b2dtrapezoid.hxx

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#pragma once
 
#include <config_options.h>
#include <basegfx/polygon/b2dpolygon.hxx>
#include <vector>
#include <basegfx/basegfxdllapi.h>
 
 
namespace basegfx { class B2DPolyPolygon; }
namespace basegfx { class B2DPoint; }
 
namespace basegfx
{
    // class to hold a single trapezoid
    class UNLESS_MERGELIBS(BASEGFX_DLLPUBLIC) B2DTrapezoid
    {
    private:
        // Geometry data. YValues are down-oriented, this means bottom should
        // be bigger than top to be below it. The constructor implementation
        // guarantees:
 
        // - mfBottomY >= mfTopY
        // - mfTopXRight >= mfTopXLeft
        // - mfBottomXRight >= mfBottomXLeft
        double              mfTopXLeft;
        double              mfTopXRight;
        double              mfTopY;
        double              mfBottomXLeft;
        double              mfBottomXRight;
        double              mfBottomY;
 
    public:
        // constructor
        B2DTrapezoid(
            const double& rfTopXLeft,
            const double& rfTopXRight,
            const double& rfTopY,
            const double& rfBottomXLeft,
            const double& rfBottomXRight,
            const double& rfBottomY);
 
        // data read access
        const double& getTopXLeft() const { return mfTopXLeft; }
        const double& getTopXRight() const { return mfTopXRight; }
        const double& getTopY() const { return mfTopY; }
        const double& getBottomXLeft() const { return mfBottomXLeft; }
        const double& getBottomXRight() const { return mfBottomXRight; }
        const double& getBottomY() const { return mfBottomY; }
 
        // convenience method to get content as Polygon
        B2DPolygon getB2DPolygon() const;
    };
 
    typedef ::std::vector< B2DTrapezoid > B2DTrapezoidVector;
 
} // end of namespace basegfx
 
 
namespace basegfx::utils
{
    // convert SourcePolyPolygon to trapezoids. The trapezoids will be appended to
    // ro_Result. ro_Result will not be cleared. If SourcePolyPolygon contains curves,
    // it's default AdaptiveSubdivision will be used.
    // CAUTION: Trapezoids are orientation-dependent in the sense that the upper and lower
    // lines have to be parallel to the X-Axis, thus this subdivision is NOT simply usable
    // for primitive decompositions. To use it, the shear and rotate parts of the
    // involved transformations HAVE to be taken into account.
    BASEGFX_DLLPUBLIC void trapezoidSubdivide(
        B2DTrapezoidVector& ro_Result,
        const B2DPolyPolygon& rSourcePolyPolygon);
 
    // directly create trapezoids from given edge. Depending on the given geometry,
    // none up to three trapezoids will be created
    void createLineTrapezoidFromEdge(
        B2DTrapezoidVector& ro_Result,
        const B2DPoint& rPointA,
        const B2DPoint& rPointB,
        double fLineWidth);
 
    // create trapezoids for all edges of the given polygon. The closed state of
    // the polygon is taken into account. If curves are contained, the default
    // AdaptiveSubdivision will be used.
    void createLineTrapezoidFromB2DPolygon(
        B2DTrapezoidVector& ro_Result,
        const B2DPolygon& rPolygon,
        double fLineWidth);
} // end of namespace basegfx::utils
 
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