This is a simplified zoom example. You should use more advanced techniques to not cram the memory with a huge resized image for the large zooms.
Do not forget to place a path to your image at the end of the script.
P.S. For the advanced zoom example look here.
# -*- coding: utf-8 -*-
# WARNING: This is a simplified zoom example.
# You should use more advanced techniques to not cram the memory
# with a huge resized image for the large zooms.
import random
import tkinter as tk
from tkinter import ttk
from PIL import Image, ImageTk
class AutoScrollbar(ttk.Scrollbar):
''' A scrollbar that hides itself if it's not needed.
Works only if you use the grid geometry manager '''
def set(self, lo, hi):
if float(lo) <= 0.0 and float(hi) >= 1.0:
self.grid_remove()
else:
self.grid()
ttk.Scrollbar.set(self, lo, hi)
def pack(self, **kw):
raise tk.TclError('Cannot use pack with this widget')
def place(self, **kw):
raise tk.TclError('Cannot use place with this widget')
class Zoom(ttk.Frame):
''' Simple zoom with mouse wheel '''
def __init__(self, mainframe, path):
''' Initialize the main Frame '''
ttk.Frame.__init__(self, master=mainframe)
self.master.title('Simple zoom with mouse wheel')
# Vertical and horizontal scrollbars for canvas
vbar = AutoScrollbar(self.master, orient="vertical")
hbar = AutoScrollbar(self.master, orient="horizontal")
vbar.grid(row=0, column=1, sticky='ns')
hbar.grid(row=1, column=0, sticky='we')
# Open image
self.image = Image.open(path)
# Create canvas and put image on it
self.canvas = tk.Canvas(self.master, highlightthickness=0,
xscrollcommand=hbar.set, yscrollcommand=vbar.set)
self.canvas.grid(row=0, column=0, sticky='nswe')
vbar.configure(command=self.canvas.yview) # bind scrollbars to the canvas
hbar.configure(command=self.canvas.xview)
# Make the canvas expandable
self.master.rowconfigure(0, weight=1)
self.master.columnconfigure(0, weight=1)
# Bind events to the Canvas
self.canvas.bind('<ButtonPress-1>', self.move_from)
self.canvas.bind('<B1-Motion>', self.move_to)
self.canvas.bind('<MouseWheel>', self.wheel) # with Windows and MacOS, but not Linux
self.canvas.bind('<Button-5>', self.wheel) # only with Linux, wheel scroll down
self.canvas.bind('<Button-4>', self.wheel) # only with Linux, wheel scroll up
# Show image and plot some random test rectangles on the canvas
self.imscale = 1.0
self.imageid = None
self.delta = 0.75
width, height = self.image.size
minsize, maxsize = 5, 20
for n in range(10):
x0 = random.randint(0, width - maxsize)
y0 = random.randint(0, height - maxsize)
x1 = x0 + random.randint(minsize, maxsize)
y1 = y0 + random.randint(minsize, maxsize)
color = ('red', 'orange', 'yellow', 'green', 'blue')[random.randint(0, 4)]
self.canvas.create_rectangle(x0, y0, x1, y1, outline="black", fill=color,
activefill="black", tags=n)
# Text is used to set proper coordinates to the image. You can make it invisible.
self.text = self.canvas.create_text(0, 0, anchor="nw", text="Scroll to zoom")
self.show_image()
self.canvas.configure(scrollregion=self.canvas.bbox('all'))
def move_from(self, event):
''' Remember previous coordinates for scrolling with the mouse '''
self.canvas.scan_mark(event.x, event.y)
def move_to(self, event):
''' Drag (move) canvas to the new position '''
self.canvas.scan_dragto(event.x, event.y, gain=1)
def wheel(self, event):
''' Zoom with mouse wheel '''
scale = 1.0
# Respond to Linux (event.num) or Windows (event.delta) wheel event
if event.num == 5 or event.delta == -120:
scale *= self.delta
self.imscale *= self.delta
if event.num == 4 or event.delta == 120:
scale /= self.delta
self.imscale /= self.delta
# Rescale all canvas objects
x = self.canvas.canvasx(event.x)
y = self.canvas.canvasy(event.y)
self.canvas.scale('all', x, y, scale, scale)
self.show_image()
self.canvas.configure(scrollregion=self.canvas.bbox('all'))
def show_image(self):
''' Show image on the Canvas '''
if self.imageid:
self.canvas.delete(self.imageid)
self.imageid = None
self.canvas.imagetk = None # delete previous image from the canvas
width, height = self.image.size
new_size = int(self.imscale * width), int(self.imscale * height)
imagetk = ImageTk.PhotoImage(self.image.resize(new_size))
# Use self.text object to set proper coordinates
self.imageid = self.canvas.create_image(self.canvas.coords(self.text),
anchor="nw", image=imagetk)
self.canvas.lower(self.imageid) # set it into background
self.canvas.imagetk = imagetk # keep an extra reference to prevent garbage-collection
path="doge2.jpg" # place path to your image here
root = tk.Tk()
app = Zoom(root, path=path)
root.mainloop()