Geom::QuadTree Class Reference

#include <quadtree.h>

Collaboration diagram for Geom::QuadTree:

[legend]

List of all members.

Public Member Functions
	QuadTree ()
Quad *	search (double x0, double y0, double x1, double y1)
void	insert (double x0, double y0, double x1, double y1, int shape)
Quad *	search (Geom::Rect const &r)
void	insert (Geom::Rect const &r, int shape)
void	erase (Quad *q, int shape)
Public Attributes
Quad *	root
double	scale
double	bx0
double	bx1
double	by0
double	by1
Private Member Functions
bool	clean_root ()

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Detailed Description

Definition at line 70 of file quadtree.h.

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Constructor & Destructor Documentation

Geom::QuadTree::QuadTree

(

)

[inline]

Definition at line 77 of file quadtree.h.

: root(0), scale(1) {}

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Member Function Documentation

bool Geom::QuadTree::clean_root

(

)

[private]

Definition at line 253 of file quadtree.cpp.

References Geom::Quad::children, Geom::Quad::data, Barcode::Code39Ext::i, and root.

Referenced by insert().

                          { 
    assert(root);

    // false if root *has* rects assigned to it.
    bool all_clean = root->data.empty(); 

    // if root has children we get false
    for(unsigned i = 0; i < 4; i++)
    {
        if(root->children[i])
        {
            all_clean = false;
        }
    }

    if(all_clean)
    {
        delete root;
        root=0;
        return true;
    }
    return false;
}

void Geom::QuadTree::erase	(	Quad *	q,
		int	shape
	)

Definition at line 236 of file quadtree.cpp.

References Geom::Quad::data, and Barcode::Code39Ext::i.

                                       {
    for(Quad::iterator i = q->data.begin();  i != q->data.end(); i++) {
        if(*i == shape) {
            q->data.erase(i);
            if(q->data.empty()) {

            }
        }
    }
    return;
}

void Geom::QuadTree::insert	(	Geom::Rect const &	r,
		int	shape
	)

Definition at line 9 of file quadtree.cpp.

References insert(), Geom::max(), and Geom::min().

                                              {
    insert(r[0].min(), r[1].min(),
           r[0].max(), r[1].max(), shape);
}

void Geom::QuadTree::insert	(	double	x0,
		double	y0,
		double	x1,
		double	y1,
		int	shape
	)

Definition at line 130 of file quadtree.cpp.

References bx0, bx1, by0, by1, Geom::Quad::children, clean_root(), Geom::Quad::data, Barcode::Code39Ext::i, samplify::q, and root.

Referenced by insert().

                                                                           {
    // loop until a quad would break the box.

    // empty root => empty QuadTree. Create initial bounding box (0,0), (1,1)
    if(root == 0) {
        root = new Quad;
            
        bx0 = 0;
        bx1 = 1;
        by0 = 0;
        by1 = 1;
    }
    Quad *q = root;

    //A temp bounding box. Same as root's bounting box (ie of the whole QuadTree)
    double bxx0 = bx0, bxx1 = bx1;
    double byy0 = by0, byy1 = by1;

    while((bxx0 > x0) ||
          (bxx1 < x1) ||
          (byy0 > y0) ||
          (byy1 < y1)) { 
        // QuadTree has small size, can't accomodate new rect. Double the size:
        unsigned i = 0;

        if(bxx0 > x0) {
            bxx0 = 2*bxx0 - bxx1;
            i += 1;
        } else {
            bxx1 = 2*bxx1 - bxx0;
        }
        if(byy0 > y0) {
            byy0 = 2*byy0 - byy1;
            i += 2;
        } else {
            byy1 = 2*byy1 - byy0;
        }
        q = new Quad;
        //check if root is empty (no rects, no quad children)
        if( clean_root() ){
            root = q;
        }
        else{
            q->children[i] = root;
            root = q;
        }
        bx0 = bxx0;
        bx1 = bxx1;
        by0 = byy0;
        by1 = byy1;
    }

