Painting Widget with QPainter

NicuPopescu

I think the solution 3 could be used with some "tricks", in order to have texts arranged in "subcells" in a "cell" ... what is a "cell"?: it is thought as successive standard(qt) table items in a row

so take any successive items in a table row, in the amount of your grid layout columns and then controls the drawText as follow:

for drawing text in a certain column(subcell) with index.column()
for drawing text in certain subcell's row with new line character "\n"
i.e.
@ painter->drawText(option.rect.adjusted(4,4,0,0),QString("\n")+your text@

I used this and it worked, and for changing text font or color by QSS I used dummy/hidden widgets styled externally and using their values in delegate's painter

maximus

Thanks for your help,

For the render method of QWidget, I don't really understand the arguments that I need to pass. Usually I use painter and option.rect (where to display) in order to paint, so i'm kind of lost with those 4 parameters

Link to function :
http://qt-project.org/doc/qt-5.0/qtwidgets/qwidget.html#render-2

Here is the full paint method of my delegate:
@//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void SpinBoxDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const {

if (option.state & QStyle::State_Selected) {
    painter->setPen(QPen( Qt::red, 5 ));
    painter->drawRect(option.rect);
    return;
}

painter->setPen(QPen( Qt::white, 1 ));

/// Type
if (index.column() == 0) {
    int value = index.model()->data(index, Qt::DisplayRole).toInt();
    QString intervalType = Interval::getTypeFromInt(value);

    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, intervalType);
}

/// Duration
else if (index.column() == 1) {
    QTime time = index.model()->data(index, Qt::DisplayRole).toTime();
    QString toDisplay = Util::showQTimeAsString(time);
    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, toDisplay );
}

/// Display Message
else if (index.column() == 2) {
    QString msg = index.model()->data(index, Qt::DisplayRole).toString();
    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, msg);
}

/// Target Power
else if (index.column() == 3) {



    //// SOLUTION 1, NOTHING IS DRAW
    EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget();
    widgetTarget->targetStart->setText("Test");
    widgetTarget->render(painter, QPoint(), option.rect, QWidget::DrawChildren );

// widgetTarget->paintEngine()

    /// SOLUTION 2 - NOT GOOD LOOKING (Color messed up)
    //        EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget();
    //        QPixmap pix = QPixmap::grabWidget(widgetTarget);
    //        painter->drawPixmap(option.rect, pix);


    /// SOLUTION 3, DRAW IT BY HAND - WORKS BUT HARD TO REPLICATE WIDGET WITH TEXT
    //        std::shared_ptr<Interval> interval(qvariant_cast<std::shared_ptr<Interval>>( index.model()->data(index, Qt::DisplayRole) ));

    //        int targetStepPower = interval->getPowerStepType();
    //        qDebug() << "TARGET STEP!" << targetStepPower;
    //        QString str_Step = Interval::getStepTypeFromInt( targetStepPower );
    //        double startFTP = interval->getFTP_start() * 100;
    //        double endFTP = interval->getFTP_end() * 100;
    //        int range = interval->getFTP_range();

    //        painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, str_Step);


}


/// Standard delegate display - Display Message
else {
    QStyleOptionViewItem viewOption(option);
    viewOption.palette.setColor(QPalette::Text, QColor(Qt::white));
    QStyledItemDelegate::paint(painter, viewOption, index);
}

}@

I will try to fix #1 and then use #3 as last resort.
Thanks!

raven-worx

try this:
@
painter->save();
EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget();
widgetTarget->resize( option.rect.size() );
widgetTarget->targetStart->setText("Test");
painter->translate(option.rect.topLeft());
widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );
painter->restore();
@

And another suggestion:
Don't create a new widget on every time your paint() method is called. No need to allocate new memory every time, beside you never delete this widget, thus it leaks.
Rather hold a single instance in your delegate class and reuse it when needed.

maximus

Thanks Raven it's working now!

https://www.dropbox.com/s/no0edjn08ei66ap/workingPaint.png

One last thing, I'll check more but if you know already, Inside this custom widget, I have QLabels but the main application stylesheet doesn't get applied to those label it seems (they should be white)
Or i can just use .setStylesheet but I like all my presentation code to be in the same place.

thanks again!

raven-worx

set the stylesheet on the QApplication instance, so even parent-less widgets get the style, or

set a parent-widget, so that i derives the stylesheet style from a widget which already has got it set in the hierarchy

maximus

Oh I totally forgot to give the widget a parent, there is the problem.
Thanks again!

maximus

The display is working fine now, but my delegate has a memory leak in the paint function now.

I made a video showing the problem in action :
https://www.youtube.com/watch?v=b882e4cEREE&feature=youtu.be

I have noted that it is in the column that I used QWidget.render(). So in the code below, if I comment column 3,4 and 5, I don't have a memory leak.
Sorry I know I asked a lot of question already, hopefully I can give back to Qt..

