I want to create a simple window showing a bit of text that is quickly changing between the three primary colours. When I try this code, the window doesn't load for a few seconds, then the text just appears red, rather than changing. What am I doing wrong? Thanks
from tkinter import *
PRIMARY = ("#FF0000", "#00FF00", "#0000FF")
class Multicolour(Frame):
def __init__(self, master):
super().__init__(master)
self.grid()
self.txt = Label(self,
text="Colour change")
self.txt.grid()
self.colour_index = 0
for i in range(3000):
self.after(10, self.change)
def change(self):
self.txt.configure(fg=PRIMARY[self.colour_index])
self.colour_index += 1
if self.colour_index > 2:
self.colour_index = 0
root = Tk()
app = Multicolour(root)
root.mainloop()
Related
This code works:
import tkinter
root = tkinter.Tk()
canvas = tkinter.Canvas(root)
canvas.grid(row = 0, column = 0)
photo = tkinter.PhotoImage(file = './test.gif')
canvas.create_image(0, 0, image=photo)
root.mainloop()
It shows me the image.
Now, this code compiles but it doesn't show me the image, and I don't know why, because it's the same code, in a class:
import tkinter
class Test:
def __init__(self, master):
canvas = tkinter.Canvas(master)
canvas.grid(row = 0, column = 0)
photo = tkinter.PhotoImage(file = './test.gif')
canvas.create_image(0, 0, image=photo)
root = tkinter.Tk()
test = Test(root)
root.mainloop()
The variable photo is a local variable which gets garbage collected after the class is instantiated. Save a reference to the photo, for example:
self.photo = tkinter.PhotoImage(...)
If you do a Google search on "tkinter image doesn't display", the first result is this:
Why do my Tkinter images not appear? (The FAQ answer is currently not outdated)
from tkinter import *
from PIL import ImageTk, Image
root = Tk()
def open_img():
global img
path = r"C:\.....\\"
img = ImageTk.PhotoImage(Image.open(path))
panel = Label(root, image=img)
panel.pack(side="bottom", fill="both")
but1 = Button(root, text="click to get the image", command=open_img)
but1.pack()
root.mainloop()
Just add global to the img definition and it will work
The problem is Python automatically deletes the references to the variable by a process known as Garbage Collection. The solution is to save the reference or to create a new reference.
The following are the ways:
Using self to increase the reference count and to save the reference.
import tkinter
class Test:
def __init__(self, master):
canvas = tkinter.Canvas(master)
canvas.grid(row = 0, column = 0)
self.photo = tkinter.PhotoImage(file = './test.gif') # Changes here
canvas.create_image(0, 0, image=self.photo) # Changes here
root = tkinter.Tk()
test = Test(root)
root.mainloop()
Saving it to a list to increase the reference count and to save the reference.
import tkinter
l=[]
class Test:
def __init__(self, master):
canvas = tkinter.Canvas(master)
canvas.grid(row = 0, column = 0)
photo = tkinter.PhotoImage(file = './test.gif')
l.append(photo)
canvas.create_image(0, 0, image=photo)
root = tkinter.Tk()
test = Test(root)
root.mainloop()
While using method 2, you can either make a global list as i did or use list inside the class. Both would work.
Some useful links:
About Garbage Collection 1
About Garbage Collection 2 (More useful)
As a rule of thumb, whenever you create your image in an indented block of code you need to safe a reference to that image. This is because of the python's automated garbage collection and it collects everything with a refcount of 0 when it destroys/leaves that frame/page/indented block of code.
