Update to 2.0.0 tree from current Fremantle build
[opencv] / src / cv / cvcontourtree.cpp
diff --git a/src/cv/cvcontourtree.cpp b/src/cv/cvcontourtree.cpp
new file mode 100644 (file)
index 0000000..5a8ad8a
--- /dev/null
@@ -0,0 +1,791 @@
+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
+//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+//  By downloading, copying, installing or using the software you agree to this license.
+//  If you do not agree to this license, do not download, install,
+//  copy or use the software.
+//
+//
+//                        Intel License Agreement
+//                For Open Source Computer Vision Library
+//
+// Copyright (C) 2000, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+//   * Redistribution's of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//   * Redistribution's in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+//   * The name of Intel Corporation may not be used to endorse or promote products
+//     derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+#include "_cv.h"
+
+#define CV_MATCH_CHECK( status, cvFun )                                    \
+  {                                                                        \
+    status = cvFun;                                                        \
+    if( status != CV_OK )                                                  \
+     goto M_END;                                                           \
+  }
+
+static CvStatus
+icvCalcTriAttr( const CvSeq * contour, CvPoint t2, CvPoint t1, int n1,
+                CvPoint t3, int n3, double *s, double *s_c,
+                double *h, double *a, double *b );
+
+/*F///////////////////////////////////////////////////////////////////////////////////////
+//    Name: icvCreateContourTree
+//    Purpose:
+//    Create binary tree representation for the contour 
+//    Context:
+//    Parameters:
+//      contour - pointer to input contour object.
+//      storage - pointer to the current storage block
+//      tree   -  output pointer to the binary tree representation 
+//      threshold - threshold for the binary tree building 
+//
+//F*/
+static CvStatus
+icvCreateContourTree( const CvSeq * contour, CvMemStorage * storage,
+                      CvContourTree ** tree, double threshold )
+{
+    CvPoint *pt_p;              /*  pointer to previos points   */
+    CvPoint *pt_n;              /*  pointer to next points      */
+    CvPoint *pt1, *pt2;         /*  pointer to current points   */
+
+    CvPoint t, tp1, tp2, tp3, tn1, tn2, tn3;
+    int lpt, flag, i, j, i_tree, j_1, j_3, i_buf;
+    double s, sp1, sp2, sn1, sn2, s_c, sp1_c, sp2_c, sn1_c, sn2_c, h, hp1, hp2, hn1, hn2,
+        a, ap1, ap2, an1, an2, b, bp1, bp2, bn1, bn2;
+    double a_s_c, a_sp1_c;
+
+    _CvTrianAttr **ptr_p, **ptr_n, **ptr1, **ptr2;      /*  pointers to pointers of triangles  */
+    _CvTrianAttr *cur_adr;
+
+    int *num_p, *num_n, *num1, *num2;   /*   numbers of input contour points   */
+    int nm, nmp1, nmp2, nmp3, nmn1, nmn2, nmn3;
+    int seq_flags = 1, i_end, prev_null, prev2_null;
+    double koef = 1.5;
+    double eps = 1.e-7;
+    double e;
+    CvStatus status;
+    int hearder_size;
+    _CvTrianAttr tree_one, tree_two, *tree_end, *tree_root;
+
+    CvSeqWriter writer;
+
+    assert( contour != NULL && contour->total >= 4 );
+    status = CV_OK;
+
+    if( contour == NULL )
+        return CV_NULLPTR_ERR;
