QGraphicsView， QGraphicsObject ，QQGraphicsSvgItem 图片接收鼠标事件拖拉收放

由于项目要求，需要加载svg格式图片和pixmap图片，并根据指定坐标在图上进行勾画，并且对相应位置接收鼠标事件。

-继承QGraphicsObject,实现加载pixmap的项

myimageitem.h

#ifndef MYIMAGEITEM_H

#define MYIMAGEITEM_H

#include <QGraphicsObject>

#include <QPainter>

#include <QVector>

#include <QGraphicsSceneMouseEvent>

#include <QMap>

class myimageitem: public QGraphicsObject

{

    Q_OBJECT

public:

    myimageitem(QRectF, rect,const QPixmap &image,QGraphicsObject *parent = nullptr);//rect 项的边框尺寸，image 图像

    ~myimageitem();

    void setRect(const QRectF &rect);

    QRectF boundingRect()const override;

    void paint(QPainter *panter, const QStyleOptionGraphicsItem *option, QWidget *widget) override;

protected:

    void mousePressEvent(QGraphicsSceneMouseEvent *event) override;

public slots:

    void onSyn(int id);

signals:

    void syn(int id);

private:

    QRectF m_rect;

    QPixmap m_pixmap;

    float deltaX; // 显示窗口大小与实际图片横轴比例

    float deltaY; // 显示窗口大小与实际图片竖轴比例

    QMap<int, bool> _rectPointSelected;// 标记矩形是否被鼠标事件选中

    QMap<int,QRectF> _rectPoint; // 保存矩形数据

};

#endif // MYIMAGEITEM_H

#include "myimageitem.h"

myimageitem::myimageitem(QRectF rect,const QPixmap &image, QGraphicsObject * parent):QGraphicsObject(parent),m_pixmap(image)

{

    deltaX = rect.width()/m_pixmap.width();

    deltaY = rect.height()/m_pixmap.height();

    QRectF rect1(0,0,200*deltaX,200*deltaY);

    QRectF rect2(200*deltaX, 200*deltaY, 200*deltaX, 200*deltaY);


　　// 初始化测试坐标数据

    _rectPoint.insert(0, rect1);

    _rectPointSelected.insert(0,false);

    _rectPoint.insert(1,rect2);

    _rectPointSelected.insert(1,false);

    setRect(rect);

}

myimageitem::~myimageitem(){

}

void myimageitem::setRect(const QRectF &rect)

{

    if(m_rect == rect){

        return;

    }

    prepareGeometryChange();

    m_rect = rect;

    update();  // 通知重绘图片

}

QRectF myimageitem::boundingRect() const{

    return m_rect; // 边界尺寸

}

void myimageitem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget){

    Q_UNUSED(option);

    Q_UNUSED(widget);

    painter->setRenderHint(QPainter::Antialiasing, true); // 打开抗锯齿

    painter->save();

    painter->drawPixmap(m_rect, m_pixmap,QRectF()); // 画图

    for(QMap<int, bool>::iterator it = _rectPointSelected.begin(); it != _rectPointSelected.end(); ++it){

        if(!it.value()){

            painter->setPen(Qt::blue); // 如果未被选中

        }else {

            painter->setPen(Qt::red); // 如果被选中

            it.value() = false; // 重绘之后选中状态重置

        }

        painter->drawRect(_rectPoint[it.key()]); // 绘制矩形

    }

    painter->restore();

}

void myimageitem::mousePressEvent(QGraphicsSceneMouseEvent *event){ // 接收鼠标事件

    if(event->button() == Qt::LeftButton){

        for(QMap<int, QRectF>::iterator it = _rectPoint.begin(); it != _rectPoint.end(); ++it){

            if(it.value().contains(event->pos())){

                prepareGeometryChange();// 保持项的索引，即使改变了项的尺寸，如果有必要会调用update()

                _rectPointSelected[it.key()] = true; // 选中矩形

//                emit syn(it.key());

            }

        }

    }

}

void myimageitem::onSyn(int id){

    prepareGeometryChange();

    _rectPointSelected[id] = true;

    update();

