I figured it out not the most elegant solution, but it will do its job:
void MainWindow::on_actionCapital_triggered()
{
QTextCursor c = ui->textEdit->textCursor();
int current = c.position();
if(capital)
{
QTextCharFormat capital2;
capital2.setFontCapitalization(QFont::MixedCase);
ui->textEdit->selectAll();
ui->textEdit->setCurrentCharFormat(capital2);
capital = false;
}
else
{
QTextCharFormat capital2;
capital2.setFontCapitalization(QFont::AllUppercase);
ui->textEdit->selectAll();
ui->textEdit->setCurrentCharFormat(capital2);
capital = true;
}
c = ui->textEdit->textCursor();
c.setPosition(current);
c.setPosition(current, QTextCursor::KeepAnchor);
ui->textEdit->setTextCursor(c);
}
With this code you can switch between all Upper case and mixed case. For some reason the setCurrentCharFormat only works when the text is selected. So I had to get the current cursor position and then select all apply the FontCapitalization and then set the cursor back to where it was.