Create resizable/multiline Tkinter/ttk Labels with word wrap - python

Is it possible to create a multi-line label with word wrap that resizes in sync with the width of its parent? In other words the wordwrap behavior of Notepad as you change the width of the NotePad window.
The use case is a dialog that needs to present a block of multi-line text (instructions) in its entirety without having the text clipped or resorting to scrollbars. The parent container will have enough vertical space to accomodate narrow widths.
I've been experimenting with Tkinter Label and Message widgets and the ttk Label widget without success. It seems that I need to hard code a pixel wraplength value vs. have these controls auto wordwrap when their text reaches the right edge of their containers. Certainly Tkinters geometry managers can help me auto-resize my labels and update their wraplength values accordingly?
Should I be looking at the Text widget instead? If so, is it possible to hide the border of a Text widget so I can use it as a multi-line label with wordwrap?
Here's a prototype of how one might do what I described above. It was inspired by Bryan Oakley's tip to use the Text widget and the following post on Stackoverflow:
In python's tkinter, how can I make a Label such that you can select the text with the mouse?
from Tkinter import *
master = Tk()
text = """
If tkinter is 8.5 or above you'll want the selection background to appear like it does when the widget is activated. Comment this out for older versions of Tkinter.
This is even more text.
The final line of our auto-wrapping label that supports clipboard copy.
""".strip()
frameLabel = Frame( master, padx=20, pady=20 )
frameLabel.pack()
w = Text( frameLabel, wrap='word', font='Arial 12 italic' )
w.insert( 1.0, text )
w.pack()
# - have selection background appear like it does when the widget is activated (Tkinter 8.5+)
# - have label background color match its parent background color via .cget('bg')
# - set relief='flat' to hide Text control borders
# - set state='disabled' to block changes to text (while still allowing selection/clipboard copy)
w.configure( bg=master.cget('bg'), relief='flat', state='disabled' )
mainloop()

Use Message widget:
The Message widget is a variant of the Label, designed to display multiline messages. The message widget can wrap text, and adjust its width to maintain a given aspect ratio.

No, there is no feature built-in to Tk to auto-word-wrap labels. However, it's doable by binding to the <Configure> event of the label and adjusting the wrap length then. This binding will fire every time the label widget is resized.
The other option, as you suggest, is to use a text widget. It is possible to entirely turn off the border if you so desire. This has always been my choice when I want word-wrapped instructional text.

Here is the code:
entry = Label(self, text=text,
anchor=NW, justify=LEFT,
relief=RIDGE, bd=2)
def y(event, entry=entry):
# FIXME: make this a global method, to prevent function object creation
# for every label.
pad = 0
pad += int(str(entry['bd']))
pad += int(str(entry['padx']))
pad *= 2
entry.configure(wraplength = event.width - pad)
entry.bind("<Configure>", y )

The tkinter.Message widget suggested by some people does NOT use TTK styling, which means that it's gonna look like garbage inside a TTK (themed) interface.
You could manually apply the background and foreground colors from your TTK theme to the tkinter.Message (by instantiating ttk.Style() and requesting the active themes' TLabel foreground and background colors from that style object), but it's not worth it... because the ancient Message widget has ZERO advantages over TTK's regular ttk.Label.
The tkinter.Message widget has an "aspect ratio" property that defines how many pixels until it wraps.
The ttk.Label instead has a wraplength= property which determines how many pixels until the words wrap. You should also use its anchor= and justify= properties to customize it to your exact desires. With these properties you can make your Label behave as the old Message widget did.
Example: ttk.Label(root, text="foo", wraplength=220, anchor=tkinter.NW, justify=tkinter.LEFT). Creates a beautifully styled label which permanently wraps its text after 220 pixels wide.
As for automatically updating the wraplength? Well, you should attach to the <Configure> event as people have said... However, if you have a completely fluid window (which resizes itself to fit all content), or a grid/frame that is fluid and contains the label, then you can't automatically calculate it that way, because the parent WINDOW/CONTAINER itself will EXPAND whenever the label grows too wide. Which means that the label will always resize itself to the maximum width it would need to fit all text. So, updating wraplength automatically is only possible if the label itself has some constraints on how wide it can grow (either via its parent container being a fixed size/maxsize, or itself being a fixed size/maxsize). In that case, sure, you can use configure to calculate new wrapping numbers to make sure the text always wraps... However, the example code by t7ko is broken and not valid anymore, just fyi.

