Apply the outline of a QTextCharFormat only on the outside of the text

[Sylve]

Unfortunately I think my second edit can not work, I have mistaken print() and paint() functions. QTextDocument has no such paint().

[Sylve]

I post my solution (in the end heavily based on the Stackoverflow one), just in case it helps anybody. Note I used Qt 6 intead of 5, but it should not matter.

from PyQt6.QtWidgets import *
import sys
from PyQt6 import QtGui
from PyQt6.QtCore import Qt
from PyQt6.QtGui import QTextDocument, QTextCursor
from PyQt6.QtGui import QColor, QPainter, QPainterPath, QBrush, QPen, QPalette, QFont
 
class MyTextDocument(QTextDocument):
    def __init__(self, parent, font):
        super().__init__()
 
        self.parent = parent
 
        self.setDefaultFont(font)
 
    def drawContents(self, painter):
 
        super().drawContents(painter)
 
        my_cursor = self.parent.textCursor()
        my_char_format = my_cursor.charFormat()
 
        my_char_format.setTextOutline(QPen(Qt.GlobalColor.red, 5))
        my_cursor.select(QTextCursor.SelectionType.Document)
        my_cursor.mergeCharFormat(my_char_format)
 
        super().drawContents(painter)
 
        my_char_format.setTextOutline(QPen(Qt.GlobalColor.transparent))
        my_cursor.mergeCharFormat(my_char_format)
 
        super().drawContents(painter)
 
 
class MyTextEdit(QTextEdit):
    def __init__(self):
        super().__init__()
 
        font = self.currentFont()
        font.setPointSize(80)
        font.setStyleStrategy(QFont.StyleStrategy.PreferAntialias)
 
        self.setDocument(MyTextDocument(self, font))
 
        self.setText("Does it work?")
        self.resize(800, 400)
 
    def paintEvent(self, event):
        painter = QPainter(self.viewport())
 
        super(MyTextEdit, self).paintEvent(event)
 
        self.document().drawContents(painter)
 
 
if __name__ == '__main__':
        app = QApplication(sys.argv)
 
        win = MyTextEdit()
        win.show()
 
        app.exec_()

from PyQt6.QtWidgets import *
import sys
from PyQt6 import QtGui
from PyQt6.QtCore import Qt
from PyQt6.QtGui import QTextDocument, QTextCursor
from PyQt6.QtGui import QColor, QPainter, QPainterPath, QBrush, QPen, QPalette, QFont

class MyTextDocument(QTextDocument):
    def __init__(self, parent, font):
        super().__init__()
        
        self.parent = parent
        
        self.setDefaultFont(font)
    
    def drawContents(self, painter):
        
        super().drawContents(painter)
        
        my_cursor = self.parent.textCursor()
        my_char_format = my_cursor.charFormat()
        
        my_char_format.setTextOutline(QPen(Qt.GlobalColor.red, 5))
        my_cursor.select(QTextCursor.SelectionType.Document)
        my_cursor.mergeCharFormat(my_char_format)
        
        super().drawContents(painter)
        
        my_char_format.setTextOutline(QPen(Qt.GlobalColor.transparent))
        my_cursor.mergeCharFormat(my_char_format)
        
        super().drawContents(painter)
        

class MyTextEdit(QTextEdit):
    def __init__(self):
        super().__init__()
        
        font = self.currentFont()
        font.setPointSize(80)
        font.setStyleStrategy(QFont.StyleStrategy.PreferAntialias)
        
        self.setDocument(MyTextDocument(self, font))
        
        self.setText("Does it work?")
        self.resize(800, 400)
        
    def paintEvent(self, event):
        painter = QPainter(self.viewport())
        
        super(MyTextEdit, self).paintEvent(event)
        
        self.document().drawContents(painter)


if __name__ == '__main__':
        app = QApplication(sys.argv)
        
        win = MyTextEdit()
        win.show()
    
        app.exec_()

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Result:



Feel free to post if you have something better in mind / any comment!

[Sylve]

I found a very concerning issue with this solution: the line

my_cursor.select(QTextCursor.SelectionType.Document)

my_cursor.select(QTextCursor.SelectionType.Document)

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calls recursively paintEvent in a infinite loop. I should find a way to disable recursive calls in paintEvent...

Try out this code to see the issue:

from PyQt5.QtWidgets import *
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QTextDocument, QTextCursor
from PyQt5.QtGui import QPainter, QPen, QFont
 
style_subs = '''	
    /* looks of subtitles */	
    QFrame {	
        background: green;
        color: white;	
        font-family: "Noto Serif CJK JP Light";
        border: 0;
    }	
'''
 
class MyTextEdit(QTextEdit):
    def __init__(self):
        super().__init__()
 
        self.setStyleSheet(style_subs)
 
        font = self.currentFont()
        font.setPointSize(80)
        font.setStyleStrategy(QFont.PreferAntialias)
        self.setFont(font)
 
        self.setText("Does it work?")
 
        self.resize(800, 400)
 
        self.n = 0
 
    def paintEvent(self, event):
        print("painting", self.n, "...")
        self.n += 1
        painter = QPainter(self.viewport())
 
        my_cursor = self.textCursor()
        my_char_format = my_cursor.charFormat()
 
        my_char_format.setTextOutline(QPen(Qt.red, 10))
        my_cursor.select(QTextCursor.SelectionType.Document)
        my_cursor.mergeCharFormat(my_char_format)
 
        self.document().drawContents(painter)
 
        my_char_format.setTextOutline(QPen(Qt.transparent))
        my_cursor.mergeCharFormat(my_char_format)
 
 
        super(MyTextEdit, self).paintEvent(event)
 
 
if __name__ == '__main__':
        app = QApplication(sys.argv)
 
        win = MyTextEdit()
        win.show()
 
        app.exec_()

from PyQt5.QtWidgets import *
import sys
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QTextDocument, QTextCursor
from PyQt5.QtGui import QPainter, QPen, QFont

style_subs = '''	
    /* looks of subtitles */	
    QFrame {	
        background: green;
        color: white;	
        font-family: "Noto Serif CJK JP Light";
        border: 0;
    }	
'''

class MyTextEdit(QTextEdit):
    def __init__(self):
        super().__init__()
        
        self.setStyleSheet(style_subs)
        
        font = self.currentFont()
        font.setPointSize(80)
        font.setStyleStrategy(QFont.PreferAntialias)
        self.setFont(font)
        
        self.setText("Does it work?")
        
        self.resize(800, 400)
        
        self.n = 0
        
    def paintEvent(self, event):
        print("painting", self.n, "...")
        self.n += 1
        painter = QPainter(self.viewport())
        
        my_cursor = self.textCursor()
        my_char_format = my_cursor.charFormat()
        
        my_char_format.setTextOutline(QPen(Qt.red, 10))
        my_cursor.select(QTextCursor.SelectionType.Document)
        my_cursor.mergeCharFormat(my_char_format)
        
        self.document().drawContents(painter)
        
        my_char_format.setTextOutline(QPen(Qt.transparent))
        my_cursor.mergeCharFormat(my_char_format)

        
        super(MyTextEdit, self).paintEvent(event)
        

if __name__ == '__main__':
        app = QApplication(sys.argv)
        
        win = MyTextEdit()
        win.show()
    
        app.exec_()

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