QGraphicsItem or QGraphicsProxyWidget?

Hi,

I need to create an image as below
Attachment 3604
It contains:
1) one or more nodes with a text label. The node is not filled when created, but will be filled with progress
2) there are one or more ports on each node connecting them together

I first looked at the Diagram Scene example, but I'll need the port(s) to know which node connecting to which port and also need to add text to the node.

Should I subclass QGraphicsItem or QGraphicsProxyWidget or something else? Thanks in advance.

Definitely not proxy widget. I'd subclass QGraphicsRectItem or QGraphicsTextItem or even compose the item from one rect item, one text item and a couple of ellipse items (or others) for the ports.

Thanks. I understood sub-class QGraphicsRectItem and QGraphicsTextItem. What do you mean by "compose the item from one rect item, one text item and a couple of ellipse items (or others) for the ports"? Have a class that contains a QGraphicsRectItem, QGraphicsTextItem, and ports? What will my paint method look like?

Quote:

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Originally Posted by ttvo

What will my paint method look like?

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You won't have one.

Code:

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QGraphicsRectItem *rect = new QGraphicsRectItem(QRectF(-50, -25, 100, 50));
rect->setFlags(QGraphicsItem::ItemIsMovable);
QGraphicsTextItem *text = new QGraphicsTextItem(rect);
QGraphicsEllipseItem *portN = new QGraphicsEllipseItem(QRectF(-5, -5, 10, 10), rect);
portN->setPos(0, -25);
QGraphicsEllipseItem *portS = new QGraphicsEllipseItem(QRectF(-5, -5, 10, 10), rect);
portS->setPos(0, 25);
QGraphicsScene scene;
scene.addItem(rect);
QGraphicsView v;
v.setScene(&scene);
v.show();

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Great, that works. I decided to subclass QGraphicsTextItem to include the draw of its boundary, eliminating the need for the QGraphicsRectItem *rect. So the ports are children of my custom text, but how am I going to be able to query how many ports a given custom text item has?

Should I make the ports as member variable of my custom text? If so, will I need to override the paint method to draw the ports (of type QGraphicsEllipseItem or QGraphicsRectItem). Thanks.

Quote:

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Originally Posted by ttvo

Great, that works. I decided to subclass QGraphicsTextItem to include the draw of its boundary, eliminating the need for the QGraphicsRectItem *rect. So the ports are children of my custom text, but how am I going to be able to query how many ports a given custom text item has?

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You need to provide some API for this in your subclass.

Quote:

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Should I make the ports as member variable of my custom text? If so, will I need to override the paint method to draw the ports (of type QGraphicsEllipseItem or QGraphicsRectItem). Thanks.

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Why does informing one object about a state of another object require reimplementing its drawing routines?