The canonical way to deal with it is to have a list of images somewhere in the global namespace and add your image-references to that list. This is convenient but not very efficient and should be used for small applications.
import tkinter as tk
global_image_list = []
global_image_list.append(tk.PhotoImage(file = 'test.png'))
An more efficient way is to bound an attribute to your widget or class that holds that reference for you, as Bryan proposed in his answer. It doesn't make a difference if you do self.image or widget.image that was assigned widget = tk.Widget(.. before. But this also might not the right approach if you want to use that image further even when the widget is destroyed and garbage collected.
import tkinter as tk
root = tk.Tk()
label = tk.Label(root, text='test')
label.image = tk.PhotoImage(file = 'test.png')
label.configure(image=label.image)
Just add global photo as the first line inside the function.
I have a question, its more an OS-based one.
I'm playing a video game and I want to be able to put a textual timer ontop of the game's screen as if it was a part of the game itself.
Now, I can write a program in any language that displays a TextBox with a timer on the screen, but if I run it, the game's process (lets call it game.exe) "loses" its focus and I get my TextBox focused and interactive by the OS.
Is there any option to display that text "ontop" of the game.exe that comes from an entire different process? as if there were "layers" to the screen. Also, this text shouldn't be intractable, clickable or make the game.exe process lose its focus.
Here's a very simple example I drew:
Thanks a lot!
Solved this using a window trick with python and tkinter with some windows api stuff.
The trick is to create a transparent non-clickable window and keep it always on top.
I've basically combined this answer with a bunch of simpler stuff like removing window's border and set to auto fullscreen.
from tkinter import *
import time
import win32gui
import win32api
from win32api import GetSystemMetrics
# WIDTH = 500
# HEIGHT = 500
WIDTH = GetSystemMetrics(0)
HEIGHT = GetSystemMetrics(1)
LINEWIDTH = 1
TRANSCOLOUR = 'gray'
title = 'Virtual whiteboard'
global old
old = ()
global HWND_t
HWND_t = 0
tk = Tk()
# tk.title(title)
tk.lift()
tk.wm_attributes("-topmost", True)
tk.wm_attributes("-transparentcolor", TRANSCOLOUR)
tk.attributes('-fullscreen', True)
state_left = win32api.GetKeyState(0x01) # Left button down = 0 or 1. Button up = -127 or -128
canvas = Canvas(tk, width=WIDTH, height=HEIGHT, highlightthickness=0)
canvas.pack()
canvas.config(cursor='tcross')
canvas.create_rectangle(0, 0, WIDTH, HEIGHT, fill=TRANSCOLOUR, outline=TRANSCOLOUR)
canvas.create_text(WIDTH/2,HEIGHT/2,fill="white",font="Arial 20", text="TEXT GOES HERE")
def putOnTop(event):
event.widget.unbind('<Visibility>')
event.widget.update()
event.widget.lift()
event.widget.bind('<Visibility>', putOnTop)
def drawline(data):
global old
if old !=():
canvas.create_line(old[0], old[1], data[0], data[1], width=LINEWIDTH)
old = (data[0], data[1])
def enumHandler(hwnd, lParam):
global HWND_t
if win32gui.IsWindowVisible(hwnd):
if title in win32gui.GetWindowText(hwnd):
HWND_t = hwnd
win32gui.EnumWindows(enumHandler, None)
tk.bind('<Visibility>', putOnTop)
tk.focus()
running = 1
while running == 1:
try:
tk.update()
time.sleep(0.01)
if HWND_t != 0:
windowborder = win32gui.GetWindowRect(HWND_t)
cur_pos = win32api.GetCursorPos()
state_left_new = win32api.GetKeyState(0x01)
if state_left_new != state_left:
if windowborder[0] < cur_pos[0] and windowborder[2] > cur_pos[0] and windowborder[1] < cur_pos[1] and windowborder[3] > cur_pos[1]:
drawline((cur_pos[0] - windowborder[0] - 5, cur_pos[1] - windowborder[1] - 30))
else:
old = ()
except Exception as e:
running = 0
print("error %r" % (e))
