#Python 3 - Win10

Tkinter Word Processor

Text Widget Font Styling 1

Brief:

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This script is a slice of my word processor project. I'm trying to get styling to function and feel good, or at least something like Microsoft 365 Word.

It feels like I'm groping around in the dark to complete the project. The built-in tkinter functions don't seem to be of use for acquired and affecting the data I want. Which I think means I don't understand how they are meant to be employed. The workings of tkinter are also a bit of a black box for me, which is frustrating to say the least.

Functionality:

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Improvements:

Issues:

Continuation of previous tags

While typing quickly continuation of previous tags is lost
New text is briefly displayed as default before previous tags are applied
Note: this is not the case for text inserted within the existing domain of the tag

Demo:

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Functionality Test:

General tag handling

Tag / untag a range
Fully tag a partially tagged range
Untag a fully tagged range

Continue text

Get previous adjacent tags
If no adjacent text, step back through spaces and newlines until text is found

Bold text
Underline text
Overstrike text
Change font

Revert to previous font

Code Snippet:

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import tkinter as tk


class Document(tk.Text):
	
	#@! Class Variables
	#================================================================================
	children     = []
	old_insert   = "1.0"
	carrot_moved = False


	#@! Constructor
	#================================================================================
	def __init__(self, *args, **kewargs):
		super().__init__(*args, **kewargs)
		# print(f"<{self.__class__.__name__}> object created <{id(self)}> ")
		Document.children.append(id(self))
		self.set_bindings()
		self.old_insert = "1.0"

		# Break bindings for special window hotkeys e.g. 'ctrl-i'
		self.tag_init()


	#@! Utility
	#================================================================================
	
	def get_sel_index(self, event=None) -> (str, str):
		
		try:
			sel_first = self.index(f"{tk.SEL}.first")
			sel_last  = self.index(f"{tk.SEL}.last")
		except:
			sel_first = self.index(f"{tk.INSERT}")
			sel_last  = self.index(f"{tk.INSERT} +1c")

		return sel_first, sel_last
	

	#@! Tags
	#================================================================================
	
	def tag_init(self):
		tag_list = {
			   'regular':{
				     '<b>' :{'foreground':'red'},
				     '<u>' :{'underline':1, 'underlinefg':'green'},
				     '<os>':{'overstrike':1, 'overstrikefg':'red'},
				     '<jl>':{'justify':'left'},
				     '<jc>':{'justify':'center'},
				     '<jr>':{'justify':'right'},
				     '<f>' :{'foreground':'red', 'font':'Helvetica 18 bold underline overstrike italic'},
				     },
			   }
		for tag in tag_list['regular']:
			self.tag_add(tag, "1.0", "1.2")
			self.tag_config(tag, tag_list['regular'][tag])

		# Broken
		# print(self.tag_config('<f>'))
	

	# Step 2 get only the ranges that intersect the selection
	def tag_ranges_in_sel(self, tag:str, start:str="", end:str="") -> [int]:
		"""Returns list of first index of intersection tag range"""
		# def overthinking_it(self, tag, start, end):
			# Q: What are we really after with all these functions?
			# A: 1 finding if there is a tag in the selected range
			# A: 2 finding if the full range IS tagged or NOT
			# A: 3 finding if part(s) of the selection range ARE tagged
			# Q: what built in tools are there to do that job?
			# A: tag_ranges()
			# Q: are they good enough?
			# A: maybe?
		
