about QGraphicsScene ，QGrahpicsView and QGrahpicsPixmapItem

[ggs0110]

hi！
I want to know the relationship about QGraphicsScene object ,QGraphicsView object and
QGraphicsPixmapItem,who can tell me? thanks a lots!

for example,one QGraphicsView can cantain one or more scene? one scene can cantain one or more item? .....
And how to add the QGraphicsPixmapItem object into the QGrahphicsScene object?

[jpn]

I suggest you start with reading about the graphics view framework and checking out the graphics view examples. QGraphicsView visualizes the contents of a (single) QGraphicsScene. Multiple views can visualize the same scene. A scene may contain loads of QGraphicsItems.

[ggs0110]

thanks jpn！
But， how to add the QGraphicsPixmapItem object into the QGrahphicsScene object? I know it can be added into the QGraphicsScene object from a doc.Am I right?

[jpn]

But， how to add the QGraphicsPixmapItem object into the QGrahphicsScene object?

The most easiest way is to use QGraphicsScene::addPixmap().

[ggs0110]

yes!
for example:

1. QGrahphicsScene* scene=new QGraphicsScene(this);
2. scene->addPixmap(filename);//filename is image file's name
3. QGraphicsView* mainview=new QGraphicsView(scene);

Now,am I add the QGraphicsPixmapItem object into the scene?

Another question is:
if the line 1 and 2 run twice,are there two QGraphicsScene object? I add the line 1,2 and 3 into the open() which to open an image file,if I execute the open() twice and to open two different image,what happened to the scene? are there two items in the scene?or there are two QGraphicsScene objects? very confused!

[Gopala Krishna]

Did you read the documentation ? (links given by jpn)
If not, please consider my friendly suggestion to go through it since you can answer all these questions yourself

Anyway here is an obligatory explation
Line 1 creates a scene object
Line 2 add a QGraphicsPixmapItem to scene. Yes, indeed it is a convienience method. Take a closer look on what scene::addPixmap() returns and you'll know the answer.
Line 3 sets up a view for the scene created above.

[ggs0110]

thanks a lot