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     41 #include "precomp.hpp"
     42 
     43 namespace cv
     44 {
     45 
     46 static int intersectLines( double x1, double dx1, double y1, double dy1,
     47                           double x2, double dx2, double y2, double dy2, double *t2 )
     48 {
     49     double d = dx1 * dy2 - dx2 * dy1;
     50     int result = -1;
     51 
     52     if( d != 0 )
     53     {
     54         *t2 = ((x2 - x1) * dy1 - (y2 - y1) * dx1) / d;
     55         result = 0;
     56     }
     57     return result;
     58 }
     59 
     60 static bool findCircle( Point2f pt0, Point2f pt1, Point2f pt2,
     61                        Point2f* center, float* radius )
     62 {
     63     double x1 = (pt0.x + pt1.x) * 0.5;
     64     double dy1 = pt0.x - pt1.x;
     65     double x2 = (pt1.x + pt2.x) * 0.5;
     66     double dy2 = pt1.x - pt2.x;
     67     double y1 = (pt0.y + pt1.y) * 0.5;
     68     double dx1 = pt1.y - pt0.y;
     69     double y2 = (pt1.y + pt2.y) * 0.5;
     70     double dx2 = pt2.y - pt1.y;
     71     double t = 0;
     72 
     73     if( intersectLines( x1, dx1, y1, dy1, x2, dx2, y2, dy2, &t ) >= 0 )
     74     {
     75         center->x = (float) (x2 + dx2 * t);
     76         center->y = (float) (y2 + dy2 * t);
     77         *radius = (float)norm(*center - pt0);
     78         return true;
     79     }
     80 
     81     center->x = center->y = 0.f;
     82     *radius = 0;
     83     return false;
     84 }
     85 
     86 
     87 static double pointInCircle( Point2f pt, Point2f center, float radius )
     88 {
     89     double dx = pt.x - center.x;
     90     double dy = pt.y - center.y;
     91     return (double)radius*radius - dx*dx - dy*dy;
     92 }
     93 
     94 
     95 static int findEnslosingCicle4pts_32f( Point2f* pts, Point2f& _center, float& _radius )
     96 {
     97     int shuffles[4][4] = { {0, 1, 2, 3}, {0, 1, 3, 2}, {2, 3, 0, 1}, {2, 3, 1, 0} };
     98 
     99     int idxs[4] = { 0, 1, 2, 3 };
    100     int i, j, k = 1, mi = 0;
    101     float max_dist = 0;
    102     Point2f center;
    103     Point2f min_center;
    104     float radius, min_radius = FLT_MAX;
    105     Point2f res_pts[4];
    106 
    107     center = min_center = pts[0];
    108     radius = 1.f;
    109 
    110     for( i = 0; i < 4; i++ )
    111         for( j = i + 1; j < 4; j++ )
    112         {
    113             float dist = (float)norm(pts[i] - pts[j]);
    114 
    115             if( max_dist < dist )
    116             {
    117                 max_dist = dist;
    118                 idxs[0] = i;
    119                 idxs[1] = j;
    120             }
    121         }
    122 
    123     if( max_dist > 0 )
    124     {
    125         k = 2;
    126         for( i = 0; i < 4; i++ )
    127         {
    128             for( j = 0; j < k; j++ )
    129                 if( i == idxs[j] )
    130                     break;
    131             if( j == k )
    132                 idxs[k++] = i;
    133         }
    134 
    135         center = Point2f( (pts[idxs[0]].x + pts[idxs[1]].x)*0.5f,
    136                           (pts[idxs[0]].y + pts[idxs[1]].y)*0.5f );
    137         radius = (float)(norm(pts[idxs[0]] - center)*1.03);
    138         if( radius < 1.f )
    139             radius = 1.f;
    140 
    141         if( pointInCircle( pts[idxs[2]], center, radius ) >= 0 &&
    142             pointInCircle( pts[idxs[3]], center, radius ) >= 0 )
    143         {
    144             k = 2; //rand()%2+2;
    145         }
    146         else
    147         {
    148             mi = -1;
    149             for( i = 0; i < 4; i++ )
    150             {
    151                 if( findCircle( pts[shuffles[i][0]], pts[shuffles[i][1]],
    152                                 pts[shuffles[i][2]], &center, &radius ) )
    153                 {
    154                     radius *= 1.03f;
    155                     if( radius < 2.f )
    156                         radius = 2.f;
