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QGraphicsItem 怎么才能让它有拖动边框缩放图形的功能 [复制链接]

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离线longwenbiao
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只看楼主 倒序阅读 楼主  发表于: 2009-11-26
— 本帖被 XChinux 从 General Qt Programming 移动到本区(2011-01-02) —
请参考一下qtdemo上的列子：Graphics View 上 Diagram Scene，在这里面只能选择，拖动图形，边框并不能被选中，我想让边框能选中来缩放大小，并且还能选中里面的图形进行修改？ 

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离线robertkun
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只看该作者 1楼 发表于: 2009-11-26
自已写了，QT，好像没这个功能呢
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离线longwenbiao
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只看该作者 2楼 发表于: 2009-11-26
关键是不会写，能给点思路不？
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离线robertkun
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只看该作者 3楼 发表于: 2009-11-26
在图形上面添加另外一个QGraphicsitem ,当修改这个图元的时候，去设置与它相关的图元的大小。
可以参考这个。。自已写的，如要有简单的方法，欢迎交流。。

复制代码
  1. #include "stdafx.h"
  2. #include "cgKeyPointElement.h"
  3. #include "cgBaseElement.h"
  4. #include "cgScene.h"
  5. #include "cgRollingItem.h"
  7. cgKeyPointElement::cgKeyPointElement(cgBaseElement* item)
  8. :QGraphicsItem()
  9. {
  10.     mItem = item;
  11.     m_drag = false;
  12.     m_moveID = 0;
  13.     m_bHover = false;
  15.     //悬浮设为TRUE
  16.     setAcceptHoverEvents(true);
  17.     //放到最底层
  18.     //setZValue(-1);
  20.     //初始化矩形的大小
  21.     m_rect.setRect(0,0,0,0);
  22.     hide();
  23.     setFlag(QGraphicsItem::ItemIsMovable,true);
  24.     setFlag(QGraphicsItem::ItemIsSelectable,false);
  25. }
  27. cgKeyPointElement::~cgKeyPointElement(void)
  28. {
  30. }
  32. QRectF cgKeyPointElement::boundingRect() const
  33. {
  34.     return m_rect;
  35. }
  37. void cgKeyPointElement::paint(QPainter* viewPainter, const QStyleOptionGraphicsItem* option, QWidget* widget /*= 0*/)
  38. {
  39.     if (!mItem)
  40.         return;
  42.     QRectF rect = m_rect;
  43.     rect.adjust(5,5, -5, -5);
  44.     
  45.     viewPainter->setPen(QPen(Qt::yellow, 3, Qt::DotLine));
  46.     viewPainter->setBrush(Qt::NoBrush);
  47.     viewPainter->drawRect(rect);
  49.     //绘制文字拖动点
  50.     viewPainter->setPen(QPen(Qt::yellow, 0, Qt::SolidLine));
  52.     if(m_bHover)
  53.     {
  54.         viewPainter->setBrush(QBrush(Qt::yellow,Qt::SolidPattern));
  55.         //TopLeft
  56.         viewPainter->drawRect(1,1,10,10);
  57.         //TopCenter
  58.         viewPainter->drawRect(m_rect.width()/2 - 6,1,10,10);
  59.         //TopRight
  60.         viewPainter->drawRect(m_rect.width()- 11,1,10,10);
  61.         //BottomLeft
  62.         viewPainter->drawRect(1,m_rect.height()- 11,10,10);
  63.         //BottomCenter
  64.         viewPainter->drawRect(m_rect.width()/2 - 6,m_rect.height()- 11,10,10);
  65.         //LeftCenter
  66.         viewPainter->drawRect(1,m_rect.height()/2 - 6,10,10);
  67.         //RightCenter
  68.         viewPainter->drawRect(m_rect.width()- 11,m_rect.height()/2 - 6,10,10);
  69.         //BottomRight
  70.         viewPainter->drawRect(m_rect.width()- 11,m_rect.height()- 11,10,10);
  72.         switch(m_moveID)
  73.         {
  74.         case 1:
  75.             {
  76.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  77.                 //TopLeft
  78.                 viewPainter->drawRect(1,1,10,10);
  79.                 break;
  80.             }
  81.         case 2:
  82.             {
  83.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  84.                 //TopCenter
  85.                 viewPainter->drawRect(m_rect.width()/2 - 6,1,10,10);
  86.                 break;
  87.             }
  88.         case 3:
  89.             {
  90.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  91.                 //TopRight
  92.                 viewPainter->drawRect(m_rect.width()- 11,1,10,10);
