QLineEdit/QTextEdit different colors while typing

tilz0R

I try to implement a QLineEdit with every bracket of different color - used for user to be able to match opening and closing bracket - I realized that this may not be really possible?

So I moved to QTextEdit that has a plaintext insert and supports color setup. One issue is that attaching to textChanged will get triggered by keyboard and when text is changed in the code - therefore I implemented a timer that is triggered every 50ms to do the job.

Now the problem is that if user sets cursor in the middle, obviously it gets auto set to the end of the line - so not really intuitive.

How to implement that instead?

This is the sketch - pyside6.4.2 is needed

# This Python file uses the following encoding: utf-8
import sys, faulthandler
from mainwindow import MainWindow
from PySide6.QtWidgets import QApplication
from PySide6 import QtWidgets, QtCore, QtGui
from PySide6.QtWidgets import *
from PySide6.QtCore import *
from PySide6.QtUiTools import *
from PySide6.QtGui import *

class MainWin(QMainWindow):
    def __init__(self):
        super().__init__()
        # Edit text
        self.textedit = QTextEdit()
        self.textedit.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
        self.textedit.setVerticalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
        self.textedit.setLineWrapMode(QTextEdit.LineWrapMode.NoWrap)
        self.textedit.setFixedHeight(30)
        self.textedit_text = ''

        # Timer
        self.timer = QTimer()
        self.timer.setInterval(100)
        self.timer.timeout.connect(self.timer_timeout)
        self.timer.start()

        # Central
        self.setCentralWidget(self.textedit)

    def timer_timeout(self):
        colors = ['black', 'red', 'blue', 'green', 'magenta', 'orange']
        text = self.textedit.toPlainText()
        if self.textedit_text == text:
            return
        self.textedit_text = text
        
        bracket_index = 0
        self.textedit.setPlainText('')
        for c in text:
            if c == '(':
                bracket_index += 1
                self.textedit.setTextColor(QtGui.QColor.fromString(colors[bracket_index % len(colors)]))
                self.textedit.insertPlainText('(')
            elif c == ')':
                self.textedit.setTextColor(QtGui.QColor.fromString(colors[bracket_index % len(colors)]))
                self.textedit.insertPlainText(')')
                if bracket_index > 0:
                    bracket_index -= 1
            else:
                self.textedit.setTextColor(QtGui.QColor.fromString(colors[0]))
                self.textedit.insertPlainText(c)

# Main application run
if __name__ == '__main__':
    faulthandler.enable()
    app = QApplication(sys.argv)
    mainwindow = MainWin()
    mainwindow.show()
    sys.exit(app.exec())

JonB

@tilz0R said in QLineEdit/QTextEdit different colors while typing:

One issue is that attaching to textChanged will get triggered by keyboard and when text is changed in the code - therefore I implemented a timer that is triggered every 50ms to do the job.

If you are in charge of the code callers to setText() you can avoid the timer per the answer in QLineEdit::textEdited() equivalent in QTextEdit?.

Now the problem is that if user sets cursor in the middle, obviously it gets auto set to the end of the line - so not really intuitive.

You would have to save the cursor position before changing and restore it afterwards.

This whole idea of changing stuff while user is typing worries me.

tilz0R

@JonB Idea is like rich text - vscode style - set colors of the brackets during typing.

I started with another option, below, which test-wise does change the colors, but it always sets color of the whole string, not random color for each character. Any idea?

# This Python file uses the following encoding: utf-8
import sys, faulthandler
from mainwindow import MainWindow
from PySide6.QtWidgets import QApplication
from PySide6 import QtWidgets, QtCore, QtGui
from PySide6.QtWidgets import *
from PySide6.QtCore import *
from PySide6.QtUiTools import *
from PySide6.QtGui import *
import random

class MainWin(QMainWindow):
    def __init__(self):
        super().__init__()
        # Edit text
        self.textedit = QTextEdit()
        #self.textedit.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
        #self.textedit.setVerticalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
        #self.textedit.setLineWrapMode(QTextEdit.LineWrapMode.NoWrap)
        self.textedit.setFixedHeight(30)
        self.textedit_text = ''

        # Timer
        self.timer = QTimer()
        self.timer.setInterval(25)
        self.timer.timeout.connect(self.timer_timeout)
        self.timer.start()

        # Central
        self.setCentralWidget(self.textedit)

    def timer_timeout(self):
        colors = ['black', 'red', 'blue', 'green', 'magenta', 'orange', 'yellow', 'brown', 'grey']
        text = self.textedit.toPlainText()
        if self.textedit_text == text:
            return
        self.textedit_text = text

        # Get cursor
        cursor = QTextCursor(self.textedit.textCursor())
        cursor.movePosition(QTextCursor.MoveOperation.Start)
        while not cursor.atEnd():
            cursor.movePosition(QTextCursor.MoveOperation.Right, QTextCursor.MoveMode.KeepAnchor)
            format = QTextCharFormat()
            format.setForeground(QColor.fromString(colors[random.randint(0, len(colors) - 1)]))
            cursor.mergeCharFormat(format)

# Main application run
if __name__ == '__main__':
    faulthandler.enable()
    app = QApplication(sys.argv)
    mainwindow = MainWin()
    mainwindow.show()
    sys.exit(app.exec())

tilz0R

This is somewhat working:

# This Python file uses the following encoding: utf-8
import sys, faulthandler
from mainwindow import MainWindow
from PySide6.QtWidgets import QApplication
from PySide6 import QtWidgets, QtCore, QtGui
from PySide6.QtWidgets import *
from PySide6.QtCore import *
from PySide6.QtUiTools import *
from PySide6.QtGui import *

class MainWin(QMainWindow):
    def __init__(self):
        super().__init__()
        # Edit text
        self.textedit = QTextEdit()
        self.textedit.setHorizontalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
        self.textedit.setVerticalScrollBarPolicy(Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
        self.textedit.setLineWrapMode(QTextEdit.LineWrapMode.NoWrap)
        self.textedit.setFixedHeight(30)
        self.textedit_text = ''

        # Timer
        self.timer = QTimer()
        self.timer.setInterval(100)
        self.timer.timeout.connect(self.timer_timeout)
        self.timer.start()

        # Central
        self.setCentralWidget(self.textedit)

    def timer_timeout(self):
        colors = ['black', 'red', 'blue', 'green', 'magenta', 'orange']
        text = self.textedit.toPlainText()
        if self.textedit_text == text:
            return
        self.textedit_text = text
        self.textedit.blockSignals(True)

        # Get cursor and position
        cursor = self.textedit.textCursor()
        pos = cursor.position()

        bracket_index = 0
        self.textedit.setPlainText('')
        for c in text:
            if c == '(':
                bracket_index += 1
                self.textedit.setTextColor(QtGui.QColor.fromString(colors[bracket_index % len(colors)]))
                self.textedit.insertPlainText('(')
            elif c == ')':
                self.textedit.setTextColor(QtGui.QColor.fromString(colors[bracket_index % len(colors)]))
                self.textedit.insertPlainText(')')
                if bracket_index > 0:
                    bracket_index -= 1
            else:
                self.textedit.setTextColor(QtGui.QColor.fromString(colors[0]))
                self.textedit.insertPlainText(c)

        # Set new position and new cursor to text edit
        cursor.setPosition(pos)
        self.textedit.setTextCursor(cursor)
        self.textedit.blockSignals(False)

# Main application run
if __name__ == '__main__':
    faulthandler.enable()
    app = QApplication(sys.argv)
    mainwindow = MainWin()
    mainwindow.show()
    sys.exit(app.exec())

friedemannkleint

Have you checked QSyntaxHighlighter ?