bug: setLineWrapMode

[magland]

I am using Qt 4.3.0 on Windows

There seems to be a serious problem with QTextEdit when using

setLineWrapMode(QTextEdit::NoWrap)

setLineWrapMode(QTextEdit::NoWrap)

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The problem is that when typing toward the bottom of a moderately large text file, the interface starts dragging and becomes very slow - the difference is striking between the top and bottom of the document, and I think it gets worse for larger files.

If I remove the "setLineWrapMode" line, then everything works fine.

For a long time, I blamed it on my syntax highlighter, but now I'm quite certain that it's a Qt bug... Anyone encounter this kind of behaviour, or have an idea for a workaround?

Not sure if it's 4.3.0-specific, Windows-specific (or even my-particular-computer-specific )

Thanks.

edit: Here's a sample program that produces the behaviour:

#include <QApplication>
#include <QTextEdit>
 
int main(int argc, char *argv[]) {
	QApplication app(argc, argv);
 
	QTextEdit edit;
 
	edit.setLineWrapMode(QTextEdit::NoWrap);
	edit.showNormal();
 
	bool ret=app.exec();
	return ret;
}

#include <QApplication>
#include <QTextEdit>

int main(int argc, char *argv[]) {
	QApplication app(argc, argv);
	
	QTextEdit edit;

	edit.setLineWrapMode(QTextEdit::NoWrap);
	edit.showNormal();

	bool ret=app.exec();
	return ret;
}

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[rajesh]

I have tested your code. it seems a bug in Qt.
after using setLineWrapMode(QTextEdit::NoWrap); I have entered a huge text then It become slow.
you can report to trolltech.

[magland]

I have tested your code. it seems a bug in Qt.
after using setLineWrapMode(QTextEdit::NoWrap); I have entered a huge text then It become slow.
you can report to trolltech.

Thanks for the confirmation that it's not just my computer . I am using the following workaround in my project, which does the job, at least untill the bug is fixed...

setLineWrapMode(QTextEdit::FixedPixelWidth);
setLineWrapColumnOrWidth(10000);

setLineWrapMode(QTextEdit::FixedPixelWidth);
setLineWrapColumnOrWidth(10000);

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[parnurzeal]

Now, I have this problem,too. It seems even newest Qt version hasn't fixed this problem,yet.