
You can see an example of this by typing:
python3 -m turtle
(Pay attention to the yellow turtle as he tries to catch up to the other turtle.)
I apologize if this answer isn't quite what you're looking for, but I'm just not sure what you mean by "hitbox." Maybe you could clarify?
I just saw this question today (2 years too late i know), and was having a similar problem / question.
What I ended up doing was running 3 distance checks (as i had increased my object size by 3) which differed along the x-axis (width). So it would check the distance between the ball(turtle) and the paddle (any 3 points and if it was shorter than X it would trigger the collision mechanic.
so it was something like :
check the ball class' ball object, and see how far away it is from the paddle,
and if its either in the center, or 30 pixels to the left or right of the center then hit.
if
ball.ball.distance(pad.paddle(), pad.paddle.ycor()) < 30 or
ball.ball.distance(pad.paddle.xcor() - 30, pad.paddle.ycor()) < 30 or
ball.ball.distance(pad.paddle.xcor() + 30, pad.paddle.ycor()) < 30

Python tkinter does not finish the drawing

i have to draw the house of santa claus with tkinter, but when using the following code it just stops after the first line
First I import turtle and open the gui screen
import turtle as t
t.Screen()
then i use this code
>>> s = 100
>>> points = [(s,0), (s,s), (0,0), (s,s), (s/2.,2.*s), (0,s), (s,0)]
>>> for p in points:
t.goto(p)
t.mainloop()
but it stops after the first line, how do i fix this?
As is specified in the documentation for turtle.mainloop:
turtle.mainloop()
Starts event loop - calling Tkinter’s mainloop function. Must be the last statement in a turtle graphics program. Must not be used if a script is run from within IDLE in -n mode (No subprocess) - for interactive use of turtle graphics
Here however it is not the last statement: it is called for each point in points. So you have to rewrite your program to:
for p in points:
t.goto(p)
t.mainloop()
If you read the second boldface part of the specification, it is not even necessary to call it: your program is not interactive. So the following program will be sufficient:
import turtle as t
t.Screen()
for p in points:
t.goto(p)

turtle onclick() method not working as it should

The following code creates a window in which a python turtle follows wherever your mouse goes. However, it draws indescriminately of whether the user is clicking to draw or not. My code is the following:
Note: You must have pythonwin installed in order for this program to work properly
import turtle, win32api
while True:
# turtle.penup()
user = win32api.GetCursorPos()
mousepos = [user[0]-510,-1*(user[1])+ 410]
turtle.goto(mousepos)
turtle.onclick(turtle.pendown())
In theory, this would only draw when the user is pressing and holding the mouse, but it doesn't work in practice. The commented code will simply cause it to not draw at all. Any advice?
turtle.onclick(turtle.pendown())
Here, you are calling pendown(), which returns probably None; then you're passing this None to onclick(). It probably means "do nothing on a click". That's probably not what you want.
According to #Gibby's comment, you want:
def clicked(*args): # args ignored
turtle.pendown()
turtle.onclick(clicked)

Python turtle.ondrag not working

I've been trying to make a paint program in Python Turtle and for some reason it won't work. I'm using the pen() tool and my code looks like this
from turtle import *
import random
pen()
bgcolor('black')
pencolor('white')
pen.ondrag(pen.goto)
listen()
mainloop()
I've look at this http://docs.python.org/2/library/turtle.html and it says to type turtle.ondrag(turtle.goto) but since I'm using the pen it should work as pen.ondrag but it doesn't, so can someone please clear this up.
Thanks Jellominer
I will simplify and clarify the code given by the questionner:
from turtle import *
ts = Screen(); tu = Turtle()
ts.listen()
ondrag(tu.goto)
mainloop()
This works. You have to click on the turtle and drag it.
First, pen() is not the function you want. Second, although Pen is a synonym for Turtle, pen is not a synonym for turtle. Here's how to go about using ondrag() if you'd like to use Pen instead of Turtle:
from turtle import Pen, Screen, mainloop
def ondrag_handler(x, y):
pen.ondrag(None) # disable handler inside handler
pen.setheading(pen.towards(x, y)) # turn toward cursor
pen.goto(x, y) # move toward cursor
pen.ondrag(ondrag_handler)
screen = Screen()
screen.bgcolor('black')
pen = Pen()
pen.color('white')
pen.shapesize(2) # make it larger so it's easier to drag
pen.ondrag(ondrag_handler)
screen.listen()
mainloop() # screen.mainloop() preferred but not in Python 2
The turtle.ondrag(turtle.goto) makes for a nice short example in the documentation but in reality isn't practical. You want to disable the event handler while handling the event otherwise the events stack up against you. And it's nice to turn the mouse towards your cursor as you drag it.
from turtle import *
ts = Screen()
ondrag(goto)
shapesize(10)
pensize(40)
speed(0)
mainloop()
I think this will surely work.
You can change the size and other things
In here you are using the default turtle .
Sorry but you'll need to take care of the indentation

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