Building a drawing program with Python and Tkinter
Python Tkinter Canvas and Graphics: Exercise-3 with Solution
Write a Python program that builds a simple drawing program with Tkinter and allows users to draw shapes (e.g., rectangles) on the Canvas.
Sample Solution:
Python Code:
import tkinter as tk
class DrawingApp:
def __init__(self, root):
self.root = root
self.root.title("Drawing Program")
self.canvas = tk.Canvas(root, width=300, height=300, bg="white")
self.canvas.pack()
self.rectangle_button = tk.Button(root, text="Draw Rectangle", command=self.draw_rectangle)
self.rectangle_button.pack()
self.rectangles = []
self.canvas.bind("<ButtonPress-1>", self.start_draw)
self.canvas.bind("<ButtonRelease-1>", self.stop_draw)
self.drawing = False
self.start_x, self.start_y = None, None
def start_draw(self, event):
self.drawing = True
self.start_x, self.start_y = event.x, event.y
def stop_draw(self, event):
if self.drawing:
end_x, end_y = event.x, event.y
rectangle = self.canvas.create_rectangle(
self.start_x, self.start_y, end_x, end_y, outline="black", width=2
)
self.rectangles.append(rectangle)
self.drawing = False
def draw_rectangle(self):
self.canvas.bind("<ButtonPress-1>", self.start_draw_rectangle)
self.canvas.bind("<ButtonRelease-1>", self.stop_draw_rectangle)
def start_draw_rectangle(self, event):
self.drawing = True
self.start_x, self.start_y = event.x, event.y
def stop_draw_rectangle(self, event):
if self.drawing:
end_x, end_y = event.x, event.y
rectangle = self.canvas.create_rectangle(
self.start_x, self.start_y, end_x, end_y, outline="black", width=2
)
self.rectangles.append(rectangle)
self.drawing = False
if __name__ == "__main__":
root = tk.Tk()
app = DrawingApp(root)
root.mainloop()
Explanation:
In the exercise above -
- Import the Tkinter library (tkinter).
- Create a DrawingApp class that manages the drawing program.
- The "start_draw()" and "stop_draw()" methods draw rectangles when the user clicks and releases the left mouse button.
- The "draw_rectangle()" method is called when the "Draw Rectangle" button is pressed. This allows the user to draw rectangles by clicking and dragging.
- Use the "<ButtonPress-1>" and "<ButtonRelease-1>" events to start and stop drawing actions.
- The drawn rectangles are stored in the self.rectangles list.
- The program sets up a basic Tkinter window with a canvas and a "button" to draw rectangles.
- The main event loop, root.mainloop(), starts the Tkinter application.
Output:
Flowchart:
Python Code Editor:
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