    157 
    158                     if( pointInCircle( pts[shuffles[i][3]], center, radius ) >= 0 &&
    159                         min_radius > radius )
    160                     {
    161                         min_radius = radius;
    162                         min_center = center;
    163                         mi = i;
    164                     }
    165                 }
    166             }
    167             CV_Assert( mi >= 0 );
    168             if( mi < 0 )
    169                 mi = 0;
    170             k = 3;
    171             center = min_center;
    172             radius = min_radius;
    173             for( i = 0; i < 4; i++ )
    174                 idxs[i] = shuffles[mi][i];
    175         }
    176     }
    177 
    178     _center = center;
    179     _radius = radius;
    180 
    181     /* reorder output points */
    182     for( i = 0; i < 4; i++ )
    183         res_pts[i] = pts[idxs[i]];
    184 
    185     for( i = 0; i < 4; i++ )
    186     {
    187         pts[i] = res_pts[i];
    188         CV_Assert( pointInCircle( pts[i], center, radius ) >= 0 );
    189     }
    190 
    191     return k;
    192 }
    193 
    194 }
    195 
    196 void cv::minEnclosingCircle( InputArray _points, Point2f& _center, float& _radius )
    197 {
    198     int max_iters = 100;
    199     const float eps = FLT_EPSILON*2;
    200     bool result = false;
    201     Mat points = _points.getMat();
    202     int i, j, k, count = points.checkVector(2);
    203     int depth = points.depth();
    204     Point2f center;
    205     float radius = 0.f;
    206     CV_Assert(count >= 0 && (depth == CV_32F || depth == CV_32S));
    207 
    208     _center.x = _center.y = 0.f;
    209     _radius = 0.f;
    210 
    211     if( count == 0 )
    212         return;
    213 
    214     bool is_float = depth == CV_32F;
    215     const Point* ptsi = points.ptr<Point>();
    216     const Point2f* ptsf = points.ptr<Point2f>();
    217 
    218     Point2f pt = is_float ? ptsf[0] : Point2f((float)ptsi[0].x,(float)ptsi[0].y);
    219     Point2f pts[4] = {pt, pt, pt, pt};
    220 
    221     for( i = 1; i < count; i++ )
    222     {
    223         pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
    224 
    225         if( pt.x < pts[0].x )
    226             pts[0] = pt;
    227         if( pt.x > pts[1].x )
    228             pts[1] = pt;
    229         if( pt.y < pts[2].y )
    230             pts[2] = pt;
    231         if( pt.y > pts[3].y )
    232             pts[3] = pt;
    233     }
    234 
    235     for( k = 0; k < max_iters; k++ )
    236     {
    237         double min_delta = 0, delta;
    238         Point2f farAway(0,0);
    239         /*only for first iteration because the alg is repared at the loop's foot*/
    240         if( k == 0 )
    241             findEnslosingCicle4pts_32f( pts, center, radius );
    242 
    243         for( i = 0; i < count; i++ )
    244         {
    245             pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x,(float)ptsi[i].y);
    246 
    247             delta = pointInCircle( pt, center, radius );
    248             if( delta < min_delta )
    249             {
    250                 min_delta = delta;
    251                 farAway = pt;
    252             }
    253         }
    254         result = min_delta >= 0;
    255         if( result )
    256             break;
    257 
    258         Point2f ptsCopy[4];
    259         // find good replacement partner for the point which is at most far away,
    260         // starting with the one that lays in the actual circle (i=3)
    261         for( i = 3; i >= 0; i-- )
    262         {
    263             for( j = 0; j < 4; j++ )
    264                 ptsCopy[j] = i != j ? pts[j] : farAway;
    265 
    266             findEnslosingCicle4pts_32f( ptsCopy, center, radius );
    267             if( pointInCircle( pts[i], center, radius ) >= 0)
    268             {
    269                 // replaced one again in the new circle?
