Qt编写自定义控件36-图片浏览器 - QTCN开发网

#ifndef IMAGEVIEW_H
#define IMAGEVIEW_H

/**
* 图片浏览器控件作者:feiyangqingyun(QQ:517216493) 2016-10-16
* 本控件来源于网络(原作者:kimtaikee(http://www.qtcn.org/bbs/read-htm-tid-45436-ds-1.html#tpc))
* 1:增加鼠标右键清空
* 2:增加设置背景色
* 3:增加设置间距和翻页图标大小
* 4:增加设置是否拉伸填充显示
* 5:增加设置是否渐变显示图像
* 6:增加设置键盘翻页
* 7:增加移动到第一张/末一张/上一张/下一张
* 8:修正内存泄露BUG及其他BUG
*/

#include <QWidget>

class QToolButton;

class ImageNum : public QWidget
{
    Q_OBJECT
public:
    ImageNum(QWidget *parent = 0);

protected:
    void paintEvent(QPaintEvent *);
    void drawBg(QPainter *painter);
    void drawText(QPainter *painter);

private:
    int totalNum;       //总数
    int currentIndex;   //当前索引

public slots:
    //设置总数
    void setTotalNum(int totalNum);
    //设置当前索引
    void setCurrentIndex(int currentIndex);
};

#ifdef quc
#if (QT_VERSION < QT_VERSION_CHECK(5,7,0))
#include <QtDesigner/QDesignerExportWidget>
#else
#include <QtUiPlugin/QDesignerExportWidget>
#endif

class QDESIGNER_WIDGET_EXPORT ImageView : public QWidget
#else
class ImageView : public QWidget
#endif

{
    Q_OBJECT
    Q_PROPERTY(QColor bgColorStart READ getBgColorStart WRITE setBgColorStart)
    Q_PROPERTY(QColor bgColorEnd READ getBgColorEnd WRITE setBgColorEnd)

    Q_PROPERTY(int bottomSpace READ getBottomSpace WRITE setBottomSpace)
    Q_PROPERTY(int buttonSpace READ getButtonSpace WRITE setButtonSpace)
    Q_PROPERTY(QSize icoSize READ getIcoSize WRITE setIcoSize)

    Q_PROPERTY(bool fill READ getFill WRITE setFill)
    Q_PROPERTY(bool fade READ getFade WRITE setFade)
    Q_PROPERTY(bool keyMove READ getKeyMove WRITE setKeyMove)

public:
    explicit ImageView(QWidget *parent = 0);
    ~ImageView();

protected:
    void paintEvent(QPaintEvent *);
    void drawBg(QPainter *painter);
    void drawImage(QPainter *painter);
    void keyPressEvent(QKeyEvent *);
    void resizeEvent(QResizeEvent *);
    void showEvent(QShowEvent *);

private:
    QColor bgColorStart;            //背景渐变开始颜色
    QColor bgColorEnd;              //背景渐变结束颜色

    int bottomSpace;                //底部间距
    int buttonSpace;                //按钮间距
    QSize icoSize;                  //翻页按钮图标大小

    bool fill;                      //是否填充
    bool fade;                      //是否渐变显示
    bool keyMove;                   //是否支持按键移动

    QToolButton *preButton;         //向前移按钮
    QToolButton *nextButton;        //向后移按钮

    QStringList imageNames;         //图片名称集合
    int currentIndex;               //当前图片索引
    QImage currentImage;            //当前图片数据

    ImageNum *num;                  //显示当前索引和总数的对象

    int totalNum;                   //总数
    double opacity;                 //当前透明值
    QTimer *timer;                  //定时器改变透明值

private slots:
    void calcGeo();
    void doFading();

public:
    QColor getBgColorStart()        const;
    QColor getBgColorEnd()          const;

    int getBottomSpace()            const;
    int getButtonSpace()            const;
    QSize getIcoSize()              const;

    bool getFill()                  const;
    bool getFade()                  const;
    bool getKeyMove()               const;

    QSize sizeHint()                const;
    QSize minimumSizeHint()         const;

public slots:
    //载入图像文件夹
    void load();
    void load(const QString &strFolder);

    //清除图像
    void clear();

    //设置背景颜色
    void setBgColorStart(const QColor &bgColorStart);
    void setBgColorEnd(const QColor &bgColorEnd);

    //设置间距
    void setBottomSpace(int bottomSpace);
    void setButtonSpace(int buttonSpace);

    //设置翻页图标大小
    void setIcoSize(const QSize &icoSize);

    //设置图像是否拉伸填充
    void setFill(bool fill);
    //设置是否渐变显示
    void setFade(bool fade);
    //设置键盘按键是否能够移动
    void setKeyMove(bool keyMove);

