《Qt5+播放gif动图》_qt5 播放gif动画-优快云博客

本文介绍了一种使用Qt库中的QMovie和QLabel组件来播放GIF动画的方法，通过示例代码展示了如何创建一个简单的动画播放器，包括加载文件、控制播放、暂停、停止以及调整播放速度等功能。

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示例代码演示了如何使用QMovie和QLabel来显示动画（GIF）。如果想要播放简单的动画而没有安装和部署多媒体框架的复杂性，QMovie最有用。

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>

class QCheckBox;
class QGridLayout;
class QHBoxLayout;
class QLabel;
class QMovie;
class QSlider;
class QSpinBox;
class QToolButton;
class QVBoxLayout;

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    void openFile(const QString &fileName);
private slots:
    void open();
    void goToFrame(int frame);
    void fitToWindow();
    void updateButtons();
    void updateFrameSlider();
private:
    Ui::Widget *ui;
private:
    void createControls();
    void createButtons();

    QString currentMovieDirectory;
    QLabel *movieLabel;
    QMovie *movie;
    QToolButton *openButton;
    QToolButton *playButton;
    QToolButton *pauseButton;
    QToolButton *stopButton;
    QToolButton *quitButton;
    QCheckBox *fitCheckBox;
    QSlider *frameSlider;
    QSpinBox *speedSpinBox;
    QLabel *frameLabel;
    QLabel *speedLabel;

    QGridLayout *controlsLayout;
    QHBoxLayout *buttonsLayout;
    QVBoxLayout *mainLayout;
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QtWidgets>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    movie = new QMovie(this);
    movie->setCacheMode(QMovie::CacheAll);

    movieLabel = new QLabel(tr("No movie loaded"));
    movieLabel->setAlignment(Qt::AlignCenter);
    movieLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
    movieLabel->setBackgroundRole(QPalette::Dark);
    movieLabel->setAutoFillBackground(true);

    currentMovieDirectory = "movies";

    createControls();
    createButtons();

    connect(movie, SIGNAL(frameChanged(int)), this, SLOT(updateFrameSlider()));
    connect(movie, SIGNAL(stateChanged(QMovie::MovieState)),
            this, SLOT(updateButtons()));
    connect(fitCheckBox, SIGNAL(clicked()), this, SLOT(fitToWindow()));
    connect(frameSlider, SIGNAL(valueChanged(int)), this, SLOT(goToFrame(int)));
    connect(speedSpinBox, SIGNAL(valueChanged(int)),
            movie, SLOT(setSpeed(int)));

    mainLayout = new QVBoxLayout;
    mainLayout->addWidget(movieLabel);
    mainLayout->addLayout(controlsLayout);
    mainLayout->addLayout(buttonsLayout);
    setLayout(mainLayout);

    updateFrameSlider();
    updateButtons();

    setWindowTitle(tr("Movie Player"));
    resize(400, 400);
}

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

void Widget::open()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Open a Movie"),
                               currentMovieDirectory);
    if (!fileName.isEmpty())
        openFile(fileName);
}

void Widget::openFile(const QString &fileName)
{
    currentMovieDirectory = QFileInfo(fileName).path();

    movie->stop();
    movieLabel->setMovie(movie);
    movie->setFileName(fileName);
    movie->start();

    updateFrameSlider();
    updateButtons();
}

void Widget::goToFrame(int frame)
{
    movie->jumpToFrame(frame);
}

void Widget::fitToWindow()
{
    movieLabel->setScaledContents(fitCheckBox->isChecked());
}

void Widget::updateFrameSlider()
{
    bool hasFrames = (movie->currentFrameNumber() >= 0);

    if (hasFrames) {
        if (movie->frameCount() > 0) {
            frameSlider->setMaximum(movie->frameCount() - 1);
        } else {
            if (movie->currentFrameNumber() > frameSlider->maximum())
                frameSlider->setMaximum(movie->currentFrameNumber());
        }
        frameSlider->setValue(movie->currentFrameNumber());
    } else {
        frameSlider->setMaximum(0);
    }
    frameLabel->setEnabled(hasFrames);
    frameSlider->setEnabled(hasFrames);
}

void Widget::updateButtons()
{
    playButton->setEnabled(movie->isValid() && movie->frameCount() != 1
                           && movie->state() == QMovie::NotRunning);
    pauseButton->setEnabled(movie->state() != QMovie::NotRunning);
    pauseButton->setChecked(movie->state() == QMovie::Paused);
    stopButton->setEnabled(movie->state() != QMovie::NotRunning);
}

void Widget::createControls()
{
    fitCheckBox = new QCheckBox(tr("Fit to Window"));

    frameLabel = new QLabel(tr("Current frame:"));

    frameSlider = new QSlider(Qt::Horizontal);
    frameSlider->setTickPosition(QSlider::TicksBelow);
    frameSlider->setTickInterval(10);

    speedLabel = new QLabel(tr("Speed:"));

    speedSpinBox = new QSpinBox;
    speedSpinBox->setRange(1, 9999);
    speedSpinBox->setValue(100);
    speedSpinBox->setSuffix(tr("%"));

    controlsLayout = new QGridLayout;
    controlsLayout->addWidget(fitCheckBox, 0, 0, 1, 2);
    controlsLayout->addWidget(frameLabel, 1, 0);
    controlsLayout->addWidget(frameSlider, 1, 1, 1, 2);
    controlsLayout->addWidget(speedLabel, 2, 0);
    controlsLayout->addWidget(speedSpinBox, 2, 1);
}

void Widget::createButtons()
{
    QSize iconSize(36, 36);

    openButton = new QToolButton;
    openButton->setIcon(style()->standardIcon(QStyle::SP_DialogOpenButton));
    openButton->setIconSize(iconSize);
    openButton->setToolTip(tr("Open File"));
    connect(openButton, SIGNAL(clicked()), this, SLOT(open()));

    playButton = new QToolButton;
    playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
    playButton->setIconSize(iconSize);
    playButton->setToolTip(tr("Play"));
    connect(playButton, SIGNAL(clicked()), movie, SLOT(start()));

    pauseButton = new QToolButton;
    pauseButton->setCheckable(true);
    pauseButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
    pauseButton->setIconSize(iconSize);
    pauseButton->setToolTip(tr("Pause"));
    connect(pauseButton, SIGNAL(clicked(bool)), movie, SLOT(setPaused(bool)));

    stopButton = new QToolButton;
    stopButton->setIcon(style()->standardIcon(QStyle::SP_MediaStop));
    stopButton->setIconSize(iconSize);
    stopButton->setToolTip(tr("Stop"));
    connect(stopButton, SIGNAL(clicked()), movie, SLOT(stop()));

    quitButton = new QToolButton;
    quitButton->setIcon(style()->standardIcon(QStyle::SP_DialogCloseButton));
    quitButton->setIconSize(iconSize);
    quitButton->setToolTip(tr("Quit"));
    connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));

    buttonsLayout = new QHBoxLayout;
    buttonsLayout->addStretch();
    buttonsLayout->addWidget(openButton);
    buttonsLayout->addWidget(playButton);
    buttonsLayout->addWidget(pauseButton);
    buttonsLayout->addWidget(stopButton);
    buttonsLayout->addWidget(quitButton);
    buttonsLayout->addStretch();
}