  93.                 break;
  94.             }
  95.         case 4:
  96.             {
  97.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  98.                 //LeftCenter
  99.                 viewPainter->drawRect(1,m_rect.height()/2 - 6,10,10);
  100.                 break;
  101.             }
  102.         case 5:
  103.             {
  104.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  105.                 //RightCenter
  106.                 viewPainter->drawRect(m_rect.width()- 11,m_rect.height()/2 - 6,10,10);
  107.                 break;
  108.             }
  109.         case 6:
  110.             {
  111.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  112.                 //BottomLeft
  113.                 viewPainter->drawRect(1,m_rect.height()- 11,10,10);
  114.                 break;
  115.             }
  116.         case 7:
  117.             {
  118.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  119.                 //BottomCenter
  120.                 viewPainter->drawRect(m_rect.width()/2 - 6,m_rect.height()- 11,10,10);
  121.                 break;
  122.             }
  123.         case 8:
  124.             {
  125.                 viewPainter->setBrush(QBrush(Qt::red,Qt::SolidPattern));
  126.                 //BottomRight
  127.                 viewPainter->drawRect(m_rect.width()- 11,m_rect.height()- 11,10,10);
  128.                 break;
  129.             }
  130.         default:
  131.             viewPainter->setBrush(QBrush(Qt::yellow,Qt::SolidPattern));
  132.             //TopLeft
  133.             viewPainter->drawRect(1,1,10,10);
  134.             //TopCenter
  135.             viewPainter->drawRect(m_rect.width()/2 - 6,1,10,10);
  136.             //TopRight
  137.             viewPainter->drawRect(m_rect.width()- 11,1,10,10);
  138.             //BottomLeft
  139.             viewPainter->drawRect(1,m_rect.height()- 11,10,10);
  140.             //BottomCenter
  141.             viewPainter->drawRect(m_rect.width()/2 - 6,m_rect.height()- 11,10,10);
  142.             //LeftCenter
  143.             viewPainter->drawRect(1,m_rect.height()/2 - 6,10,10);
  144.             //RightCenter
  145.             viewPainter->drawRect(m_rect.width()- 11,m_rect.height()/2 - 6,10,10);
  146.             //BottomRight
  147.             viewPainter->drawRect(m_rect.width()- 11,m_rect.height()- 11,10,10);
  148.         }//End switch
  149.     }//END IF
  150.     else
  151.     {
  152.         viewPainter->setBrush(QBrush(Qt::yellow,Qt::SolidPattern));
  153.         //TopLeft
  154.         viewPainter->drawRect(1,1,10,10);
  155.         //TopCenter
  156.         viewPainter->drawRect(m_rect.width()/2 - 6,1,10,10);
  157.         //TopRight
  158.         viewPainter->drawRect(m_rect.width()- 11,1,10,10);
  159.         //BottomLeft
  160.         viewPainter->drawRect(1,m_rect.height()- 11,10,10);
  161.         //BottomCenter
  162.         viewPainter->drawRect(m_rect.width()/2 - 6,m_rect.height()- 11,10,10);
  163.         //LeftCenter
  164.         viewPainter->drawRect(1,m_rect.height()/2 - 6,10,10);
  165.         //RightCenter
  166.         viewPainter->drawRect(m_rect.width()- 11,m_rect.height()/2 - 6,10,10);
  167.         //BottomRight
  168.         viewPainter->drawRect(m_rect.width()- 11,m_rect.height()- 11,10,10);
  169.     }
  171. }    
  174. void cgKeyPointElement::mousePressEvent ( QGraphicsSceneMouseEvent * ev)
  175. {
  176.     m_lastPos = ev->pos();
  177.     mOldRect = m_rect;
  179.     QGraphicsItem * item = dynamic_cast<QGraphicsItem *>(mItem);
  180.     if (item)
  181.         item->setSelected(true);
  183.     QGraphicsItem::mousePressEvent(ev);
  184. }
  186. void cgKeyPointElement::mouseMoveEvent ( QGraphicsSceneMouseEvent * ev)
  187. {
  189.     QPointF now_pos = ev->pos();
  190.     QPointF item_pos = pos();
