1_7_canvas.py

import tkinter as tk
import ttkbootstrap as ttk

# setup
window = ttk.Window(themename = 'solar')
window.geometry('600x400')
window.title('Canvas')

# canvas 
canvas = tk.Canvas(window, bg = 'white')
canvas.pack()

# canvas.create_rectangle((50, 20, 100, 200), fill = 'red', width = 10, dash = (4,2,1,1), outline = 'green')
# canvas.create_oval((200, 0, 300, 100), fill = 'green')
# canvas.create_arc(
# 	(200, 0, 300, 100), 
# 	fill = 'red', 
# 	start = 45, 
# 	extent = 140, 
# 	style = tk.CHORD, 
# 	outline = 'red', 
# 	width = 1)

# canvas.create_line((0, 0, 100, 150), fill = 'blue')
# canvas.create_polygon((0,0, 100,200, 300,50, 150, -50), fill = 'gray')

# canvas.create_text((100,200), text = 'this is some text', fill = 'green', width = 10)

# canvas.create_window((150,100), window = ttk.Button(window, text= 'this is text in a canvas'))

# Exercise
# use event binding to create a basic paint app
def draw_on_canvas(event):
	x = event.x
	y = event.y
	canvas.create_oval((x - brush_size / 2,y - brush_size / 2, x + brush_size / 2,y + brush_size / 2), fill = 'black')

def brush_size_adjust(event):
	global brush_size
	if event.delta > 0:
		brush_size += 4
	else:
		brush_size -= 4

	brush_size = max(0,min(brush_size, 50))
	

brush_size = 2
canvas.bind('<Motion>', draw_on_canvas)
canvas.bind('<MouseWheel>', brush_size_adjust)

# run
window.mainloop()