ImageFileSequence.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_MEDIA_IMAGE_FILE_SEQUENCE_H
#define META_OCEAN_MEDIA_IMAGE_FILE_SEQUENCE_H
 
#include "ocean/media/Media.h"
#include "ocean/media/ImageSequence.h"
 
#include "ocean/base/Thread.h"
 
namespace Ocean
{
 
namespace Media
{
 
/*
 * This class implements the base class for all image sequences based on actual files (and not on databases containing images).
 * the class is mainly an intermediate helper class to simplify the implementation of an ImageSequence based on files.
 * @ingroup media
 */
class OCEAN_MEDIA_EXPORT ImageFileSequence :
    public virtual ImageSequence,
    protected Thread
{
    public:
 
        /**
         * Returns the duration of the finite medium.
         * @see FiniteMedium::duration().
         */
        double duration() const override;
 
        /**
         * Returns the duration without speed consideration.
         * @see FiniteMedium::normalDuration().
         */
        double normalDuration() const override;
 
        /**
         * Returns the recent position of the finite medium.
         * @see FiniteMedium::position().
         */
        double position() const override;
 
        /**
         * Returns the speed of the finite medium.
         * The speed of an image sequence is identical with the preferred frame rate (fps).
         * @return The current speed of this image sequence in fps, with range [0, infinity)
         */
        float speed() const override;
 
        /**
         * Returns the url of the current image.
         * @see ImageSequence::currentUrl().
         */
        std::string currentUrl() const override;
 
        /**
         * Returns the number of images part of the sequence.
         * @see ImageSequence::images().
         */
        unsigned int images() const override;
 
        /**
         * Starts the medium.
         * @see Medium::start().
         */
        bool start() override;
 
        /**
         * Pauses the medium.
         * @see Medium::pause().
         */
        bool pause() override;
 
        /**
         * Stops the medium.
         * @see Medium::stop().
         */
        bool stop() override;
 
        /**
         * Returns whether the medium is started currently.
         * @see Medium::isStarted().
         */
        bool isStarted() const override;
 
        /**
         * Returns the start timestamp.
         * @see FiniteMedium::startTimestamp().
         */
        Timestamp startTimestamp() const override;
 
        /**
         * Returns the pause timestamp.
         * @see FiniteMedium::pauseTimestamp().
         */
        Timestamp pauseTimestamp() const override;
 
        /**
         * Returns the stop timestamp.
         * @see FiniteMedium::stopTimestamp().
         */
        Timestamp stopTimestamp() const override;
 
        /**
         * Sets the recent position of the finit medium.
         * @see FiniteMedium::setPosition().
         */
        bool setPosition(const double position) override;
 
        /**
         * Sets the speed of the finite medium.
         * The speed of an image sequence is identical with the preferred frame rate (fps).
         * @param speed The speed to be set in fps, with range [0, infinity)
         * @see setPreferredFrameFrequency().
         */
        bool setSpeed(const float speed) override;
 
        /**
         * Forces the loading of the next image in the sequence.
         * @see ImageSequence::forceNextFrame().
         */
        bool forceNextFrame() override;
 
    protected:
 
        /**
         * Creates a new image file sequence by a given url.
         * @param url Url of the image
         */
        explicit ImageFileSequence(const std::string& url);
 
        /**
         * Destructs an image file sequence object.
         */
        ~ImageFileSequence() override;
 
        /**
         * Thread run function.
         * @see Thread::threadRun().
         */
        void threadRun()  override;
 
        /**
         * Determines the image sequence parameters.
         * @return True, if succeeded
         */
        bool determineSequence();
 
        /**
         * Returns the filename of a specific sequence image.
         * @param index Index of the sequence image to create the filename for
         * @return Sequence image filename
         */
        std::string imageFilename(const unsigned int index) const;
 
        /**
         * Loads a new image specified by the filename.
         * @param filename Filename of the image to be loaded
         * @param timestamp Frame timestamp to be used
         * @param frame Optional frame receiving the image data, otherwise the frame will be added to the frame container
         * @return True, if succeeded
         */
        virtual bool loadImage(const std::string& filename, const Timestamp timestamp, Frame* frame = nullptr) = 0;
 
    protected:
 
        /// Start timestamp.
        Timestamp mediumStartTimestamp;
 
        /// Pause timestamp.
        Timestamp mediumPauseTimestamp;
 
        /// Stop timestamp.
        Timestamp mediumStopTimestamp;
 
        /// Image sequence prefix filename.
        std::string mediumFilenamePrefix;
 
        /// Image sequence filename type.
        std::string mediumFilenameType;
 
        /// Next frame in the sequence.
        Frame mediumNextFrame;
};
 
}
 
}
 
#endif // META_OCEAN_MEDIA_IMAGE_FILE_SEQUENCE_H