    270                 pts[i] = farAway;
    271                 break;
    272             }
    273         }
    274     }
    275 
    276     if( !result )
    277     {
    278         radius = 0.f;
    279         for( i = 0; i < count; i++ )
    280         {
    281             pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x,(float)ptsi[i].y);
    282             float dx = center.x - pt.x, dy = center.y - pt.y;
    283             float t = dx*dx + dy*dy;
    284             radius = MAX(radius, t);
    285         }
    286 
    287         radius = (float)(std::sqrt(radius)*(1 + eps));
    288     }
    289 
    290     _center = center;
    291     _radius = radius;
    292 }
    293 
    294 
    295 // calculates length of a curve (e.g. contour perimeter)
    296 double cv::arcLength( InputArray _curve, bool is_closed )
    297 {
    298     Mat curve = _curve.getMat();
    299     int count = curve.checkVector(2);
    300     int depth = curve.depth();
    301     CV_Assert( count >= 0 && (depth == CV_32F || depth == CV_32S));
    302     double perimeter = 0;
    303 
    304     int i, j = 0;
    305     const int N = 16;
    306     float buf[N];
    307 
    308     if( count <= 1 )
    309         return 0.;
    310 
    311     bool is_float = depth == CV_32F;
    312     int last = is_closed ? count-1 : 0;
    313     const Point* pti = curve.ptr<Point>();
    314     const Point2f* ptf = curve.ptr<Point2f>();
    315 
    316     Point2f prev = is_float ? ptf[last] : Point2f((float)pti[last].x,(float)pti[last].y);
    317 
    318     for( i = 0; i < count; i++ )
    319     {
    320         Point2f p = is_float ? ptf[i] : Point2f((float)pti[i].x,(float)pti[i].y);
    321         float dx = p.x - prev.x, dy = p.y - prev.y;
    322         buf[j] = dx*dx + dy*dy;
    323 
    324         if( ++j == N || i == count-1 )
    325         {
    326             Mat bufmat(1, j, CV_32F, buf);
    327             sqrt(bufmat, bufmat);
    328             for( ; j > 0; j-- )
    329                 perimeter += buf[j-1];
    330         }
    331         prev = p;
    332     }
    333 
    334     return perimeter;
    335 }
    336 
    337 // area of a whole sequence
    338 double cv::contourArea( InputArray _contour, bool oriented )
    339 {
    340     Mat contour = _contour.getMat();
    341     int npoints = contour.checkVector(2);
    342     int depth = contour.depth();
    343     CV_Assert(npoints >= 0 && (depth == CV_32F || depth == CV_32S));
    344 
    345     if( npoints == 0 )
    346         return 0.;
    347 
    348     double a00 = 0;
    349     bool is_float = depth == CV_32F;
    350     const Point* ptsi = contour.ptr<Point>();
    351     const Point2f* ptsf = contour.ptr<Point2f>();
    352     Point2f prev = is_float ? ptsf[npoints-1] : Point2f((float)ptsi[npoints-1].x, (float)ptsi[npoints-1].y);
    353 
    354     for( int i = 0; i < npoints; i++ )
    355     {
    356         Point2f p = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
    357         a00 += (double)prev.x * p.y - (double)prev.y * p.x;
    358         prev = p;
    359     }
    360 
    361     a00 *= 0.5;
    362     if( !oriented )
    363         a00 = fabs(a00);
    364 
    365     return a00;
    366 }
    367 
    368 
    369 cv::RotatedRect cv::fitEllipse( InputArray _points )
    370 {
    371     Mat points = _points.getMat();
    372     int i, n = points.checkVector(2);
    373     int depth = points.depth();
    374     CV_Assert( n >= 0 && (depth == CV_32F || depth == CV_32S));
    375 
    376     RotatedRect box;
    377 
    378     if( n < 5 )
    379         CV_Error( CV_StsBadSize, "There should be at least 5 points to fit the ellipse" );
    380 
    381     // New fitellipse algorithm, contributed by Dr. Daniel Weiss
    382     Point2f c(0,0);
    383     double gfp[5], rp[5], t;
    384     const double min_eps = 1e-8;
    385     bool is_float = depth == CV_32F;
    386     const Point* ptsi = points.ptr<Point>();
    387     const Point2f* ptsf = points.ptr<Point2f>();
    388 
    389     AutoBuffer<double> _Ad(n*5), _bd(n);
    390     double *Ad = _Ad, *bd = _bd;
    391 
    392     // first fit for parameters A - E
    393     Mat A( n, 5, CV_64F, Ad );
    394     Mat b( n, 1, CV_64F, bd );
    395     Mat x( 5, 1, CV_64F, gfp );
    396 
    397     for( i = 0; i < n; i++ )
    398     {
    399         Point2f p = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
    400         c += p;
    401     }
    402     c.x /= n;
    403     c.y /= n;
    404 
    405     for( i = 0; i < n; i++ )
    406     {
    407         Point2f p = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
    408         p -= c;
    409 
    410         bd[i] = 10000.0; // 1.0?
