2. Turtle screen

The code below shows code to set up a window for a turtle to draw in.

The use of each line is detailed below.

import turtle

s = turtle.Screen()
s.bgcolor("white")
s.title("Turtle Screen")
s.setup (width=800, height=600, startx=0, starty=0)

# turtle drawing to go here

turtle.done()

2.1. Screen class

See: https://docs.python.org/3/library/turtle.html#turtle.Screen

Setup the screen for drawing in.

Start by importing the inbuilt turtle library.

The class Screen() defines graphics windows for turtles to draw in.
This function should be used when turtle is used as a standalone tool for doing graphics.
The last line, turtle.done(), has been included in the examples below so the window stays open.

import turtle

s = turtle.Screen()

# turtle drawing to go here

turtle.done()

2.2. Screen colours

See: https://docs.python.org/3/library/turtle.html#turtle.bgcolor

See: https://docs.python.org/3/library/turtle.html#turtle.colormode

Set the screen color mode.

turtle.colormode(cmode=None): cmode - set to one of the values 1.0 or 255. The default config has turtles starting with a cmode of 1.0

If colormode is 1, a colour, as a rgb tuple, is written with values from 0 to 1, such as (0.2, 0.8, 0.55).

If colormode is 255, a colour, as a rgb tuple, is written with values from 0 to 255, such as (50, 193, 143).

If cmode=None, the cmode value is returned.

When s = turtle.Screen(), s.colormode(cmode=255) can be used as below.

Set the screen color.

turtle.bgcolor(*args): args - a color string or three numbers in the range 0 to 1 or 255 depending on the colormode or a 3-tuple of such numbers.

Color stings can be a named color such as “orange” or a hex color such as “#800080”.

If colormode is 1, a colour is a rgb tuple such as (0.2, 0.8, 0.55),

If colormode is 255, a colour is a rgb tuple such as (50, 193, 143)

When s = turtle.Screen(), s.bgcolor("white") can be used as below.

The code below sets the background to white.

import turtle

s = turtle.Screen()
s.bgcolor("white")

# turtle drawing to go here

turtle.done()

Change the colormode to 255, so that the background can be set using the rgb tuple (50, 193, 143).

import turtle

s = turtle.Screen()
s.colormode(cmode=255)
s.bgcolor((50, 193, 143))

# turtle drawing to go here

turtle.done()

Tasks

Modify the code above to draw a yellow background.
Draw a cyan background using rgb value of (0, 255, 255).

2.3. Screen title

See: https://docs.python.org/3/library/turtle.html#turtle.title

Set the screen title.

turtle.title(titlestring): titlestring - a string that is shown in the titlebar of the turtle graphics window

When s = turtle.Screen(), s.title("Turtle Screen") can be used as below.

import turtle

s = turtle.Screen()
s.bgcolor("white")
s.title("Turtle Screen")

# turtle drawing to go here

turtle.done()

Tasks

Modify the code above to set the screen title to “Turtle Race”.

2.4. Screen size and position

See: https://docs.python.org/3/library/turtle.html#turtle.setup

Set the screen size and position.

turtle.setup(width=0.5, height=0.75, startx=None, starty=None): Set the size and position of the main window.

width - if an integer, a size in pixels; if a float, a fraction of the screen; default 0.5

height - if an integer, the height in pixels; if a float, a fraction of the screen; default 0.75

startx - if positive, start position in pixels from the left edge of the screen; if negative from the right edge, if None, center window horizontally; default None

starty - if positive, start position in pixels from the top edge of the screen; if negative from the bottom edge, if None, center window vertically; default None

When s = turtle.Screen(), s.setup() can be used as below.

import turtle

s = turtle.Screen()
s.bgcolor("white")
s.title("Turtle Screen")
s.setup(width=800, height=600, startx=None, starty=None)

# turtle drawing to go here

turtle.done()

Tasks

Modify the code above to have a screen of 600 by 400, with the left edge 40 pixels from the screen edge and the top edge at the top of the screen.

2.5. Using screen events

See: https://docs.python.org/3/library/turtle.html#turtle.mainloop

Use turtle.mainloop() or turtle.done() to keep the window open.
When used, it must be the last statement in the file.
The window’s close icon must be clicked to close the window.

import turtle

s = turtle.Screen()
s.bgcolor("white")
s.title("Turtle Screen")
s.setup (width=800, height=600, startx=0, starty=0)

# turtle drawing to go here

turtle.done()

2.6. Exit on click

See: https://docs.python.org/3/library/turtle.html#turtle.exitonclick

Close the Turtle window when the mouse is clicked.

Use turtle.exitonclick() instead of turtle.done()

turtle.exitonclick(): Also turtle.bye()

Shut the turtle graphics window when the mouse is clicked on the Screen.

When s = turtle.Screen(), s.exitonclick() can be used as below.

import turtle

s = turtle.Screen()
s.bgcolor("white")
s.title("Turtle Screen")
s.setup (width=800, height=600, startx=0, starty=0)

# turtle drawing to go here

s.exitonclick()
# turtle.done()

Tasks

Modify the code to require a mouse click to close the turtle window.

import turtle

s = turtle.Screen()
s.bgcolor("lightblue")
s.title("Turtle Screen")

# turtle drawing to go here

turtle.done()