ConvexHull2D Class Reference

#include <OpenMS/DATASTRUCTURES/ConvexHull2D.h>

Collaboration diagram for ConvexHull2D:

Public Types
typedef DPosition< 2 >	PointType
typedef std::vector< PointType >	PointArrayType
typedef PointArrayType::size_type	SizeType
typedef PointArrayType::const_iterator	PointArrayTypeConstIterator
typedef std::map< PointType::CoordinateType, DBoundingBox< 1 > >	HullPointType

Public Member Functions
	ConvexHull2D ()
	default constructor More...
	ConvexHull2D (const ConvexHull2D &)=default
	Copy constructor. More...
	ConvexHull2D (ConvexHull2D &&)=default
	Move constructor. More...
ConvexHull2D &	operator= (const ConvexHull2D &rhs)
	assignment operator More...
ConvexHull2D &	operator= (ConvexHull2D &&) &=default
	move assignment operator More...
bool	operator== (const ConvexHull2D &rhs) const
	equality operator More...
void	clear ()
	removes all points More...
const PointArrayType &	getHullPoints () const
	accessor for the outer points More...
void	setHullPoints (const PointArrayType &points)
	accessor for the outer(!) points (no checking is performed if this is actually a convex hull) More...
DBoundingBox< 2 >	getBoundingBox () const
	returns the bounding box of the feature hull points More...
bool	addPoint (const PointType &point)
void	addPoints (const PointArrayType &points)
Size	compress ()
	Allows to reduce the disk/memory footprint of a hull. More...
void	expandToBoundingBox ()
bool	encloses (const PointType &point) const
	returns if the point lies in the feature hull More...

Protected Attributes
HullPointType	map_points_
	internal structure maintaining the hull and enabling queries to encloses() More...
PointArrayType	outer_points_
	just the list of points of the outer hull (derived from map_points_ or given by user) More...

Detailed Description

@brief A 2-dimensional hull representation in [counter]clockwise direction - depending on axis labelling.

The current implementation does not guarantee to produce convex hulls.
It can still store 'old' convex hulls from featureXML without problems, but does not support the enclose() query in this case,
and you will get an exception. As an alternative, you can use my_hull.getBoundingBox().encloses(), which yields similar results,
and will always work.

If you are creating new hull from peaks (e.g. during FeatureFinding), the generated hulls of a feature are defined as
a range in m/z dimension for each RT scan (thus might be non-convex). This has the advantage that one can clearly see
where points range within each scan (although missing points within this range are still not shown).
When hulls are created like this, the encloses() function is supported, and works as expected, i.e.
for the shape defined by this hull (view it in TOPPView) it answers whether the point is inside the shape.

However, once you store the hull in featureXML and load it again, the encloses() function is not supported any longer, because the old convex hulls did not save min&max for each scan. (to support encloses() at least for the new hulls, one would need to check if there exists a min&max value for each scan --> then the query would be valid and the inner representation can be filled. Old featureXML's are not supported in any case.)

The outer hullpoints can be queried by getHullPoints().

Improvement:

For chromatograms we could postprocess the input and remove points in intermediate RT scans, which are currently reported but make the number of points rather large.

Member Typedef Documentation

HullPointType

typedef std::map<PointType::CoordinateType, DBoundingBox<1> > HullPointType

PointArrayType

typedef std::vector<PointType> PointArrayType

PointArrayTypeConstIterator

typedef PointArrayType::const_iterator PointArrayTypeConstIterator

PointType

typedef DPosition<2> PointType

SizeType

typedef PointArrayType::size_type SizeType

Constructor & Destructor Documentation

ConvexHull2D() [1/3]

ConvexHull2D

(

)

default constructor

ConvexHull2D() [2/3]

ConvexHull2D ( const ConvexHull2D &  )

default

Copy constructor.

ConvexHull2D() [3/3]

ConvexHull2D ( ConvexHull2D &&  )

default

Move constructor.

Member Function Documentation

addPoint()

bool addPoint

(

const PointType &

point

)

adds a point to the hull if it is not already contained. Returns if the point was added. this will trigger recomputation of the outer hull points (thus points set with setHullPoints() will be lost)

addPoints()

void addPoints

(

const PointArrayType &

points

)

adds points to the hull if it is not already contained. this will trigger recomputation of the outer hull points (thus points set with setHullPoints() will be lost)

clear()

void clear

(

)

removes all points

compress()

Size compress

(

)

Allows to reduce the disk/memory footprint of a hull.

Removes points from the hull which lie on a straight line and do not contribute to the hulls shape. Should be called before saving to disk.

Example: Consider a series of 3 scans with the same dimension in m/z. After calling compress, the points from the second scan will be removed, since they do not contribute to the convex hull.

Returns

Number of removed scans

encloses()

bool encloses

(

const PointType &

point

)

const

returns if the point lies in the feature hull

This function is only supported if the hull is created using addPoint() or addPoints(), but not when using setHullPoints(). If you require the latter functionality, then augment this function.

Exceptions

Exception::NotImplemented

if only hull points (outer_points_), but no internal structure (map_points_) is given

expandToBoundingBox()

void expandToBoundingBox

(

)

    @brief Expand a convex hull to its bounding box.

    This reduces the size of a convex hull to four points, its

bounding box, thus reducing size when storing the information. Note that this leads to an enclosed area that can be significantly larger than the original convex hull.

getBoundingBox()

DBoundingBox<2> getBoundingBox

(

)

const

returns the bounding box of the feature hull points

getHullPoints()

const PointArrayType& getHullPoints

(

)

const

accessor for the outer points

operator=() [1/2]

ConvexHull2D& operator=

(

const ConvexHull2D &

rhs

)

assignment operator

operator=() [2/2]

ConvexHull2D& operator= ( ConvexHull2D &&  ) &

default

move assignment operator

operator==()

bool operator==

(

const ConvexHull2D &

rhs

)

const

equality operator

setHullPoints()

void setHullPoints

(

const PointArrayType &

points

)

accessor for the outer(!) points (no checking is performed if this is actually a convex hull)

Referenced by MRMTransitionGroupPicker::pickFragmentChromatograms(), and MRMTransitionGroupPicker::pickPrecursorChromatograms().

Member Data Documentation

map_points_

HullPointType map_points_

protected

internal structure maintaining the hull and enabling queries to encloses()

outer_points_

PointArrayType outer_points_

mutableprotected

just the list of points of the outer hull (derived from map_points_ or given by user)