Build Your Own Paint App with Python With Source Code

Paint App Using Python With Source Code

Introduction :

In this tutorial, we’ll create a simple paint application using Python. Our paint app will allow users to draw various shapes on a canvas, choose colors, and undo their last action. We will use the turtle module for drawing and the free games module for vector handling. This paint app enables you to draw lines, squares, and other shapes on a canvas. It also features color selection and an undo function. This project is an excellent way to practice working with the turtle graphics module and handling user interactions in Python

Required Modules :

To run this project, you’ll need the turtle and free games modules. You can install the free games module using pip:

				
					 pip install freegames

How to Run the Code :

1. Install Dependencies:

○ Ensure you have Python installed.
○ Install the freegames module using pip.

2. Run the Code:

○ Save the provided code in a file named paint_app.py.
Run the script using Python:

				
					 python paint_app.py

3. Use the App:

○ Click to start drawing a shape.
○ Click again to finish the shape.
○ Pressthe keys to change the color or shape:
■ K:Black
■ W:White
■ G:Green
■ B:Blue
■ R:Red
■ l:Line
■ s:Square
■ c:Circle (not yet implemented)
■ r:Rectangle (not yet implemented)
■ t:Triangle (not yet implemented)
○ Pressuto undo the last action.

Code Explanation :

Let’s walk through the key parts of the code:

1. Importing Module

				
					 from turtle import *
 from freegames import vector

Weimport the turtle module for drawing and the vector class from freegames to handle
points on the canvas.

2. Drawing Functions

Line Function:.

				
					 def line(start, end):
 "Draw line from start to end."
 up()
 goto(start.x, start.y)
 down()
 goto(end.x, end.y)

Draws a straight line between two points

3. Square Function:

				
					 def square(start, end):
 "Draw square from start to end."
 up()
 goto(start.x, start.y)
 down()
 begin_fill()
 for count in range(4):
 forward(end.x- start.x)
 left(90)
 end_fill()

Drawsasquare using the start and end points.

4. Circle, Rectangle, Triangle Functions:

				
					 def circle(start, end):
 "Draw circle from start to end."
 pass # TODO
 def rectangle(start, end):
 "Draw rectangle from start to end."
 pass # TODO
 def triangle(start, end):
 "Draw triangle from start to end."
 pass # TODO

Thesefunctions are placeholders for future implementation.

5. Tap Function

				
					 def tap(x, y):
 "Store starting point or draw shape."
 start = state['start']
 if start is None:
 state['start'] = vector(x, y)
 else:
 shape = state['shape']
 end = vector(x, y)
 shape(start, end)
 state['start'] = None

Handles mouse clicks to either store the starting point or draw the selected shape.

6. Store Function

				
					 def store(key, value):
 "Store value in state at key."
 state[key] = value

Stores the selected shape or color in the state dictionary.

5. Initialize the App

				
					 state = {'start': None, 'shape': line}
 setup(420, 420, 370, 0)
 onscreenclick(tap)
 listen()
 onkey(undo, 'u')
 onkey(lambda: color('black'), 'K')
 onkey(lambda: color('white'), 'W')
 onkey(lambda: color('green'), 'G')
 onkey(lambda: color('blue'), 'B')
 onkey(lambda: color('red'), 'R')
 onkey(lambda: store('shape', line), 'l')
 onkey(lambda: store('shape', square), 's')
 onkey(lambda: store('shape', circle), 'c')
onkey(lambda: store('shape', rectangle), 'r')
 onkey(lambda: store('shape', triangle), 't')
 done()

setup() initializes the canvas.
● onscreenclick() registers the tap function for mouse clicks.
● listen() sets up the app to listen for keyboard input.
● onkey() registers key bindings for various colors and shapes.
● done() starts the turtle graphics loop

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Source Code :

				
					from turtle import *
from freegames import vector

def line(start, end):
    "Draw line from start to end."
    up()
    goto(start.x, start.y)
    down()
    goto(end.x, end.y)

def square(start, end):
    "Draw square from start to end."
    up()
    goto(start.x, start.y)
    down()
    begin_fill()
    for count in range(4):
        forward(end.x - start.x)
        left(90)
    end_fill()

def circle(start, end):
    "Draw circle from start to end."
    pass  # TODO

def rectangle(start, end):
    "Draw rectangle from start to end."
    pass  # TODO

def triangle(start, end):
    "Draw triangle from start to end."
    pass  # TODO

def tap(x, y):
    "Store starting point or draw shape."
    start = state['start']
    if start is None:
        state['start'] = vector(x, y)
    else:
        shape = state['shape']
        end = vector(x, y)
        shape(start, end)
        state['start'] = None

def store(key, value):
    "Store value in state at key."
    state[key] = value

state = {'start': None, 'shape': line}
setup(420, 420, 370, 0)
onscreenclick(tap)
listen()
onkey(undo, 'u')
onkey(lambda: color('black'), 'K')
onkey(lambda: color('white'), 'W')
onkey(lambda: color('green'), 'G')
onkey(lambda: color('blue'), 'B')
onkey(lambda: color('red'), 'R')
onkey(lambda: store('shape', line), 'l')
onkey(lambda: store('shape', square), 's')
onkey(lambda: store('shape', circle), 'c')
onkey(lambda: store('shape', rectangle), 'r')
onkey(lambda: store('shape', triangle), 't')
done()