gvviewerinput.h

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//
// Copyright (C) 2017 Graeme Walker
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
// ===
///
/// \file gvviewerinput.h
///

#ifndef GV_VIEWERINPUT__H
#define GV_VIEWERINPUT__H

#include "gdef.h"
#include "gnet.h"
#include "gdatetime.h"
#include "geventhandler.h"
#include "gtimer.h"
#include "gpublisher.h"
#include "gfatpipe.h"
#include "grimagetype.h"
#include "grimagedata.h"
#include "grimagedecoder.h"
#include <string>
#include <vector>
#include <iostream>

namespace Gv
{
    class ViewerInput ;
    class ViewerInputHandler ;
    struct ViewerInputConfig ;
}

/// \class Gv::ViewerInputHandler
/// A callback interface for Gv::ViewerInput.
/// 
class Gv::ViewerInputHandler
{
public:
    virtual void onInput( int dx , int dy , int channels , const char * p , size_t n ) = 0 ;
        ///< Called to deliver a raw image.

    virtual ~ViewerInputHandler() ;
        ///< Destructor.
} ;

/// \class Gv::ViewerInputConfig
/// A structure to hold configuration for a Gv::ViewerInput object.
/// 
struct Gv::ViewerInputConfig
{
    int m_scale ;
    bool m_static ; // one frame
    G::EpochTime m_rate_limit ; // inter-frame delay
    explicit ViewerInputConfig( int scale = 1 , bool static_ = false ) :
        m_scale(scale) ,
        m_static(static_) ,
        m_rate_limit(0)
    {
    }
} ;

/// \class Gv::ViewerInput
/// An input channel for images. Images are decoded as necessary.
/// 
class Gv::ViewerInput : private GNet::EventHandler
{
public:
    G_EXCEPTION( Closed , "viewer input channel closed" ) ;
    typedef ViewerInputHandler Handler ;

    ViewerInput( ViewerInputHandler & , const ViewerInputConfig & , 
        const std::string & channel , int shmem_fd , int pipe_fd ) ;
            ///< Constructor.

    ~ViewerInput() ;
        ///< Destructor.

    int fd() const ;
        ///< Returns the file descriptor that is being used for notification.

    const char * data() const ;
        ///< Returns the data as a standard luma or rgb-interleaved buffer.

    size_t size() const ;
        ///< Returns the data() size.

    int dx() const ;
        ///< Returns the image width.

    int dy() const ;
        ///< Returns the image height.

    int channels() const ;
        ///< Returns the number of channels (one or three).

    Gr::ImageType type() const ;
        ///< Returns the type for the decoded image.

private:
    ViewerInput( const ViewerInput & ) ;
    void operator=( const ViewerInput & ) ;
    virtual void readEvent() override ;
    virtual void onException( std::exception & ) override ;
    static Gr::ImageType subsample( std::vector<char> & , const Gr::ImageType & , int , bool , bool ) ;
    void onRateTimeout() ;
    void onQuiescentTimeout() ;
    bool read( std::vector<char> & ) ;
    bool decode() ;

public:
    ViewerInputHandler & m_input_handler ;
    int m_scale ;
    bool m_static ;
    bool m_first ;
    G::EpochTime m_rate_limit ;
    int m_fd ;
    unique_ptr<G::FatPipe::Receiver> m_pipe ;
    unique_ptr<G::PublisherSubscription> m_channel ;
    std::vector<char> m_buffer ;
    std::vector<char> m_tmp ;
    Gr::ImageType m_type_in ;
    std::string m_type_in_str ;
    Gr::ImageType m_type_out ; // raw
    GNet::Timer<ViewerInput> m_rate_timer ;
    GNet::Timer<ViewerInput> m_quiescent_timer ;
    Gr::ImageData m_decoder_tmp ;
    Gr::ImageDecoder m_decoder ;
    char * m_data_out ;
} ;

#endif