UBuntu18.04 Qt之双HDMI接2个4K屏并分别设置分辨率、主屏、副屏

一、设置HDMI-2为主屏

在main函数里面添加：

#include "mainwindow.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);{long nTotal = 0;char cData[2048] = {0};FILE *fstream = popen("xrandr | grep 'HDMI-2 connected'", "r");if(fstream){while(fgets(cData, sizeof(cData), fstream)){nTotal++;}pclose(fstream);}if(nTotal > 0){system("xrandr --output HDMI-2 --primary --left-of HDMI-1 --auto");}}MainWindow w;w.show();return a.exec();
}

二、代码切换程序在主屏或副屏显示

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>namespace Ui {
class MainWindow;
}class MainWindow : public QWidget
{Q_OBJECTpublic:explicit MainWindow(QWidget *parent = 0);~MainWindow();private slots:void StartTimer();void OnClickBtn1();void OnClickBtn2();void OnClickBtn3();void OnClickBtn4();void OnClickBtn5();private:void SetPos(int nScreen);private:void timerEvent(QTimerEvent*);private:int m_nTimerID;private:int m_nScreebResolutions;int m_nScreenID;
};#endif // MAINWINDOW_H

MainWIndow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QLabel>
#include <QScreen>
#include <QPushButton>
#include <QHBoxLayout>
#include <QDesktopWidget>void OutPut(const char* cData)
{FILE* pFile = fopen("/opt/NVMS/111.log", "ab+");if(pFile){fwrite(cData, 1, strlen(cData), pFile);fclose(pFile);}
}MainWindow::MainWindow(QWidget *parent) :QWidget(parent)
{QLabel* p = new QLabel("123", this);QPushButton* qBtn1 = new QPushButton("0_1920", this);qBtn1->setFixedSize(100, 50);connect(qBtn1, &QPushButton::clicked, this, &MainWindow::OnClickBtn1);QPushButton* pBtn2 = new QPushButton("0_3840", this);pBtn2->setFixedSize(100, 50);connect(pBtn2, &QPushButton::clicked, this, &MainWindow::OnClickBtn2);QPushButton* qBtn3 = new QPushButton("1_1920", this);qBtn3->setFixedSize(100, 50);connect(qBtn3, &QPushButton::clicked, this, &MainWindow::OnClickBtn3);QPushButton* pBtn4 = new QPushButton("1_3840", this);pBtn4->setFixedSize(100, 50);connect(pBtn4, &QPushButton::clicked, this, &MainWindow::OnClickBtn4);QPushButton* pBtn5 = new QPushButton("Query", this);pBtn5->setFixedSize(100, 50);connect(pBtn5, &QPushButton::clicked, this, &MainWindow::OnClickBtn5);QHBoxLayout* pLayout = new QHBoxLayout(this);pLayout->addWidget(p, 0, Qt::AlignLeft | Qt::AlignTop);pLayout->addWidget(qBtn1, 0, Qt::AlignLeft | Qt::AlignTop);pLayout->addWidget(pBtn2, 0, Qt::AlignLeft | Qt::AlignTop);pLayout->addWidget(qBtn3, 0, Qt::AlignLeft | Qt::AlignTop);pLayout->addWidget(pBtn4, 0, Qt::AlignLeft | Qt::AlignTop);pLayout->addWidget(pBtn5, 0, Qt::AlignLeft | Qt::AlignTop);//m_nScreenID = 0;m_nScreebResolutions = 0;SetPos(m_nScreenID);
}MainWindow::~MainWindow()
{}void MainWindow::StartTimer()
{}void MainWindow::timerEvent(QTimerEvent*)
{SetPos(m_nScreenID);if(m_nScreenID == 1){OnClickBtn5();}
}void MainWindow::SetPos(int nScreen)
{char cData[2048] = {0};QDesktopWidget* desktopWidget = QApplication::desktop();QRect rect = desktopWidget->availableGeometry(nScreen);QRect rect1 = desktopWidget->screenGeometry(nScreen);/*if(m_nScreenID == 0){*/setGeometry(rect);sprintf(cData, "AAA:%d   %d   %d   %d   %d\n", nScreen, rect.left(), rect.top(), rect.width(), rect.height());/*}else{setGeometry(QRect(rect1.left(), rect1.top(), rect1.width(), rect1.height()));sprintf(cData, "AAA:%d   %d   %d   %d   %d\n", nScreen, rect1.left(), rect1.top(), rect1.width(), rect1.height());}*/OutPut(cData);/*{int nScreenNum = qApp->desktop()->screenCount();for(int i = 0; i < nScreenNum; i++){QScreen* qScreen = qApp->screens().at(i);memset(cData, 0, 2048);sprintf(cData, "BBB:%d   %d   %d   %d   %d   %d\n", nScreenNum, nScreen, qScreen->geometry().left(), qScreen->geometry().top(), qScreen->geometry().width(), qScreen->geometry().height());OutPut(cData);}memset(cData, 0, 2048);sprintf(cData, "CCC:%d   %d   %d   %d   %d   %d\n", nScreenNum, nScreen, rect1.left(), rect1.top(), rect1.width(), rect1.height());OutPut(cData);}*/
}void MainWindow::OnClickBtn1()
{char cData[2048] = {0};FILE *fstream = popen("xrandr --output HDMI-2 --mode 1920x1080 --left-of HDMI-1", "r");//xrandr -s 1920x1080 --screen 0if(fstream){while(fgets(cData, sizeof(cData), fstream)){OutPut(cData);}pclose(fstream);}m_nScreenID = 0;m_nScreebResolutions = 0;m_nTimerID = startTimer(1000);
}void MainWindow::OnClickBtn2()
{char cData[2048] = {0};FILE *fstream = popen("xrandr --output HDMI-2 --mode 3840x2160 --left-of HDMI-1", "r");//xrandr -s 3840x2160 --screen 0if(fstream){while(fgets(cData, sizeof(cData), fstream)){OutPut(cData);}pclose(fstream);}m_nScreenID = 0;m_nScreebResolutions = 1;m_nTimerID = startTimer(1000);
}
void MainWindow::OnClickBtn3()
{char cData[2048] = {0};FILE *fstream = popen("xrandr --output HDMI-1 --mode 1920x1080 --right-of HDMI-2 ", "r");if(fstream){while(fgets(cData, sizeof(cData), fstream)){OutPut(cData);}pclose(fstream);}m_nScreenID = 1;m_nScreebResolutions = 0;m_nTimerID = startTimer(1000);
}void MainWindow::OnClickBtn4()
{char cData[2048] = {0};FILE *fstream = popen("xrandr --output HDMI-1 --mode 3840x2160 --right-of HDMI-2 ", "r");if(fstream){while(fgets(cData, sizeof(cData), fstream)){OutPut(cData);}pclose(fstream);}m_nScreenID = 1;m_nScreebResolutions = 1;m_nTimerID = startTimer(1000);
}void MainWindow::OnClickBtn5()
{char cData[2048] = {0};FILE *fstream = popen("xrandr ", "r");if(fstream){while(fgets(cData, sizeof(cData), fstream)){OutPut(cData);}pclose(fstream);}
}

左边的4k显示器和右边的4k显示器分别显示程序的主界面