libVLC 视频窗口上叠加透明窗口

很多时候，我们需要在界面上画一些三角形、文字等之类的东西，我们之需要重写paintEvent方法，比如像这样

void Widget::paintEvent(QPaintEvent *event)

以下就是重写的代码。

void Widget::paintEvent(QPaintEvent *event)
{
    //创建QPainter对象，指明父对象，否则不能看见
    QPainter painter(this);
 
    //先画一条线
    QPen pen;
 
    //设置线宽
    pen.setWidth(2);
 
    //设置颜色
    pen.setColor(Qt::red);
 
    //设置线的样式 实线、虚线
    pen.setStyle(Qt::DashDotLine);
 
    //设置线端点样式
    pen.setCapStyle(Qt::RoundCap);
 
    //设置画笔
    painter.setPen(pen);
 
    //画线
    painter.drawLine(10,10,100,100);
 
    //设置画刷
    QBrush brush;
 
    //画刷设置颜色
    brush.setColor(Qt::yellow);
 
    //设置填充样式
    brush.setStyle(Qt::SolidPattern);
 
    //设置画刷
    painter.setBrush(brush);
 
    //画四边形
    painter.drawRect(QRect(300,300,50,50));
 
    //画多边形，三角形
    QPoint points[] = {
        QPoint(200,200),
        QPoint(200,260),
        QPoint(260,260),
    };
    painter.drawPolygon(points,3);
 
    //设置字体
    QFont font;
 
    //字体大小
    font.setPointSize(30);
 
    //粗体
    font.setBold(true);
 
    //设置字体
    painter.setFont(font);
 
    //画字
    painter.drawText(400,400,QString("Qt"));
}

运行如下图所示：

更多QPainter相关的东西，请看：

Qt QPainter绘图_qt painter-CSDN博客

但是现在我们需要在播放视频的界面上绘制窗体，像下面这样。

这里我叠加了一个Widget在上面，widget上放了两个控件，一个label和一个comboBox。

ui原型如下所示：

首先我们需要定义一个叠加窗体类TopWidget，

这个类很简单，设置了窗体无边框和透明。

	//窗口无边框
	setWindowFlags(Qt::FramelessWindowHint | Qt::Window);

	// 窗口透明
	this->setAttribute(Qt::WA_TranslucentBackground);

然后重写绘图事件。

#pragma once

#include 
#include 
#include 
#include "ui_TopWidget.h"

class TopWidget : public QWidget
{
	Q_OBJECT

public:
	TopWidget(QWidget *parent = nullptr);
	~TopWidget();

protected:
	void paintEvent(QPaintEvent *pEvent);

private:
	Ui::TopWidgetClass ui;
};


#include "TopWidget.h"

TopWidget::TopWidget(QWidget *parent)
	: QWidget(parent)
{
	ui.setupUi(this);

	//窗口无边框
	setWindowFlags(Qt::FramelessWindowHint | Qt::Window);

	// 窗口透明
	this->setAttribute(Qt::WA_TranslucentBackground);
}

TopWidget::~TopWidget()
{}

void TopWidget::paintEvent(QPaintEvent *pEvent)
{
	QStyleOption opt;
	opt.initFrom(this);
	QPainter p(this);
	style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);//绘制样式
}

在主界面中，创建叠加窗体对象：

    TopWidget *m_widget = nullptr;	
    
    m_widget = new TopWidget(this);
	m_widget->setStyleSheet(QString("background-color: rgba(255, 0, 0, 0%);"));
	m_widget->show();

重写绘图和窗体移动事件：我们需要在主窗体移动的时候，叠加窗体跟随着主窗体移动。

void showWidget::paintEvent(QPaintEvent *event)
{
	QStyleOption opt;
	opt.initFrom(this);
	QPainter p(this);
	style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);//绘制样式

	QPoint pos_form = ui.widgetShow->mapToGlobal(ui.widgetShow->pos());
	m_widget->move(pos_form);
	m_widget->setGeometry(pos_form.x(), pos_form.y(), ui.widgetShow->width(), ui.widgetShow->height());
}

void showWidget::moveEvent(QMoveEvent *event)
{
	QPoint pos_form = ui.widgetShow->mapToGlobal(ui.widgetShow->pos());
	m_widget->move(pos_form);
	m_widget->setGeometry(pos_form.x(), pos_form.y(), ui.widgetShow->width(), ui.widgetShow->height());
}

