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Diffstat (limited to 'src/libpcp_qwt/src/qwt_clipper.cpp')
| -rw-r--r-- | src/libpcp_qwt/src/qwt_clipper.cpp | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/src/libpcp_qwt/src/qwt_clipper.cpp b/src/libpcp_qwt/src/qwt_clipper.cpp new file mode 100644 index 0000000..fea3fd4 --- /dev/null +++ b/src/libpcp_qwt/src/qwt_clipper.cpp @@ -0,0 +1,486 @@ +/* -*- mode: C++ ; c-file-style: "stroustrup" -*- ***************************** + * Qwt Widget Library + * Copyright (C) 1997 Josef Wilgen + * Copyright (C) 2002 Uwe Rathmann + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the Qwt License, Version 1.0 + *****************************************************************************/ + +#include "qwt_clipper.h" +#include "qwt_point_polar.h" +#include <qrect.h> + +#if QT_VERSION < 0x040601 +#define qAtan(x) ::atan(x) +#endif + +namespace QwtClip +{ + // some templates used for inlining + template <class Point, typename T> class LeftEdge; + template <class Point, typename T> class RightEdge; + template <class Point, typename T> class TopEdge; + template <class Point, typename T> class BottomEdge; + + template <class Point> class PointBuffer; +} + +template <class Point, typename Value> +class QwtClip::LeftEdge +{ +public: + inline LeftEdge( Value x1, Value, Value, Value ): + d_x1( x1 ) + { + } + + inline bool isInside( const Point &p ) const + { + return p.x() >= d_x1; + } + + inline Point intersection( const Point &p1, const Point &p2 ) const + { + double dy = ( p1.y() - p2.y() ) / double( p1.x() - p2.x() ); + return Point( d_x1, ( Value ) ( p2.y() + ( d_x1 - p2.x() ) * dy ) ); + } +private: + const Value d_x1; +}; + +template <class Point, typename Value> +class QwtClip::RightEdge +{ +public: + inline RightEdge( Value, Value x2, Value, Value ): + d_x2( x2 ) + { + } + + inline bool isInside( const Point &p ) const + { + return p.x() <= d_x2; + } + + inline Point intersection( const Point &p1, const Point &p2 ) const + { + double dy = ( p1.y() - p2.y() ) / double( p1.x() - p2.x() ); + return Point( d_x2, ( Value ) ( p2.y() + ( d_x2 - p2.x() ) * dy ) ); + } + +private: + const Value d_x2; +}; + +template <class Point, typename Value> +class QwtClip::TopEdge +{ +public: + inline TopEdge( Value, Value, Value y1, Value ): + d_y1( y1 ) + { + } + + inline bool isInside( const Point &p ) const + { + return p.y() >= d_y1; + } + + inline Point intersection( const Point &p1, const Point &p2 ) const + { + double dx = ( p1.x() - p2.x() ) / double( p1.y() - p2.y() ); + return Point( ( Value )( p2.x() + ( d_y1 - p2.y() ) * dx ), d_y1 ); + } + +private: + const Value d_y1; +}; + +template <class Point, typename Value> +class QwtClip::BottomEdge +{ +public: + inline BottomEdge( Value, Value, Value, Value y2 ): + d_y2( y2 ) + { + } + + inline bool isInside( const Point &p ) const + { + return p.y() <= d_y2; + } + + inline Point intersection( const Point &p1, const Point &p2 ) const + { + double dx = ( p1.x() - p2.x() ) / double( p1.y() - p2.y() ); + return Point( ( Value )( p2.x() + ( d_y2 - p2.y() ) * dx ), d_y2 ); + } + +private: + const Value d_y2; +}; + +template<class Point> +class QwtClip::PointBuffer +{ +public: + PointBuffer( int capacity = 0 ): + m_capacity( 0 ), + m_size( 0 ), + m_buffer( NULL ) + { + if ( capacity > 0 ) + reserve( capacity ); + } + + ~PointBuffer() + { + if ( m_buffer ) + qFree( m_buffer ); + } + + inline void setPoints( int numPoints, const Point *points ) + { + reserve( numPoints ); + + m_size = numPoints; + qMemCopy( m_buffer, points, m_size * sizeof( Point ) ); + } + + inline void reset() + { + m_size = 