Python with tkinter aspect ratio issue - python

I am attempting to create a simple window that maintains a square shape when resized, using python 3.6.4 and tkinter 8.6. Here is my code that produces a window, but does not maintain its aspect ratio when resized.
import tkinter as tk
w = tk.Tk()
w.aspect(1,1,1,1)
w.mainloop()

maybe you can use a canvas to make that, he detect event (image size changed) and .place relative x and relative y. I tryed make a script to help you, but you need make somes changes
from tkinter import *
# create a canvas with no internal border
canvas = Canvas(bd=0, highlightthickness=0)
canvas.pack(fill=BOTH, expand=1)
lastw, lasth = canvas.winfo_width(), canvas.winfo_height()
# track changes to the canvas size and draw
# a rectangle which fills the visible part of
# the canvas
def configure(event):
global lastw, lasth
canvas.delete("all")
w, h = event.width, event.height
try:
label.config(font = ('Arial ', int(12 * ((w - lastw) / (h - lasth))))) # -- this formula need change :3
except ZeroDivisionError: pass
lastw, lasth = canvas.winfo_width(), canvas.winfo_height()
canvas.bind("<Configure>", configure)
label = Label(canvas, text = "YOLO")
label.place(relx = 0.5, rely = 0.5) # - this make the widget automatic change her pos
mainloop()
you can see how this work here http://effbot.org/zone/tkinter-window-size.htm

Related

Python: auto slideshow with PIL/TkInter with no saving images

I´m designing a slideshow with no user intervention, where:
a. Every image is generated by the Python script itself
b. There´s no file saving, for performance reasons
c. Every image is shown in fullscreen for a certain time
d. It´s a loop that´s supposed to never end. There´s always going to be an image to show
So far, by adapting code found in a few pages, I have it running. But every image is shown for X time and then the desktop background appears for a second or so.
I´d like to have a smooth switching from one file to next, such as FEH does. As a matter of fact, I´m trying to replace FEH because I need finer control of the display of each file (for instance, changing the time it appears on screen).
Here´s my code:
from PIL import Image
from PIL import ImageFont
from PIL import ImageDraw
from PIL import ImageTk
import tkinter
def show_center(pil_image, msDelay):
root = tkinter.Tk()
w, h = root.winfo_screenwidth(), root.winfo_screenheight()
root.overrideredirect(1)
root.geometry("%dx%d+0+0" % (w, h))
root.focus_set()
root.attributes("-topmost", True)
canvas = tkinter.Canvas(root, width=w, height=h, highlightthickness=0)
canvas.pack()
canvas.configure(background='black')
image = ImageTk.PhotoImage(pil_image)
imagesprite = canvas.create_image(w / 2, h / 2, image=image)
root.after(msDelay, root.destroy)
root.mainloop()
### script body
while True:
# loads common background image
img = Image.open(baseImage)
draw = ImageDraw.Draw(img)
# here: image customization
draw.rectangle(....)
draw.text(....)
img.paste(....)
# shows this file
thisDelay = some Number Calculation
show_center(img, thisDelay)
Any ideas on how to avoid the desktop appearing between images? This will run in a headless Raspberry. I´m using Python3 on Raspbian.
Thanks in advance!
You can use after() instead of the while loop and simply use Label instead of Canvas:
import tkinter as tk
from PIL import Image, ImageTk, ImageDraw, ImageFont
import time
import random
def update_image():
# sample drawing
image = base_image.copy()
draw = ImageDraw.Draw(image)
draw.rectangle((100, 100, 500, 400), outline=random.choice(('red', 'green', 'blue', 'magenta', 'gold', 'orange')))
draw.text((120, 120), f"""{time.strftime("%F %T")}""")
# update image
tkimg = ImageTk.PhotoImage(image)
label.config(image=tkimg)
label.image = tkimg # save a reference to avoid garbage collected
ms_delay = random.randint(1000, 9000) # sample delay calculation
root.after(ms_delay, update_image)
root = tk.Tk()
root.attributes("-fullscreen", 1, "-topmost", 1)
base_image = Image.open("/path/to/base/image")
# label for showing image
label = tk.Label(root, bg="black")
label.pack(fill="both", expand=1)
update_image() # start the slide show
root.mainloop()
Well, it´s working quite well.
The solution required a bit of logic (maybe it makes sense not to destroy the object for every image) and a bit of good old trial & error.
The changes were:
Init the canvas only once, use global vars to make it persistent
For every image, call the display function and keep calling root.update() until the required timeout is reached
So, the prior function gets divided, and it looks like:
global canvas, root
global w, h
def init_image():
global canvas, root
global w, h
root = tkinter.Tk()
w, h = root.winfo_screenwidth(), root.winfo_screenheight()
root.overrideredirect(1)
root.geometry("%dx%d+0+0" % (w, h))
root.focus_set()
root.attributes("-topmost", True)
canvas = tkinter.Canvas(root, width=w, height=h, highlightthickness=0)
canvas.pack()
canvas.configure(background='black')
return
def show_center(pil_image, msDelay):
global canvas, root
global w, h
image = ImageTk.PhotoImage(pil_image)
imagesprite = canvas.create_image(w / 2, h / 2, image=image)
inicio = int(time.time() * 1000)
while 1:
root.update()
if (int(time.time() * 1000) - inicio) > msDelay:
break
return
Function init_image() is called once at beginning, and function show_center() is called for every image as the original post.
I hope this can be useful to anybody trying to accomplish the same.

