QT播放介面設計

今天寫了個QT的實時視訊播放介面，其實要寫一個播放介面非常容易，以下為程式碼
首先定義一個用於播放的控制元件：
* PlsyItem.h

#ifndef PLAYITEM_H
#define PLAYITEM_H

#include <QObject>
#include <QGraphicsItem>
#include <QImage>

class PlayItem : public QObject, public QGraphicsPixmapItem
{
    Q_OBJECT
public:
    explicit PlayItem(QObject *parent = nullptr);
    PlayItem(const QImage &qimg);
    ~PlayItem();
    void setQImage(const QImage &qimg);
};

#endif // PLAYITEM_H

• PlsyItem.cpp

#include "PlayItem.h"

PlayItem::PlayItem(QObject *parent) : QObject(parent)
{
}

PlayItem::PlayItem(const QImage &qimg)
{
    this->setPixmap(QPixmap::fromImage(qimg));
    this->update();
}

PlayItem::~PlayItem()
{
}

void PlayItem::setQImage(const QImage &qimg)
{
    this->setPixmap(QPixmap::fromImage(qimg));
    this->update();
}

然後定義一個 QGraphicsView，用於顯示
* PlayWidget.h

#ifndef PLAYWIDGET_H
#define PLAYWIDGET_H

#include <QGraphicsView>
#include <QGraphicsScene>
#include <opencv2/core/core.hpp>
#include "PlayItem.h"

class PlayWidget : public QGraphicsView
{
    Q_OBJECT
public:
    PlayWidget();

public slots:
    void getResult(const QImage &qimg);


private:
//    QImage Mat2QImage(const cv::Mat &img);
    void updateScene();

    // event
    void wheelEvent(QWheelEvent *event);

private:
    PlayItem* m_play_item_ptr;
    QGraphicsScene* m_img_scene_ptr;
    cv::Mat m_img;

    double m_zoom_factor;
};

#endif // PLAYWIDGET_H

• PlayWidget.cpp

#include "PlayWidget.h"

#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/core/core.hpp>
#include <QWheelEvent>


PlayWidget::PlayWidget()
{
    m_img_scene_ptr = new QGraphicsScene();
    this->setScene(m_img_scene_ptr);
    m_play_item_ptr = new PlayItem();
    m_img_scene_ptr->addItem(m_play_item_ptr);

    double width_scale = double(this->width()) / double(1280);
    double height_scale = double(this->height()) / double(720);
    m_zoom_factor = width_scale < height_scale ? width_scale : height_scale;
    this->updateScene();
}

void PlayWidget::getResult(const QImage &qimg)
{
    m_play_item_ptr->setQImage(qimg);
}

void PlayWidget::updateScene()
{
    QMatrix matrix;
    matrix.scale(m_zoom_factor, m_zoom_factor);
    this->setMatrix(matrix);
}

void PlayWidget::wheelEvent(QWheelEvent *event)
{
    if(event->delta() > 0)
        m_zoom_factor *= 1.15;
    else
        m_zoom_factor *= 0.9;
    this->updateScene();
}

然後將PlayWidget類作為主視窗或者某個窗體的控制元件即可，當PlayWidget收到QImage，便可以顯示出來，而且可以縮放