  192.     int w_offset = now_pos.x() - m_lastPos.x();
  193.     int h_offset = now_pos.y() - m_lastPos.y();
  195.     if(m_drag)
  196.     {
  197.         switch(m_moveID)
  198.         {
  199.         case 1:
  200.             prepareGeometryChange();
  201.             m_rect.setWidth(m_rect.width() - w_offset);
  202.             m_rect.setHeight(m_rect.height() - h_offset);
  203.             setPos(item_pos + QPointF(w_offset,h_offset));
  204.             break;
  205.         case 2:
  206.             prepareGeometryChange();
  207.             m_rect.setHeight(m_rect.height() - h_offset);
  208.             setPos(item_pos+QPointF(0,h_offset));
  209.             break;
  210.         case 3:
  211.             prepareGeometryChange();
  212.             m_rect.setWidth(now_pos.x());
  213.             m_rect.setHeight(m_rect.height() - h_offset);
  214.             setPos(item_pos+QPointF(0,h_offset));
  215.             break;
  216.         case 4:
  217.             m_rect.setWidth(m_rect.width() - w_offset);
  218.             setPos(item_pos+QPointF(w_offset,0));
  219.             break;
  220.         case 5:
  221.             prepareGeometryChange();
  222.             m_rect.setWidth(now_pos.x());
  223.             break;
  224.         case 6:
  225.             prepareGeometryChange();
  226.             m_rect.setWidth(m_rect.width() - w_offset);
  227.             m_rect.setHeight(now_pos.y());
  228.             setPos(item_pos + QPointF(w_offset,0));
  229.             break;
  230.         case 7:
  231.             prepareGeometryChange();
  232.             m_rect.setHeight(now_pos.y());
  233.             break;
  234.         case 8:
  235.             prepareGeometryChange();
  236.             m_rect.setWidth(now_pos.x());
  237.             m_rect.setHeight(now_pos.y());
  238.             break;
  239.         default:
  240.             QGraphicsItem::mouseMoveEvent(ev);
  241.             break;
  242.         }
  243.     }
  244.     else
  245.     {
  246.         mItem->setMoving(true);
  247.         QGraphicsItem::mouseMoveEvent(ev);
  248.     }
  249. }
  251. void cgKeyPointElement::mouseReleaseEvent ( QGraphicsSceneMouseEvent * ev)
  252. {
  254.     QPointF now_pos = ev->pos();
  255.     qreal width_offset = m_rect.width() - mOldRect.width();
  256.     qreal height_offset = m_rect.height() - mOldRect.height();
  257.     qreal scaleWidth = 1.0;
  258.     qreal scaleHeight = 1.0;
  260.     QGraphicsItem * item = dynamic_cast<QGraphicsItem *>(mItem);
  261.     if(m_drag)
  262.     {
  263.         // 获取到最原始的放大倍数
  264.         QRectF rect = item->boundingRect();
  265.         if (mItem)
  266.         {
  267.             // 设置放大倍数
  268.             mItem->setRect(QRectF(0, 0, m_rect.width(), m_rect.height()));
  269.         }
  270.     }
  272.     if (item)
  273.     {
  274.         mItem->setMoving(false);
  275.         item->setPos(this->pos());
  276.     }
  277.     QGraphicsItem::mouseReleaseEvent(ev);
  279.     m_drag = false;
  280. }
  282. void cgKeyPointElement::hoverMoveEvent(QGraphicsSceneHoverEvent * ev)
  283. {
  284.     QPointF m_hoverPos = ev->pos();
  286.     qreal Rect_W = m_rect.width();
  287.     qreal Rect_W2 = m_rect.width()/2;
  289.     qreal Rect_H = m_rect.height();
  290.     qreal Rect_H2 = m_rect.height()/2;
  292.     int halfDis = 15;
  293.     int distance = 20;
  295.     if(((Rect_W2 - halfDis) < m_hoverPos.x() &&  m_hoverPos.x() < (Rect_W2 + halfDis))&&
  296.         ((Rect_H - distance) < m_hoverPos.y() && m_hoverPos.y() < (Rect_H + distance)))
  297.     {
  298.         //BottomCenter
  299.         setCursor(Qt::SizeVerCursor);
  300.         m_moveID = 7;
  301.         m_bHover = true;
  302.         m_drag = true;
  304.     }
  305.     else if(((Rect_W2 - halfDis) < m_hoverPos.x() &&  m_hoverPos.x() < (Rect_W2 + halfDis))&&
