# Tk_zoom_object.py

# Tk_zoom_object.py

import tkinter as tk

root = tk.Tk()
canvas = tk.Canvas(root, width=400, height=400, background="bisque")
canvas.pack(fill="both", expand=True)

# start with one rectangle
canvas.create_rectangle(10, 5, 75, 100, outline="", fill="blue")

# add a new item, and apply the same scale to it
obj = canvas.create_rectangle(75, 5, 200, 100, outline="", fill="red") # ??? outline leaves traces
canvas.create_text(25,100, anchor="nw", text="""
    Left click and drag to move the canvas
    Scroll to zoom
    Right click to zoom all by recent""")

current_scale = [0, 0, 1.05, 1.05]

# move
def move_start(event):
    canvas.scan_mark(event.x, event.y)
def move_move(event):
    canvas.scan_dragto(event.x, event.y, gain=1)

# zoom
def zoom(event):
    global current_scale
    if (event.delta > 0):
        sc = -0.05
        ctr = -1
    else:
        sc = 0.05
        ctr = -1
    current_scale = [0, 0, 1+sc, 1+sc]
    canvas.scale(obj, *current_scale)

def draw(event):
    canvas.scale("all", *current_scale)

# Mouse bindings to the canvas
canvas.bind("<ButtonPress-1>", move_start)
canvas.bind("<B1-Motion>", move_move)
root.bind_all("<MouseWheel>", zoom)
canvas.bind("<ButtonPress-3>", draw)

root.mainloop()