完整源码：

#pragma once
#define LIBVLC_USE_PTHREAD_CANCEL 1
#include 
#include "ui_showWidget.h"
#include 
#include 
#include 

#include 
#include 
#include 
#include 
#include 
#include 
#include "TopWidget.h"

enum Rate
{
	Rate2X,
	Rate1_5X,
	Rate1_25X,
	Rate1_0X,
	Rate0_75X,
	Rate0_5X
};

class showWidget : public QWidget
{
    Q_OBJECT

public:
    showWidget(QWidget *parent = nullptr);
    ~showWidget();

protected:
	virtual void mouseDoubleClickEvent(QMouseEvent *event);
	virtual void keyPressEvent(QKeyEvent *event);
	virtual bool eventFilter(QObject *watched, QEvent *event);
	virtual void paintEvent(QPaintEvent *event);
	virtual void moveEvent(QMoveEvent *event);

private slots:
	void slotOpenFile();
	void slotPlay();
	void slotPause();
	void slotStop();
	void slotValueChanged(int value);
	void slotCurrentIndexChanged(int index);
	void slotSnap();

private:
	//事件处理回调
	static void vlcEvents(const libvlc_event_t *ev, void *param);

private:
    Ui::showWidgetClass ui;

private:
	libvlc_instance_t *vlc_base = nullptr;
	libvlc_media_t *vlc_media = nullptr;
	libvlc_media_player_t *vlc_mediaPlayer = nullptr;

	QList m_lstRate;

	TopWidget *m_widget = nullptr;
};


#include "showWidget.h"
#include 
#include 
#include 

#pragma execution_character_set("utf-8")

showWidget::showWidget(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);

	m_widget = new TopWidget(this);
	m_widget->setStyleSheet(QString("background-color: rgba(255, 0, 0, 0%);"));
	m_widget->show();

	this->setWindowTitle("视频播放器");

	ui.cbxRate->setCurrentIndex(Rate1_0X);

	m_lstRate setFocusPolicy(Qt::NoFocus);
	ui.btnPlay->setFocusPolicy(Qt::NoFocus);
	ui.btnPause->setFocusPolicy(Qt::NoFocus);
	ui.btnStop->setFocusPolicy(Qt::NoFocus);
	ui.hSliderVolumn->setFocusPolicy(Qt::NoFocus);
	ui.cbxRate->setFocusPolicy(Qt::NoFocus);

	ui.horizontalSlider->installEventFilter(this);

	connect(ui.btnOpen, &QPushButton::clicked, this, &showWidget::slotOpenFile);
	connect(ui.btnPlay, &QPushButton::clicked, this, &showWidget::slotPlay);
	connect(ui.btnPause, &QPushButton::clicked, this, &showWidget::slotPause);
	connect(ui.btnStop, &QPushButton::clicked, this, &showWidget::slotStop);
	connect(ui.btnSnap, &QPushButton::clicked, this, &showWidget::slotSnap);
	connect(ui.hSliderVolumn, &QSlider::valueChanged, this, &showWidget::slotValueChanged);
	connect(ui.cbxRate,SIGNAL(currentIndexChanged(int)), this, SLOT(slotCurrentIndexChanged(int)));
}

showWidget::~showWidget()
{
	libvlc_release(vlc_base); //减少libvlc实例的引用计数，并销毁
}

void showWidget::mouseDoubleClickEvent(QMouseEvent *event)
{
	if (this->isFullScreen())
	{
		this->showNormal();
	}
	else
	{
		this->showFullScreen();
	}
}

void showWidget::keyPressEvent(QKeyEvent *event)
{
	if (!vlc_mediaPlayer)
		return;

	int value = ui.hSliderVolumn->value();
	if (event->key() == Qt::Key_W)	//添加音量
	{
		qDebug() key() == Qt::Key_S)	//减小音量
	{
		slotValueChanged(value - 10);
	}
	else if (event->key() == Qt::Key_Space)
	{
		if (vlc_mediaPlayer && libvlc_media_player_get_state(vlc_mediaPlayer) == libvlc_Playing)
		{
			libvlc_media_player_pause(vlc_mediaPlayer);
		}
		else if (vlc_mediaPlayer && libvlc_media_player_get_state(vlc_mediaPlayer) == libvlc_Paused)
		{
			libvlc_media_player_play(vlc_mediaPlayer);
		}
	}
}

bool showWidget::eventFilter(QObject *watched, QEvent *event)
{
	if (watched == ui.horizontalSlider) {
		if (event->type() == QEvent::MouseButtonPress) {
			if (!vlc_mediaPlayer)
				return false;

