C++ KoPathPoint::isSmooth方法代码示例

QList<KoSubpath *> KarbonSimplifyPath::split( const KoPathShape &path )
{
    QList<KoSubpath *> res;
    KoSubpath *subpath = new KoSubpath;
    res.append( subpath );

    for ( int i = 0; i < path.pointCount(); ++i )
    {
        KoPathPoint *p = path.pointByIndex( KoPathPointIndex(0, i) );
        // if the path separates two subpaths
        // (if it isn't smooth nor the first or last point)
        if ( i != 0  &&  i != path.pointCount()-1 )
        {
            KoPathPoint *prev = path.pointByIndex( KoPathPointIndex(0, i-1) );
            KoPathPoint *next = path.pointByIndex( KoPathPointIndex(0, i+1) );
            if ( ! p->isSmooth(prev, next) )
            {
                // create a new subpath
                subpath->append( new KoPathPoint(*p) );
                subpath = new KoSubpath;
                res.append( subpath );
            }
        }
        subpath->append( new KoPathPoint(*p) );
    }

    return res;
}

//.........这里部分代码省略.........

    // TODO: not sure if we should only touch flat segment joins as the original algorithm

    m_path->clear();

    int subpathCount = m_copy->subpathCount();
    for( int subpathIndex = 0; subpathIndex < subpathCount; ++subpathIndex )
    {
        int pointCount = m_copy->pointCountSubpath( subpathIndex );
        if( ! pointCount )
            continue;

        // check if we have sufficient number of points
        if( pointCount < 3 )
        {
            // copy the only segment
            KoPathSegment s = m_copy->segmentByIndex( KoPathPointIndex( subpathIndex, 0 ) );
            m_path->moveTo( m_copy->pointByIndex( KoPathPointIndex( subpathIndex, 0 ) )->point() );
            addSegment( m_path, s );

            continue;
        }

        KoPathSegment prevSeg = m_copy->segmentByIndex( KoPathPointIndex( subpathIndex, pointCount-1 ) );
        KoPathSegment nextSeg = m_copy->segmentByIndex( KoPathPointIndex( subpathIndex, 0 ) );
        KoPathSegment lastSeg;

        KoPathPoint * currPoint = nextSeg.first();
        KoPathPoint * firstPoint = 0;
        KoPathPoint * lastPoint = 0;

        // check if first path point is a smooth join with the closing segment
        bool firstPointIsCorner = m_copy->isClosedSubpath( subpathIndex ) 
                && ! currPoint->isSmooth( prevSeg.first(), nextSeg.second() );

        // Begin: take care of the first path point
        if( firstPointIsCorner )
        {
            // split the previous segment at length - radius
            qreal prevLength = prevSeg.length();
            qreal prevSplit = prevLength > m_radius ? prevSeg.paramAtLength( prevLength-m_radius ) : 0.5;
            QPair<KoPathSegment,KoPathSegment> prevParts = prevSeg.splitAt( prevSplit );

            // split the next segment at radius
            qreal nextLength = nextSeg.length();
            qreal nextSplit = nextLength > m_radius ? nextSeg.paramAtLength( m_radius ) : 0.5;
            QPair<KoPathSegment,KoPathSegment> nextParts = nextSeg.splitAt( nextSplit );

            // calculate smooth tangents
            QPointF P0 = prevParts.first.second()->point();
            QPointF P3 = nextParts.first.second()->point();
            qreal tangentLength1 = 0.5 * QLineF( P0, currPoint->point() ).length();
            qreal tangentLength2 = 0.5 * QLineF( P3, currPoint->point() ).length();
            QPointF P1 = P0 - tangentLength1 * tangentAtEnd( prevParts.first );
            QPointF P2 = P3 - tangentLength2 * tangentAtStart( nextParts.second );

            // start the subpath
            firstPoint = m_path->moveTo( prevParts.second.first()->point() );
            // connect the split points with curve
            // TODO: shall we create a correct arc?
            m_path->curveTo( P1, P2, P3 );

            prevSeg = nextParts.second;
            lastSeg = prevParts.first;
        }
        else