Roll up image implementation using canvas - Python

I want an image to scroll up inside a canvas. But I am unable to do it.
import tkinter
def scroll_image(event):
global roll
roll = roll - 10
canvas1.itemconfig(canvas1.create_image(20, roll, image=i))
roll = 10
windows = tkinter.Tk()
windows.title("My Application")
# Adding canvas to show image there
canvas1 = tkinter.Canvas(windows, width=200, height=100)
i = tkinter.PhotoImage(file="Capture.gif")
canvas1.create_image(20, 20, image=i)
# trying to implement roll-up image
canvas1.itemconfig(canvas1.create_image(20, 20, image=i))
canvas1.bind("<Configure>", scroll_image)
canvas1.grid(column=0, row=2)
windows.mainloop()
I tried using loops but I noticed that loops are running as expected but unfortunately the canvas update is taking place only once. So I removed the loop. But I need to find a way out to implement a roll up image.
Image is moving up and down.
This example use
module PIL/pillow to load jpg/png instead of gif
after(time_in_millisecond, function_name) to repeat function which moves image
img_id to use only one image (instead of creating many images with create_image)
canvas.move(ID, offset_x, offset_y) to move image (or other object)
canvas.coords(ID) to get current positon of image (or other object)
canvas.pack(fill='both', expand=True) to use full window. Canvas will use full window even when you resize window.
Code:
import tkinter as tk
from PIL import Image, ImageTk
def scroll_image():
global offset_y # inform function that you want to assign value to external variable instead of local one.
# move image
canvas.move(img_id, offset_x, offset_y)
# get current position
x, y = canvas.coords(img_id)
print(x, y)
# set position (if you don't use canvas.move)
#canvas.coords(img_id, x+offset_x, y+offset_y)
# x += offset_x
# y += offset_y
# change direction
if y <= -100 or y >= 0:
offset_y = -offset_y
# repeat after 20ms
root.after(20, scroll_image)
offset_x = 0
offset_y = -3
root = tk.Tk()
canvas = tk.Canvas(root)
canvas.pack(fill='both', expand=True) # use full window
#photo = tk.PhotoImage(file="Capture.gif")
image = Image.open("image.jpg")
photo = ImageTk.PhotoImage(image)
img_id = canvas.create_image(0, 0, image=photo)
# start scrolling
scroll_image()
root.mainloop()
You can use also canvas.coords(ID, x, y) to set new position.
More examples on GitHub for: Tkinter and other Python's modules

Tkinter recursive behavior with '<Configure>' callback

I try to have a tkinter.Frame that have a full screen image and some buttons underneath it
WIDTH, HEIGHT = 800, 600
root = Tk()
mainframe = Frame(root, padding="3 3 12 12")
mainframe.pack(fill=BOTH, expand=True)
infovariable = StringVar()
infovariable_label = Label(mainframe, textvariable=infovariable, anchor=S)
infovariable_label.pack(fill=X, side=TOP)
label = Label(mainframe)
label.pack(fill=BOTH, expand=True)
image_base = Image.open('hello.jpg')
# setting the photo
image = (image_base
.resize(2500, 1000)
.crop(0, 0, WIDTH,HEIGHT))
label.configure(image=photo)
When I do a window resize, I want my photo to be the same dimensions (width/height), if I do that:
def onResize(event):
global WIDTH, HEIGHT
WIDTH = event.width
HEIGHT = max(0, event.height - 50)
# setting the photo
image = (image_base
.resize(2500, 1000)
.crop(0, 0, WIDTH,HEIGHT))
root.bind('<Configure>', onResize)
The resize, makes the image change size, then call the resize again, having a window that infinitely resizes.
I have the same problem as this thread:
odd behavior with '<Configure>' callback
When you bind to the root window, that binding applies to every child of the root window, too, due to how tkinter uses binding tags.
Part of the solution is to change your onResize to only change the size of the image if the event.widget represents the root window. There may be other problems, but that's the first.
You also need to make sure you account for borders. If you make the image the same size of the window, but the label has a one pixel border, that will cause the label to grow, which will cause the root window to grow, which will start the process all over again.
Another answer related to bind tags is here: https://stackoverflow.com/a/2472992/7432