		# guard statement
		ranges = self.tag_ranges(tag)
		if () == ranges: return []

		if start == "":
			start, end = self.get_sel_index()

		intersections = []
		
		for index in range(0, len(ranges), 2):
			range_start = ranges[index]
			range_end   = ranges[index+1]
		 	
		 	# Q: We want to know if; range does or does NOT intersect selection.
			if self.compare(range_start, "<", end) and self.compare(range_end, ">", start):
				intersections.append(index) # print("range is IN selection")
			else:
				pass # print("range is OUTside selection")

		return intersections


	# Step 3 determine if tag range encompasses the selection
	def tag_range_match_sel(self, tag:str, range_indices:[], start:str="", end:str="") -> bool:
		"""Returns True if tag range matches selection"""
		
		# guard statement
		ranges = self.tag_ranges(tag)
		if () == ranges: return False
		
		if start == "":
			start, end = self.get_sel_index()

		if 1 == len(range_indices):
			index 		= range_indices[0]
			range_start = ranges[index]
			range_end 	= ranges[index+1]
			
			if self.compare(range_start, "<=", start) and self.compare(range_end, ">=", end):
				return True
		
		return False


	def check_tags(self, event=None):
		ranges = self.tag_ranges_in_sel('bold')
		self.tag_range_match_sel('bold', ranges)


	def bold(self, event=None) -> None:
		self.set_tag('<b>')
	

	def underline(self, event=None) -> None:
		self.set_tag('<u>')
	

	def overstrike(self, event=None) -> None:
		self.set_tag('<os>')
	

	def justify(self, event=None) -> None:
		self.set_tag('<jl>')
	

	def fon(self, event=None) -> None:
		self.set_tag('<f>')
		self.tag_raise('<f>')


	def set_tag(self, tag:str, event=None) -> None:
		sel_first, sel_last = self.get_sel_index()
		tag_detected = self.tag_ranges_in_sel(tag)
		part_tagged = self.tag_range_match_sel(tag, tag_detected)
		
		if not tag_detected or not part_tagged:
			self.tag_add(tag, sel_first, sel_last)
		else:
			self.tag_remove(tag, sel_first, sel_last)


	def carry_over(self, step):
		"""Continues a style"""
		index = self.index(f"{tk.INSERT} -{step}c")
		char = self.get(index)
		while '\n' == char or ' ' == char:
			if "1.0" == index:
				return
			index = self.index(f"{index} -1c")
			char = self.get(index)

		tags = self.tag_names(index)
		
		for tag in tags:
			self.tag_add(tag, index, tk.INSERT)


	def valid_over(self, event, step):
		# ISSUE: update is not fast enough, style only continues if typing is slow
		ignore = ['space', 'Left', 'Right', 'Up', 'Down', 'Control_L', 'Control_R', 'End', 'Home', 'Prior', 'Next']
		
		if event.keysym not in ignore:
			self.carry_over(step)


	#@! Status Info
	#================================================================================
	def carrot_move(self, event=None):
		new_insert = self.index(tk.INSERT)
		
		if self.old_insert != new_insert:
			self.old_insert = new_insert
			carrot_moved = True
			print("carrot_move", new_insert) # update index on release
		else:
			carrot_moved = False


	#@! Inputs
	#================================================================================
	
	def set_bindings(self):
		self.bind("<Key>", self.any_key_down)
		self.bind("<KeyRelease>", self.any_key_up)
		self.bind("<Control-b>", self.bold)
		self.bind("<Control-u>", self.underline)
		self.bind("<Control-f>", self.fon)
		self.bind("<Control-minus>", self.overstrike)
		self.bind("<Control-bracketright>", self.overstrike)


	def any_key_down(self, event=None):
		self.valid_over(event, 1)
	

	def any_key_up(self, event=None):
		self.carrot_move(event)
		self.valid_over(event, 2)
		


root = tk.Tk()
text = Document(root, height=4)
text.pack()

text.insert("1.0", "This is helvetica font\n", "font_hel")
text.insert("1.0", "This is terminal font\n", "font_term")
text.tag_config('font_hel', font='Helvetica 12')
text.tag_config('font_term', font='Terminal 12')

root.mainloop()

Credits and Resources:

Code formatted via: http://hilite.me/ : Styling: Python, monokai

Valtyr | Tri it!

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Tuesday, January 25, 2022

Python 3 - Win10: Tkinter 1 - Word Processor - Text Widget - Font Styling 1