Related

Is There a Way to Always have a Place Widget Relative to Another Widget(Such as Pack)

So, I'm using the place method to have a widget overlap other widgets, but its position is relative (with winfo) to a widget that uses pack. When the parent frame is resized, the pack position will change, but the place position will not.
This is my code:
from tkinter import *
root = Tk()
root.geometry("200x300")
search = Entry(root)
search.pack()
search.update()
x = search.winfo_x()
y = search.winfo_y()
width = search.winfo_width()
height = search.winfo_height()
frame = LabelFrame(root, width=width, height=200)
frame.place(x=x, y=y+height)
root.mainloop()
The LabelFrame stays in its x and y position when the window is resized. The Entry widget will be used as a search bar and I want autocompletion under it. There will be widgets under the entry widget and the autocompletion will only appear when you are typing (That's not what I'm looking for though. Its just more exposition if you need it). So, is there a way to have the place widget always be relative to the pack widget. If you have any answers, thank you:)
If your goal is to put one widget relative to another, place lets you do that. It's great for things like tooltips or other transient widgets that don't otherwise fit into a normal layout.
The easiest way to do that is to make the widget a child of the controlling widget. For example, for your frame to be placed relative to the search box you can make it a child of the search box. If it's inconvenient to do that, you can use the in_ parameter to tell place which widget is the other widget.
For example, to place your labelframe immediately below the search box and with the same width as the search box you might do it something like this:
frame.place(
in_=search,
bordermode="outside",
anchor="nw",
relx=0,
rely=1.0,
y=5,
relwidth=1.0
)
This is what the options mean:
in_=search: place the frame relative to the search box
bordermode="outside": relative measurements are from the outside of the border (default is "inside")
anchor="nw": place the widget so that the northwest corner of the frame is at the computed coordinate
relx=0: place the anchor point 0% from the left edge of the search box
rely=1.0: place the frame at 100% of the height of the search box
y=5: add 5 pixels to the computed position so it floats just a little below the window
relwidth=1.0: make the width of the frame 100% the width of the search box.
Obviously you don't have to use y=5, I just added it to illustrate the additive behavior of using rely and y.

Tkinter: disable text widget content auto resize (newline), when user resize window

Advice: i'm working on Windows 8.1, with Python and Tkinter at last version; i wrote from tkinter import * to post less code here, i know that it is a bad practice, use for example import tkinter as tk instead.
I'm coding my first text editor, and i have a problem when i resize the main windows. When i run the program it display on screen a window with dimension 750x500 pixel. So far, all ok, i can write text without problem (note that menu_bar and other features are work-in progress, but we dont care about them). Problem is with Text widget when user tries to resize window with cursor. The content of the text practically adapts to the size of the window (the length of each string is reduced or increased based on the width of the window). But i don't want that this happen. I want that Text widget changes his width automatically in base of window size, but the content mustn't be adapted. I hope that you understand my question, if not, i will try to explain better.
I have searched on online reference if there's a parameter to set this option, but i haven't found anything.
How to solve the problems concerning the Text widget and resizing the window?
from tkinter import *
root = Tk()
root.geometry("750x500")
content_text = Text(root, wrap=WORD, bg="grey25", undo=True, cursor="",
insertbackground="red", foreground="white", font="courier 12")
content_text.pack(fill=BOTH, expand=True)
scroll_bar = Scrollbar(content_text)
content_text.configure(yscrollcommand=scroll_bar.set, selectbackground="dodgerblue")
scroll_bar.configure(command=content_text.yview)
scroll_bar.pack(side=RIGHT, fill=Y)
if __name__ == '__main__':
root.mainloop()
You can't do what you want. If you have wrapping turned on, text will always wrap at the edge of the window. When you change the width of the window, the text will re-wrap to the new width. There is no configuration option to tell the widget to wrap at any other place.