}

-继承QGraphicsSvgItem

mygriditem.h

#ifndef MYGRIDITEM_H
#define MYGRIDITEM_H

#include <QtSvg/QGraphicsSvgItem>

#include <QGraphicsSceneMouseEvent>

#include <QtSvg/QSvgRenderer>

#include <QPainter>

class mygriditem :public QGraphicsSvgItem

{

    Q_OBJECTpublic:

    mygriditem(QRectF boundRect,const QString &svgFile,const QSize svgSize,QGraphicsSvgItem *parent  = nullptr);// 导入svg格式图片文件 和尺寸

    ~mygriditem();

    QRectF boundingRect()const override;

    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)override;

signals:

    void syn(int id);

public slots:

    void onSyn(int id);

protected:

    void mousePressEvent(QGraphicsSceneMouseEvent *event) override;

private:

    QRectF _boundRect; // 边界矩形

    QSvgRenderer *_svgRender;

    float _xDelta;

    float _yDelta;

    QMap<int, bool> _rectPointSelected;

    QMap<int,QRectF> _rectPoint;

};

#endif // MYGRIDITEM_H

#include "mygriditem.h"

mygriditem::mygriditem(QRectF boundRect,const QString &svgFile,const QSize svgSize ,QGraphicsSvgItem *parent):QGraphicsSvgItem(parent),

    _boundRect(boundRect)

{

    _svgRender = new QSvgRenderer(svgFile); //加载svg图

    _xDelta = _boundRect.width()/svgSize.width();

    _yDelta = _boundRect.height()/ svgSize.height();

    QRectF rect1(0*_xDelta,0*_yDelta,60*_xDelta,60*_yDelta);

    QRectF rect2(60*_xDelta,60*_yDelta,60*_xDelta,60*_yDelta);

    _rectPoint.insert(0, rect1);

    _rectPoint.insert(1 ,rect2);

    _rectPointSelected.insert(0, false);

    _rectPointSelected.insert(1, false);

}

mygriditem::~mygriditem(){

}

void mygriditem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget){

    Q_UNUSED(option);

    Q_UNUSED(widget);

    painter->setRenderHint(QPainter::Antialiasing, true);

    painter->save();

    _svgRender->render(painter, _boundRect); // 绘制svg图片

//    QGraphicsSvgItem::paint(painter, option, widget);

    for(QMap<int,bool>::iterator it = _rectPointSelected.begin(); it != _rectPointSelected.end() ;++it){

        if(it.value()){

            painter->setPen(Qt::red);

            it.value() = false;

        }else {

            painter->setPen(Qt::green);

        }

        painter->setBrush(Qt::green);

        painter->drawRect(_rectPoint[it.key()]);

    }

    painter->restore();

}

QRectF mygriditem::boundingRect() const{

    return _boundRect;

}

void mygriditem::mousePressEvent(QGraphicsSceneMouseEvent *event){

    if(event->button() == Qt::LeftButton){

        for(QMap<int, QRectF>::iterator it = _rectPoint.begin(); it != _rectPoint.end(); ++ it){

            if(it.value().contains(event->pos())){

                prepareGeometryChange();

                _rectPointSelected[it.key()] = true;

                update();

 //               emit syn(it.key());

            }

        }

    }

}

void mygriditem::onSyn(int id){

    prepareGeometryChange();

    _rectPointSelected[id] = true;

    update();

}

-继承QGraphicsView 实现缩放拖拽（这部分参考其它博主）

mygraphicsview.h

#ifndef MYGRAPHICSVIEW_H

#define MYGRAPHICSVIEW_H

#include <QGraphicsView>

#include <QKeyEvent>

class mygraphicsview:public QGraphicsView

{

public:

    explicit mygraphicsview(QWidget *parent = nullptr);

    ~mygraphicsview();

      // 平移速度

    void setTranslateSpeed(qreal speed);

    qreal translateSpeed() const;

    // 缩放的增量

    void setZoomDelta(qreal delta);

    qreal zoomDelta() const;

  protected:

      // 上/下/左/右键向各个方向移动、加/减键进行缩放、空格/回车键旋转

      void keyPressEvent(QKeyEvent *event) Q_DECL_OVERRIDE;

      // 平移

      void mouseMoveEvent(QMouseEvent *event) Q_DECL_OVERRIDE;

      void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;

      void mouseReleaseEvent(QMouseEvent *event) Q_DECL_OVERRIDE;

