Results 1 to 5 of 5

Thread: Calling setPos() on custom QGraphicsPixmapItem doesn't update item in GraphicsScene

  1. #1
    Join Date
    Apr 2020
    Posts
    7
    Thanks
    1
    Qt products
    Qt5

    Default Calling setPos() on custom QGraphicsPixmapItem doesn't update item in GraphicsScene

    Hello, I'm working on a little poker game and I am having a graphical glitch I would like to understand better and fix. For my "Card" class I subclassed QGraphicsPixmap items and added a 52-card "deck" to my QGraphicsScene.

    During runtime, I click on a button to deal the cards which then calls setPos() on the first three to simulate a flop.

    The problem is, the cards don't appear to fully draw themselves right away (see photos). When I resize the window suddenly they pop into full view. The QGraphicsView is not being updated when a card position changes.

    I tested calling setPos() on my background image which is a regular QGraphicsPixmap item and it moves properly and immediately updates the entire QGraphicsScene, so I'm thinking it has to be some error I've made while creating my "Card" class, but I'm not sure what I'm doing wrong.

    pokerTable.cpp (relevant portion)
    Qt Code:
    1. void PokerTable::dealFlop()
    2. {
    3. m_deck->burnCard();
    4.  
    5. m_flopCard1 = m_deck->dealCard(); // dealCard() returns a pointer to a Card, stored in these data members
    6. m_flopCard2 = m_deck->dealCard();
    7. m_flopCard3 = m_deck->dealCard();
    8.  
    9. m_flopCard1->setPos(m_flopCard1Position); //QPointF positions
    10. m_flopCard2->setPos(m_flopCard2Position);
    11. m_flopCard3->setPos(m_flopCard3Position);
    12. }
    To copy to clipboard, switch view to plain text mode 

    Card.h
    Qt Code:
    1. #ifndef CARD_H
    2. #define CARD_H
    3.  
    4. #include <QGraphicsPixmapItem>
    5. #include <QLabel>
    6.  
    7. class Card : public QGraphicsPixmapItem
    8. {
    9. public:
    10. enum class Rank
    11. {
    12. TWO,
    13. THREE,
    14. FOUR,
    15. FIVE,
    16. SIX,
    17. SEVEN,
    18. EIGHT,
    19. NINE,
    20. TEN,
    21. JACK,
    22. QUEEN,
    23. KING,
    24. ACE,
    25. MAX_RANKS
    26. };
    27.  
    28. enum class Suit
    29. {
    30. CLUBS,
    31. DIAMONDS,
    32. HEARTS,
    33. SPADES,
    34. MAX_SUITS
    35. };
    36.  
    37. Card();
    38.  
    39. Card(const Card &card2);
    40.  
    41. Card& operator=(const Card &card);
    42.  
    43. int getCardValue();
    44.  
    45. void setRank(int rank);
    46.  
    47. void setSuit(int suit);
    48.  
    49. void setTexture(QPixmap texture);
    50.  
    51. void setSprite();
    52.  
    53. void printCard();
    54.  
    55. protected:
    56. virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override;
    57.  
    58. virtual QRectF boundingRect() const override;
    59.  
    60. private:
    61. QPixmap m_texture;
    62. QPointF m_sprite;
    63.  
    64. Rank m_rank;
    65. Suit m_suit;
    66. };
    67.  
    68. #endif // CARD_H
    To copy to clipboard, switch view to plain text mode 