change size of tkinter messagebox

In python, I am attempting the change the width of the tkinter messagebox window so that text can fit on one line.
import tkinter as tk
from tkinter import messagebox
root = tk.Tk()
messagebox.showinfo("info","this information goes beyond the width of the messagebox")
root.mainloop()
It's not possible to adjust the size of messagebox.
When to use the Message Widget
The widget can be used to display short text messages, using a single font. You can often use a plain Label instead. If you need to display text in multiple fonts, use a Text widget. -effbot
Also see:
Can I adjust the size of message box created by tkMessagebox?
#CharleyPathak is correct. You either need to put a newline in the middle of the text, because message boxes can display multiple lines, or create a custom dialog box.
Heres another method that gets the effect youre looking for but doesnt use messagebox. it looks a lot longer but it just offers much more in terms of customization.
def popupmsg():
popup = tk.Tk()
def leavemini():
popup.destroy()
popup.wm_title("Coming Soon")
popup.wm_attributes('-topmost', True) # keeps popup above everything until closed.
popup.wm_attributes("-fullscreen", True) # I chose to make mine fullscreen with transparent effects.
popup.configure(background='#4a4a4a') # this is outter background colour
popup.wm_attributes("-alpha", 0.95) # level of transparency
popup.config(bd=2, relief=FLAT) # tk style
# this next label (tk.button) is the text field holding your message. i put it in a tk.button so the sizing matched the "close" button
# also want to note that my button is very big due to it being used on a touch screen application.
label = tk.Button(popup, text="""PUT MESSAGE HERE""", background="#3e3e3e", font=headerfont,
width=30, height=11, relief=FLAT, state=DISABLED, disabledforeground="#3dcc8e")
label.pack(pady=18)
close_button = tk.Button(popup, text="Close", font=headerfont, command=leavemini, width=30, height=6,
background="#4a4a4a", relief=GROOVE, activebackground="#323232", foreground="#3dcc8e",
activeforeground="#0f8954")
close_button.pack()
I managed to have a proper size for my
"tkMessageBox.showinfo(title="Help", message = str(readme))" this way:
I wanted to show a help file (readme.txt).
def helpfile(filetype):
if filetype==1:
with open("readme.txt") as f:
readme = f.read()
tkMessageBox.showinfo(title="Help", message = str(readme))
I opened the file readme.txt and EDITED IT so that the length of all lines did not exeed about 65 chars. That worked well for me. I think it is important NOT TO HAVE LONG LINES which include CR/LF in between. So format the txt file properly.

Tkinter Widget color does not change

When I put a widget inside the frame, the color of the frame vanishes. If it was 'black' before, then after putting a widget(label) inside the frame, the color again becomes white.
Here's my code:
from tkinter import *
root = Tk()
root.geometry("700x600")
f = Frame(root, height = 400, width = 400, bg = 'black')
f.pack()
id = Label(f, text = "Email:", fg = 'blue', font = ('Kristen ITC', 18))
id.pack()
Your Frame is resizing itself to the Label. You need to set...:
...
f.pack_propagate(False)
f.pack()
...
In order for the Frame to maintain its own dimension without affected by the its children widgets.
By default, widgets shrink or expand to fit their contents. When you add the button, the frame shrinks down to fit.
It appears you want the frame to take up just a part of the root window. Instead of explicitly giving the frame a width and height, it's usually better to let tkinter do that for you. Fill the frame with whatever widgets you want, and let tkinter decide how big the frame should be. Then, use appropriate options for grid or pack to arrange them logically. When tkinter is allowed to make widgets the right size, you'll end up with a much more responsive UI.
For example, if you set the fill and expand options when you call pack on the frame, it will not shrink to fit. If you later need to add more widgets, you won't have to modify other parts of your code to make them fit.
f.pack(fill="both", expad=True)
You can also turn off this "shrink to fit" feature by calling f.pack_propagate(False), but that is rarely the right solution because it forces you to calculate sizes, and your calculations may be wrong if you run the program on a system with different fonts or different resolutions.

How to changes fonts using ttk themed widgets in windows

On OS X, ttk.Style().configure('TLabelframe.label', font='helvetica 14 bold') works to change the font used by the ttk.LabelFrame widget. On Windows, ttk.Style().configure('TLabelframe.label', font='arial 14 bold') has no effect other than returning the same font info to ttk.Style().lookup('TLabelframe.label','font').
I've tried different font names and formats, creating a derived style, using TkDefaultFont and just changing the size, and different widgets (TButton.label, TCheckbutton.label). So far, no matter what I've tried, it always appears to use TkDefaultFont in the default size.
Changing the font setting in python27/tcl/tk8.5/ttk/xpTheme.tcl (the default theme on windows) does change the font being displayed. Removing the -font TkDefaultFont setting from the theme settings does not change what is displayed.
Any suggestions as to how this actually works?
Edit: I hadn't tried changing the font for the Label widget before, and that one actually works.
I believe the code in this area is buggy and will open a ticket. Using 'TLableframe.Label' (note uppercase 'L' in 'Label' works. 'TButton.label' and 'TButton.Label' don't work, but just 'TButton' does; 'TCheckbutton' is the same. I was unable to change the fonts for 'TEntry' with any combination, including adding 'textarea.'
It looks like for ttk.LabelFrame, you have to create a separate ttk.Label widget, and then assign it to the LabelFrame using the labelwidget= operand. You can set whatever font/style on the Label widget that you desire and that will be reflected in the LabelFrame. Note, you don't call the geometry manager for the Label widget. Just instantiate it, then assign it to the LabelFrame.
This also means that you can assign almost any widget you want, such as a ttk.Checkbutton, if you wanted to control the state of child controls within the LabelFrame. You'd have to write the code for this, but visually, it'd enable/disable the child controls based on the state of the Checkbutton.
Source: http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/ttk-LabelFrame.html

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