Windows操作系统提供了多种便捷的截图方式,常见的有以下几种:
- 全屏截图:通过按下PrtSc键(Print Screen),可以截取整个屏幕的内容。截取的图像会保存在剪贴板中,可以通过Ctrl+V粘贴到图片编辑工具或其他软件的输入框中。
- 当前窗口截图:同时按下Alt + PrtSc键,可以截取当前活动的窗口。同样,截图内容会被保存在剪贴板中。
- 矩形截图:使用快捷键Windows + Shift + S,可以选择矩形截图模式,然后拖动鼠标选取屏幕上的任意矩形区域进行截图。
- 自由形状截图:同样使用Windows + Shift + S快捷键,可以选择任意形状截图模式,允许你自由绘制截图区域的形状。
libVLC 中通过libvlc_video_take_snapshot核心接口来截图。
以下是如何使用 libVLC 设置视频裁剪区域的基本步骤:
1. 初始化 libVLC 和媒体播放器
首先,你需要初始化 libVLC 实例和媒体播放器对象。
#include <vlc/vlc.h>
int main(int argc, char* argv[])
{
libvlc_instance_t* inst;
libvlc_media_player_t* mp;
libvlc_media_t* m;
// 加载 libVLC 引擎
inst = libvlc_new(0, NULL);
// 创建一个新的 item
m = libvlc_media_new_location(inst, "your_video_path_here");
mp = libvlc_media_player_new_from_media(m);
// 不再需要媒体对象
libvlc_media_release(m);
}
2. 播放视频
// 播放媒体播放器
libvlc_media_player_play(mp);
// 保持程序运行,直到视频播放完成
while (libvlc_media_player_is_playing(mp)) {
// 可以在这里加入延时
}
// 清理 libVLC
libvlc_media_player_stop(mp);
libvlc_media_player_release(mp);
libvlc_release(inst);
return 0;
3.截图
这里为了方便,路径写死了。
if (vlc_mediaPlayer)
{
QString path = "./snap.png";
libvlc_video_take_snapshot(vlc_mediaPlayer, 0, path.toUtf8().data(), 0, 0);
}
以下是VLC播放器中使用的截图界面,我们仿照这个做一个界面。
以下是效果图。
菜单添加action,并响应槽函数。
m_snapAction = m_videoMenu->addAction("截图");
connect(m_snapAction, &QAction::triggered, this, &showWidget::slotSnap);
槽函数如下图所示,为了方便,路径写死了。
void showWidget::slotSnap()
{
if (vlc_mediaPlayer)
{
QString path = "./snap.png";
libvlc_video_take_snapshot(vlc_mediaPlayer, 0, path.toUtf8().data(), 0, 0);
}
}
生成目录下snap.png。
完整源码:
#pragma once
#define LIBVLC_USE_PTHREAD_CANCEL 1
#include <QtWidgets/QWidget>
#include "ui_showWidget.h"
#include <QMenu>
#include <QActionGroup>
#include <vlc/vlc.h>
#include <QDebug>
#include <QFileDialog>
#include <QThread>
#include <QMouseEvent>
#include <QKeyEvent>
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 mousePressEvent(QMouseEvent *event);
virtual void mouseDoubleClickEvent(QMouseEvent *event);
virtual void keyPressEvent(QKeyEvent *event);
private slots:
void slotOpenFile();
void slotPlay();
void slotPause();
void slotStop();
void slotValueChanged(int value);
void slotCurrentIndexChanged(int index);
void slotActionTriggered(QAction *action);
void slotCropActionTriggered(QAction *action);
void slotScaleActionTriggered(QAction *action);
void slotSnap();
private:
//事件处理回调
static void vlcEvents(const libvlc_event_t *ev, void *param);
//初始化menu
void initMenu();
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<float> m_lstRate;
QMenu *m_menu = nullptr;
QAction *m_video = nullptr;
QAction *m_scaleAction = nullptr; //缩放
QAction *m_aspectRatioAction = nullptr; //宽高比
QAction *m_cropAction = nullptr; //裁剪
QAction *m_snapAction = nullptr;//截图
QMenu *m_videoMenu = nullptr;
//宽高比
QMenu *m_aspectRatioMenu = nullptr;
QAction *m_default = nullptr;
QAction *m_16_9 = nullptr;
QAction *m_4_3 = nullptr;
QAction *m_1_1 = nullptr;
QAction *m_16_10 = nullptr;
QAction *m_2_21_1 = nullptr;
QAction *m_2_35_1= nullptr;
QAction *m_2_38_1 = nullptr;
QAction *m_5_4 = nullptr;
QActionGroup *m_group = nullptr;
QAction *m_preAspectRatio = nullptr;
//宽高比
//裁剪
QMenu *m_cropMenu = nullptr;
QAction *m__cropDefault = nullptr;
QAction *m__crop16_10 = nullptr;
QAction *m__crop16_9 = nullptr;
QAction *m__crop4_3 = nullptr;
QAction *m__crop1_85_1 = nullptr;
QAction *m__crop2_21_1 = nullptr;
QAction *m__crop2_35_1 = nullptr;
QAction *m__crop2_39_1 = nullptr;
QAction *m__crop5_3 = nullptr;
QAction *m__crop5_4 = nullptr;
QAction *m__crop1_1 = nullptr;
QActionGroup *m_cropGroup = nullptr;
QAction *m_preCrop= nullptr;
//裁剪
//缩放
QMenu *m_scaleMenu = nullptr;
QAction *m_scale1_4 = nullptr;
QAction *m_scale1_2 = nullptr;
QAction *m_scale1_1 = nullptr;
QAction *m_scale2_1 = nullptr;
QActionGroup *m_scaleGroup = nullptr;
QAction *m_preScale = nullptr;
//缩放
char *m_defalutRate = nullptr;
char *m_defalutCrop = nullptr;
float m_defalutScale = 0;
};
cpp
#include "showWidget.h"
#include <QTimer>
#include <QTime>
#pragma execution_character_set("utf-8")
