WordUnderCursor not working (word being detected when not on top of any words)

[ZeHgS]

Hi everyone!
Why is a word being detected as being under the cursor here? The red arrow in the image starts where the cursor actually is. No matter where I place it, as long as it is inside the window, the program thinks a word is being selected. If the cursor is below the text, it defaults to the very last one. If the cursor is above, it defaults to the first one.

Thanks a lot!

from PyQt5.QtWidgets import QTextEdit, QMainWindow, QApplication
from PyQt5.QtGui import QMouseEvent, QTextCursor


class Editor(QTextEdit):
    def __init__(self):
        super(Editor, self).__init__()
        # make sure this widget is tracking the mouse position at all times
        self.setMouseTracking(True)

    def mouseMoveEvent(self, mouse_event: QMouseEvent) -> None:
        if self.underMouse():
            # create a QTextCursor at that position and select text
            text_cursor = self.cursorForPosition(mouse_event.pos())
            text_cursor.select(QTextCursor.WordUnderCursor)

            word_under_cursor = text_cursor.selectedText()
            print(word_under_cursor)

            # replace substring with placeholder so that repeat occurrences aren't highlighted as well
            selected_word_placeholder = self.replace_selected_text_with_placeholder(text_cursor)

            word_under_cursor = '<span style="background-color: #FFFF00;font-weight:bold;">' + word_under_cursor + '</span>'

            # replace the sentence with the new formatting
            self.setHtml(self.toPlainText().replace(selected_word_placeholder, word_under_cursor))

    def replace_in_html(self, old_string, new_string):
        old_html = self.toHtml()
        new_html = old_html.replace(old_string, new_string)
        self.setHtml(new_html)

    # use placeholder so that repeat occurrences of the word are not highlighted
    def replace_selected_text_with_placeholder(self, text_cursor):
        # remove the selected word to be replaced by the placeholder
        text_cursor.removeSelectedText()

        # create a placeholder with as many characters as the original word
        word_placeholder = ''
        for char in range(10):
            word_placeholder += '@'
        text_cursor.insertText(word_placeholder)

        return word_placeholder


def set_up(main_window):
    title_editor = Editor()
    title_editor.setText('Venda quente original xiaomi redmi airdots 2 tws fones de ouvido sem fio bluetooth fones controle ai gaming headset come')

    main_window.setCentralWidget(title_editor)
    main_window.show()


application = QApplication([])
window = QMainWindow()

set_up(window)

application.exec()

[SGaist]

Hi,

Looking at the implementation, I would say it gives you the text cursor "closest" to your mouse position.

[JonB]

@SGaist
The thing the OP may not like is that for the text_cursor.select(QTextCursor.WordUnderCursor) the docs state:

Selects the word under the cursor. If the cursor is not positioned within a string of selectable characters, no text is selected.

It's hard to see how "If the cursor is not positioned within a string of selectable characters" comes about for the OP given where he's trying to place it away from any words.

@ZeHgS
Given the implementation of cursorForPosition(mouse_event.pos()) I think you would have to look at just where the mouse position is to detect it's not really on any word.

[SGaist]

@JonB one problem here is likely the difference between the text cursor and the mouse cursor which can be at different positions at the same time.

[ZeHgS]

Thank you both very much for replying! I will implement an extra check, then. Thanks!