Insert fill circle into cell of QTableWidget

[juaniyoalm]

But if you modified only the value of a cell if work fine.

How could I then modify the value? It has to be modified from the world class. Could I put a signal when modified with the setdata method?

[mrjj]

@juaniyoalm
Hi
You can add add signal to World class and connect it to the model. and then emit it
to have model call DataChanged. OR give World a pointer to the model and use models
API to change data and inform view.

• But if you modified only the value of a cell if work fine.
  im not sure what u say here.

[juaniyoalm]

@mrjj
I want to say that if I do this

getCell(0,0)->setFood(rand()&255);
     

The UI update fine and model unknown data either

[mrjj]

@juaniyoalm
Ok. not really sure how,
but didnt check the latest version.
Also if the VIEW get an update/paintEvent it will re-read the indexes so i guess
its via the normal paint/update/redraw.

[juaniyoalm]

@mrjj

I have already solved the problem. I have created a signal in the Cell class that is emited when the value of the cell is modified. This signal sends the cell to the slots. Then I created a slot in the MainView class and connected each cell of the model's matrix with that slot. This slot creates a QModelIndex and issues a dataChanged for the model to update the view. Besides, I had to save the position of the cell in the cell class.

Emit Signal:

void Cell::setFood(int food)
{
    if(this->fungus != food) {
        this->fungus = food;
        emit this->updateModel(this);
    }
}

Slot:

void MainWindow::foodChanged(Cell *cell)
{
    QModelIndex aux = model->index(cell->place.first, cell->place.second);
    model->dataChanged(aux, aux);
}

Connections:

    for (int i = 0; i < this->rows; i++) {
        for (int j = 0; j < this->columns; j++) {
            connect(this->model->mundo->getCell(i, j), &Cell::updateModel, this, &MainWindow::foodChanged);
        }
    }

Now I need pass the value of the circle also in the data method so that the delegate's paint method can receive it ...
Any example of how to do it?

[SGaist]

As I already suggested many times: use custom roles. So in your paint function, request the data using the roles specific to the parameters you want to get.

[juaniyoalm]

@SGaist

Yes, but I unknown how to do it...

[SGaist]

QVariant data = model->data(MyModel::MyCustomRole);

In your model:

QVariant MyModelModel::data(const QModelIndex &index, int role = Qt::DisplayRole) const
{
// usual stuff
if (role == MyModel::MyCustomRole) {
    return mound->getCell(index.row(), index.column())->myCoolProperty;
}
}

[juaniyoalm]

@SGaist

But I need both values to be at the same time in the delegate's paint method.

I modify the value of the items of the cells in internal methods of the World class, not from model, then emit signal that is received by the slot located in the MainWindows class and this emit dataChange signal of the model, as I wrote before.

[mrjj]

@juaniyoalm
Hi
Can we talk about the actual data ?
What is the data for the circle ?
you say "value of the circle"
can u specify what that means ?
The delegate has access to the cell so it can have any values at the same time.
So to avoid confusing, could you tell what data you need to paint the circle ?

[juaniyoalm]

@mrjj
Yeah, I need size array of fungivores in each cell to paint circle. This value can get it whit a method of Cell class.

The data method of model can you see above.

[mrjj]

@juaniyoalm
well just do as @SGaist suggests and the delegate can use your custom role(s)
to get the data it needs.
user roles are nothing complicated at all.
its just an id that let you assign a vlue to that id for an index.
like
model->setData(model->index(0,0), 90 , Qt::UserRole + 1 );

To avoid to ugly code and stupid mistakes, we define it as a const.
constexpr int CircleData = Qt::UserRole+1;
constexpr int SomeOtherData = Qt::UserRole+2;

and use instead of the raw value. This is a must to do. :)

[juaniyoalm]

@mrjj
But the problem is that I don't change the value with model->setData...., as I told you, I change it with methods place in Cell class and after emit signals to notified to model and call dataChanged method...

[mrjj]

@juaniyoalm

i dont see that matters with roles.
the delegate ask model and model get from the vector/cell so
should just be fine.

[juaniyoalm]

@mrjj

I can not return a cell in the data method of the model because it gives me an error:

[mrjj]

@juaniyoalm
you try to return a Cell pointer.
Should be like
mundo->getCell(index.row(), index.column())->somePublicVariable
or
mundo->getCell(index.row(), index.column())->Func(); // return some data, int , float , etc

Why you want to return the cell pointer ?
Just return some of its data

[juaniyoalm]

@mrjj

I think I'm not understanding ... hah.

If I put the following:

When I modify the value in this method:

Or these:

That signals activate this method (slot):

But in no time I pass the role and then the model does not know what data to return...

[mrjj]

Hi
The view itself ask for
Qt::DisplayRole and Qt::EditRole ( if u edit cell )
the new roles was for the delegate to request data it needs.

You did study for more than a few minutes the
http://doc.qt.io/qt-5/model-view-programming.html
right ?

[juaniyoalm]

@mrjj

Ok, I understand now. The problems are solved:

QVariant CellModel::data(const QModelIndex &index, int role) const
{
    if(!index.isValid())
        return QVariant();

    if(index.row() >= mundo->getWorld().size() || index.row() < 0 ||
           index.column() >= mundo->getWorld()[0].size() || index.column() < 0)
        return QVariant();

    if(role == CircleSize)
    {
        return this->mundo->getCell(index.row(), index.column())->getFungivoresSize();
    }

    if(role == FoodCount)
    {
        return this->mundo->getCell(index.row(), index.column())->getFood();
    }
    return QVariant();
}

And paint method:

void CellDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    int cellValue = index.model()->data(index, Qt::UserRole+2).toInt();
    qreal circleValue = index.model()->data(index, Qt::UserRole+1).toInt();

    qreal circleRealValue = (circleValue*20)/50;

    painter->save();
    painter->fillRect(option.rect, QBrush(QColor((255 - cellValue), 255, 51)));

    painter->setBrush(Qt::blue);
    painter->drawEllipse(static_cast<QPointF>(option.rect.center()), circleRealValue, circleRealValue);
    painter->setRenderHint(QPainter::Antialiasing, true);
    painter->setPen(Qt::NoPen);

    painter->restore();
}

[mrjj]

Hi
Super.
Note you should try to reuse the CircleSize, FoodCount constexpr if possible
instead of Qt::UserRole+1.
you can just make a .h file and put them there and let both
model and delegate include it.