Qt官方示例-屏幕截图

void Screenshot::shootScreen()
{
    /* 获取主屏幕 */
    QScreen *screen = QGuiApplication::primaryScreen();
    if (const QWindow *window = windowHandle())
        screen = window->screen();
    ...

    if (delaySpinBox->value() != 0)
        QApplication::beep(); /* 让电脑哔一声 */

    /* 获取屏幕内容(QPixmap) */
    originalPixmap = screen->grabWindow(0);
    ...
}

if (!originalPixmap.save(fileName)) {
    QMessageBox::warning(this, tr("Save Error"), tr("The image could not be saved to \"%1\".")
                         .arg(QDir::toNativeSeparators(fileName)));
}

C:\Qt\{你的Qt版本}\Examples\{你的Qt版本}\widgets\desktop\screenshot