qt编写一段程序，实现导入图片，可以用滑动条对图片亮度和对比度进行调节

以下是一个简单的基于Qt的图片亮度和对比度调节程序示例：

#include <QApplication>
#include <QMainWindow>
#include <QFileDialog>
#include <QSlider>
#include <QLabel>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QGraphicsPixmapItem>
#include <QImage>

class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent = nullptr) : QMainWindow(parent) {
        this->setWindowTitle("Image Brightness and Contrast Adjustment");

        // 创建滑动条和标签
        brightnessSlider = new QSlider(Qt::Horizontal);
        brightnessSlider->setRange(-100, 100);
        brightnessSlider->setValue(0);
        brightnessLabel = new QLabel(QString("Brightness: %1").arg(brightnessSlider->value()));

        contrastSlider = new QSlider(Qt::Horizontal);
        contrastSlider->setRange(-100, 100);
        contrastSlider->setValue(0);
        contrastLabel = new QLabel(QString("Contrast: %1").arg(contrastSlider->value()));

        // 创建布局
        QVBoxLayout *vLayout = new QVBoxLayout();
        vLayout->addWidget(brightnessSlider);
        vLayout->addWidget(brightnessLabel);
        vLayout->addWidget(contrastSlider);
        vLayout->addWidget(contrastLabel);

        QHBoxLayout *hLayout = new QHBoxLayout();
        hLayout->addLayout(vLayout);

        // 创建图形视图和场景
        QGraphicsScene *scene = new QGraphicsScene();
        QGraphicsView *view = new QGraphicsView(scene);
        hLayout->addWidget(view);

        // 信号槽连接
        connect(brightnessSlider, SIGNAL(valueChanged(int)), this, SLOT(onBrightnessChanged(int)));
        connect(contrastSlider, SIGNAL(valueChanged(int)), this, SLOT(onContrastChanged(int)));

        // 创建主窗口
        QWidget *centralWidget = new QWidget();
        centralWidget->setLayout(hLayout);
        this->setCentralWidget(centralWidget);

        // 加载默认图片
        loadImage(":/images/default.png");
    }

private slots:
    void onBrightnessChanged(int value) {
        brightnessLabel->setText(QString("Brightness: %1").arg(value));
        adjustImage();
    }

    void onContrastChanged(int value) {
        contrastLabel->setText(QString("Contrast: %1").arg(value));
        adjustImage();
    }

private:
    QSlider *brightnessSlider;
    QLabel *brightnessLabel;
    QSlider *contrastSlider;
    QLabel *contrastLabel;
    QGraphicsPixmapItem *pixmapItem;

    void loadImage(const QString &fileName) {
        QImage image(fileName);
        if (image.isNull()) {
            return;
        }
        pixmapItem = new QGraphicsPixmapItem(QPixmap::fromImage(image));
        QGraphicsScene *scene = pixmapItem->scene();
        scene->clear();
        scene->addItem(pixmapItem);
    }

    void adjustImage() {
        if (!pixmapItem) {
            return;
        }

        // 获取亮度和对比度值
        int brightness = brightnessSlider->value();
        int contrast = contrastSlider->value();

        // 调整亮度和对比度
        QPixmap pixmap = pixmapItem->pixmap();
        QImage image = pixmap.toImage();
        int width = image.width();
        int height = image.height();
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                QRgb oldPixel = image.pixel(x, y);
                int red = qRed(oldPixel) + brightness;
                int green = qGreen(oldPixel) + brightness;
                int blue = qBlue(oldPixel) + brightness;

                red = qMin(qMax(red, 0), 255);
                green = qMin(qMax(green, 0), 255);
                blue = qMin(qMax(blue, 0), 255);

                red = (contrast + 100) * (red - 128) / 100 + 128;
                green = (contrast + 100) * (green - 128) / 100 + 128;
                blue = (contrast + 100) * (blue - 128) / 100 + 128;

                red = qMin(qMax(red, 0), 255);
                green = qMin(qMax(green, 0), 255);
                blue = qMin(qMax(blue, 0), 255);

                image.setPixel(x, y, qRgb(red, green, blue));
            }
        }
        pixmapItem->setPixmap(QPixmap::fromImage(image));
    }
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);
    MainWindow mainWindow;
    mainWindow.show();
    return app.exec();
}

该程序创建了一个主窗口，包括一个用于调整亮度和对比度的滑动条和标签，以及一个用于显示图片的图形视图和场景。用户可以通过打开文件对话框来选择需要处理的图片，并通过滑动条调整亮度和对比度。在调整亮度和对比度时，程序将计算出新的像素值，并将其设置为图像的新像素值。