Qt + freerdp，要求 freerdp 版本为 2.9，请给出示例代码

以下是一个基本的Qt程序，它使用FreeRDP 2.9库连接到远程Windows机器。这个程序创建一个窗口，在窗口中显示远程机器的桌面。

#include <QtCore>
#include <QtGui>
#include <QApplication>
#include <QMainWindow>
#include <QHBoxLayout>

#include <freerdp/client.h>
#include <freerdp/version.h>

class RdpClient : public QMainWindow
{
    Q_OBJECT

public:
    RdpClient(QWidget *parent = 0);
    ~RdpClient();

    void start();
    void stop();

protected:
    void paintEvent(QPaintEvent *event);
    void resizeEvent(QResizeEvent *event);

private:
    freerdp *rdp;
    QPixmap pixmap;
};

RdpClient::RdpClient(QWidget *parent)
    : QMainWindow(parent)
{
    QPalette palette = this->palette();
    palette.setColor(QPalette::Window, Qt::black);
    this->setPalette(palette);

    this->setWindowTitle("RdpClient");

    QHBoxLayout *layout = new QHBoxLayout(this);
    QWidget *centralWidget = new QWidget(this);
    centralWidget->setLayout(layout);
    this->setCentralWidget(centralWidget);
}

RdpClient::~RdpClient()
{
    stop();
}

void RdpClient::start()
{
    rdp = freerdp_new();
    rdp->settings->hostname = "192.168.1.100";
    rdp->settings->port = 3389;
    rdp->settings->username = "user";
    rdp->settings->password = "password";
    rdp->settings->width = this->width();
    rdp->settings->height = this->height();
    rdp->settings->color_depth = 24;
    rdp->settings->performance_flags |= PERF_ENABLE_FONT_SMOOTHING;
    rdp->settings->performance_flags |= PERF_ENABLE_DESKTOP_COMPOSITION;
    rdp->settings->performance_flags |= PERF_ENABLE_MENU_ANIMATIONS;
    rdp->settings->performance_flags |= PERF_ENABLE_THEMING;

    freerdp_context *context;
    context = freerdp_context_new(freerdp);
    freerdp_context_set_pixel_format(context, PIXEL_FORMAT_XRGB32);

    freerdp_set_context_callback(rdp, (pContextNew)freerdp_context_new);
    freerdp_set_context_callback(rdp, (pContextFree)freerdp_context_free);
    freerdp_set_context(rdp, context);

    freerdp_connect(rdp);

    while (rdp->connected)
    {
        freerdp_get_event(rdp->instance);
    }
}

void RdpClient::stop()
{
    freerdp_disconnect(rdp);
    freerdp_free(rdp);
    rdp = NULL;
}

void RdpClient::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
    painter.drawPixmap(0, 0, pixmap);
}

void RdpClient::resizeEvent(QResizeEvent *event)
{
    rdp->settings->width = this->width();
    rdp->settings->height = this->height();
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    RdpClient rdpClient;
    rdpClient.setMinimumSize(800, 600);
    rdpClient.show();

    rdpClient.start();

    return app.exec();
}

请注意，您需要在Qt项目的.pro文件中添加以下内容，以将FreeRDP库链接到您的应用程序中：

LIBS += -lfreerdp-client2 \
        -lfreerdp-core2 \
        -lfreerdp-gdi2 \
        -lfreerdp-rail2 \
        -lfreerdp-utils2

希望这可以帮助您开始使用Qt和FreeRDP 2.9。