+    if( contour->total < 4 )
+        return CV_BADSIZE_ERR;
+
+    if( !CV_IS_SEQ_POINT_SET( contour ))
+        return CV_BADFLAG_ERR;
+
+
+/*   Convert Sequence to array    */
+    lpt = contour->total;
+    pt_p = pt_n = NULL;
+    num_p = num_n = NULL;
+    ptr_p = ptr_n = ptr1 = ptr2 = NULL;
+    tree_end = NULL;
+
+    pt_p = (CvPoint *) cvAlloc( lpt * sizeof( CvPoint ));
+    pt_n = (CvPoint *) cvAlloc( lpt * sizeof( CvPoint ));
+
+    num_p = (int *) cvAlloc( lpt * sizeof( int ));
+    num_n = (int *) cvAlloc( lpt * sizeof( int ));
+
+    hearder_size = sizeof( CvContourTree );
+    seq_flags = CV_SEQ_POLYGON_TREE;
+    cvStartWriteSeq( seq_flags, hearder_size, sizeof( _CvTrianAttr ), storage, &writer );
+
+    ptr_p = (_CvTrianAttr **) cvAlloc( lpt * sizeof( _CvTrianAttr * ));
+    ptr_n = (_CvTrianAttr **) cvAlloc( lpt * sizeof( _CvTrianAttr * ));
+
+    memset( ptr_p, 0, lpt * sizeof( _CvTrianAttr * ));
+    memset( ptr_n, 0, lpt * sizeof( _CvTrianAttr * ));
+
+    if( pt_p == NULL || pt_n == NULL )
+        return CV_OUTOFMEM_ERR;
+    if( ptr_p == NULL || ptr_n == NULL )
+        return CV_OUTOFMEM_ERR;
+
+/*     write fild for the binary tree root   */
+/*  start_writer = writer;   */
+
+    tree_one.pt.x = tree_one.pt.y = 0;
+    tree_one.sign = 0;
+    tree_one.area = 0;
+    tree_one.r1 = tree_one.r2 = 0;
+    tree_one.next_v1 = tree_one.next_v2 = tree_one.prev_v = NULL;
+
+    CV_WRITE_SEQ_ELEM( tree_one, writer );
+    tree_root = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+    if( cvCvtSeqToArray( contour, (char *) pt_p ) == (char *) contour )
+        return CV_BADPOINT_ERR;
+
+    for( i = 0; i < lpt; i++ )
+        num_p[i] = i;
+
+    i = lpt;
+    flag = 0;
+    i_tree = 0;
+    e = 20.;                    /*  initial threshold value   */
+    ptr1 = ptr_p;
+    ptr2 = ptr_n;
+    pt1 = pt_p;
+    pt2 = pt_n;
+    num1 = num_p;
+    num2 = num_n;
+/*  binary tree constraction    */
+    while( i > 4 )
+    {
+        if( flag == 0 )
+        {
+            ptr1 = ptr_p;
+            ptr2 = ptr_n;
+            pt1 = pt_p;
+            pt2 = pt_n;
+            num1 = num_p;
+            num2 = num_n;
+            flag = 1;
+        }
+        else
+        {
+            ptr1 = ptr_n;
+            ptr2 = ptr_p;
+            pt1 = pt_n;
+            pt2 = pt_p;
+            num1 = num_n;
+            num2 = num_p;
+            flag = 0;
+        }
+        t = pt1[0];
+        nm = num1[0];
+        tp1 = pt1[i - 1];
+        nmp1 = num1[i - 1];
+        tp2 = pt1[i - 2];
+        nmp2 = num1[i - 2];
+        tp3 = pt1[i - 3];
+        nmp3 = num1[i - 3];
+        tn1 = pt1[1];
+        nmn1 = num1[1];
+        tn2 = pt1[2];
+        nmn2 = num1[2];
+
+        i_buf = 0;
+        i_end = -1;
+        CV_MATCH_CHECK( status,
+                        icvCalcTriAttr( contour, t, tp1, nmp1, tn1, nmn1, &s, &s_c, &h, &a,
+                                        &b ));
+        CV_MATCH_CHECK( status,
+                        icvCalcTriAttr( contour, tp1, tp2, nmp2, t, nm, &sp1, &sp1_c, &hp1,
+                                        &ap1, &bp1 ));
+        CV_MATCH_CHECK( status,
+                        icvCalcTriAttr( contour, tp2, tp3, nmp3, tp1, nmp1, &sp2, &sp2_c, &hp2,
+                                        &ap2, &bp2 ));
+        CV_MATCH_CHECK( status,
+                        icvCalcTriAttr( contour, tn1, t, nm, tn2, nmn2, &sn1, &sn1_c, &hn1,
