gvmask.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 gvmask.h
///

#ifndef GV_MASK__H
#define GV_MASK__H

#include "gdef.h"
#include "gtime.h"
#include "grimagedata.h"
#include "grpnm.h"
#include <string>
#include <vector>
#include <istream>

namespace Gv
{
    class Mask ;
}

/// \class Gv::Mask
/// Implements a binary mask over an image that can be edited by mouse actions, 
/// and that can be stored on disk.
/// 
class Gv::Mask
{
public:
    Mask( int dx , int dy , const std::string & file = std::string() , bool create = false ) ;
        ///< Constructor, optionally reading the mask from an existing
        ///< file. If the file is a different size from the parameters 
        ///< then its contents are resampled to fit.

    bool empty() const ;
        ///< Returns true if empty.

    void write( const G::Path & filename ) const ;
        ///< Writes to file.

    bool update() ;
        ///< Updates the mask from the file. Returns true if updated.

    void scale( int factor ) ;
        ///< Scales down.

    void up( int x , int y , bool shift , bool control ) ;
        ///< Called on mouse-up. Commits any down()/move() edits.

    void move( int x , int y ) ;
        ///< Called on mouse-move. Modifies the current edit.

    void down( int x , int y , bool shift , bool control ) ;
        ///< Called on mouse-down. Starts an edit.

    bool masked( int x , int y ) const ;
        ///< Returns true if the pixel is masked.

    bool masked( size_t ) const ;
        ///< Optimised overload, ignoring the current edit.

    G::EpochTime time() const ;
        ///< Returns the timestamp on the mask file at 
        ///< construction, not affected by any calls
        ///< to write().

private:
    Mask( const Mask & ) ;
    void operator=( const Mask & ) ;
    int clip_x( int ) const ;
    int clip_y( int ) const ;
    bool fill( std::vector<bool>& , int , int , int , int , bool ) ;
    void sample( const Gr::ImageData & image_data , const Gr::PnmInfo & info ) ;
    void findOrCreate( bool ) ;
    void open( std::ifstream & file ) ;
    Gr::PnmInfo read( std::ifstream & file , Gr::ImageData & image_data ) ;

private:
    int m_dx ;
    int m_dy ;
    G::Path m_path ;
    bool m_empty ;
    std::vector<bool> m_map ;
    std::vector<bool> m_map_current ;
    bool m_down ;
    int m_down_x ;
    int m_down_y ;
    bool m_down_shift ;
    int m_move_x ;
    int m_move_y ;
    G::EpochTime m_file_time ;
} ;

inline
bool Gv::Mask::masked( size_t offset ) const
{
    return m_map[offset] ;
}

inline
bool Gv::Mask::masked( int x , int y ) const
{
    const size_t offset = y * m_dx + x ;
    if( m_down && m_down_shift )
        return m_map[offset] && !m_map_current[offset] ;
    else
        return m_map[offset] || m_map_current[offset] ;
}

#endif