0; + } + + inline int size() const + { + return m_size; + } + + inline Point *data() const + { + return m_buffer; + } + + inline Point &operator[]( int i ) + { + return m_buffer[i]; + } + + inline const Point &operator[]( int i ) const + { + return m_buffer[i]; + } + + inline void add( const Point &point ) + { + if ( m_capacity <= m_size ) + reserve( m_size + 1 ); + + m_buffer[m_size++] = point; + } + +private: + inline void reserve( int size ) + { + if ( m_capacity == 0 ) + m_capacity = 1; + + while ( m_capacity < size ) + m_capacity *= 2; + + m_buffer = ( Point * ) qRealloc( + m_buffer, m_capacity * sizeof( Point ) ); + } + + int m_capacity; + int m_size; + Point *m_buffer; +}; + +using namespace QwtClip; + +template <class Polygon, class Rect, class Point, typename T> +class QwtPolygonClipper +{ +public: + QwtPolygonClipper( const Rect &clipRect ): + d_clipRect( clipRect ) + { + } + + Polygon clipPolygon( const Polygon &polygon, bool closePolygon ) const + { +#if 0 + if ( d_clipRect.contains( polygon.boundingRect() ) ) + return polygon; +#endif + + PointBuffer<Point> points1; + PointBuffer<Point> points2( qMin( 256, polygon.size() ) ); + + points1.setPoints( polygon.size(), polygon.data() ); + + clipEdge< LeftEdge<Point, T> >( closePolygon, points1, points2 ); + clipEdge< RightEdge<Point, T> >( closePolygon, points2, points1 ); + clipEdge< TopEdge<Point, T> >( closePolygon, points1, points2 ); + clipEdge< BottomEdge<Point, T> >( closePolygon, points2, points1 ); + + Polygon p; + p.resize( points1.size() ); + qMemCopy( p.data(), points1.data(), points1.size() * sizeof( Point ) ); + + return p; + } + +private: + template <class Edge> + inline void clipEdge( bool closePolygon, + PointBuffer<Point> &points, PointBuffer<Point> &clippedPoints ) const + { + clippedPoints.reset(); + + if ( points.size() < 2 ) + { + if ( points.size() == 1 ) + clippedPoints.add( points[0] ); + return; + } + + const Edge edge( d_clipRect.x(), d_clipRect.x() + d_clipRect.width(), + d_clipRect.y(), d_clipRect.y() + d_clipRect.height() ); + + int lastPos, start; + if ( closePolygon ) + { + start = 0; + lastPos = points.size() - 1; + } + else + { + start = 1; + lastPos = 0; + + if ( edge.isInside( points[0] ) ) + clippedPoints.add( points[0] ); + } + + const uint nPoints = points.size(); + for ( uint i = start; i < nPoints; i++ ) + { + const Point &p1 = points[i]; + const Point &p2 = points[lastPos]; + + if ( edge.isInside( p1 ) ) + { + if ( edge.isInside( p2 ) ) + { + clippedPoints.add( p1 ); + } + else + { + clippedPoints.add( edge.intersection( p1, p2 ) ); + clippedPoints.add( p1 ); + } + } + else + { + if ( edge.isInside( p2 ) ) + { + clippedPoints.add( edge.intersection( p1, p2 ) ); + } + } + lastPos = i; + } + } + + const Rect d_clipRect; +}; + +class QwtCircleClipper +{ +public: + QwtCircleClipper( const QRectF &r ); + QVector<QwtInterval> clipCircle( const QPointF &, double radius ) const; + +private: + enum Edge + { + Left, + Top, + Right, + Bottom, + + NEdges + }; + + QList<QPointF> cuttingPoints( + Edge, const QPointF &pos, double radius ) const; + + double toAngle( const QPointF &, const QPointF & ) const; + + const QRectF d_rect; +}; + + +QwtCircleClipper::QwtCircleClipper( const QRectF &r ): + d_rect( r ) +{ +} + +QVector<QwtInterval> QwtCircleClipper::clipCircle( + const QPointF &pos, double radius ) const +{ + QList<QPointF> points; + for ( int edge = 0; edge < NEdges; edge++ ) + points += cuttingPoints( ( Edge )edge, pos, radius ); + + QVector<QwtInterval> intv; + if ( points.size() <= 0 ) + { + QRectF cRect( 0, 0, 2 * radius, 2 * radius ); + cRect.moveCenter( pos ); + if ( d_rect.contains( cRect ) ) + intv += QwtInterval( 0.0, 2 * M_PI ); + } + else + { + QList<double> angles; + for ( int i = 0; i < points.size(); i++ ) + angles += toAngle( pos, points[i] ); + qSort( angles ); + + const int in = d_rect.contains( qwtPolar2Pos( pos, radius, + angles[0] + ( angles[1] - angles[0] ) / 2 ) ); + + if ( in ) + { + for ( int i = 0; i < angles.size() - 1; i += 2 ) + intv += QwtInterval( angles[i], angles[i+1] ); + } + else + { + for ( int i = 1; i < angles.size() - 1; i += 2 ) + intv += QwtInterval( angles[i], angles[i+1] ); + intv += QwtInterval( angles.last(), angles.first() ); + } + } + + return intv; +} + +double QwtCircleClipper::toAngle( + const QPointF &from, const QPointF &to ) const +{ + if ( from.x() == to.x() ) + return from.y() <= to.y() ? M_PI / 2.0 : 3 * M_PI / 2.0; + + const double m = qAbs( ( to.y() - from.y() ) / ( to.x() - from.x() ) ); + + double angle = qAtan( m ); + if ( to.x() > from.x() ) + { + if ( to.y() > from.y() ) + angle = 2 * M_PI - angle; + } + else + { + if ( to.y() > from.y() ) + angle = M_PI + angle; + else + angle = M_PI - angle; + } + + return angle; +} + +QList<QPointF> QwtCircleClipper::cuttingPoints( + Edge edge, const QPointF &pos, double radius ) const +{ + QList<QPointF> points; + + if ( edge == Left || edge == Right ) + { + const double x = ( edge == Left ) ? d_rect.left() : d_rect.right(); + if ( qAbs( pos.x() - x ) < radius ) + { + const double off = qSqrt( qwtSqr( radius ) - qwtSqr( pos.x() - x ) ); + const double m_y1 = pos.y() + off; + if ( m_y1 >= d_rect.top() && m_y1 <= d_rect.bottom() ) + points += QPointF( x, m_y1 ); + + const double m_y2 = pos.y() - off; + if ( m_y2 >= d_rect.top() && m_y2 <= d_rect.bottom() ) + points += QPointF( x, m_y2 ); + } + } + else + { + const double y = ( edge == Top ) ? d_rect.top() : d_rect.bottom(); + if ( qAbs( pos.y() - y ) < radius ) + { + const double off = qSqrt( qwtSqr( radius ) - qwtSqr( pos.y() - y ) ); + const double x1 = pos.x() + off; + if ( x1 >= d_rect.left() && x1 <= d_rect.right() ) + points += QPointF( x1, y ); + + const double m_x2 = pos.x() - off; + if ( m_x2 >= d_rect.left() && m_x2 <= d_rect.right() ) + points += QPointF( m_x2, y ); + } + } + return points; +} + +/*! + Sutherland-Hodgman polygon clipping + + \param clipRect Clip rectangle + \param polygon Polygon + \param closePolygon True, when the polygon is closed + + \return Clipped polygon +*/ +QPolygon QwtClipper::clipPolygon( + const QRect &clipRect, const QPolygon &polygon, bool closePolygon ) +{ + QwtPolygonClipper<QPolygon, QRect, QPoint, int> clipper( clipRect ); + return clipper.clipPolygon( polygon, closePolygon ); +} + +/*! + Sutherland-Hodgman polygon clipping + + \param clipRect Clip rectangle + \param polygon Polygon + \param closePolygon True, when the polygon is closed + + \return Clipped polygon +*/ +QPolygonF QwtClipper::clipPolygonF( + const QRectF &clipRect, const QPolygonF &polygon, bool closePolygon ) +{ + QwtPolygonClipper<QPolygonF, QRectF, QPointF, double> clipper( clipRect ); + return clipper.clipPolygon( polygon, closePolygon ); +} + +/*! + Circle clipping + + clipCircle() devides a circle into intervals of angles representing arcs + of the circle. When the circle is completely inside the clip rectangle + an interval [0.0, 2 * M_PI] is returned. + + \param clipRect Clip rectangle + \param center Center of the circle + \param radius Radius of the circle + + \return Arcs of the circle +*/ +QVector<QwtInterval> QwtClipper::clipCircle( const QRectF &clipRect, + const QPointF ¢er, double radius ) +{ + QwtCircleClipper clipper( clipRect ); + return clipper.clipCircle( center, radius ); +} |