    while(q) {
        // Find the center of the temp bounding box
        double cx = (bxx0 + bxx1)/2;
        double cy = (byy0 + byy1)/2;
        unsigned i = 0;
        assert(x0 >= bxx0);
        assert(x1 <= bxx1);
        assert(y0 >= byy0);
        assert(y1 <= byy1);

        if(x0 >= cx) {
            i += 1;
            bxx0 = cx; // zoom in a quad
        } else if(x1 <= cx) {
            bxx1 = cx;
        } else{
            // rect does not fit in one unique quarter (in X axis) of the temp bounding box
            break;
        }
        if(y0 >= cy) {
            i += 2;
            byy0 = cy;
        } else if(y1 <= cy) {
            byy1 = cy;
        } else{
            // rect does not fit in one unique quarter (in Y axis) of the temp bounding box
            break;
        }

        // check if rect's bounding box has size 1x1. This means that rect is defined by 2 points
        // that are in the same place.
        if( ( fabs(bxx0 - bxx1) < 1.0 ) && ( fabs(byy0 - byy1) < 1.0 )){
            bxx0 = floor(bxx0);
            bxx1 = floor(bxx1);
            byy0 = floor(byy0);
            byy1 = floor(byy1);
            break;
        }

        /*
        1 rect does fit in one unique quarter of the temp bounding box. And we have found which.
        2 temp bounding box = bounding box of this quarter. 
        3 "Go in" this quarter (create if doesn't exist)
        */
        assert(i < 4);
        Quad *qq = q->children[i];
        if(qq == 0) {
            qq = new Quad;
            q->children[i] = qq;
        }
        q = qq;
    }
    q->data.push_back(shape);
}

Quad * Geom::QuadTree::search

(

Geom::Rect const &

r

)

Definition at line 4 of file quadtree.cpp.

References Geom::max(), Geom::min(), and search().

                                    {
    return search(r[0].min(), r[1].min(),
                  r[0].max(), r[1].max());
}

Quad * Geom::QuadTree::search	(	double	x0,
		double	y0,
		double	x1,
		double	y1
	)

Definition at line 15 of file quadtree.cpp.

References bx1, by1, Geom::Quad::children, Barcode::Code39Ext::i, samplify::q, and root.

Referenced by search().

                                                                 {
    Quad *q = root;
        
    double bxx0 = bx1, bxx1 = bx1;
    double byy0 = by1, byy1 = by1;
    while(q) {
        double cx = (bxx0 + bxx1)/2;
        double cy = (byy0 + byy1)/2;
        unsigned i = 0;
        if(x0 >= cx) {
            i += 1;
            bxx0 = cx; // zoom in a quad
        } else if(x1 <= cx) {
            bxx1 = cx;
        } else
            break;
        if(y0 >= cy) {
            i += 2;
            byy0 = cy;
        } else if(y1 <= cy) {
            byy1 = cy;
        } else
            break;
        
        assert(i < 4);
        Quad *qq = q->children[i];
        if(qq == 0) break; // last non-null
        q = qq;
    }
    return q;
}

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Member Data Documentation

double Geom::QuadTree::bx0

Definition at line 74 of file quadtree.h.

Referenced by insert().

double Geom::QuadTree::bx1

Definition at line 74 of file quadtree.h.

Referenced by insert(), and search().

double Geom::QuadTree::by0

Definition at line 75 of file quadtree.h.

Referenced by insert().

double Geom::QuadTree::by1

Definition at line 75 of file quadtree.h.

Referenced by insert(), and search().

Quad* Geom::QuadTree::root

Definition at line 72 of file quadtree.h.

Referenced by clean_root(), insert(), and search().

double Geom::QuadTree::scale

Definition at line 73 of file quadtree.h.

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The documentation for this class was generated from the following files:

• quadtree.h
• quadtree.cpp