Pictures won't display - possible qt coordinate system confusion

[MarkoSan]

How do I add QImage to QGraphicsScene? I am reading docs and I just do not get it ...

[jpn]

How do I add QImage to QGraphicsScene? I am reading docs and I just do not get it ...

Again, use QGraphicsPixmapItems. I thought you said you already got one visible. You may use QPixmap::fromImage() to convert a QImage to QPixmap.

[MarkoSan]

I tried to used it before, something did not work. I gor some errors about QGraphicsPixelItem contructor that is private or sometinhg lke that.

[jpn]

I tried to used it before, something did not work. I gor some errors about QGraphicsPixelItem contructor that is private or sometinhg lke that.

The copy constructor of QGraphicsPixmapItem is private which means that you cannot copy QGraphicsPixmapItems.

The easiest way is to use the convenience method of QGraphicsScene:

QGraphicsPixmapItem* item = scene->addPixmap(pixmap);
item->setPos(...);

QGraphicsPixmapItem* item = scene->addPixmap(pixmap);
item->setPos(...);

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but you can create QGraphicsPixmapItems yourself as well:

QGraphicsPixmapItem* item = new QGraphicsPixmapItem(pixmap, parent);
scene->addItem(item);
item->setPos(...);

QGraphicsPixmapItem* item = new QGraphicsPixmapItem(pixmap, parent);
scene->addItem(item);
item->setPos(...);

To copy to clipboard, switch view to plain text mode 

[MarkoSan]

The copy constructor of QGraphicsPixmapItem is private which means that you cannot copy QGraphicsPixmapItems.

The easiest way is to use the convenience method of QGraphicsScene:

QGraphicsPixmapItem* item = scene->addPixmap(pixmap);
item->setPos(...);

QGraphicsPixmapItem* item = scene->addPixmap(pixmap);
item->setPos(...);

To copy to clipboard, switch view to plain text mode 

but you can create QGraphicsPixmapItems yourself as well:

QGraphicsPixmapItem* item = new QGraphicsPixmapItem(pixmap, parent);
scene->addItem(item);
item->setPos(...);

QGraphicsPixmapItem* item = new QGraphicsPixmapItem(pixmap, parent);
scene->addItem(item);
item->setPos(...);

To copy to clipboard, switch view to plain text mode 

And one more question: why is the copy contructor of QGraphicsPixmapItem private, I mean, what do we gain with that?

Thank you very very much for help, let me now dig into it and i will report results.

[jpn]

And one more question: why is the copy contructor of QGraphicsPixmapItem private, I mean, what do we gain with that?

It's a programmatical technique to prevent objects from getting copied. Sometimes it makes no sense to copy an object, like a QObject or a QGraphicsItem. Both QObjects and QGraphicsItems are organized in object trees where each object has an optional parent and children. What should happen when such object is copied? Should children get copied? Should parent get copied as well? Should possible signal-slot connections get copied? What person A would expect to happen would be most likely different than person B would expect. The result would be chaotic no matter how the functionality was implemented. Therefore it's just better to prevent it from happening.

PS. Did you notice that your signature says "kUbutnu"?

[MarkoSan]

It's a programmatical technique to prevent objects from getting copied. Sometimes it makes no sense to copy an object, like a QObject or a QGraphicsItem. Both QObjects and QGraphicsItems are organized in object trees where each object has an optional parent and children. What should happen when such object is copied? Should children get copied? Should parent get copied as well? Should possible signal-slot connections get copied? What person A would expect to happen would be most likely different than person B would expect. The result would be chaotic no matter how the functionality was implemented. Therefore it's just better to prevent it from happening.

PS. Did you notice that your signature says "kUbutnu"?

Thanks for explanation, and, YES, I DID NOTICE my signature says kUbutnu , but I wondered who will correct me first. I bet on wysotta but you did it before him.

[MarkoSan]

Ok, jpn, I again tumbed into wall. Loaded pics are different sizes, how do I limit the size of every loaded pic to, for example, to 100x100 points?

[jpn]

I wondered who will correct me first. I bet on wysotta but you did it before him.

Heh, it's been buggering me for a while but I couldn't resist myself anymore..

Ok, jpn, I again tumbed into wall. Loaded pics are different sizes, how do I limit the size of every loaded pic to, for example, to 100x100 points?

Well, it depends a bit what you want to achieve. Both QPixmap and graphics items are scalable. See QPixmap::scaled() and QGraphicsItem::scale().

[MarkoSan]

Well, these pictures will be placed on "ghost" circle coordinates. And this is ugly if every pic has different size, so every created pixmap must be scaled to predefined size, let me try.

And, let me correct signature so you will not bothered again.

[jpn]

Warning: out of topic

And, let me correct signature

One might still argue about its "correctness". Or did you ever see it written like that?

[wysota]

Warning: out of topic

One might still argue about its "correctness".

I would... It's Kubuntu or KUbuntu. The "K" stands for KDE which is written with a capital letter.

[wysota]

I bet on wysotta but you did it before him.

I don't read signatures

About your question: use QPixmap::scaled() or QImage::scaled().