showWidget::showWidget(QWidget *parent)
: QWidget(parent)
{
ui.setupUi(this);
this->setWindowTitle("视频播放器");
ui.cbxRate->setCurrentIndex(Rate1_0X);
m_lstRate << 2.0 << 1.5 << 1.25 << 1.0 << 0.75 << 0.5;
initMenu();
ui.btnOpen->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);
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::mousePressEvent(QMouseEvent *event)
{
switch (event->button())
{
case Qt::RightButton:
//this->setWindowState(Qt::WindowMinimized);
m_menu->exec(event->globalPos());
break;
default:
QWidget::mousePressEvent(event);
}
}
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() << "up";
slotValueChanged(value+10);
}
else if (event->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);
}
}
}
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_base = libvlc_new(0, NULL);
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);
m_defalutRate = libvlc_video_get_aspect_ratio(vlc_mediaPlayer);
m_defalutCrop = libvlc_video_get_crop_geometry(vlc_mediaPlayer);
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", lang ? lang : "N/A");
libvlc_media_track_t **tracks;
int track_count = libvlc_media_tracks_get(vlc_media,&tracks);
for (unsigned i = 0; i < track_count; i++)
{
libvlc_media_track_t* track = tracks[i];
// 显示轨道信息
printf("Track #%u: %s\n", i, track->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
}
}
//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);
m_defalutScale = libvlc_video_get_scale(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::slotActionTriggered(QAction *action)
{
if (!vlc_mediaPlayer)
return;
if (action == m_default)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer,m_defalutRate);
else if(action == m_16_9)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "16:9");
else if (action == m_4_3)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "4:3");
else if (action == m_1_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "1:1");
else if (action == m_16_10)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "16:10");
else if (action == m_2_21_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "221:100");
else if (action == m_2_35_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "235:100");
else if (action == m_2_38_1)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "238:100");
else if (action == m_5_4)
libvlc_video_set_aspect_ratio(vlc_mediaPlayer, "5:4");
action->setIcon(QIcon(":/image/images/point.png"));
m_preAspectRatio->setIcon(QIcon());
m_preAspectRatio = action;
}
void showWidget::slotCropActionTriggered(QAction *action)
{
if (!vlc_mediaPlayer)
return;
if (action == m__cropDefault)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, m_defalutCrop);
else if (action == m__crop16_10)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "16:10");
else if (action == m__crop16_9)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "16:9");
else if (action == m__crop4_3)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "4:3");
else if (action == m__crop1_85_1)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "185:100");
else if (action == m__crop2_21_1)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "221:100");
else if (action == m__crop2_35_1)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "235:100");
else if (action == m__crop2_39_1)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "239:100");
else if (action == m__crop5_3)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "5:3");
else if (action == m__crop5_4)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "5:4");
else if (action == m__crop1_1)
libvlc_video_set_crop_geometry(vlc_mediaPlayer, "1:1");
action->setIcon(QIcon(":/image/images/point.png"));
m_preCrop->setIcon(QIcon());
m_preCrop = action;
}
void showWidget::slotScaleActionTriggered(QAction *action)
{
if (!vlc_mediaPlayer)
return;
if (action == m_scale1_4)
libvlc_video_set_scale(vlc_mediaPlayer, 0.25);
else if (action == m_scale1_2)
libvlc_video_set_scale(vlc_mediaPlayer, 0.5);
else if (action == m_scale1_1)