python tkinter hide the window during widget creation

I have a small annoying problem so I come to you to see if you can help to solve it.
I have the following code in Python2.7:
# main window
root = tk.Tk()
root.title('My application')
# create the objects in the main window
w = buildWidgetClass(root)
# size of the screen (monitor resolution)
screenWi = root.winfo_screenwidth()
screenHe = root.winfo_screenheight()
# now that widgets are created, find the widht and the height
root.update()
guiWi = root.winfo_width()
guiHe = root.winfo_height()
# position of the window
x = screenWi / 2 - guiWi / 2
y = screenHe / 2 - guiHe / 2
root.geometry("%dx%d+%d+%d" % (guiWi, guiHe, x, y))
So I create the main window (without any size) I insert widgets inside, then I define the size of the result, and place it in the middle of the screen.
The number of widget in the window may vary, so the resulting size!
So far, so good, it works ! My only problem is that the window first appear in the left top corner of the screen, then repositioned to the center. Not a big deal, but not really professional neither.
So my idea was to hide the main window during the widgets creation time and then make it appearing after having defined the geometry.
So after the first line, I added :
root.withdraw()
then at the end :
root.update()
root.deiconify()
but when the window reappear, it wasn't re-sized by the widget and have a size of 1x1 !!
I tried to replace root.withdraw() by root.iconify(), the window is correctly re-sized but, surprisingly, isn't deiconified at the end !!!
I'm a little bit lost on this ...
Using root.winfo_reqwidth instead of root.winfo_width may help in your case.
Finally with the input of kalgasnik, I have a working code
# main window
root = tk.Tk()
# hide the main window during time we insert widgets
root.withdraw()
root.title('My application')
# create the objects in the main window with .grid()
w = buildWidgetClass(root)
# size of the screen (monitor resolution)
screenWi = root.winfo_screenwidth()
screenHe = root.winfo_screenheight()
# now that widgets are created, find the width and the height
root.update()
# retrieve the requested size which is different as the current size
guiWi = root.winfo_reqwidth()
guiHe = root.winfo_reqheight()
# position of the window
x = (screenWi - guiWi) / 2
y = (screenHe - guiHe) / 2
root.geometry("%dx%d+%d+%d" % (guiWi, guiHe, x, y))
# restore the window
root.deiconify()
Thanks a lot to both of you for your time and your help

How to center a tkinter window and retain the "fit to children" behavior?

I have a window whose content changes. Sometimes the content is larger than the window, so the window expands to fit it's children. However, when I center a window using a call to "geometry", the window no longer resizes. Below, you will find code that illustrates this.
If you comment out the delayed center() function call, you'll notice that the window expands to fit its content. If you leave it as is, the window centers, but no longer expands to fit its content.
Is it possible to center a window AND have it continue to resize to fit its content?
from Tkinter import *
import ttk
def center(root):
w = root.winfo_screenwidth()
h = root.winfo_screenheight()
rootsize = tuple(int(_) for _ in root.geometry().split('+')[0].split('x'))
x = w/2 - rootsize[0]/2
y = h/2 - rootsize[1]/2
root.geometry("%dx%d+%d+%d" % (rootsize + (x, y)))
root = Tk()
var = StringVar()
var.set('Small Text')
label = ttk.Label(root, textvariable=var)
label.grid(column=0, row=0)
# Change the text label in a couple of seconds.
def changeit():
var.set('BIG TXT - ' * 5)
root.after(2000, changeit)
# Comment out this center call and the label expands.
root.after(100, lambda: center(root))
root.mainloop()
When you call the geometry command, don't provide a width and height -- just supply the x/y values. When you give it an explicit width and height, you're telling Tk "I want the window to be exactly this size" so it turns it's auto-resize behavior off.
root.geometry("+%d+%d" % (rootsize + (x, y)))
Also, you can use winfo_width() and winfo_height() to get the actual size of the window, instead of parsing the output of the geometry method.

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