+                                        &an1, &bn1 ));
+
+
+        j_3 = 3;
+        prev_null = prev2_null = 0;
+        for( j = 0; j < i; j++ )
+        {
+            tn3 = pt1[j_3];
+            nmn3 = num1[j_3];
+            if( j == 0 )
+                j_1 = i - 1;
+            else
+                j_1 = j - 1;
+
+            CV_MATCH_CHECK( status, icvCalcTriAttr( contour, tn2, tn1, nmn1, tn3, nmn3,
+                                                    &sn2, &sn2_c, &hn2, &an2, &bn2 ));
+
+            if( (s_c < sp1_c && s_c < sp2_c && s_c <= sn1_c && s_c <= sn2_c && s_c < e) ||
+                (((s_c == sp1_c && s_c <= sp2_c) || (s_c == sp2_c && s_c <= sp1_c)) &&
+                s_c <= sn1_c && s_c <= sn2_c && s_c < e && j > 1 && prev2_null == 0) ||
+                (s_c < eps && j > 0 && prev_null == 0) )
+            {
+                prev_null = prev2_null = 1;
+                if( s_c < threshold )
+                {
+                    if( ptr1[j_1] == NULL && ptr1[j] == NULL )
+                    {
+                        if( i_buf > 0 )
+                            ptr2[i_buf - 1] = NULL;
+                        else
+                            i_end = 0;
+                    }
+                    else
+                    {
+/*   form next vertex  */
+                        tree_one.pt = t;
+                        tree_one.sign = (char) (CV_SIGN( s ));
+                        tree_one.r1 = h / a;
+                        tree_one.r2 = b / a;
+                        tree_one.area = fabs( s );
+                        tree_one.next_v1 = ptr1[j_1];
+                        tree_one.next_v2 = ptr1[j];
+
+                        CV_WRITE_SEQ_ELEM( tree_one, writer );
+                        cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+                        if( ptr1[j_1] != NULL )
+                            ptr1[j_1]->prev_v = cur_adr;
+                        if( ptr1[j] != NULL )
+                            ptr1[j]->prev_v = cur_adr;
+
+                        if( i_buf > 0 )
+                            ptr2[i_buf - 1] = cur_adr;
+                        else
+                        {
+                            tree_end = (_CvTrianAttr *) writer.ptr;
+                            i_end = 1;
+                        }
+                        i_tree++;
+                    }
+                }
+                else
+/*   form next vertex    */
+                {
+                    tree_one.pt = t;
+                    tree_one.sign = (char) (CV_SIGN( s ));
+                    tree_one.area = fabs( s );
+                    tree_one.r1 = h / a;
+                    tree_one.r2 = b / a;
+                    tree_one.next_v1 = ptr1[j_1];
+                    tree_one.next_v2 = ptr1[j];
+
+                    CV_WRITE_SEQ_ELEM( tree_one, writer );
+                    cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+                    if( ptr1[j_1] != NULL )
+                        ptr1[j_1]->prev_v = cur_adr;
+                    if( ptr1[j] != NULL )
+                        ptr1[j]->prev_v = cur_adr;
+
+                    if( i_buf > 0 )
+                        ptr2[i_buf - 1] = cur_adr;
+                    else
+                    {
+                        tree_end = cur_adr;
+                        i_end = 1;
+                    }
+                    i_tree++;
