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// header for BOOL
#include <tools/solar.h>

#include <vector>
#include <utility>
class Point;
class Rectangle;
namespace binfilter {

class Line;
class XPolygon;
class XPolyPolygon;

/**	@descr	This class clips single lines and polygons at a given rectangle.
        All of it's methods are static, therefore no object has to be created.
        
        It uses the Liang-Biarsky parametric line-clipping algorithm as described in:
            Computer Graphics: principles and practice, 2nd ed.,
            James D. Foley et al.,
            Section 3.12.4 on page 117.
*/
class SchCalculationHelper
{
public:
    /** like Rectangle::IsInside, but the result is FALSE, if
        the Point is on the Border of the Rectangle
     */
//	static BOOL IsPointInsideRectangle( const Point& rPoint, const Rectangle& rRect );

    /**	@descr	The line is clipped at the rectangle.  If the line lies completely or partly
             inside the clipping area then TRUE is returned and the line is modified accordingly.
             If the line lies completely outside the clipping area then FALSE is returned and the
             line remains unmodified.
             The line may be degenerate in that both of it's end points have the same 
             coordinates.
        @param	aLine	The line to be clipped.  It is modified to a part that lies completely
            inside the clipping area if such a part exists.
        @param	rRectangle	The clipping area.
        @return	TRUE is returned if the line lies completely or partly inside the clipping area.
     */

    /**	@descr	The intersection between an open polygon and a rectangle is
            calculated and the resulting lines are placed into the poly-polygon aResult.
        @param	rPolygon	The polygon is required to be open, ie. it's start and end point
            have different coordinates and that it is continuous, ie. has no holes.
        @param	rRectangle	The clipping area.
        @param	aResult	The resulting lines that are the parts of the given polygon lying inside
            the clipping area are stored into aResult whose prior content is deleted first.
     */
    static void IntersectPolygonWithRectangle( const XPolygon& rPolygon, const Rectangle& rRectangle,
                                               XPolyPolygon& aResult );

    /** @descr Calculates the intersection between a set of open polygons and a
               rectangle.  This function iterates over all polygons contained in
               rPolyPolygon and calls IntersectPolygonWithRectangle() for it.
               The resulting XPolyPolygons are then put together into aResult.
        @param rPolyPolygon  A set of polygons that must be open.
        @param rRectangle    The clipping region
        @param rOutResult    The resulting lines representing rPolyPolygon clipped
                             at rRectangle.
     */

    /** @descr calculates natural cubic splines for the given set of points.

        @param rPoints is a vector of tuples containing x and y coordinate of
               points that are to be interpolated.
        @param nGranularity The number of interpolation points between two
               x-values given in rPoints

        @param rOutResult A polygon (split up into more, if the number of points
               is too high as to fit into a single XPolygon) that contains all
               line segments between the interpolated points.  It should contain
               (rPoints.size() * nGranularity) points.

        @param nDPIX resolution in x-direction to reduce the number of points.
               A value of 0 (default) means do not take into account.

        @param nDPIY resolution in y-direction to reduce the number of points.
               A value of 0 (default) means do not take into account.
     */

private:
    /**	@descr	The line given by it's two endpoints rP0 and rP1 is clipped at the rectangle
            rRectangle.  If there is at least a part of it visible then TRUE is returned and
            the endpoints of that part are stored in rP0 and rP1.  The points rP0 and rP1
            may have the same coordinates.
        @param	rP0 Start point of the line to clip.  Modified to contain a start point inside
            the clipping area if possible.
        @param	rP1 End point of the line to clip.  Modified to contain an end point inside
            the clipping area if possible.
        @param	rRectangle Clipping area.
        @return	If the line lies completely or partly inside the clipping area then TRUE
            is returned.  If the line lies completely outside then FALSE is returned and rP0 and
            rP1 are left unmodified.
    */
    static	BOOL	clip2d	(Point & rP0, Point & rP1, const Rectangle& rRectangle);
    
    /**	@descr	This is a supporting function for clip2d.  It computes a new parametric 
            value for an entering (dTE) or leaving (dTL) intersection point with one
            of the edges bounding the clipping area.
            For explanation of the parameters please refer to the literature reference 
            given above.
    */
    static	BOOL	CLIPt	(double fDenom, double fNum, double & fTE, double & fTL);
};

} //namespace binfilter
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