    Card.cpp (relevant portion)
    Qt Code:
    1. #include "Card.h"
    2. #include <QPainter>
    3. #include <iostream>
    4.  
    5. Card::Card()
    6. : m_sprite{ QPointF(0, 0) }
    7. {
    8. setScale(0.2);
    9. setFlag(ItemSendsGeometryChanges, true);
    10. }
    11.  
    12. Card::Card(const Card &card2)
    13. {
    14. m_texture = card2.m_texture;
    15. m_sprite = card2.m_sprite;
    16.  
    17. m_rank = card2.m_rank;
    18. m_suit = card2.m_suit;
    19. }
    20.  
    21. Card& Card::operator=(const Card &card)
    22. {
    23. m_texture = card.m_texture;
    24. m_sprite = card.m_sprite;
    25.  
    26. m_rank = card.m_rank;
    27. m_suit = card.m_suit;
    28.  
    29. return *this;
    30. }
    31.  
    32. void Card::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
    33. {
    34. painter->drawPixmap(x(), y(), m_texture, m_sprite.x(), m_sprite.y(), 560, 780);
    35. }
    36.  
    37. QRectF Card::boundingRect() const
    38. {
    39. return QRectF(0, 0, 560, 780);
    40. }
    To copy to clipboard, switch view to plain text mode 

  2. #2
    Join Date
    Apr 2020
    Posts
    7
    Thanks
    1
    Qt products
    Qt5

    Default Re: Calling setPos() on custom QGraphicsPixmapItem doesn't update item in GraphicsSce

    I still don't know what I'm doing wrong, but here is another clue if it helps anyone.

    When I create a card, and set it to move right by 100 pixels and down by 100 pixels on a button click, a little bit of the image disappears with each click until it's gone completely (see photos). But I resize my window at any time, the card image pops back into full view, in the correct updated position. Either the QGraphicsView or QGraphicsScene is not registering changes in my card positions?

    Calling "m_pokerscene.update()" (m_pokerScene is my QGraphicsView) every time after I change the position of a Card item is a crude fix that works, but is cumbersome, should be unnecessary and would just cover up whatever my real problem is.

    Any thoughts? I appreciate it!
    Attached Images Attached Images

  3. #3
    Join Date
    Jan 2008
    Location
    Alameda, CA, USA
    Posts
    4,715
    Thanks
    259
    Thanked 759 Times in 749 Posts
    Qt products
    Qt5
    Platforms
    Windows Android

    Default Re: Calling setPos() on custom QGraphicsPixmapItem doesn't update item in GraphicsSce

    Set the QGraphicsItem::ItemSendsGeometryChanges flag on your card items.
    <=== 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.

  4. #4
    Join Date
    Apr 2020
    Posts
    7
    Thanks
    1
    Qt products
    Qt5

    Default Re: Calling setPos() on custom QGraphicsPixmapItem doesn't update item in GraphicsSce

    Quote Originally Posted by d_stranz View Post
    Set the QGraphicsItem::ItemSendsGeometryChanges flag on your card items.
    I did that already in the constructor, should it be somewhere else?

  5. #5
    Join Date
    Jan 2008
    Location
    Alameda, CA, USA
    Posts
    4,715
    Thanks
    259
    Thanked 759 Times in 749 Posts
    Qt products
    Qt5
    Platforms
    Windows Android

    Default Re: Calling setPos() on custom QGraphicsPixmapItem doesn't update item in GraphicsSce

    Hmmm, maybe that flag only applies when the ItemIsMovable flag is also set and the user interactively drags the item.

    I don't think there is any alternative to the QGraphicsScene::update() call.
    <=== 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.

Similar Threads

  1. Replies: 7
    Last Post: 31st October 2010, 13:21
  2. QCursor::setPos() - doesn't work
    By Piskvorkar in forum Qt Programming
    Replies: 0
    Last Post: 21st March 2010, 14:24
  3. GraphicsView/GraphicsScene does not update
    By robicjedi in forum Qt Programming
    Replies: 5
    Last Post: 3rd February 2010, 00:33
  4. Replies: 1
    Last Post: 26th August 2009, 16:47
  5. How to move an item on a GraphicsScene
    By Holy in forum Qt Programming
    Replies: 17
    Last Post: 25th July 2008, 15:40

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Digia, Qt and their respective logos are trademarks of Digia Plc in Finland and/or other countries worldwide.