    //移动到第一张
    void moveFirst();
    //移动到末一张
    void moveLast();
    //上一张
    void movePrevious();
    //下一张
    void moveNext();
    //移动到指定索引图片
    void moveTo(int index);

signals:
    //总数发生改变时触发
    void totalNumChanged(int totalNum);
    //当前图片索引发生改变时触发
    void currentIndexChanged(int currentIndex);
};

#endif // IMAGEVIEW_H

ImageView::ImageView(QWidget *parent) :    QWidget(parent)
{
    setStyleSheet(".QToolButton{background-color:rgba(0,0,0,0);border-style:none;}");

    bgColorStart = QColor(100, 100, 100);
    bgColorEnd = QColor(60, 60, 60);

    bottomSpace = 10;
    buttonSpace = 10;
    icoSize = QSize(65, 65);

    fade = false;
    fill = false;
    keyMove = false;

    totalNum = 0;
    currentIndex = -1;

    num = new ImageNum(this);
    connect(this, SIGNAL(totalNumChanged(int)), num, SLOT(setTotalNum(int)));
    connect(this, SIGNAL(currentIndexChanged(int)), num, SLOT(setCurrentIndex(int)));

    preButton = new QToolButton(this);
    nextButton = new QToolButton(this);

    preButton->setIconSize(icoSize);
    nextButton->setIconSize(icoSize);

    preButton->setIcon(QIcon(":/image/btn_pre_normal.png"));
    nextButton->setIcon(QIcon(":/image/btn_next_normal.png"));

    connect(preButton, SIGNAL(clicked()), this, SLOT(movePrevious()));
    connect(nextButton, SIGNAL(clicked()), this, SLOT(moveNext()));

    opacity = 1.0;
    timer = new QTimer(this);
    timer->setInterval(50);
    connect(timer, SIGNAL(timeout()), this, SLOT(doFading()));

    QAction *action_load = new QAction("载入", this);
    connect(action_load, SIGNAL(triggered(bool)), this, SLOT(load()));
    this->addAction(action_load);

    QAction *action_clear = new QAction("清空", this);
    connect(action_clear, SIGNAL(triggered(bool)), this, SLOT(clear()));
    this->addAction(action_clear);

    this->setContextMenuPolicy(Qt::ActionsContextMenu);
    calcGeo();
}

ImageView::~ImageView()
{
    if (timer->isActive()) {
        timer->stop();
    }
}

void ImageView::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
    drawBg(&painter);

    if (totalNum > 0) {
        drawImage(&painter);
    }
}

void ImageView::drawBg(QPainter *painter)
{
    painter->save();
    painter->setPen(Qt::NoPen);
    QLinearGradient bgGradient(QPoint(0, 0), QPoint(0, height()));
    bgGradient.setColorAt(0.0, bgColorStart);
    bgGradient.setColorAt(1.0, bgColorEnd);
    painter->setBrush(bgGradient);
    painter->drawRect(rect());
    painter->restore();
}

void ImageView::drawImage(QPainter *painter)
{
    painter->save();
    painter->setOpacity(opacity);

    if (fill) {
        painter->drawImage(rect(), currentImage);
        painter->restore();
    } else {
        //按照比例自动居中绘制
        int imageWidth = currentImage.width();
        int imageHeight = currentImage.height();
        int imageX = rect().center().x() - imageWidth / 2;
        int imageY = rect().center().y() - imageHeight / 2;
        QPoint point(imageX, imageY);

        painter->drawImage(point, currentImage);
        painter->restore();
    }
}

void ImageView::keyPressEvent(QKeyEvent *keyEvent)
{
    if (keyEvent->key() == Qt::Key_Left || keyEvent->key() == Qt::Key_Up) {
        movePrevious();
    } else if (keyEvent->key() == Qt::Key_Right || keyEvent->key() == Qt::Key_Down) {
        moveNext();
    }
}

void ImageView::resizeEvent(QResizeEvent *)
{
    calcGeo();
}

void ImageView::showEvent(QShowEvent *)
{
    calcGeo();
}

void ImageView::calcGeo()
{
    QPoint prePoint(buttonSpace, (height() - preButton->height()) / 2);
    preButton->move(prePoint);

    QPoint nextPoint(width() - buttonSpace - preButton->width(), (height() - preButton->height()) / 2);
    nextButton->move(nextPoint);

    QPoint numPoint(width() / 2 - num->width() / 2, height() - bottomSpace - preButton->height() / 2 - num->height() / 2);
    num->move(numPoint);
}

void ImageView::doFading()
{
    opacity += 0.05;

    if (opacity > 1.0) {
        opacity = 1.0;
        timer->stop();
    }

    update();
}