			QMouseEvent *mouse = static_cast(event);
			libvlc_time_t totalLen = libvlc_media_player_get_length(vlc_mediaPlayer);
			QPoint pos = mouse->pos();
			libvlc_服务器托管time_t time = 0;
			time = (double)pos.x() / ui.horizontalSlider->width() * totalLen;
			libvlc_media_player_set_time(vlc_mediaPlayer, time);

			return true;
		}
		else {
			return false;
		}
	}
	else {
		// pass the event on to the parent class
		return QWidget::eventFilter(watched, event);
	}
}

void showWidget::paintEvent(QPaintEvent *event)
{
	QStyleOption opt;
	opt.initFrom(this);
	QPainter p(this);
	style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);//绘制样式

	QPoint pos_form = ui.widgetShow->mapToGlobal(ui.widgetShow->pos());
	m_widget->move(pos_form);
	m_widget->setGeometry(pos_form.x(), pos_form.y(), ui.widgetShow->width(), ui.widgetShow->height());
}

void showWidget::moveEvent(QMoveEvent *event)
{
	QPoint pos_form = ui.widgetShow->mapToGlobal(ui.widgetShow->pos());
	m_widget->move(pos_form);
	m_widget->setGeometry(pos_form.x(), pos_form.y(), ui.widgetShow->width(), ui.widgetShow->height());
}

void showWidget::slotOpenFile()
{
	/*选择文件*/
	QString filename = QFileDialog::getOpenFileName(this, "选择打开的文件", "D:/", tr("*.*"));
	std::replace(filename.begin(), filename.end(), QChar('/'), QChar(''));

	vlc_media = libvlc_media_new_path(vlc_base, filename.toUtf8().data());
	if (!vlc_media) {
		return;
	}

	// 创建libvlc实例和媒体播放器
	vlc_mediaPlayer = libvlc_media_player_new_from_media(vlc_media);
	if (!vlc_mediaPlayer) {
		return;
	}
	
	// 等待元数据加载完成
	libvlc_media_parse(vlc_media);


	libvlc_video_set_mouse_input(vlc_mediaPlayer, 0);
	libvlc_video_set_key_input(vlc_mediaPlayer, 0);

	// 获取各种元数据
	const char *title = libvlc_media_get_meta(vlc_media, libvlc_meta_Title);
	const char *artist = libvlc_media_get_meta(vlc_media, libvlc_meta_Artist);
	const char *album = libvlc_media_get_meta(vlc_media, libvlc_meta_Album);
	const char *url = libvlc_media_get_meta(vlc_media, libvlc_meta_URL);
	const char *date = libvlc_media_get_meta(vlc_media, libvlc_meta_Date);
	const char *lang = libvlc_media_get_meta(vlc_media, libvlc_meta_Language);
	int duration = libvlc_media_get_duration(vlc_media);  // 获取时长（单位：毫秒）

	qDebug("Title: %s", title ? title : "N/A");
	qDebug("Artist: %s", artist ? artist : "N/A");
	qDebug("Album: %s", album ? album : "N/A");
	qDebug("Duration: %d ms", duration);
	qDebug("url: %s", url ? url : "N/A");
	qDebug("date: %s", date ? date : "N/A");
	qDebug("lang: %s", 服务器托管lang ? lang : "N/A");
	
	libvlc_media_track_t **tracks;
	int track_count = libvlc_media_tracks_get(vlc_media,&tracks);
	for (unsigned i = 0; i psz_description);

