/**
* Does spike-reduction on the given point-array's stack-top.
*
* Spikes are path segments of which one goes forward, and the sucessor
* goes backward on the predecessor's segment:
*
* 2 0 1
* x------x<-----x
* (0 is stack-top in point-array)
*
* This will be reduced to
* 1 0
* x------x
*
* Preconditions:
* - No other spikes exist in the whole point-array except at most
* one at the end
* - No two succeeding points are ever equal
* - For each two succeeding points either p1.x == p2.x or p1.y == p2.y holds
* true
* - No such spike exists where 2 is situated between 0 and 1.
*
* Postcondition:
* - No spikes exist in the whole point-array
*
* If no spike is found, the point-array is left unchanged.
* @return \c true if an actual reduction was done
*/
inline static bool reduceSpike(QValueVector< QPoint > &pointArray)
{
if(pointArray.size() < 3)
return false;
QValueVector< QPoint >::Iterator it = pointArray.end();
QPoint p0 = *--it;
QPoint p1 = *--it;
QPoint p2 = *--it;
bool elide = false;
if((p0.x() == p1.x() && p1.x() == p2.x() && ((p1.y() < p0.y() && p0.y() < p2.y()) || (p2.y() < p0.y() && p0.y() < p1.y())
|| (p1.y() < p2.y() && p2.y() < p0.y()) || (p0.y() < p2.y() && p2.y() < p1.y())
|| (elide = p2.y() == p0.y() && p0.y() < p1.y()) || (elide = p1.y() < p0.y() && p0.y() == p2.y())))
|| (p0.y() == p1.y() && p1.y() == p2.y() && ((p1.x() < p0.x() && p0.x() < p2.x()) || (p2.x() < p0.x() && p0.x() < p1.x())
|| (p1.x() < p2.x() && p2.x() < p0.x()) || (p0.x() < p2.x() && p2.x() < p1.x())
|| (elide = p2.x() == p0.x() && p0.x() < p1.x()) || (elide = p1.x() < p0.x() && p0.x() == p2.x()))))
{
// kdDebug(6040) << "spikered p2" << (elide ? " (elide)" : "") << ": " << p2 << " p1: " << p1 << " p0: " << p0 << endl;
pointArray.pop_back();
pointArray.pop_back();
if(!elide)
pointArray.push_back(p0);
return true;
}
return false;
}
/**
* Reduces segment separators.
*
* A segment separator separates a segment into two segments, thus causing
* two adjacent segment with the same orientation.
*
* 2 1 0
* x-------x---->x
* (0 means stack-top)
*
* Here, 1 is a segment separator. As segment separators not only make
* the line drawing algorithm inefficient, but also make the spike-reduction
* fail, they must be eliminated:
*
* 1 0
* x------------>x
*
* Preconditions:
* - No other segment separators exist in the whole point-array except
* at most one at the end
* - No two succeeding points are ever equal
* - For each two succeeding points either p1.x == p2.x or p1.y == p2.y holds
* true
* - No such spike exists where 2 is situated between 0 and 1.
*
* Postcondition:
* - No segment separators exist in the whole point-array
*
* If no segment separator is found at the end of the point-array, it is
* left unchanged.
* @return \c true if a segment separator was actually reduced.
*/
inline static bool reduceSegmentSeparator(QValueVector< QPoint > &pointArray)
{
if(pointArray.size() < 3)
return false;
QValueVector< QPoint >::Iterator it = pointArray.end();
QPoint p0 = *--it;
QPoint p1 = *--it;
QPoint p2 = *--it;
// kdDebug(6040) << "checking p2: " << p2 << " p1: " << p1 << " p0: " << p0 << endl;
if((p0.x() == p1.x() && p1.x() == p2.x() && ((p2.y() < p1.y() && p1.y() < p0.y()) || (p0.y() < p1.y() && p1.y() < p2.y())))
|| (p0.y() == p1.y() && p1.y() == p2.y() && ((p2.x() < p1.x() && p1.x() < p0.x()) || (p0.x() < p1.x() && p1.x() < p2.x()))))
{
// kdDebug(6040) << "segred p2: " << p2 << " p1: " << p1 << " p0: " << p0 << endl;
pointArray.pop_back();
pointArray.pop_back();
pointArray.push_back(p0);
return true;
}
return false;
}
void load( const QString& filename )
{
QFile file( filename );
if ( !file.open( IO_ReadOnly ) )
{
Console::instance()->send( tr( "Unable to open %1!\n" ).arg( filename ) );
return;
}
filenames.push_back( filename );
QXmlInputSource input( &file );
QXmlSimpleReader reader;
reader.setFeature( "http://trolltech.com/xml/features/report-whitespace-only-CharData", false );
reader.setContentHandler( this );
reader.setErrorHandler( this );
reader.parse( &input, false );
filenames.pop_back();
}
bool endDocument()
{
levels.pop_back();
locators.pop();
return true;
}
