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// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_basegfx.hxx"

#include <basegfx/range/b2drange.hxx>
#include <basegfx/range/b2irange.hxx>
#include <basegfx/range/b2ibox.hxx>


namespace basegfx
{
    namespace
    {
        /** Generic implementation of the difference set computation

            @tpl RangeType 
            Type to operate on. Must provide ValueType and TraitsType
            nested types.
         */
		template< class RangeType > void doComputeSetDifference( 
            ::std::vector< RangeType >&	o_rRanges,
            const RangeType&			a,
            const RangeType&			b )
		{
            o_rRanges.clear();

            // special-casing the empty rect case (this will fail most
            // of the times below, because of the DBL_MIN/MAX special
            // values denoting emptyness in the rectangle.
            if( a.isEmpty() )
            {
                o_rRanges.push_back( b );
                return;
            }
            if( b.isEmpty() )
            {
                o_rRanges.push_back( a );
                return;
            }

			const typename RangeType::ValueType 					ax(a.getMinX());
			const typename RangeType::ValueType 					ay(a.getMinY());
			const typename RangeType::TraitsType::DifferenceType 	aw(a.getWidth());
			const typename RangeType::TraitsType::DifferenceType 	ah(a.getHeight());
			const typename RangeType::ValueType 					bx(b.getMinX());
			const typename RangeType::ValueType 					by(b.getMinY());
			const typename RangeType::TraitsType::DifferenceType	bw(b.getWidth());
			const typename RangeType::TraitsType::DifferenceType	bh(b.getHeight());

			const typename RangeType::TraitsType::DifferenceType	h0( (by > ay) ? by - ay : 0 );
			const typename RangeType::TraitsType::DifferenceType	h3( (by + bh < ay + ah) ? ay + ah - by - bh : 0 );
			const typename RangeType::TraitsType::DifferenceType 	w1( (bx > ax) ? bx - ax : 0 );
			const typename RangeType::TraitsType::DifferenceType	w2( (ax + aw > bx + bw) ? ax + aw - bx - bw : 0 );
			const typename RangeType::TraitsType::DifferenceType	h12( (h0 + h3 < ah) ? ah - h0 - h3 : 0 );

            // TODO(E2): Use numeric_cast instead of static_cast here,
            // need range checks!
			if (h0 > 0)
				o_rRanges.push_back( 
                    RangeType(ax,ay,
                              static_cast<typename RangeType::ValueType>(ax+aw),
                              static_cast<typename RangeType::ValueType>(ay+h0)) );

			if (w1 > 0 && h12 > 0)
				o_rRanges.push_back( 
                    RangeType(ax,
                              static_cast<typename RangeType::ValueType>(ay+h0),
                              static_cast<typename RangeType::ValueType>(ax+w1),
                              static_cast<typename RangeType::ValueType>(ay+h0+h12)) );

			if (w2 > 0 && h12 > 0)
				o_rRanges.push_back( 
                    RangeType(static_cast<typename RangeType::ValueType>(bx+bw),
                              static_cast<typename RangeType::ValueType>(ay+h0),
                              static_cast<typename RangeType::ValueType>(bx+bw+w2),
                              static_cast<typename RangeType::ValueType>(ay+h0+h12)) );

			if (h3 > 0)
				o_rRanges.push_back( 
                    RangeType(ax,
                              static_cast<typename RangeType::ValueType>(ay+h0+h12),
                              static_cast<typename RangeType::ValueType>(ax+aw),
                              static_cast<typename RangeType::ValueType>(ay+h0+h12+h3)) );
		}
    }

    ::std::vector< B2IRange >& computeSetDifference( ::std::vector< B2IRange >&	o_rResult,
                                                     const B2IRange&			rFirst,
                                                     const B2IRange&			rSecond )
    {
        doComputeSetDifference( o_rResult, rFirst, rSecond );

        return o_rResult;
    }

    ::std::vector< B2DRange >& computeSetDifference( ::std::vector< B2DRange >&	o_rResult,
                                                     const B2DRange&			rFirst,
                                                     const B2DRange&			rSecond )
    {
        doComputeSetDifference( o_rResult, rFirst, rSecond );

        return o_rResult;
    }

    ::std::vector< B2IBox >& computeSetDifference( ::std::vector< B2IBox >&	o_rResult,
                                                   const B2IBox&			rFirst,
                                                   const B2IBox&			rSecond )
    {
        doComputeSetDifference( o_rResult, rFirst, rSecond );

        return o_rResult;
    }

} // end of namespace basegfx

// eof