    411         Ad[i*5] = -(double)p.x * p.x; // A - C signs inverted as proposed by APP
    412         Ad[i*5 + 1] = -(double)p.y * p.y;
    413         Ad[i*5 + 2] = -(double)p.x * p.y;
    414         Ad[i*5 + 3] = p.x;
    415         Ad[i*5 + 4] = p.y;
    416     }
    417 
    418     solve(A, b, x, DECOMP_SVD);
    419 
    420     // now use general-form parameters A - E to find the ellipse center:
    421     // differentiate general form wrt x/y to get two equations for cx and cy
    422     A = Mat( 2, 2, CV_64F, Ad );
    423     b = Mat( 2, 1, CV_64F, bd );
    424     x = Mat( 2, 1, CV_64F, rp );
    425     Ad[0] = 2 * gfp[0];
    426     Ad[1] = Ad[2] = gfp[2];
    427     Ad[3] = 2 * gfp[1];
    428     bd[0] = gfp[3];
    429     bd[1] = gfp[4];
    430     solve( A, b, x, DECOMP_SVD );
    431 
    432     // re-fit for parameters A - C with those center coordinates
    433     A = Mat( n, 3, CV_64F, Ad );
    434     b = Mat( n, 1, CV_64F, bd );
    435     x = Mat( 3, 1, CV_64F, gfp );
    436     for( i = 0; i < n; i++ )
    437     {
    438         Point2f p = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
    439         p -= c;
    440         bd[i] = 1.0;
    441         Ad[i * 3] = (p.x - rp[0]) * (p.x - rp[0]);
    442         Ad[i * 3 + 1] = (p.y - rp[1]) * (p.y - rp[1]);
    443         Ad[i * 3 + 2] = (p.x - rp[0]) * (p.y - rp[1]);
    444     }
    445     solve(A, b, x, DECOMP_SVD);
    446 
    447     // store angle and radii
    448     rp[4] = -0.5 * atan2(gfp[2], gfp[1] - gfp[0]); // convert from APP angle usage
    449     if( fabs(gfp[2]) > min_eps )
    450         t = gfp[2]/sin(-2.0 * rp[4]);
    451     else // ellipse is rotated by an integer multiple of pi/2
    452         t = gfp[1] - gfp[0];
    453     rp[2] = fabs(gfp[0] + gfp[1] - t);
    454     if( rp[2] > min_eps )
    455         rp[2] = std::sqrt(2.0 / rp[2]);
    456     rp[3] = fabs(gfp[0] + gfp[1] + t);
    457     if( rp[3] > min_eps )
    458         rp[3] = std::sqrt(2.0 / rp[3]);
    459 
    460     box.center.x = (float)rp[0] + c.x;
    461     box.center.y = (float)rp[1] + c.y;
    462     box.size.width = (float)(rp[2]*2);
    463     box.size.height = (float)(rp[3]*2);
    464     if( box.size.width > box.size.height )
    465     {
    466         float tmp;
    467         CV_SWAP( box.size.width, box.size.height, tmp );
    468         box.angle = (float)(90 + rp[4]*180/CV_PI);
    469     }
    470     if( box.angle < -180 )
    471         box.angle += 360;
    472     if( box.angle > 360 )
    473         box.angle -= 360;
    474 
    475     return box;
    476 }
    477 
    478 
    479 namespace cv
    480 {
    481 
    482 // Calculates bounding rectagnle of a point set or retrieves already calculated
    483 static Rect pointSetBoundingRect( const Mat& points )
    484 {
    485     int npoints = points.checkVector(2);
    486     int depth = points.depth();
    487     CV_Assert(npoints >= 0 && (depth == CV_32F || depth == CV_32S));
    488 
    489     int  xmin = 0, ymin = 0, xmax = -1, ymax = -1, i;
    490     bool is_float = depth == CV_32F;
    491 
    492     if( npoints == 0 )
    493         return Rect();
