CPSC120B - Day 22 Notes

So far we have created graphical programs using turtle
But turtle isn’t very good for creating animations
The underlying graphical system that turtle is built on is difficult to use
So I created a module to make creating animations easier
Using module that is not built-in requires an extra step
Before importing it, you have to put the module’s .py file in the same directory and the .py file that is using it.
The graphics module’s documentation has a link to the graphics.py file you can use during lab
To draw an oval use the draw_oval function, need to specify the x, y, width, and height
```
import graphics
graphics.draw_oval(0, 0, 100, 100)
```
Note the coordinate system is different than turtle, (0, 0) is in the upper left and positive y is down

Can also change the outline, fill, and thickness

import graphics
graphics.draw_oval(100, 100, 100, 200, 'red', 'blue', 5)

To create an animation, need to draw multiple times

import graphics
for i in range(100)
    graphics.draw_oval(i, i, 100, 100)

To add a delay, use the wait function

import graphics
for i in range(100)
    graphics.draw_oval(i, i, 100, 100)
    graphics.wait()

To remove the trail, need to clear the screen

import graphics
for i in range(100)
    graphics.clear()
    graphics.draw_oval(i, i, 100, 100)
    graphics.wait()

For the lab today you will need to draw images using the grahpics module
The graphics module can only draw gif images
To find a gif do a google image search and filetype:gif to your search terms
Put the image in the same directory and you .py file and the graphic.py file
Draw an image with the draw_image function
```
graphics.draw_image('ball.gif', 0, 0)
```
The first argument is the name of the image file, don’t for get the quotes
The second and third arguments are the x and y coordinates of the center of the image

CPSC120B
Fundamentals of Computer Science