fgl::FGPointArray Struct Reference

#include <base.h>

Collaboration diagram for fgl::FGPointArray:

[legend]List of all members.

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Detailed Description

The FGPointArray class provides an array of points.

A FGPointArray is an array of FGPoint objects. In addition to the functions provided by QMemArray, FGPointArray provides some point-specific functions.

For convenient reading and writing of the point data use setPoints(), putPoints(), point(), and setPoint().

For geometry operations use boundingRect() and translate(). There is also the FGMatrix::map() function for more general transformations of FGPointArrays. You can also create arcs and ellipses with makeArc() and makeEllipse().

Among others, FGPointArray is used by QPainter::drawLineSegments(), QPainter::drawPolyline(), QPainter::drawPolygon() and QPainter::drawCubicBezier().

Note that because this class is a QMemArray, copying an array and modifying the copy modifies the original as well, i.e. a shallow copy. If you need a deep copy use copy() or detach(), for example:

    void drawGiraffe( const FGPointArray & r, QPainter * p )
    {
        FGPointArray tmp = r;
        tmp.detach();
        // some code that modifies tmp
        p->drawPoints( tmp );
    }

If you forget the tmp.detach(), the const array will be modified.

See also:

FGMatrix

Public Member Functions
void	resize (unsigned new_size)
bool	isEmpty (void) const
	FGPointArray ()
	~FGPointArray ()
	FGPointArray (unsigned int nPoints)
	FGPointArray (const FGPointArray &old)
	FGPointArray (unsigned int nPoints, FGPoint *points)
	FGPointArray (unsigned int nPoints, FGCOORD points[][2])
	FGPointArray (const FGRect &r, bool closed=false)
	FGPointArray (unsigned int nPoints, const FGCOORD *points)
void	SetPoints (unsigned int nPoints, const FGCOORD *points)
void	SetPoints (unsigned nPoints, int firstx, int firsty,...)
void	SetPoints (unsigned int nPoints, const double *points)
void	translate (int dx, int dy)
FGRect	BoundingRect () const
bool	contains (const FGPoint &p) const
bool	contains (int x, int y) const
Public Attributes
unsigned int	vertices
FGPoint *	array
bool	allocated

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Constructor & Destructor Documentation

fgl::FGPointArray::FGPointArray (   )  [inline]

Constructs a null point array. See also: isNull()

fgl::FGPointArray::~FGPointArray (   )  [inline]

Destroys the point array.

fgl::FGPointArray::FGPointArray (  unsigned int  nPoints  )  [inline]

Constructs a point array with room for size points. Makes a null array if size == 0. See also: resize(), isNull()

fgl::FGPointArray::FGPointArray (  const FGPointArray &  old  )  [inline]

Constructs a deep copy of the point array a.

fgl::FGPointArray::FGPointArray (  unsigned int  nPoints, FGPoint *  points )  [inline]

Constructs a point array with nPoints points, taken from the FGPoint array. Equivalent to setPoints(nPoints, points).

fgl::FGPointArray::FGPointArray (  unsigned int  nPoints, FGCOORD  points[][2] )  [inline]

Constructs a point array with nPoints points, taken from the points array. Equivalent to SetPoints(nPoints, points).

fgl::FGPointArray::FGPointArray (  const FGRect &  r, bool  closed = false )  [inline]

Constructs a point array from the rectangle r. If closed is FALSE, then the point array just contains the following four points in the listed order: r.topLeft(), r.topRight(), r.bottomRight() and r.bottomLeft(). If closed is TRUE, then a fifth point is set to r.topLeft().

fgl::FGPointArray::FGPointArray (  unsigned int  nPoints, const FGCOORD *  points )  [inline]

Constructs a point array with nPoints points, taken from the points array. Equivalent to SetPoints(nPoints, points).

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Member Function Documentation

FGRect fgl::FGPointArray::BoundingRect (   )  const

Compute the bounding rect of polygon vertices.

bool fgl::FGPointArray::contains (  int  x, int  y )  const

Returns TRUE if the point x, y is inside this rectangle; otherwise returns FALSE.

bool fgl::FGPointArray::contains (  const FGPoint &  p  )  const

Returns: TRUE if the point p is inside this object; otherwise returns FALSE.

bool fgl::FGPointArray::isEmpty (  void   )  const [inline]

Returns TRUE if the array is empty; otherwise returns FALSE. An empty rectangle has a zero number of vertices.

void fgl::FGPointArray::resize (  unsigned  new_size  )  [inline]

Resizes the array of the FGPoints.

void fgl::FGPointArray::SetPoints (  unsigned int  nPoints, const double *  points )  [inline]

void fgl::FGPointArray::SetPoints (  unsigned  nPoints, int  firstx, int  firsty,   ... )  [inline]

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Resizes the array to nPoints and sets the points in the array to the values taken from the variable argument list. Returns TRUE if successful, or FALSE if the array could not be resized (typically due to lack of memory). The example code creates an array with two points (1,2) and (3,4): FGPointArray a; a.SetPoints( 2, 1,2, 3,4 ); The points are given as a sequence of integers, starting with firstx then firsty, and so on. See also: resize(), putPoints()

void fgl::FGPointArray::SetPoints (  unsigned int  nPoints, const FGCOORD *  points )  [inline]

void fgl::FGPointArray::translate (  int  dx, int  dy )  [inline]

Translates all points in the array by (dx, dy).

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