+                }
+            }
+            else
+/*   the current triangle is'not LMIAT    */
+            {
+                prev_null = 0;
+                switch (prev2_null)
+                {
+                case 0:
+                    break;
+                case 1:
+                    {
+                        prev2_null = 2;
+                        break;
+                    }
+                case 2:
+                    {
+                        prev2_null = 0;
+                        break;
+                    }
+                }
+                if( j != i - 1 || i_end == -1 )
+                    ptr2[i_buf] = ptr1[j];
+                else if( i_end == 0 )
+                    ptr2[i_buf] = NULL;
+                else
+                    ptr2[i_buf] = tree_end;
+                pt2[i_buf] = t;
+                num2[i_buf] = num1[j];
+                i_buf++;
+            }
+/*    go to next vertex    */
+            tp3 = tp2;
+            tp2 = tp1;
+            tp1 = t;
+            t = tn1;
+            tn1 = tn2;
+            tn2 = tn3;
+            nmp3 = nmp2;
+            nmp2 = nmp1;
+            nmp1 = nm;
+            nm = nmn1;
+            nmn1 = nmn2;
+            nmn2 = nmn3;
+
+            sp2 = sp1;
+            sp1 = s;
+            s = sn1;
+            sn1 = sn2;
+            sp2_c = sp1_c;
+            sp1_c = s_c;
+            s_c = sn1_c;
+            sn1_c = sn2_c;
+
+            ap2 = ap1;
+            ap1 = a;
+            a = an1;
+            an1 = an2;
+            bp2 = bp1;
+            bp1 = b;
+            b = bn1;
+            bn1 = bn2;
+            hp2 = hp1;
+            hp1 = h;
+            h = hn1;
+            hn1 = hn2;
+            j_3++;
+            if( j_3 >= i )
+                j_3 = 0;
+        }
+
+        i = i_buf;
+        e = e * koef;
+    }
+
+/*  constract tree root  */
+    if( i != 4 )
+        return CV_BADFACTOR_ERR;
+
+    t = pt2[0];
+    tn1 = pt2[1];
+    tn2 = pt2[2];
+    tp1 = pt2[3];
+    nm = num2[0];
+    nmn1 = num2[1];
+    nmn2 = num2[2];
+    nmp1 = num2[3];
+/*   first pair of the triangles   */
+    CV_MATCH_CHECK( status,
+                    icvCalcTriAttr( contour, t, tp1, nmp1, tn1, nmn1, &s, &s_c, &h, &a, &b ));
+    CV_MATCH_CHECK( status,
+                    icvCalcTriAttr( contour, tn2, tn1, nmn1, tp1, nmp1, &sn2, &sn2_c, &hn2,
+                                    &an2, &bn2 ));
+/*   second pair of the triangles   */
+    CV_MATCH_CHECK( status,
+                    icvCalcTriAttr( contour, tn1, t, nm, tn2, nmn2, &sn1, &sn1_c, &hn1, &an1,
+                                    &bn1 ));
+    CV_MATCH_CHECK( status,
+                    icvCalcTriAttr( contour, tp1, tn2, nmn2, t, nm, &sp1, &sp1_c, &hp1, &ap1,
+                                    &bp1 ));
+
+    a_s_c = fabs( s_c - sn2_c );
+    a_sp1_c = fabs( sp1_c - sn1_c );
+
+    if( a_s_c > a_sp1_c )
+/*   form child vertexs for the root     */
+    {
+        tree_one.pt = t;
+        tree_one.sign = (char) (CV_SIGN( s ));
+        tree_one.area = fabs( s );
+        tree_one.r1 = h / a;
+        tree_one.r2 = b / a;
+        tree_one.next_v1 = ptr2[3];
+        tree_one.next_v2 = ptr2[0];
+
+        tree_two.pt = tn2;
+        tree_two.sign = (char) (CV_SIGN( sn2 ));
+        tree_two.area = fabs( sn2 );
+        tree_two.r1 = hn2 / an2;
+        tree_two.r2 = bn2 / an2;
+        tree_two.next_v1 = ptr2[1];