      // 放大/缩小

      void wheelEvent(QWheelEvent *event) Q_DECL_OVERRIDE;

  public Q_SLOTS:

      void zoomIn();  // 放大

      void zoomOut();  // 缩小

      void zoom(float scaleFactor); // 缩放 - scaleFactor缩放的比例因子

      void translate(QPointF delta);  // 平移

  private:

      Qt::MouseButton m_translateButton;  // 平移按钮

      qreal m_translateSpeed;  // 平移速度

      qreal m_zoomDelta;  // 缩放的增量

      bool m_bMouseTranslate;  // 平移标识

      QPoint m_lastMousePos;  // 鼠标最后按下的位置

      qreal m_scale;  // 缩放值

};

#endif // MYGRAPHICSVIEW_H

#include "mygraphicsview.h"

#define VIEW_CENTER viewport()->rect().center()

#define VIEW_WIDTH  viewport()->rect().width()

#define VIEW_HEIGHT viewport()->rect().height()

mygraphicsview::mygraphicsview(QWidget *parent):QGraphicsView(parent),

  m_translateButton(Qt::LeftButton),

        m_scale(1.0),

        m_zoomDelta(0.1),

        m_translateSpeed(1.0),

        m_bMouseTranslate(false)

{

    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

       setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

       setCursor(Qt::PointingHandCursor);

       setRenderHint(QPainter::Antialiasing);

//       setSceneRect(INT_MIN/2, INT_MIN/2, INT_MAX, INT_MAX);

//       setSceneRect(0,0,5472, 3648);

//       centerOn(0, 0);

}

mygraphicsview::~mygraphicsview(){

}

// 平移速度

void mygraphicsview::setTranslateSpeed(qreal speed)

{

    // 建议速度范围

    Q_ASSERT_X(speed >= 0.0 && speed <= 2.0,

               "InteractiveView::setTranslateSpeed", "Speed should be in range [0.0, 2.0].");

    m_translateSpeed = speed;

}

qreal mygraphicsview::translateSpeed() const

{

    return m_translateSpeed;

}

// 缩放的增量

void mygraphicsview::setZoomDelta(qreal delta)

{

    // 建议增量范围

    Q_ASSERT_X(delta >= 0.0 && delta <= 1.0,

               "InteractiveView::setZoomDelta", "Delta should be in range [0.0, 1.0].");

    m_zoomDelta = delta;

}

qreal mygraphicsview::zoomDelta() const

{

    return m_zoomDelta;

}

// 上/下/左/右键向各个方向移动、加/减键进行缩放、空格/回车键旋转

void mygraphicsview::keyPressEvent(QKeyEvent *event)

{

    switch (event->key()) {

    case Qt::Key_Up:

        translate(QPointF(0, -2));  // 上移

        break;

    case Qt::Key_Down:

        translate(QPointF(0, 2));  // 下移

        break;

    case Qt::Key_Left:

        translate(QPointF(-2, 0));  // 左移

        break;

    case Qt::Key_Right:

        translate(QPointF(2, 0));  // 右移

        break;

    case Qt::Key_Plus:  // 放大

        zoomIn();

        break;

    case Qt::Key_Minus:  // 缩小

        zoomOut();

        break;

    case Qt::Key_Space:  // 逆时针旋转

        rotate(-5);

        break;

    case Qt::Key_Enter:  // 顺时针旋转

    case Qt::Key_Return:

        rotate(5);

        break;

    default:

        QGraphicsView::keyPressEvent(event);

    }

}

// 平移

void mygraphicsview::mouseMoveEvent(QMouseEvent *event)

{

    if (m_bMouseTranslate){

        QPointF mouseDelta = mapToScene(event->pos()) - mapToScene(m_lastMousePos);

        translate(mouseDelta);

    }

    m_lastMousePos = event->pos();

    QGraphicsView::mouseMoveEvent(event);

}

void mygraphicsview::mousePressEvent(QMouseEvent *event)

{

    if (event->button() == m_translateButton) {

        // 当光标底下没有 item 时才能移动

        QPointF point = mapToScene(event->pos());

        if (scene()->itemAt(point, transform()) != NULL)  {

            m_bMouseTranslate = true;

            m_lastMousePos = event->pos();

        }

    }

    QGraphicsView::mousePressEvent(event);

}

void mygraphicsview::mouseReleaseEvent(QMouseEvent *event)

