As the title suggests, I'm wondering if it's possible to get the height of a frame full of widgets before it is packed and displayed.
Here is some example code:
import tkinter as tk
root = tk.Tk()
frame = tk.Frame(root, bg='green')
label = tk.Label(frame, text='hello')
label.pack(side='top')
button = tk.Button(frame, text='Test Button')
button.pack(side='top')
print(frame['height']) # Outputs 0
frame.pack(side='top')
root.mainloop()
I want to be able to do this so that if the frame is taller than a specific threshold, it will instead go inside a scrollable canvas.
Thanks.
As stated in TheLizzard's comment, I can do this by using the following code:
...
frame.update()
print(frame.winfo_reqheight())
frame.pack(side='top')
...
Related
I'm trying to center text in the frame using LabelFrame function. My code is below.
import tkinter as tk
window = tk.Tk()
for i in range(9):
for j in range(9):
frame = tk.LabelFrame(
master=window,
relief=tk.RAISED,
borderwidth=5,
width=50,
height=50,
text=i+j,
labelanchor = 'n'
)
frame.grid(row=i, column=j)
window.geometry("500x500")
window.mainloop()
Argument labelanchor that specify position gives only options on the edge of the frame. Is there any simple way to center text inside of the frame using LabelFrame?
Is there any simple way to center text inside of the frame using LabelFrame?
The text of the labelframe can only appear along the edges of the frame. If you wish for text to appear inside the frame, you must create a Label and add it to the frame.
Using a frame and a label
If you wish to put other widgets in the frame and don't want this text to interfere with the other widgets, this is a perfect opportunity to use place.
The following example adds the label "Hello, world" to appear in the center of the widget. A button is placed in the frame just to show that its placement is not affected by the label, or vise versa. The screenshots show what the frame looks like naturally and when the window is resized.
import tkinter as tk
root = tk.Tk()
lf = tk.Frame(root, bd=2, relief="groove")
lf_label = tk.Label(lf, text="Hello, world")
lf_label.place(relx=.5, rely=.5, anchor="c")
lf.pack(padx=20, pady=20, fill="both", expand=True)
b = tk.Button(lf, text="Click me")
b.pack(padx=10, pady=10)
root.mainloop()
Using only a label
You can add widgets inside any other widget. So, instead of a frame you could just use a label. By default, the text will be centered, and just like with the previous example it won't affect the layout of other widgets.
I haven't included screenshots because the results are identical to the previous example.
import tkinter as tk
root = tk.Tk()
lf = tk.Label(text="Hello, world", bd=2, relief="groove")
lf.pack(padx=20, pady=20, fill="both", expand=True)
b = tk.Button(lf, text="Click me")
b.grid(row=0, column=0)
root.mainloop()
I am learning Python GUI programming with tkinter. I wanted to place a frame in my root window using the grid geometry manager, specify a height, and have the frame expand to the full width of the root window. I tried to do this using the sticky options but this does not produce the desired result. How do I make the frame expand to the full width of the window without manually specifying the width?
Code:
import tkinter
import tkinter.ttk
win = tkinter.Tk()
win.geometry('600x600')
frame = tkinter.Frame(win, height=300)
frame.configure(bg='red')
frame.grid(column=0, sticky=tkinter.E + tkinter.W)
win.mainloop()
I believe this code will achieve the result you are looking for (note that call to grid_columnconfigure is on win, which is the parent of your frame widget):
import tkinter
import tkinter.ttk
win = tkinter.Tk()
win.geometry('600x600')
frame = tkinter.Frame(win, bg='red', height=300)
frame.grid(row=0, column=0, sticky='ew')
win.grid_columnconfigure(0,weight=1)
win.mainloop()
Most of the topics I came across deals with how to not shrink the Frame with contents, but I'm interested in shrinking it back after the destruction of said contents. Here's an example:
import tkinter as tk
root = tk.Tk()
lbl1 = tk.Label(root, text='Hello!')
lbl1.pack()
frm = tk.Frame(root, bg='black')
frm.pack()
lbl3 = tk.Label(root, text='Bye!')
lbl3.pack()
lbl2 = tk.Label(frm, text='My name is Foo')
lbl2.pack()
So far I should see this in my window:
Hello!
My name is Foo
Bye!
That's great, but I want to keep the middle layer interchangeable and hidden based on needs. So if I destroy the lbl2 inside:
lbl2.destroy()
I want to see:
Hello!
Bye!
But what I see instead:
Hello!
███████
Bye!
I want to shrink frm back to basically non-existence because I want to keep the order of my main widgets intact. Ideally, I want to run frm.pack(fill=tk.BOTH, expand=True) so that my widgets inside can scale accordingly. However if this interferes with the shrinking, I can live without fill/expand.
