Wrong cursor shape in QTextEdit with non-ascii

Yves Judd

I'm using Qt 5.11 with QTextEdit on Windows, the cursor shape (vertical line) look like flag if it contains non-ascii.

#include <QApplication>
#include <QTextEdit>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QTextEdit textedit;
    textedit.show();

    return a.exec();
}

Can anybody help me ?

SGaist

Hi and welcome to devnet,

How do you insert that in your QTextEdit ?

Yves Judd

This post is deleted!

Yves Judd

@SGaist Input from keyboard or call QTextEdit::setText I got same result.

SGaist

Can you post a text sample that can be used to reproduce this ?

PeAlbe

If you look inside QTextLayout::drawCursor, which actually paints the text cursor, you will see something like:

if (d->layoutData->hasBidi) {
        const int arrow_extent = 4;
        int sign = rightToLeft ? -1 : 1;
        p->drawLine(QLineF(x, y, x + (sign * arrow_extent/2), y + arrow_extent/2));
        p->drawLine(QLineF(x, y+arrow_extent, x + (sign * arrow_extent/2), y + arrow_extent/2));
}

that flag can be set to true by the function checkForBidi() inside qtextengine.cpp, which does the following:

    bool checkForBidi() const
    {
        if (baseLevel != 0)
            return true;
        for (int i = 0; i < length; ++i) {
            if (text[i].unicode() >= 0x590) {
                switch (text[i].direction()) {
                case QChar::DirR: case QChar::DirAN:
                case QChar::DirLRE: case QChar::DirLRO: case QChar::DirAL:
                case QChar::DirRLE: case QChar::DirRLO: case QChar::DirPDF:
                case QChar::DirLRI: case QChar::DirRLI: case QChar::DirFSI: case QChar::DirPDI:
                    return true;
                default:
                    break;
                }
            }
        }
        return false;
    }

I would like to avoid recompiling Qt libraries for a small thing like this, yet I find that arrow-thing on the cursor annoying, especially if you set the cursor width to 0 to make it invisible.

SGaist

It's not a "non-ascii" thing. It's when you have text containing chars that makes it bidirectional. However, it might be a good idea to raise the question about drawing that triangle when the cursor with is 0. You should check the bug report system to see if there's already something related.