Inverted QTextEdit

[TMan]

Hi all,

I've taken an example from Qt labs (http://labs.trolltech.com/blogs/2009/06/09/night-mode-in-qwebview/), trying to apply this to a QTextEdit.

Ultimately, this should give me a QTextEdit with all colors reversed, which I find easier on the eyes :)

Anyway, problem with this code is that after changing the setting (press F3), it should repaint the entire widget, but I can not get it to do so. I've tried both update() and repaint().

Any help would be appreciated!



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#include <QtCore>
#include <QtGui>

#if QT_VERSION < 0x0040500
#error You need Qt 4.5 or newer
#endif

class NightModeView : public QTextEdit
{
Q_OBJECT

public:

NightModeView(QWidget *parent = 0): QTextEdit(parent), invert(true) {
connect(this, SIGNAL(titleChanged(const QString&)), SLOT(setWindowTitle(const QString&)));
}

private:

bool invert;

void paintEvent(QPaintEvent *event) {
QTextEdit::paintEvent(event);
if (invert) {
QPainter p(viewport());
p.setCompositionMode(QPainter::CompositionMode_Dif ference);
p.fillRect(rect(), Qt::white);
p.end();
}
}

void keyPressEvent(QKeyEvent *event) {
if (event->key() == Qt::Key_F3) {
invert = !invert;
update();
event->accept();
return;
}
QTextEdit::keyPressEvent(event);
}

};

#include "webnightmode.moc"

int main(int argc, char **argv)
{
#ifdef Q_WS_X11
QApplication::setGraphicsSystem("raster");
#endif

QApplication app(argc, argv);

NightModeView w;
w.show();

QMessageBox::information(&w, "Hint", "Use F3 to toggle night mode");

return app.exec();
}

[TMan]

If its any help, if I replace the

update();

in the code above with

hide ();
show ();


it does repaint the entire widget! However, that's obviously a dirty hack and not what I want.

[shentian]

QTextEdit is a QAbstractScrollArea. A ScrollArea delegates the painting of the content to its viewport. So use:


viewport()->update();