{

    if (event->button() == m_translateButton)

        m_bMouseTranslate = false;

    QGraphicsView::mouseReleaseEvent(event);

}

// 放大/缩小

void mygraphicsview::wheelEvent(QWheelEvent *event)

{

    // 滚轮的滚动量

    QPoint scrollAmount = event->angleDelta();

    // 正值表示滚轮远离使用者放大负值表示朝向使用者缩小

    scrollAmount.y() > 0 ? zoomIn() : zoomOut();

}

// 放大

void mygraphicsview::zoomIn()

{

    zoom(1 + m_zoomDelta);

}

// 缩小

void mygraphicsview::zoomOut()

{

    zoom(1 - m_zoomDelta);

}

// 缩放 - scaleFactor缩放的比例因子

void mygraphicsview::zoom(float scaleFactor)

{

    // 防止过小或过大

    qreal factor = transform().scale(scaleFactor, scaleFactor).mapRect(QRectF(0, 0, 1, 1)).width();

    if (factor < 0.5 || factor > 100)

        return;

    scale(scaleFactor, scaleFactor);

    m_scale *= scaleFactor;

}

// 平移

void mygraphicsview::translate(QPointF delta)

{

    // 根据当前 zoom 缩放平移数

    delta *= m_scale;

    delta *= m_translateSpeed;

    // view 根据鼠标下的点作为锚点来定位 scene

    setTransformationAnchor(QGraphicsView::AnchorUnderMouse);

    QPoint newCenter(VIEW_WIDTH / 2 - delta.x(),  VIEW_HEIGHT / 2 - delta.y());

    centerOn(mapToScene(newCenter));

    // scene 在 view 的中心点作为锚点

    setTransformationAnchor(QGraphicsView::AnchorViewCenter);

}

-测试代码

cview.h

#ifndef CVIEW_H

#define CVIEW_H

#include <QWidget>

#include <QGraphicsScene>

#include <QtSvg/QSvgRenderer>

#include <QtSvg/QGraphicsSvgItem>

#include<QGraphicsGridLayout>

#include <QGraphicsLayout>

#include "mygraphicsview.h"

#include "myimageitem.h"

#include "mygriditem.h"

QT_BEGIN_NAMESPACE

namespace Ui { class CView; }

QT_END_NAMESPACE

class CView : public QWidget

{

    Q_OBJECT

public:

    CView(QWidget *parent = nullptr);

    ~CView();

private:

    Ui::CView *ui;

    QGraphicsScene *_scene;

    QGraphicsObject *_codeImgae;

};

#endif // CVIEW_H

#include "cview.h"

#include "./ui_cview.h"

CView::CView(QWidget *parent)

    : QWidget(parent),

    ui(new Ui::CView),

    _scene(new QGraphicsScene)

{

    ui->setupUi(this);

    QPixmap pixmap;

    pixmap.load("XXX.png"); // 传入自己的图片

    float pixWidth = pixmap.width();

    float pixHeight = pixmap.height();

    float deltaX = ui->graphicsView_2->width()/pixWidth;

    float deltaY = ui->graphicsView_2->height()/pixHeight;

    int viewW = ui->graphicsView_2->width();

    int viewH = ui->graphicsView_2->height();

    _codeImgae = new myimageitem(QRectF(0, 0,viewH, viewH),pixmap);

    _scene->addItem(_codeImgae);

    ui->graphicsView_2->setScene(_scene);

    float w = ui->graphicsView->width();

    float h = ui->graphicsView->height();

     mygriditem *svg_render = new mygriditem(QRectF(0,0,w,h),QString("XXX.svg"));// 传入自己的图片

    QGraphicsScene *svgScene = new QGraphicsScene();

    svgScene->addItem(svg_render);

    QList<QGraphicsItem*> items = svgScene->items();

    ui->graphicsView->setScene(svgScene);

}

CView::~CView()

{

    delete ui;

}

巴特西

QGraphicsView， QGraphicsObject ，QQGraphicsSvgItem 图片接收鼠标事件拖拉收放

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巴特西

QGraphicsView， QGraphicsObject ，QQGraphicsSvgItem 图片接收鼠标事件 拖拉 收放

最新文章

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QGraphicsView， QGraphicsObject ，QQGraphicsSvgItem 图片接收鼠标事件拖拉收放