Do you think that the line
"widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );"
could trigger an infinite loop? I'm failing to see where all that memory goes.. I should probably learn to use the debugger also -_-

@//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void SpinBoxDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const {

qDebug() << "paintNow...";
if (option.state & QStyle::State_Selected) {
    painter->setPen(QPen( Qt::red, 5 ));
    painter->drawRect(option.rect);
    return;
}

painter->setPen(QPen( Qt::white, 1 ));

/// Type
if (index.column() == 0) {
    int value = index.model()->data(index, Qt::DisplayRole).toInt();
    QString intervalType = Interval::getTypeFromInt(value);

    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, intervalType);
}

/// Duration
else if (index.column() == 1) {
    QTime time = index.model()->data(index, Qt::DisplayRole).toTime();
    QString toDisplay = Util::showQTimeAsString(time);
    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, toDisplay );
}

/// Display Message
else if (index.column() == 2) {
    QString msg = index.model()->data(index, Qt::DisplayRole).toString();
    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter, msg);
}

/// Target Power
else if (index.column() == 3) {


    EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget(ptrParent, "POWER");
    std::shared_ptr<Interval> interval(qvariant_cast<std::shared_ptr<Interval>>( index.model()->data(index, Qt::DisplayRole) ));

    int targetStepPower = interval->getPowerStepType();
    double startFTP = interval->getFTP_start() * 100;
    double endFTP = interval->getFTP_end() * 100;
    int range = interval->getFTP_range();

    widgetTarget->stepComboBox->setCurrentIndex(targetStepPower);
    widgetTarget->targetStartValue->setValue(startFTP);
    widgetTarget->targetEndValue->setValue(endFTP);
    widgetTarget->targetRangeValue->setValue(range);

    painter->save();
    widgetTarget->resize( option.rect.size() );
    painter->translate(option.rect.topLeft());
    widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );
    painter->restore();

}

/// Target Cadence
else if (index.column() == 4) {


    EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget(ptrParent, "CADENCE");
    std::shared_ptr<Interval> interval(qvariant_cast<std::shared_ptr<Interval>>( index.model()->data(index, Qt::DisplayRole) ));

    int targetStepCadence = interval->getCadenceStepType();
    int startCadence = interval->getCadence_start();
    int endCadence = interval->getCadence_end();
    int range = interval->getCadence_range();

    widgetTarget->stepComboBox->setCurrentIndex(targetStepCadence);
    widgetTarget->targetStartValue->setValue(startCadence);
    widgetTarget->targetEndValue->setValue(endCadence);
    widgetTarget->targetRangeValue->setValue(range);

    painter->save();
    widgetTarget->resize( option.rect.size() );
    painter->translate(option.rect.topLeft());
    widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );
    painter->restore();

}

/// Target Cadence
else if (index.column() == 5) {


    EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget(ptrParent, "HR");
    std::shared_ptr<Interval> interval(qvariant_cast<std::shared_ptr<Interval>>( index.model()->data(index, Qt::DisplayRole) ));

    int targetStepHR = interval->getHRStepType();
    double startHR = interval->getHR_start() *100;
    double endHR = interval->getHR_end() *100;
    int range = interval->getHR_range();

    widgetTarget->stepComboBox->setCurrentIndex(targetStepHR);
    widgetTarget->targetStartValue->setValue(startHR);
    widgetTarget->targetEndValue->setValue(endHR);
    widgetTarget->targetRangeValue->setValue(range);

    painter->save();
    widgetTarget->resize( option.rect.size() );
    painter->translate(option.rect.topLeft());
    widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );
    painter->restore();

}


/// Standard delegate display - Display Message
else {
    QStyleOptionViewItem viewOption(option);
    viewOption.palette.setColor(QPalette::Text, QColor(Qt::white));
    QStyledItemDelegate::paint(painter, viewOption, index);
}

}@

maximus

something wrong with the line
@widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );@
i comment this and don't get memory leak.. i'll post if I find a solution

[Edit: The function paint of my delegate is being called non-stop when the TableView is active.. still investigating why]

maximus

Finally I used drawText as it is easier and more versatile, doesn't have the memory problem I had with QWidget.render()
needs more coding but at least what you code is what you get
Thanks for your help again! :)

@ else if (index.column() == 3 && paint) {

    painter->save();
    EditTargetPowerWidget *widgetTarget = new EditTargetPowerWidget(ptrParent, "POWER");
    std::shared_ptr<Interval> interval(qvariant_cast<std::shared_ptr<Interval>>( index.model()->data(index, Qt::DisplayRole) ));

    int targetStepPower = interval->getPowerStepType();
    double startFTP = interval->getFTP_start() * 100;
    double endFTP = interval->getFTP_end() * 100;
    int range = interval->getFTP_range();

    widgetTarget->stepComboBox->setCurrentIndex(targetStepPower);
    widgetTarget->targetStartValue->setValue(startFTP);
    widgetTarget->targetEndValue->setValue(endFTP);
    widgetTarget->targetRangeValue->setValue(range);

// widgetTarget->resize( option.rect.size() );
// painter->translate(option.rect.topLeft());
// widgetTarget->render(painter, QPoint(), QRegion(), QWidget::DrawWindowBackground );

    QString targetStep_str = Interval::getStepTypeFromInt(targetStepPower);
    QString target_str = "["+ QString::number(startFTP)  + " - " + QString::number(endFTP) + "]";
    QString range_str = "±" + QString::number(range);
    QString target1 = tr("Target: ");
    QString range1 = tr("Range: ");
    QString watts = tr(" Watts");
    QString pFtp = tr(" % FTP");


    painter->drawText(option.rect, Qt::AlignLeft | Qt::AlignVCenter,
                      targetStep_str + "\n" +
                      target1 +  target_str + pFtp + "\n" +
                      range1 + range_str + watts);


    painter->restore();


}@

maximus

I modified my code to improve memory and find where is the problem. I think it is a memory leak with the createEditor() that doesn't get deleted after each use.

