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/*
*
* (c) Vladi Belperchinov-Shabanski "Cade" <cade@biscom.net> 1998-2003
*
* SEE `README',`LICENSE' OR `COPYING' FILE FOR LICENSE AND OTHER DETAILS!
*
* $Id: scroll.cpp,v 1.4 2003/01/29 22:59:27 cade Exp $
*
*/
#include <assert.h>
#ifndef ASSERT
#define ASSERT assert
#endif
#include "scroll.h"
void ScrollPos::home()
{
if ( ! _size ) return;
_pos = _min;
_page = _min;
fix();
};
void ScrollPos::end()
{
if ( ! _size ) return;
_pos = _max;
fix();
};
void ScrollPos::up()
{
if ( ! _size ) return;
ASSERT( check() );
_pos--;
if ( _pos < _min )
{
if ( wrap )
_pos = _max;
else
_pos = _min;
}
if ( _pos < _page ) _page--;
fix();
};
void ScrollPos::down()
{
if ( ! _size ) return;
ASSERT( check() );
_pos++;
if ( _pos > _max )
{
if ( wrap )
_pos = _min;
else
_pos = _max;
}
if ( _pos > _page + _pagesize - 1 ) _page++;
fix();
};
void ScrollPos::pageup()
{
if ( ! _size ) return;
ASSERT( check() );
if ( _pos != _page)
_pos = _page;
else
_pos -= _pagesize;
fix();
};
void ScrollPos::pagedown()
{
if ( ! _size ) return;
ASSERT( check() );
if ( _pos != _page + _pagesize -1 )
_pos = _page + _pagesize - 1;
else
{
_pos += _pagesize;
if ( _page + _pagesize <= _max ) _page += _pagesize;
}
fix();
};
void ScrollPos::go( int new_pos )
{
_pos = new_pos;
fix();
}
void ScrollPos::fix()
{
if ( _pos < _min ) _pos = _min;
if ( _pos > _max ) _pos = _max;
if ( _page < _min ) _page = _min;
if ( _page > _max ) _page = _max;
if ( _pos < _page || _pos > _page + _pagesize - 1 )
{
if ( _pagesize )
_page = ( _pos / _pagesize ) * _pagesize;
else
_page = 0;
}
ASSERT( check() );
}
int ScrollPos::check()
{
if ( ! _size ) return 1;
if ( _pos < _min ) return 0;
if ( _pos > _max ) return 0;
if ( _page < _min ) return 0;
if ( _page > _max ) return 0;
if ( _pos < _page ) return 0;
if ( _pagesize < 0 ) return 0;
if ( _pagestep < 1 ) return 0;
if ( _pos >= _page + _pagesize ) return 0;
return 1;
}
// eof scroll.cpp
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