b2dbeziertools.cxx

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#include <basegfx/curve/b2dbeziertools.hxx>
#include <basegfx/curve/b2dcubicbezier.hxx>
#include <algorithm>
 
namespace basegfx
{
    B2DCubicBezierHelper::B2DCubicBezierHelper(const B2DCubicBezier& rBase, sal_uInt32 nDivisions)
    :   mnEdgeCount(0)
    {
        const bool bIsBezier(rBase.isBezier());
 
        if(bIsBezier)
        {
            // check nDivisions; at least one is needed, but also prevent too big values
            if(nDivisions < 1)
            {
                nDivisions = 1;
            }
            else if(nDivisions > 1000)
            {
                nDivisions = 1000;
            }
 
            // set nEdgeCount
            mnEdgeCount = nDivisions + 1;
 
            // fill in maLengthArray
            maLengthArray.clear();
            maLengthArray.reserve(mnEdgeCount);
            B2DPoint aCurrent(rBase.getStartPoint());
            double fLength(0.0);
 
            for(sal_uInt32 a(1);;)
            {
                const B2DPoint aNext(rBase.interpolatePoint(static_cast<double>(a) / static_cast<double>(mnEdgeCount)));
                const B2DVector aEdge(aNext - aCurrent);
 
                fLength += aEdge.getLength();
                maLengthArray.push_back(fLength);
 
                if(++a < mnEdgeCount)
                {
                    aCurrent = aNext;
                }
                else
                {
                    const B2DPoint& aLastNext(rBase.getEndPoint());
                    const B2DVector aLastEdge(aLastNext - aNext);
 
                    fLength += aLastEdge.getLength();
                    maLengthArray.push_back(fLength);
                    break;
                }
            }
        }
        else
        {
            maLengthArray.clear();
            maLengthArray.push_back(rBase.getEdgeLength());
            mnEdgeCount = 1;
        }
    }
 
    double B2DCubicBezierHelper::distanceToRelative(double fDistance) const
    {
        if(fDistance <= 0.0)
        {
            return 0.0;
        }
 
        const double fLength(getLength());
 
        if(fTools::moreOrEqual(fDistance, fLength))
        {
            return 1.0;
        }
 
        // fDistance is in ]0.0 .. fLength[
 
        if(mnEdgeCount == 1)
        {
            // not a bezier, linear edge
            return fDistance / fLength;
        }
 
        // it is a bezier
        std::vector< double >::const_iterator aIter = std::lower_bound(maLengthArray.begin(), maLengthArray.end(), fDistance);
        const sal_uInt32 nIndex(aIter - maLengthArray.begin());
        const double fHighBound(maLengthArray[nIndex]);
        const double fLowBound(nIndex ?  maLengthArray[nIndex - 1] : 0.0);
        const double fLinearInterpolatedLength((fDistance - fLowBound) / (fHighBound - fLowBound));
 
        return (static_cast< double >(nIndex) + fLinearInterpolatedLength) / static_cast< double >(mnEdgeCount);
    }
 
} // end of namespace basegfx
 
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