I would like to know if there is an example of this technique
"source":http://qt-project.org/doc/qt-5.0/qtwidgets/itemviews-spinboxdelegate.html
Furthermore it is also possible to reuse (and avoid deleting) the editor widget by reimplementing the destroyEditor() function

I tried but the createEditor and setEditorData are "const" function and I can't store any pointer there..
[EDIT: I removed the const in createEditor but now the function is now longer called, I wanted to create all my editor in the Constructor and reuse the same.. this technique doesn't work -_-]

I changed the way I change my model using a pointer in Qvariant rather than passing the whole object in a Qvariant, it helps but the memory used is still too high,

@//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
void SpinBoxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const {

/// Type
if (index.column() == 0) {
    IntervalComboBox *comboBox = static_cast<IntervalComboBox*>(editor);
    int value = comboBox->currentIndex();
    model->setData(index, value, Qt::EditRole);
}

/// Duration
else if (index.column() == 1) {
    QTimeEdit *timeEdit = static_cast<QTimeEdit*>(editor);
    QTime time1 = timeEdit->time();
    model->setData(index, time1, Qt::EditRole);
}

/// Display Message
else if (index.column() == 2) {
    QLineEdit *lineEdit = static_cast<QLineEdit*>(editor);
    QString msg = lineEdit->text();
    model->setData(index, msg, Qt::EditRole);
}

/// Target Power
else if (index.column() == 3) {
    
    EditTargetPowerWidget *targetWidget = static_cast<EditTargetPowerWidget*>(editor);
    
    int targetStepPower = targetWidget->stepComboBox->currentIndex();
    Interval::StepType stepType = static_cast<Interval::StepType>( targetStepPower );
    double startFTP = targetWidget->targetStartValue->value()/100;
    double endFTP = targetWidget->targetEndValue->value()/100;
    int range = targetWidget->targetRangeValue->value();
    
    
    Interval *interval = (Interval*) index.model()->data(index, Qt::DisplayRole).value<void *>();
    interval->setPowerData(stepType, startFTP, endFTP, range);
    
    /// MEMORY STILL INCREASE BY 2MB EACH EDIT, pointer *targetWidget not deleted?
    
    /// Break model/view architecture here...
    ///        model->setData(index, variant, Qt::EditRole);
}

@

maximus

Found the problem!

In the paint(), I was using a Widget and not deleting it after using it..

@ else if (index.column() == 3 && paint) {

    painter->save();
    EditTargetPowerWidget *targetWidget = new EditTargetPowerWidget(ptrParent, "POWER");


    Interval *interval = (Interval*) index.model()->data(index, Qt::DisplayRole).value<void *>();

    int targetStepPower = interval->getPowerStepType();
    double startFTP = interval->getFTP_start() * 100;
    double endFTP = interval->getFTP_end() * 100;
    int range = interval->getFTP_range();

    targetWidget->stepComboBox->setCurrentIndex(targetStepPower);
    targetWidget->targetStartValue->setValue(startFTP);
    targetWidget->targetEndValue->setValue(endFTP);
    targetWidget->targetRangeValue->setValue(range);


    targetWidget->resize( option.rect.size() );
    painter->translate(option.rect.topLeft());
    targetWidget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );


    painter->restore();
    delete targetWidget;


}@

maximus

Found the problem!

I forgot to delete a pointer of my QWidget in the paint() function. this was increasing the memory usage each time.

@
else if (index.column() == 3 && paint) {

    painter->save();
    EditTargetPowerWidget *targetWidget = new EditTargetPowerWidget(ptrParent, "POWER");

    Interval *interval = (Interval*) index.model()->data(index, Qt::DisplayRole).value<void *>();

    int targetStepPower = interval->getPowerStepType();
    double startFTP = interval->getFTP_start() * 100;
    double endFTP = interval->getFTP_end() * 100;
    int range = interval->getFTP_range();

    targetWidget->stepComboBox->setCurrentIndex(targetStepPower);
    targetWidget->targetStartValue->setValue(startFTP);
    targetWidget->targetEndValue->setValue(endFTP);
    targetWidget->targetRangeValue->setValue(range);

    targetWidget->resize( option.rect.size() );
    painter->translate(option.rect.topLeft());
    targetWidget->render(painter, QPoint(), QRegion(), QWidget::DrawChildren );


    painter->restore();
    delete targetWidget;

}@