+        tree_two.next_v2 = ptr2[2];
+
+        CV_WRITE_SEQ_ELEM( tree_one, writer );
+        cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+        if( s_c > sn2_c )
+        {
+            if( ptr2[3] != NULL )
+                ptr2[3]->prev_v = cur_adr;
+            if( ptr2[0] != NULL )
+                ptr2[0]->prev_v = cur_adr;
+            ptr1[0] = cur_adr;
+
+            i_tree++;
+
+            CV_WRITE_SEQ_ELEM( tree_two, writer );
+            cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+            if( ptr2[1] != NULL )
+                ptr2[1]->prev_v = cur_adr;
+            if( ptr2[2] != NULL )
+                ptr2[2]->prev_v = cur_adr;
+            ptr1[1] = cur_adr;
+
+            i_tree++;
+
+            pt1[0] = tp1;
+            pt1[1] = tn1;
+        }
+        else
+        {
+            CV_WRITE_SEQ_ELEM( tree_two, writer );
+            cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+            if( ptr2[1] != NULL )
+                ptr2[1]->prev_v = cur_adr;
+            if( ptr2[2] != NULL )
+                ptr2[2]->prev_v = cur_adr;
+            ptr1[0] = cur_adr;
+
+            i_tree++;
+
+            CV_WRITE_SEQ_ELEM( tree_one, writer );
+            cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+            if( ptr2[3] != NULL )
+                ptr2[3]->prev_v = cur_adr;
+            if( ptr2[0] != NULL )
+                ptr2[0]->prev_v = cur_adr;
+            ptr1[1] = cur_adr;
+
+            i_tree++;
+
+            pt1[0] = tn1;
+            pt1[1] = tp1;
+        }
+    }
+    else
+    {
+        tree_one.pt = tp1;
+        tree_one.sign = (char) (CV_SIGN( sp1 ));
+        tree_one.area = fabs( sp1 );
+        tree_one.r1 = hp1 / ap1;
+        tree_one.r2 = bp1 / ap1;
+        tree_one.next_v1 = ptr2[2];
+        tree_one.next_v2 = ptr2[3];
+
+        tree_two.pt = tn1;
+        tree_two.sign = (char) (CV_SIGN( sn1 ));
+        tree_two.area = fabs( sn1 );
+        tree_two.r1 = hn1 / an1;
+        tree_two.r2 = bn1 / an1;
+        tree_two.next_v1 = ptr2[0];
+        tree_two.next_v2 = ptr2[1];
+
+        CV_WRITE_SEQ_ELEM( tree_one, writer );
+        cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+        if( sp1_c > sn1_c )
+        {
+            if( ptr2[2] != NULL )
+                ptr2[2]->prev_v = cur_adr;
+            if( ptr2[3] != NULL )
+                ptr2[3]->prev_v = cur_adr;
+            ptr1[0] = cur_adr;
+
+            i_tree++;
+
+            CV_WRITE_SEQ_ELEM( tree_two, writer );
+            cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+            if( ptr2[0] != NULL )
+                ptr2[0]->prev_v = cur_adr;
+            if( ptr2[1] != NULL )
+                ptr2[1]->prev_v = cur_adr;
+            ptr1[1] = cur_adr;
+
+            i_tree++;
+
+            pt1[0] = tn2;
+            pt1[1] = t;
+        }
+        else
+        {
+            CV_WRITE_SEQ_ELEM( tree_two, writer );
+            cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+            if( ptr2[0] != NULL )
+                ptr2[0]->prev_v = cur_adr;
+            if( ptr2[1] != NULL )
+                ptr2[1]->prev_v = cur_adr;
+            ptr1[0] = cur_adr;
+
+            i_tree++;
+
+            CV_WRITE_SEQ_ELEM( tree_one, writer );
+            cur_adr = (_CvTrianAttr *) (writer.ptr - writer.seq->elem_size);
+
+            if( ptr2[2] != NULL )