		// 这里可以获取到每一个轨道的信息，比如轨道类型 track->i_type
		// 可能是 libvlc_track_video, libvlc_track_audio 或者 libvlc_track_text (字幕)

		if (track->i_type == libvlc_track_video) {
			// 处理视频轨道信息
			qDebug("width = %d",track->video->i_width);
			qDebug("height = %d", track->video->i_height);
			qDebug("rate_num = %d", track->video->i_frame_rate_num);
			qDebug("rate_den = %d", track->video->i_frame_rate_den);
		}
		else if (track->i_type == libvlc_track_audio) {
			// 处理音频轨道信息
			qDebug("channels = %d", track->audio->i_channels);
			qDebug("rate = %d", track->audio->i_rate);
		}
		else if (track->i_type == libvlc_track_text) {
			// 处理字幕轨道信息
			qDebug("psz_encoding = %s", track->subtitle->psz_encoding);
		}
	}

	//获取事件管理器
	libvlc_event_manager_t *em = libvlc_media_player_event_manager(vlc_mediaPlayer);

	// 注册事件监听器
	libvlc_event_attach(em, libvlc_MediaPlayerTimeChanged, vlcEvents, this);
	libvlc_event_attach(em, libvlc_MediaPlayerEndReached, vlcEvents, this);
	libvlc_event_attach(em, libvlc_MediaPlayerStopped, vlcEvents, this);
	libvlc_event_attach(em, libvlc_MediaPlayerPlaying, vlcEvents, this);
	libvlc_event_attach(em, libvlc_MediaPlayerPaused, vlcEvents, this);

	libvlc_media_player_set_hwnd(vlc_mediaPlayer, (void *)ui.widgetShow->winId());

	QTimer::singleShot(1000, this, &showWidget::slotPlay);

}

void showWidget::slotPlay()
{
	if (vlc_mediaPlayer)
		libvlc_media_player_play(vlc_mediaPlayer);
}

void showWidget::slotPause()
{
	if (vlc_mediaPlayer)
		libvlc_media_player_pause(vlc_mediaPlayer);
}

void showWidget::slotStop()
{
	if (vlc_mediaPlayer)
		libvlc_media_player_stop(vlc_mediaPlayer);
}

void showWidget::slotValueChanged(int value)
{
	if (vlc_mediaPlayer)
		libvlc_audio_set_volume(vlc_mediaPlayer, value);
}

void showWidget::slotCurrentIndexChanged(int index)
{
	if (vlc_mediaPlayer)
		libvlc_media_player_set_rate(vlc_mediaPlayer, m_lstRate[index]);
}


void showWidget::slotSnap()
{
	if (vlc_mediaPlayer)
	{
		QString path = "./snap.png";
		libvlc_video_take_snapshot(vlc_mediaPlayer, 0, path.toUtf8().data(), 0, 0);
	}
}

//事件回调
void showWidget::vlcEvents(const libvlc_event_t *ev, void *param)
{
	showWidget *w = (showWidget*)param;
	//处理不同的事件
	switch (ev->type) {
	case libvlc_MediaPlayerTimeChanged:
	{
		//qDebug() vlc_mediaPlayer);
		libvlc_time_t lenSec = len / 1000;

		libvlc_time_t totalLen = libvlc_media_player_get_length(w->vlc_mediaPlayer);
		libvlc_time_t totalLenSec = totalLen / 1000;

		int thh, tmm, tss;
		thh = lenSec / 3600;
		tmm = (lenSec % 3600) / 60;
		tss = (lenSec % 60);
		QTime time(thh, tmm, tss);
		w->ui.lbCurTime->setText(time.toString("hh:mm:ss"));

		thh = totalLenSec / 3600;
		tmm = (totalLenSec % 3600) / 60;
		tss = (totalLenSec % 60);
		QTime TotalTime(thh, tmm, tss);
		w->ui.lbTotalTime->setText(TotalTime.toString("hh:mm:ss"));

		double pos = (double)lenSec / totalLenSec * 100;
		w->ui.horizontalSlider->setValue(pos);
	}
		break;
	case libvlc_MediaPlayerEndReached:
		qDebug() 

更多参考：

Qt+FFmpeg+opengl从零制作视频播放器-1.项目介绍_qt opengl视频播放器-CSDN博客

libVLC 提取视频帧使用OpenGL渲染-CSDN博客

QT UDP通信（单播、广播、组播）-CSDN博客

QCharts -1.概述-CSDN博客

服务器托管，北京服务器托管，服务器租用 http://www.fwqtg.net

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