I've tried the following:
pack_propagate(0): This actually doesn't expand the frame at all past pack().
Re-run frm.pack(): but this ruins the order of my main widgets.
.geometry(''): This only works on the root window - doesn't exist for Frames.
frm.config(height=0): Oddly, this doesn't seem to change anything at all.
frm.pack_forget(): From this answer, however it doesn't bring it back.
The only option it leaves me is using a grid manager, which works I suppose, but not exactly what I'm looking for... so I'm interested to know if there's another way to achieve this.
When you destroy the last widget within a frame, the frame size is no longer managed by pack or grid. Therefore, neither pack nor grid knows it is supposed to shrink the frame.
A simple workaround is to add a small 1 pixel by 1 pixel window in the frame so that pack still thinks it is responsible for the size of the frame.
Here's an example based off of the code in the question:
import tkinter as tk
root = tk.Tk()
lbl1 = tk.Label(root, text='Hello!')
lbl1.pack()
frm = tk.Frame(root, bg='black')
frm.pack()
lbl3 = tk.Label(root, text='Bye!')
lbl3.pack()
lbl2 = tk.Label(frm, text='My name is Foo')
lbl2.pack()
def delete_the_label():
lbl2.destroy()
if len(frm.winfo_children()) == 0:
tmp = tk.Frame(frm, width=1, height=1, borderwidth=0, highlightthickness=0)
tmp.pack()
root.update_idletasks()
tmp.destroy()
button = tk.Button(root, text="Delete the label", command=delete_the_label)
button.pack()
root.mainloop()
Question: Shrink a Frame after removing the last widget?
Bind to the <'Expose'> event and .configure(height=1) if no children.
Reference:
Expose
An Expose event is generated whenever all or part of a widget should be redrawn
import tkinter as tk
class App(tk.Tk):
def __init__(self):
super().__init__()
tk.Label(self, text='Hello!').pack()
self.frm = frm = tk.Frame(self, bg='black')
frm.pack()
tk.Label(self, text='Bye!').pack()
tk.Label(frm, text='My name is Foo').pack()
self.menubar = tk.Menu()
self.config(menu=self.menubar)
self.menubar.add_command(label='delete', command=self.do_destroy)
self.menubar.add_command(label='add', command=self.do_add)
frm.bind('<Expose>', self.on_expose)
def do_add(self):
tk.Label(self.frm, text='My name is Foo').pack()
def do_destroy(self):
w = self.frm
if w.children:
child = list(w.children).pop(0)
w.children[child].destroy()
def on_expose(self, event):
w = event.widget
if not w.children:
w.configure(height=1)
if __name__ == "__main__":
App().mainloop()
Question: Re-run frm.pack(): but this ruins the order of my main widgets.
frm.pack_forget(), however it doesn't bring it back.
Pack has the options before= and after. This allows to pack a widget relative to other widgets.
Reference:
-before
Use its master as the master for the slaves, and insert the slaves just before other in the packing order.
Example using before= and self.lbl3 as anchor. The Frame are removed using .pack_forget() if no children and get repacked at the same place in the packing order.
Note: I show only the relevant parts!
class App(tk.Tk):
def __init__(self):
...
self.frm = frm = tk.Frame(self, bg='black')
frm.pack()
self.lbl3 = tk.Label(self, text='Bye!')
self.lbl3.pack()
...
def on_add(self):
try:
self.frm.pack_info()
except:
self.frm.pack(before=self.lbl3, fill=tk.BOTH, expand=True)
tk.Label(self.frm, text='My name is Foo').pack()
def on_expose(self, event):
w = event.widget
if not w.children:
w.pack_forget()
Tested with Python: 3.5 - 'TclVersion': 8.6 'TkVersion': 8.6
I am working on this table in tkinter made from a bunch of treeveiw widgets. The idea is to get a table where I can add lines, select lines and edit them. In the code below you can add lines to the table by pushing the button. I now want to control the height of each row by configuring the style. However, when I use style the alignment of the treeview widgets is messed up, see attached picture. Any suggestions how to fix this?
EDIT: The problem is the added space between the widgets.