  306.         (- distance < m_hoverPos.y() && m_hoverPos.y() < distance))
  307.     {
  308.         //TopCenter
  309.         setCursor(Qt::SizeVerCursor);
  310.         m_moveID = 2;
  311.         m_bHover = true;
  312.         m_drag = true;
  314.     }
  315.     else if(((Rect_W - distance) < m_hoverPos.x() &&  m_hoverPos.x() < (Rect_W + distance))&&
  316.         (- distance < m_hoverPos.y() && m_hoverPos.y() < distance))
  317.     {
  318.         //TopRight
  319.         setCursor(Qt::SizeBDiagCursor);
  320.         m_moveID = 3;
  321.         m_bHover = true;
  322.         m_drag = true;
  324.     }
  325.     else if((- distance < m_hoverPos.x() &&  m_hoverPos.x() < distance)&&
  326.         (- distance < m_hoverPos.y() && m_hoverPos.y() < distance))
  327.     {
  328.         //TopLeft
  329.         setCursor(Qt::SizeFDiagCursor);
  330.         m_moveID = 1;
  331.         m_bHover = true;
  332.         m_drag = true;
  334.     }
  335.     else if(((Rect_W - distance) < m_hoverPos.x() &&  m_hoverPos.x() < (Rect_W + distance))&&
  336.         ((Rect_H - distance) < m_hoverPos.y() && m_hoverPos.y() < (Rect_H + distance)))
  337.     {
  338.         //BottomRight
  339.         setCursor(Qt::SizeFDiagCursor);
  340.         m_moveID = 8;
  341.         m_bHover = true;
  342.         m_drag = true;
  344.     }
  345.     else if(((- distance < m_hoverPos.x() &&  m_hoverPos.x() < distance))&&
  346.         ((Rect_H - distance) < m_hoverPos.y() && m_hoverPos.y() < (Rect_H + distance)))
  347.     {
  348.         //BottomLeft
  349.         setCursor(Qt::SizeBDiagCursor);
  350.         m_moveID = 6;
  351.         m_bHover = true;
  352.         m_drag = true;
  354.     }
  355.     else if(((Rect_W - distance) < m_hoverPos.x() &&  m_hoverPos.x() < (Rect_W + distance))&&
  356.         ((Rect_H2 - halfDis) < m_hoverPos.y() && m_hoverPos.y() < (Rect_H2 + halfDis)))
  357.     {
  358.         //RightCenter
  359.         setCursor(Qt::SizeHorCursor);
  360.         m_moveID = 5;
  361.         m_bHover = true;
  362.         m_drag = true;
  364.     }
  365.     else if(((- distance < m_hoverPos.x() &&  m_hoverPos.x() < distance))&&
  366.         ((Rect_H2 - halfDis) < m_hoverPos.y() && m_hoverPos.y() < (Rect_H2 + halfDis)))
  367.     {
  368.         //LeftCenter
  369.         setCursor(Qt::SizeHorCursor);
  370.         m_moveID = 4;
  371.         m_bHover = true;
  372.         m_drag = true;
  374.     }
  375.     else
  376.     {
  377.         //Revert
  378.         setCursor(Qt::ArrowCursor);
  379.         m_moveID = 0;
  380.         m_bHover = false;
  381.         m_drag = false;
  383.     }
  384.     update();
  385.     QGraphicsItem::hoverMoveEvent(ev);
  386. }
  388. void cgKeyPointElement::hoverLeaveEvent ( QGraphicsSceneHoverEvent * ev)
  389. {
  390.     m_bHover = false;
  392.     QGraphicsItem::hoverLeaveEvent(ev);
  393. }
  395. void cgKeyPointElement::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *ev)
  396. {
  397.     hide();
  400.     QGraphicsItem::mouseDoubleClickEvent(ev);
  401. }
  403. void cgKeyPointElement::setBoundingRect(QRectF rect)
  404. {
  405.     prepareGeometryChange();
  406.     m_rect = rect;
  407. }
                                              简单的生活使人快乐！
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离线longwenbiao
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只看该作者 4楼 发表于: 2009-11-26
非常感谢，我研究下
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离线penghoujia
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只看该作者 5楼 发表于: 2009-12-02
如果是组合图形需要放大和缩小那怎么做呢，
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离线babybluema
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只看该作者 6楼 发表于: 2010-03-18
同问，组合图形该怎么处理拖动边框缩放图形功能
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