gvviewerwindow.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 gvviewerwindow.h
///

#ifndef GV_VIEWERWINDOW__H
#define GV_VIEWERWINDOW__H

#include "gdef.h"
#include <exception>

namespace Gv
{
    class ViewerWindowConfig ;
    class ViewerWindowHandler ;
    class ViewerWindow ;
}

/// \class Gv::ViewerWindowConfig
/// A configuration structure for Gv::ViewerWindow.
/// 
struct Gv::ViewerWindowConfig
{
    std::string m_title ;
    std::string m_mask_file ;
    bool m_static ;
    bool m_mouse_moves ;
} ;

/// \class Gv::ViewerWindowHandler
/// A callback interface for Gv::ViewerWindow.
/// 
class Gv::ViewerWindowHandler
{
public:
    virtual void onChar( char ) = 0 ;
        ///< Called when a key is pressed.

    virtual void onMouseButtonDown( int x , int y , bool shift , bool control ) = 0 ;
        ///< Called when the left mouse button is pressed.

    virtual void onMouseButtonUp( int x , int y , bool shift , bool control ) = 0 ;
        ///< Called when the left mouse button is released.

    virtual void onMouseMove( int x , int y ) = 0 ;
        ///< Called when the mouse moves (typically also depending on whether
        ///< ViewerWindowConfig::m_mouse_moves is set). Coordinates can be negative 
        ///< if the mouse is moved outside the window with the button pressed.

    virtual void onInvalid() = 0 ;
        ///< Called when the window needs to be re-display()ed.

    virtual ~ViewerWindowHandler() {}
        ///< Destructor.
} ;

/// \class Gv::ViewerWindow
/// An abstract base class for a viewer window. The concrete derived class 
/// is chosen by the factory class.
/// 
class Gv::ViewerWindow
{
public:
    typedef ViewerWindowHandler Handler ;
    typedef ViewerWindowConfig Config ;

    static ViewerWindow * create( Handler & , ViewerWindow::Config , int image_dx , int image_dy ) ;
        ///< A factory function that returns a new'ed ViewerWindow.
        ///< 
        ///< The dx and dy parameters are the size of the image
        ///< that triggered the creation of the window, not necessarily
        ///< the size of the window.
        ///< 
        ///< The new window should have its init() method called immediately
        ///< after construction.

    virtual void init() = 0 ;
        ///< An initialisation function that is called after contstruction.
        ///< Keeping it as a separate function makes cleanup simpler in the 
        ///< face of exceptions, for some derived classes.

    virtual void display( int dx , int dy , int channels , const char * , size_t ) = 0 ;
        ///< Displays the given image.

    virtual int dx() const = 0 ;
        ///< Returns the width of the window. This may not be the same as what was
        ///< passed to the constructor. The mouse coordinates relate to this value.

    virtual int dy() const = 0 ;
        ///< Returns the height of the window. This may not be the same as what was
        ///< passed to the constructor. The mouse coordinates relate to this value.

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

#endif