kicad/include/preview_items/multistep_geom_manager.h

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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2017 Kicad Developers, see AUTHORS.txt for contributors.
*
* 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 2
* 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, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#ifndef PREVIEW_ITEMS_MULTISTEP_GEOMETRY_MANAGER_H
#define PREVIEW_ITEMS_MULTISTEP_GEOMETRY_MANAGER_H
#include <math/vector2d.h>
#include <algorithm>
namespace KIGFX {
namespace PREVIEW {
/**
* A geometry manager that works by accepting a sequence of points
* and advancing though stages of geometric construction with each
* point "locked in".
*
* For example, constructing an arc might go:
* - Set origin
* - Set start point
* - Set end point
*
* The exact steps and how the points translate to geometry depends on
* the subclass.
*/
class MULTISTEP_GEOM_MANAGER
{
public:
virtual ~MULTISTEP_GEOM_MANAGER()
{}
/**
* Add a point to the construction manager
*
* @param aPt the new point
* @param aLockIn whether to "lock in" the point, and move the
* geometry manager to the next (or previous) step. False to
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* update geometry and not affect manager state
*/
void AddPoint( const VECTOR2I& aPt, bool aLockIn )
{
// hold onto the raw point separately to the managed geometry
m_lastPoint = aPt;
// update the geometry
bool accepted = acceptPoint( aPt );
// advance or regress the manager
if( aLockIn )
performStep( accepted );
setGeometryChanged();
}
/**
* Undo the last point, and move the manager back to the previous
* step
*/
void RemoveLastPoint()
{
performStep( false );
// process the last point again, but in the previous step mode
// it doesn't matter if accepted or not, as long as the geometry
// is regenerated if needed
acceptPoint( GetLastPoint() );
setGeometryChanged();
}
/**
* @return true if the manager is in the initial state
*/
bool IsReset() const
{
return m_step == 0;
}
/**
* Reset the manager to the initial state
*/
void Reset()
{
m_step = 0;
setGeometryChanged();
}
/**
* @return true if the manager reached the final state
*/
bool IsComplete() const
{
return m_step == getMaxStep();
}
/**
* Gets the last point added (locked in or not). This can
* be useful when drawing previews, as the point given isn't always
* what gets locked into the geometry, if that step doesn't have
* full degrees of freedom
*/
VECTOR2I GetLastPoint() const
{
return m_lastPoint;
}
/**
* @return true if the geoemtry has changed, eg such that a client
* should redraw
*/
bool HasGeometryChanged() const
{
return m_changed;
}
/**
* Clear the geometry changed flag, call after the client code has
* updated everything as needed.
*/
void ClearGeometryChanged()
{
m_changed = false;
}
protected:
///> Mark the geometry as changed for clients to notice
void setGeometryChanged()
{
m_changed = true;
}
///> Get the current stage of the manager
int getStep() const
{
return m_step;
}
private:
///> Function that accepts a point for a stage, or rejects it
///> to return to the previous stage
virtual bool acceptPoint( const VECTOR2I& aPt ) = 0;
/**
* The highest step this manager has - used to recognise completion
* and to clamp the step as it advances.
*/
virtual int getMaxStep() const = 0;
///> Moves the manager forward or backward through the stages
void performStep( bool aForward )
{
m_step += aForward ? 1 : -1;
// clamp to allowed values
m_step = std::min( std::max( m_step, 0 ), getMaxStep() );
}
///> Has the gemotry changed such that a client should redraw?
bool m_changed = false;
///> The last (raw) point added, which is usually the cursor position
VECTOR2I m_lastPoint;
/**
* The current manager step, from 0 to some highest number that
* depends on the manager
*/
int m_step = 0;
};
} // PREVIEW
} // KIGFX
#endif // PREVIEW_ITEMS_MULTIPOINT_GEOMETRY_MANAGER_H