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Ubuntu上Qt之简单图片浏览器

2018-06-27 10:06:38来源：未知阅读 ()

>>主要功能：

　　　　（1）图片切换浏览，上一张/下一张。

　　　　（2）图片放大、缩小。包括两种机制：鼠标滚轮和按钮放大/缩小。

　　　　（3）图片自动循环播放，间隔2s。点击播放后，其他操作均无效，直至点击暂停。

　　　　（4）图片顺时钟旋转，每次90度。可在放大/缩小状态下旋转，或者相反。

　　　　（5）在图片被放大/缩小/旋转后，点击还原或者切换图片时，自动恢复为默认大小。

>>最终效果：

（1）点击播放按钮：

（2）暂停后，点击下一张：

（3）点击放大（或鼠标滚轮往前滚动）：

（4）点击还原：

（5）点击缩小（或鼠标滚轮往后滑动）：

（6）点击上一张：

（7）点击旋转：

（8）点击缩小（或鼠标滚轮往后）：

（9）点击还原：

>>添加程序：

　　新建Gui工程，名为MyPictureView，类名MyPictureView，基类选择QWidget。

mypictureview.h

#ifndef MYPICTUREVIEW_H
#define MYPICTUREVIEW_H

#include <QWidget>
#include <QVector>
#include <QPixmap>
#include <QTimer>
#include <QFileDialog>
#include <QString>
#include <QLabel>
#include <QWheelEvent>


namespace Ui {
class MyPictureView;
}

class MyPictureView : public QWidget
{
    Q_OBJECT

public:
    MyPictureView(QVector<QPixmap *> &pictures);

    ~MyPictureView();

private slots:
    void on_btn_prev_clicked();

    void on_btn_spin_clicked();

    void on_btn_play_stop_clicked();

    void on_btn_orig_clicked();

    void on_btn_next_clicked();

    void on_btn_big_clicked();

    void on_btn_smal_clicked();

    void wheelEvent(QWheelEvent * event);

    void pic_showloop();

private:
    Ui::MyPictureView *ui;
    QVector<QPixmap *>  &pictures_;
    QTimer *timer;
    QPixmap pix;
    QLabel *label;

    void pic_show1();
    void pic_show2();

    bool isPlaying;
    float scale;
    int size;
    int currentIndex;
    int imageAngle;
};

#endif // MYPICTUREVIEW_H

mypictureview.h

mypictureview.cpp

#include "mypictureview.h"
#include "ui_mypictureview.h"

MyPictureView::MyPictureView(QVector<QPixmap *> &pictures)
    : pictures_(pictures),
    ui(new Ui::MyPictureView)
{
    ui->setupUi(this);

    scale = 1;
    currentIndex = 0;     // Current picture index
    size = pictures_.size();
    isPlaying = false;
    imageAngle = 0;

    label = new QLabel;
    ui->scrollArea->setWidget(label);
    ui->scrollArea->setAlignment(Qt::AlignCenter);   //显示位置，对齐方式

    timer = new QTimer;
    timer->setInterval(2 * 1000);   //2s
    connect(timer,SIGNAL(timeout()),this,SLOT(pic_showloop()));

    label->setAlignment(Qt::AlignCenter);

    if(size > 0)
        pic_show1();
}

MyPictureView::~MyPictureView()
{
    delete ui;
}


void MyPictureView::on_btn_prev_clicked()       //上一张
{
    timer->stop();

    scale = 1;
    imageAngle = 0;
    currentIndex--;
    if(currentIndex<0)
        currentIndex=size-1;

    pic_show1();
}

void MyPictureView::on_btn_spin_clicked()       //旋转
{
    imageAngle += 1;
    imageAngle = imageAngle % 4;

    pic_show2();
}

void MyPictureView::on_btn_play_stop_clicked()      //播放、暂停，间隔2s
{
    isPlaying = !isPlaying;

    if(isPlaying)
    {
        ui->btn_play_stop->setText(tr("暂停"));
        timer->start();
        ui->btn_big->setEnabled(false);
        ui->btn_next->setEnabled(false);
        ui->btn_orig->setEnabled(false);
        ui->btn_prev->setEnabled(false);
        ui->btn_smal->setEnabled(false);
        ui->btn_spin->setEnabled(false);
    }
    else
    {
        ui->btn_play_stop->setText(tr("播放"));
        timer->stop();
        ui->btn_big->setEnabled(true);
        ui->btn_next->setEnabled(true);
        ui->btn_orig->setEnabled(true);
        ui->btn_prev->setEnabled(true);
        ui->btn_smal->setEnabled(true);
        ui->btn_spin->setEnabled(true);
    }
}

void MyPictureView::on_btn_orig_clicked()       //还原
{
    timer->stop();
    scale = 1;
    imageAngle = 0;

    pic_show1();
}

void MyPictureView::on_btn_next_clicked()       //下一张
{
    timer->stop();
    scale = 1;
    imageAngle = 0;
    currentIndex++;
    if(currentIndex>size-1)
        currentIndex = 0;

    pic_show1();
}

void MyPictureView::on_btn_big_clicked()        //放大
{
    timer->stop();
    scale = scale*1.25;         //和0.8对应，放大次数和缩小次数点击相同次，会还原到原来的样子

    if(imageAngle != 0)
        pic_show2();
    else
        pic_show1();
}

void MyPictureView::on_btn_smal_clicked()       //缩小
{
    timer->stop();
    scale = scale*0.8;

    if(imageAngle != 0)
        pic_show2();
    else
        pic_show1();
}

void MyPictureView::wheelEvent(QWheelEvent *event)          //滚轮放大或缩小
{
    int num = event->delta();
    if(!isPlaying)
    {
        if(num > 0)
            on_btn_big_clicked();
        else
            on_btn_smal_clicked();
    }
}

void MyPictureView::pic_show1()          //显示图片
{
    pix = (*pictures_[currentIndex]).scaled(640*scale,360*scale,Qt::KeepAspectRatio);

    label->setPixmap(pix);
}

void MyPictureView::pic_show2()     //旋转后的显示
{
    QMatrix leftmatrix;

    leftmatrix.rotate(90*imageAngle);

    pix = (*pictures_[currentIndex]).scaled(640*scale,360*scale,Qt::KeepAspectRatio);
    label->setPixmap(pix.transformed(leftmatrix,Qt::SmoothTransformation));
}

void MyPictureView::pic_showloop()      //循环显示图片
{
    scale = 1;

    currentIndex ++;
    if(currentIndex > size-1)
        currentIndex = 0;
    pic_show1();

}

mypictureview.cpp

main.cpp

#include "mypictureview.h"
#include <QApplication>

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

    QVector<QPixmap *> pictures;
    pictures.push_back(new QPixmap(":/pictures/1"));
    pictures.push_back(new QPixmap(":/pictures/2"));
    pictures.push_back(new QPixmap(":/pictures/3"));
    pictures.push_back(new QPixmap(":/pictures/4"));
    pictures.push_back(new QPixmap(":/pictures/5"));
    pictures.push_back(new QPixmap(":/pictures/6"));
    pictures.push_back(new QPixmap(":/pictures/7"));
    pictures.push_back(new QPixmap(":/pictures/8"));

    MyPictureView view(pictures);

    // Disable maximize and minimize button
    view.setWindowFlags(view.windowFlags()
                    & ~Qt::WindowMaximizeButtonHint
                    & ~Qt::WindowMinimizeButtonHint);
    view.show();

    return a.exec();
}