libvlc_video_set_scale(vlc_mediaPlayer, 1);
else if (action == m_scale2_1)
libvlc_video_set_scale(vlc_mediaPlayer, 2);
action->setIcon(QIcon(":/image/images/point.png"));
m_preScale->setIcon(QIcon());
m_preScale = action;
}
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媒体播放器时间已更改";
qint64 len = libvlc_media_player_get_time(w->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() << "VLC播放完毕.";
break;
case libvlc_MediaPlayerStopped:
qDebug() << "VLC停止播放";
break;
case libvlc_MediaPlayerPlaying:
qDebug() << "VLC开始播放";
break;
case libvlc_MediaPlayerPaused:
qDebug() << "VLC暂停播放";
break;
}
}
void showWidget::initMenu()
{
//总菜单
m_menu = new QMenu(this);
m_video = m_menu->addAction("视频");
//视频菜单
m_videoMenu = new QMenu(this);
m_scaleAction = m_videoMenu->addAction("缩放");
m_aspectRatioAction = m_videoMenu->addAction("宽高比");
m_cropAction = m_videoMenu->addAction("裁剪");
m_snapAction = m_videoMenu->addAction("截图");
connect(m_snapAction, &QAction::triggered, this, &showWidget::slotSnap);
m_video->setMenu(m_videoMenu);
//宽高比菜单
m_aspectRatioMenu = new QMenu(this);
m_aspectRatioAction->setMenu(m_aspectRatioMenu);
//设置宽高比菜单
m_default = m_aspectRatioMenu->addAction(QIcon(":/image/images/point.png"), "默认");
m_16_9 = m_aspectRatioMenu->addAction("16:9");
m_4_3 = m_aspectRatioMenu->addAction("4:3");
m_1_1 = m_aspectRatioMenu->addAction("1:1");
m_16_10 = m_aspectRatioMenu->addAction("16:10");
m_2_21_1 = m_aspectRatioMenu->addAction("2.21:1");
m_2_35_1 = m_aspectRatioMenu->addAction("2.35:1");
m_2_38_1 = m_aspectRatioMenu->addAction("2.38:1");
m_5_4 = m_aspectRatioMenu->addAction("5:4");
m_preAspectRatio = m_default;
m_group = new QActionGroup(this);
m_group->addAction(m_default);
m_group->addAction(m_16_9);
m_group->addAction(m_4_3);
m_group->addAction(m_1_1);
m_group->addAction(m_16_10);
m_group->addAction(m_2_21_1);
m_group->addAction(m_2_35_1);
m_group->addAction(m_2_38_1);
m_group->addAction(m_5_4);
connect(m_group, &QActionGroup::triggered, this, &showWidget::slotActionTriggered);
//设置裁剪菜单
m_cropMenu = new QMenu(this);
m_cropAction->setMenu(m_cropMenu);
m__cropDefault = m_cropMenu->addAction(QIcon(":/image/images/point.png"), "默认");
m__crop16_10 = m_cropMenu->addAction("16:10");
m__crop16_9 = m_cropMenu->addAction("16:9");
m__crop4_3 = m_cropMenu->addAction("4:3");
m__crop1_85_1 = m_cropMenu->addAction("1.85:1");
m__crop2_21_1 = m_cropMenu->addAction("2.21:1");
m__crop2_35_1 = m_cropMenu->addAction("2.35:1");
m__crop2_39_1 = m_cropMenu->addAction("2.39:1");
m__crop5_3 = m_cropMenu->addAction("5:3");
m__crop5_4 = m_cropMenu->addAction("5:4");
m__crop1_1 = m_cropMenu->addAction("1:1");
m_preCrop = m__cropDefault;
m_cropGroup = new QActionGroup(this);
m_cropGroup->addAction(m__cropDefault);
m_cropGroup->addAction(m__crop16_10);
m_cropGroup->addAction(m__crop16_9);
m_cropGroup->addAction(m__crop4_3);
m_cropGroup->addAction(m__crop1_85_1);
m_cropGroup->addAction(m__crop2_21_1);
m_cropGroup->addAction(m__crop2_35_1);
m_cropGroup->addAction(m__crop2_39_1);
m_cropGroup->addAction(m__crop5_3);
m_cropGroup->addAction(m__crop5_4);
m_cropGroup->addAction(m__crop1_1);
connect(m_cropGroup, &QActionGroup::triggered, this, &showWidget::slotCropActionTriggered);
//设置缩放菜单
m_scaleMenu = new QMenu(this);
m_scaleAction->setMenu(m_scaleMenu);
m_scale1_4 = m_scaleMenu->addAction("1:4 四分之一");
m_scale1_2 = m_scaleMenu->addAction("1:2 二分之一");
m_scale1_1 = m_scaleMenu->addAction(QIcon(":/image/images/point.png"),"1:1 原始");
m_scale2_1 = m_scaleMenu->addAction("2:1 双倍");
m_scaleGroup = new QActionGroup(this);
m_scaleGroup->addAction(m_scale1_4);
m_scaleGroup->addAction(m_scale1_2);
m_scaleGroup->addAction(m_scale1_1);
m_scaleGroup->addAction(m_scale2_1);
m_preScale = m_scale1_1;
connect(m_scaleGroup, &QActionGroup::triggered, this, &showWidget::slotScaleActionTriggered);
}
更多参考:
https://sunnnnnn666.blog.csdn.net/article/details/137023036
标签:视频,addAction,抓图,mediaPlayer,media,vlc,nullptr,libvlc,libVLC From: https://blog.csdn.net/wzz953200463/article/details/137087320