[Qt-interest] Problem drawning in the GUI Thread with Data from another Thread
O Caldas
caldaz.sheep at gmail.com
Fri Jul 3 01:32:42 CEST 2009
oh, and here is the code of the paintEvent() method:
void PopGraph::paintEvent(QPaintEvent*){
QPainter painter2(this);
painter2.drawImage(QPoint(0,0), *buffer);
}
buffer is an atribute QImage* of the class
2009/7/2 O Caldas <caldaz.sheep at gmail.com>
> hi, my application draws a horizontal graphics of the data generated by the
> thread. it uses vectors that are directly modified by the worker thread.
> ive
> tryed to send the vectors in the signal but it stays the same.
>
> here is the code that create the image that will be draw :
>
> void PopGraph::graphUpdate(){
> delete(buffer);
> buffer = new QImage(size(), QImage::Format_ARGB32);
> QSize d = size();
> long long nMax = (int)ceil(log10(_d->getPopulationMax()));
> double yscale = d.height()/(double)nMax;
> int tickscale = 1;
>
> // draw horizontal tick marks
> Qt::PenStyle style = Qt::PenStyle(Qt::SolidPattern);
> Qt::PenCapStyle cap = Qt::PenCapStyle(Qt::FlatCap);
> Qt::PenJoinStyle join = Qt::PenJoinStyle(Qt::MiterJoin);
> QPainter painter(buffer);
> painter.fillRect(rect(), Qt::white);
>
> painter.setPen(QPen(Qt::black, 1, style ,cap,join));
> for (int i=0; i<=nMax; i++) {
> int y = size().height()-(int)(i*yscale);
> painter.drawLine(0, y, d.width(), y);
> char st[6] = "10^";
> strcat(st, intToStr(i));
> painter.drawText(0, y, QString(st));//("10^" + String.valueOf(i),
> 0, y);
> }
> // draw vertical (date) tick marks
> long long lastday = -1;
> vector<long long> hours = _d->getPopulationHours();
> int end = d.width();
> if (hours.size()<d.width())
> end = hours.size();
> for (int i=0; i<end; i++) {
> if (lastday != hours[hours.size()-i-1]/24) {
> lastday = hours[hours.size()-i-1]/24;
> painter.drawLine(d.width()-i, 0, d.width()-i, d.height());
> painter.drawText(d.width()-i+1, 11, QString(
> intToStr(lastday+1)));
> }
> }
> // draw antigen level curves
> vector<Antigen*>* pops = _d->getAntigens();
> vector<QColor> popcolors = _d->getAntigenColors();
> int s = _d->getAntigenLevels().size();
>
> for (int j=0; j<s; j++) {
> painter.setPen(popcolors[j]);
> // draw legend
> painter.drawText(0,
> painter.fontMetrics().ascent()*(j+1),QString(pops->at(j)->getName()->data()));
>
> // draw curves
> vector< long long > data = _d->getAntigenLevels()[j];
> end = d.width();
> if (data.size()<(unsigned )d.width())
> end = data.size();
> for (int i=0; i<end; i+=2) // just plot every other hour
> if (data[data.size()-i-1]>0){
>
> painter.drawRect(d.width()-i-1,
> d.height()-1-(int)
> (log10(data[data.size()-i-1])*yscale),
> 2,
> 2);
> }
> }
> // draw T cell level curves
> s = _d->getTCellColors().size();
> for (int j=0; j<s; j++) {
> painter.setPen(_d->getTCellColors()[j]);
> // draw legend
> if (_d->getTCells()->size()<10)
> painter.drawText(0,
> painter.fontMetrics().ascent()*(j+1+(_d->getAntigens()->size())),
> QString(_d->getTCells()->at(j)->getName()->data()));
> // draw curves
> vector<long long> data = _d->getTCellLevels()[j];
> end = d.width();
> if (data.size()<(unsigned )d.width()) end = data.size();
> for (int i=0; i<end-1; i++){
> if ((data[data.size()-i-1]>0) && (data[data.size()-i-2]>0)){
> painter.drawLine(d.width()-i-1,
> d.height()-(int)
> (log10(data[data.size()-i-2])*yscale),
> d.width()-i,
> d.height()-(int)
> (log10(data[data.size()-i-1])*yscale));
>
> }
> }
>
> }
> // if(contador == 1){
> // contador =0;
> update();
>
> // }
>
> }
>
> thanks for your help!
>
> 2009/7/2 Sean Harmer <sean.harmer at maps-technology.com>
>
> On Thursday 02 Jul 2009 06:27:05 O Caldas wrote:
>> > Hi, im working on a project where I have two threads, one Worker thread,
>> > that do some calculations,
>> > and one GUI Thread, that draw some graphics in a QWidget.
>> >
>> > The Worker thread is a class that inherits from QThread, and the GUI
>> Thread
>> > is the main thread obviously.
>> >
>> > Im geting the worker thread to send a signal every end of calculation
>> step,
>> > and connecting this signal
>> > to the method that draws the graphic in the GUI Thread
>> >
>> > like this:
>> >
>> > connect(calculator, SIGNAL(calculated(),this,
>> > SLOT(updateView()));
>> >
>> > The problem is, when the calculation gets to fast, the GUI thread just
>> bugs
>> > and the program terminates.
>> > It seems that the calculator thread starts sending too much signals and
>> the
>> > GUI thread cant handle it,
>> > or something like this.
>> >
>> > i've tryed to use Qt::BlockingQueuedConnection but it is too slow.
>> >
>> > if someone knows what im doing wrong, or the right way to build a
>> program
>> > like that please help!
>> It sounds like you are taking the right general approach. What does your
>> app
>> have to do in order to visualise the results? How do you get the data to
>> the
>> main thread as I notice your signal does not marshall any data across to
>> it?
>>
>> If the visualisation in the main thread really is very expensive to
>> perform
>> then maybe you should only visualise every n'th frame. You could maybe
>> make
>> this an option that the user can set depending upon the performance of
>> their
>> graphics subsystem.
>>
>> Sounds like you have identified the bottle neck in your app. If you
>> provide
>> some more information we might be able to help you improve it.
>>
>> Cheers,
>>
>> Sean
>>
>> _______________________________________________
>> Qt-interest mailing list
>> Qt-interest at trolltech.com
>> http://lists.trolltech.com/mailman/listinfo/qt-interest
>>
>
>
>
> --
> Daniel Mendes Caldas
>
>
--
Daniel Mendes Caldas
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