+                ptr2[2]->prev_v = cur_adr;
+            if( ptr2[3] != NULL )
+                ptr2[3]->prev_v = cur_adr;
+            ptr1[1] = cur_adr;
+
+            i_tree++;
+
+            pt1[0] = t;
+            pt1[1] = tn2;
+
+        }
+    }
+
+/*    form root   */
+    s = cvContourArea( contour );
+
+    tree_root->pt = pt1[1];
+    tree_root->sign = 0;
+    tree_root->area = fabs( s );
+    tree_root->r1 = 0;
+    tree_root->r2 = 0;
+    tree_root->next_v1 = ptr1[0];
+    tree_root->next_v2 = ptr1[1];
+    tree_root->prev_v = NULL;
+
+    ptr1[0]->prev_v = (_CvTrianAttr *) tree_root;
+    ptr1[1]->prev_v = (_CvTrianAttr *) tree_root;
+
+/*     write binary tree root   */
+/*    CV_WRITE_SEQ_ELEM (tree_one, start_writer);   */
+    i_tree++;
+/*  create Sequence hearder     */
+    *((CvSeq **) tree) = cvEndWriteSeq( &writer );
+/*   write points for the main segment into sequence header   */
+    (*tree)->p1 = pt1[0];
+
+  M_END:
+
+    cvFree( &ptr_n );
+    cvFree( &ptr_p );
+    cvFree( &num_n );
+    cvFree( &num_p );
+    cvFree( &pt_n );
+    cvFree( &pt_p );
+
+    return status;
+}
+
+/****************************************************************************************\
+
+ triangle attributes calculations 
+
+\****************************************************************************************/
+static CvStatus
+icvCalcTriAttr( const CvSeq * contour, CvPoint t2, CvPoint t1, int n1,
+                CvPoint t3, int n3, double *s, double *s_c,
+                double *h, double *a, double *b )
+{
+    double x13, y13, x12, y12, l_base, nx, ny, qq;
+    double eps = 1.e-5;
+
+    x13 = t3.x - t1.x;
+    y13 = t3.y - t1.y;
+    x12 = t2.x - t1.x;
+    y12 = t2.y - t1.y;
+    qq = x13 * x13 + y13 * y13;
+    l_base = cvSqrt( (float) (qq) );
+    if( l_base > eps )
+    {
+        nx = y13 / l_base;
+        ny = -x13 / l_base;
+
+        *h = nx * x12 + ny * y12;
+
+        *s = (*h) * l_base / 2.;
+
+        *b = nx * y12 - ny * x12;
+
+        *a = l_base;
+/*   calculate interceptive area   */
+        *s_c = cvContourArea( contour, cvSlice(n1, n3+1));
+    }
+    else
+    {
+        *h = 0;
+        *s = 0;
+        *s_c = 0;
+        *b = 0;
+        *a = 0;
+    }
+
+    return CV_OK;
+}
+
+/*F///////////////////////////////////////////////////////////////////////////////////////
+//    Name: cvCreateContourTree
+//    Purpose:
+//    Create binary tree representation for the contour 
+//    Context:
+//    Parameters:
+//      contour - pointer to input contour object.
+//      storage - pointer to the current storage block
+//      tree   -  output pointer to the binary tree representation 
+//      threshold - threshold for the binary tree building 
+//
+//F*/
+CV_IMPL CvContourTree*
+cvCreateContourTree( const CvSeq* contour, CvMemStorage* storage, double threshold )
+{
+    CvContourTree* tree = 0;
+    
+    IPPI_CALL( icvCreateContourTree( contour, storage, &tree, threshold ));
+
+    return tree;
+}
+
+
+/*F///////////////////////////////////////////////////////////////////////////////////////
+//    Name: icvContourFromContourTree
+//    Purpose:
+//    reconstracts contour from binary tree representation  
+//    Context:
+//    Parameters:
+//      tree   -  pointer to the input binary tree representation 
+//      storage - pointer to the current storage block
+//      contour - pointer to output contour object.
