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Thread: how to make the QGraphicsScene resize automaticly

  1. #1
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    Default how to make the QGraphicsScene resize automaticly

    I put a QGraphicsItem on a QGraphicsScene。When the item enlarge,the Scene will enlarge automaticly.
    But the problem is when the item shrink, the Scene can not shrink automaticly.
    who can give me some advice to make the QGraphicsScene resize automaticly whenever the item enlarge or shrink?
    I will be very very grateful...

  2. #2
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    Default Re: how to make the QGraphicsScene resize automaticly

    who can give me some advice to make the QGraphicsScene resize automaticly whenever the item enlarge or shrink?
    By default scene will grow when items are added or moved, by will not shrink when items are removed or moved. Scene should be explicitly shrinked using code like this.
    Qt Code:
    1. //Calculates and returns the bounding rect of all items on the scene.
    2. //This function works by iterating over all items, and because if this, it can be slow for large scenes.
    3. QRectF rect = scene.itemsBoundingRect();
    4. scene.setSceneRect(rect);
    To copy to clipboard, switch view to plain text mode 

    Put this code in a slot connected to QGraphicsScene::changed() signal. That should appear as automatic.
    When you know how to do it then you may do it wrong.
    When you don't know how to do it then it is not that you may do it wrong but you may not do it right.

  3. The following user says thank you to Santosh Reddy for this useful post:

    aliks-os (2nd November 2016)

  4. #3
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    Default Re: how to make the QGraphicsScene resize automaticly

    Hi, I have the same issue - if anyone could answer, that would be swell.
    Thanks

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    Default Re: how to make the QGraphicsScene resize automaticly

    Someone -did- answer: Santosh Reddy, in 2013. So if his code didn't solve -your- issue, then you don't have the same issue.
    <=== The Great Pumpkin says ===>
    Please use CODE tags when posting source code so it is more readable. Click "Go Advanced" and then the "#" icon to insert the tags. Paste your code between them.

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