I'm trying to teach myself the tkinter module by programming minesweeper. I have created a grid with buttons and a method to set an image flag to cells. It works, in that when you press the right mouse button the image of the button changes as desired, but when you right click on the next button the image just moves to the next button, rather than creating a second flag. I want to be able to place a new flag image on each cell that I right click, rather than just shuffle the image around. Here's my code:
import tkinter as Tk
def main():
root = Tk.Tk()
root.geometry('{}x{}'.format(700, 700))
instance = Minesweeper(root, 10, 10)
root.mainloop()
class Minesweeper:
def __init__(self, parent, height, width):
self.top_frame = Tk.Frame(parent)
self.top_frame.place(anchor=Tk.CENTER, relx=0.5, rely=0.5)
self.frames = []
self.buttons = []
index = 0
for x in range(height):
for y in range(width):
self.frames.append(Tk.Frame(self.top_frame, height=50, width=50))
self.buttons.append(Tk.Button(self.frames[index], bg="white"))
self.frames[index].grid_propagate(False)
self.frames[index].columnconfigure(0, weight=1)
self.frames[index].rowconfigure(0, weight=1)
self.frames[index].grid(row=x, column=y)
self.buttons[index].grid(sticky="wens")
self.buttons[index].bind('<Button-3>', self.flag)
index += 1
def flag(self, event):
self.flag = Tk.PhotoImage(file="flag.png")
event.widget.configure(image=self.flag)
if __name__ == "__main__":
main()
Seems that the below fixed it:
def flag(self, event):
self.flag = Tk.PhotoImage(file="flag.png")
event.widget.image = self.flag # <---- this seemed to fix it
event.widget.configure(image=self.flag)
Here is my code:
from tkinter import *
import textwrap
GUI = Tk()
note_frame = Frame(GUI)
note_frame.grid(row=0, column=0)
note_scrollbar = Scrollbar(note_frame)
note_scrollbar.pack(side=RIGHT, fill=Y)
note_container = Canvas(note_frame, yscrollcommand = note_scrollbar.set)
note_container.pack()
note_scrollbar.config(command=note_container.yview)
def configure_note_container(event):
note_container.config(scrollregion=note_container.bbox("all"),
width=200, height=200)
note_list = Frame(note_container, width=200, height=200)
note_container.create_window((0,0), window=note_list, anchor='nw')
note_list.bind("<Configure>", configure_note_container)
for x in range(100):
exec(textwrap.dedent(
"""
label_{0} = Label(note_list, text='{0}', bg="white")
label_{0}.grid(column=0, row={0})
""".format(x)))
GUI.mainloop()
I am trying to get the labels to stretch out to fill the X width of the grid cell within the frame (which is within a canvas so that I can use a scrollbar), but I don't know how to do it - when the note_container gets configured, it seems to cancel out any adjustment of size. grid_propagate doesn't seem to work either.
Any help is appreciated. thanks.
I'm trying to open a window (QWidget) when clicking on a button. My problem is that the second window doesn't show up when I click on the button no matter what I've tried. The two windows are created using QTDesigner.
Here is a little snippet explaining what I'm trying to do:
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from win1 import *
from win2 import *
import sys
class win1(QWidget, Ui_Win1):
def __init__(self, parent = None):
self.parent = parent
QWidget.__init__(self)
self.setupUi(parent)
self.connect(self.pushButton, SIGNAL("clicked()"), self.on_btn_clicked)
def on_btn_clicked(self):
self.child = win2(self.parent)
self.child.show()
class win2(QWidget, Ui_Win2):
def __init__(self, parent = None):
QWidget.__init__(self)
self.setupUi(parent)
def main(args):
app = QApplication(args)
win = QWidget()
a = win1(win)
win.show()
result = app.exec_()
if __name__=="__main__":
main(sys.argv)
What am I missing here ?
Thanks.
Not sure, but two random thoughts:
If you add a print statement to on_btn_clicked, do you see anything when you click on the button? This would diagnose whether it's an event triggering issue
Does it work if you change the setupUI(parent) commands to setupUI(self)?