+//      criteria - criteria for the definition threshold value
+//                 for the contour reconstracting (level or precision)
+//F*/
+CV_IMPL CvSeq*
+cvContourFromContourTree( const CvContourTree*  tree,
+                          CvMemStorage*  storage,
+                          CvTermCriteria  criteria )
+{
+    CvSeq* contour = 0;
+    _CvTrianAttr **ptr_buf = 0;     /*  pointer to the pointer's buffer  */
+    int *level_buf = 0;
+    int i_buf;
+
+    int lpt;
+    double area_all;
+    double threshold;
+    int cur_level;
+    int level;
+    int seq_flags;
+    char log_iter, log_eps;
+    int out_hearder_size;
+    _CvTrianAttr *tree_one = 0, tree_root;  /*  current vertex  */
+
+    CvSeqReader reader;
+    CvSeqWriter writer;
+
+    CV_FUNCNAME("cvContourFromContourTree");
+
+    __BEGIN__;
+
+    if( !tree )
+        CV_ERROR( CV_StsNullPtr, "" );
+
+    if( !CV_IS_SEQ_POLYGON_TREE( tree ))
+        CV_ERROR( CV_StsBadArg, "" );
+
+    criteria = cvCheckTermCriteria( criteria, 0., 100 );
+
+    lpt = tree->total;
+    ptr_buf = NULL;
+    level_buf = NULL;
+    i_buf = 0;
+    cur_level = 0;
+    log_iter = (char) (criteria.type == CV_TERMCRIT_ITER ||
+                       (criteria.type == CV_TERMCRIT_ITER + CV_TERMCRIT_EPS));
+    log_eps = (char) (criteria.type == CV_TERMCRIT_EPS ||
+                      (criteria.type == CV_TERMCRIT_ITER + CV_TERMCRIT_EPS));
+
+    cvStartReadSeq( (CvSeq *) tree, &reader, 0 );
+
+    out_hearder_size = sizeof( CvContour );
+
+    seq_flags = CV_SEQ_POLYGON;
+    cvStartWriteSeq( seq_flags, out_hearder_size, sizeof( CvPoint ), storage, &writer );
+
+    ptr_buf = (_CvTrianAttr **) cvAlloc( lpt * sizeof( _CvTrianAttr * ));
+    if( log_iter )
+        level_buf = (int *) cvAlloc( lpt * (sizeof( int )));
+
+    memset( ptr_buf, 0, lpt * sizeof( _CvTrianAttr * ));
+
+/*     write the first tree root's point as a start point of the result contour  */
+    CV_WRITE_SEQ_ELEM( tree->p1, writer );
+/*     write the second tree root"s point into buffer    */
+
+/*     read the root of the tree   */
+    CV_READ_SEQ_ELEM( tree_root, reader );
+
+    tree_one = &tree_root;
+    area_all = tree_one->area;
+
+    if( log_eps )
+        threshold = criteria.epsilon * area_all;
+    else
+        threshold = 10 * area_all;
+
+    if( log_iter )
+        level = criteria.max_iter;
+    else
+        level = -1;
+
+/*  contour from binary tree constraction    */
+    while( i_buf >= 0 )
+    {
+        if( tree_one != NULL && (cur_level <= level || tree_one->area >= threshold) )
+/*   go to left sub tree for the vertex and save pointer to the right vertex   */
+/*   into the buffer     */
+        {
+            ptr_buf[i_buf] = tree_one;
+            if( log_iter )
+            {
+                level_buf[i_buf] = cur_level;
+                cur_level++;
+            }
+            i_buf++;
+            tree_one = tree_one->next_v1;
+        }
+        else
+        {
+            i_buf--;
+            if( i_buf >= 0 )
+            {
+                CvPoint pt = ptr_buf[i_buf]->pt;
+                CV_WRITE_SEQ_ELEM( pt, writer );
+                tree_one = ptr_buf[i_buf]->next_v2;
+                if( log_iter )
+                {
+                    cur_level = level_buf[i_buf] + 1;
+                }
+            }
+        }
+    }
+
+    contour = cvEndWriteSeq( &writer );
+    cvBoundingRect( contour, 1 );
+
+    __CLEANUP__;
+    __END__;
+
+    cvFree( &level_buf );
+    cvFree( &ptr_buf );
+
+    return contour;
+}
+