The code for the table is:
from tkinter import *
from tkinter import ttk
class MyApp(Tk):
def __init__(self):
super(MyApp, self).__init__()
self.geometry('950x500+100+100')
self.NewTree = []
label = Label(self,text='Table with some data', font=("Arial Bold", 25))
label.pack()
self.addLine()
master_frame = Frame(self, bd=3, relief=RIDGE)
master_frame.pack(side=BOTTOM)
# Create a frame for the canvas and scrollbar(s).
frame2 = Frame(master_frame)
frame2.pack(side = BOTTOM)
# Add a canvas in that frame.
self.canvas = Canvas(frame2)
self.canvas.grid(row=0, column=0)
# Create a vertical scrollbar linked to the canvas.
vsbar = Scrollbar(frame2, orient=VERTICAL, command=self.canvas.yview)
vsbar.grid(row=0, column=1, sticky=NS)
self.canvas.configure(yscrollcommand=vsbar.set)
# Create a frame on the canvas to contain the buttons.
self.table_frame = Frame(self.canvas)
# Create canvas window to hold the buttons_frame.
self.canvas.create_window((0,0), window=self.table_frame, anchor=NW)
def addLine(self):
#Make button for adding step
bt = Button(self,text='Add Line',command=lambda: self.addLineMethod())
bt.config(width=9, height=1)
bt.pack()
def addLineMethod(self):
lineNumber = int(len(self.NewTree)/5)
for index in range(5):
s = ttk.Style()
s.configure('MyStyle.Treeview', rowheight=25)
self.NewTree.append(ttk.Treeview(self.table_frame, height=1,show="tree",columns=("0"),style='MyStyle.Treeview'))
#Works fine when using this line instead of those above
#self.NewTree.append(ttk.Treeview(self.table_frame, height=1,show="tree",columns=("0")))
self.NewTree[index+5*lineNumber].grid(row=lineNumber, column=index+1)
self.NewTree[index+5*lineNumber]['show'] = ''
item = str(index+5*lineNumber)
self.NewTree[index+5*lineNumber].column("0", width=180, anchor="w")
self.NewTree[index+5*lineNumber].insert("", "end",item,text=item,values=('"Text text text"'))
self.table_frame.update_idletasks() # Needed to make bbox info available.
bbox = self.canvas.bbox(ALL) # Get bounding box of canvas with Buttons.
# Define the scrollable region as entire canvas with only the desired
# number of rows and columns displayed.
self.canvas.configure(scrollregion=bbox, width=925, height=200)
app = MyApp()
app.mainloop()
Her is a picture of the table with some lines.
Put the style configuration in the __init__() function and the effect will go away. I'm not clear as to why this works.
def __init__(self):
...
s = ttk.Style()
s.configure('MyStyle.Treeview', rowheight=20)
The size of Tkinter windows can be controlled via the following methods:
.minsize()
.maxsize()
.resizable()
Are there equivalent ways to control the size of Tkinter or ttk Frames?
#Bryan: I changed your frame1.pack code to the following:
frame1.pack(fill='both', expand=True)
frame1.bind( '<Configure>', maxsize )
And I added this event handler:
# attempt to prevent frame from growing past a certain size
def maxsize( event=None ):
print frame1.winfo_width()
if frame1.winfo_width() > 200:
print 'frame1 wider than 200 pixels'
frame1.pack_propagate(0)
frame1.config( width=200 )
return 'break'
The above event handler detects that a frame's width is too big, but is unable to prevent the increase in size from happening. Is this a limitation of Tkinter or have I misunderstood your explanation?
There is no single magic function to force a frame to a minimum or fixed size. However, you can certainly force the size of a frame by giving the frame a width and height. You then have to do potentially two more things: when you put this window in a container you need to make sure the geometry manager doesn't shrink or expand the window. Two, if the frame is a container for other widget, turn grid or pack propagation off so that the frame doesn't shrink or expand to fit its own contents.
Note, however, that this won't prevent you from resizing a window to be smaller than an internal frame. In that case the frame will just be clipped.
import Tkinter as tk
root = tk.Tk()
frame1 = tk.Frame(root, width=100, height=100, background="bisque")
frame2 = tk.Frame(root, width=50, height = 50, background="#b22222")
frame1.pack(fill=None, expand=False)
frame2.place(relx=.5, rely=.5, anchor="c")
root.mainloop()
A workaround - at least for the minimum size: You can use grid to manage the frames contained in root and make them follow the grid size by setting sticky='nsew'. Then you can use root.grid_rowconfigure and root.grid_columnconfigure to set values for minsize like so:
from tkinter import Frame, Tk
class MyApp():
def __init__(self):
self.root = Tk()
self.my_frame_red = Frame(self.root, bg='red')
self.my_frame_red.grid(row=0, column=0, sticky='nsew')
self.my_frame_blue = Frame(self.root, bg='blue')
self.my_frame_blue.grid(row=0, column=1, sticky='nsew')
self.root.grid_rowconfigure(0, minsize=200, weight=1)
self.root.grid_columnconfigure(0, minsize=200, weight=1)
self.root.grid_columnconfigure(1, weight=1)
self.root.mainloop()
if __name__ == '__main__':
app = MyApp()
But as Brian wrote (in 2010 :D) you can still resize the window to be smaller than the frame if you don't limit its minsize.