On sexta-feira, 27 de setembro de 2013 23:13:44, Alexander Syvak wrote: > This is the code of the function saving screenshots. This code is used in > threads analizing screenshots. > Debugging the app. when one thread has been paused inside QImage save > method and other thread wake up invoking the lines below
On the *same* QImage?
Like I said, I need to know what each thread is doing. Saving a QImage from
any thread should be acceptable, provided no other thread is using the same
QImage.
>
> QFile screenshot_iodev(mk_screenshot_path(screenshot_idx++));
>
> return screenshot.save( &screenshot_iodev, format_raw_ptr );
>
> where QImage::save returns false failing here
>
> bool QImageWriter::canWrite() const
>
> {
>
> if (d->device && !d->handler && (d->handler =
> createWriteHandlerHelper(d->device, d->format)) == 0) {
>
> d->imageWriterError = QImageWriter::UnsupportedFormatError;
>
> d->errorString = QT_TRANSLATE_NOOP(QImageWriter,
>
> QLatin1String("Unsupported
> image format"));
>
> return false;
>
> }
>
>
>
>
>
>
> 2013/9/27 Thiago Macieira <thiago.macie...@intel.com>
>
> > On sexta-feira, 27 de setembro de 2013 16:12:37, Alexander Syvak wrote:
> > > Hello,
> > >
> > > the method save_screenshot() is used to save a QImage object using
> > > bool QImage::save ( const
> > > QString<http://doc.crossplatform.ru/qt/4.6.x/qstring.html>&
> > > *fileName*, const char * *format* = 0, int *quality* = -1 ) const
> > >
> > > Howver, it appears that QImage is working with one I/O device and
> > > returns
> > > false if it's busy, i.e. a thread paused at a moment of executing the
> >
> > save
> >
> > > method.
> >
> > Any thread? What is this other thread doing? Also, threads don't pause
> > except
> > if you're using the debugger.
> >
> > It's far more likely that your mistake can be found in what this other
> > thread
> > is doing.
> >
> > > Is it better to use
> > > bool QImage::save (
> > > QIODevice<http://doc.crossplatform.ru/qt/4.6.x/qiodevice.html>*
> > > *device*, const char * *format* = 0, int *quality* = -1 ) const
> > >
> > > method instead with its own I/O device for each thread or
> > >
> > > to create QMutexLocker in the save_screenshot() method?
> >
> > --
> > Thiago Macieira - thiago.macieira (AT) intel.com
> >
> > Software Architect - Intel Open Source Technology Center
> >
> > _______________________________________________
> > Interest mailing list
> > Interest@qt-project.org
> > http://lists.qt-project.org/mailman/listinfo/interest
--
Thiago Macieira - thiago.macieira (AT) intel.com
Software Architect - Intel Open Source Technology Center
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