    494 
    495     const Point* pts = points.ptr<Point>();
    496     Point pt = pts[0];
    497 
    498 #if CV_SSE4_2
    499     if(cv::checkHardwareSupport(CV_CPU_SSE4_2))
    500     {
    501         if( !is_float )
    502         {
    503             __m128i minval, maxval;
    504             minval = maxval = _mm_loadl_epi64((const __m128i*)(&pt)); //min[0]=pt.x, min[1]=pt.y
    505 
    506             for( i = 1; i < npoints; i++ )
    507             {
    508                 __m128i ptXY = _mm_loadl_epi64((const __m128i*)&pts[i]);
    509                 minval = _mm_min_epi32(ptXY, minval);
    510                 maxval = _mm_max_epi32(ptXY, maxval);
    511             }
    512             xmin = _mm_cvtsi128_si32(minval);
    513             ymin = _mm_cvtsi128_si32(_mm_srli_si128(minval, 4));
    514             xmax = _mm_cvtsi128_si32(maxval);
    515             ymax = _mm_cvtsi128_si32(_mm_srli_si128(maxval, 4));
    516         }
    517         else
    518         {
    519             __m128 minvalf, maxvalf, z = _mm_setzero_ps(), ptXY = _mm_setzero_ps();
    520             minvalf = maxvalf = _mm_loadl_pi(z, (const __m64*)(&pt));
    521 
    522             for( i = 1; i < npoints; i++ )
    523             {
    524                 ptXY = _mm_loadl_pi(ptXY, (const __m64*)&pts[i]);
    525 
    526                 minvalf = _mm_min_ps(minvalf, ptXY);
    527                 maxvalf = _mm_max_ps(maxvalf, ptXY);
    528             }
    529 
    530             float xyminf[2], xymaxf[2];
    531             _mm_storel_pi((__m64*)xyminf, minvalf);
    532             _mm_storel_pi((__m64*)xymaxf, maxvalf);
    533             xmin = cvFloor(xyminf[0]);
    534             ymin = cvFloor(xyminf[1]);
    535             xmax = cvFloor(xymaxf[0]);
    536             ymax = cvFloor(xymaxf[1]);
    537         }
    538     }
    539     else
    540 #endif
    541     {
    542         if( !is_float )
    543         {
    544             xmin = xmax = pt.x;
    545             ymin = ymax = pt.y;
    546 
    547             for( i = 1; i < npoints; i++ )
    548             {
    549                 pt = pts[i];
    550 
    551                 if( xmin > pt.x )
    552                     xmin = pt.x;
    553 
    554                 if( xmax < pt.x )
    555                     xmax = pt.x;
    556 
    557                 if( ymin > pt.y )
    558                     ymin = pt.y;
    559 
    560                 if( ymax < pt.y )
    561                     ymax = pt.y;
    562             }
    563         }
    564         else
    565         {
    566             Cv32suf v;
    567             // init values
    568             xmin = xmax = CV_TOGGLE_FLT(pt.x);
    569             ymin = ymax = CV_TOGGLE_FLT(pt.y);
    570 
    571             for( i = 1; i < npoints; i++ )
    572             {
    573                 pt = pts[i];
    574                 pt.x = CV_TOGGLE_FLT(pt.x);
    575                 pt.y = CV_TOGGLE_FLT(pt.y);
    576 
    577                 if( xmin > pt.x )
    578                     xmin = pt.x;
    579 
    580                 if( xmax < pt.x )
    581                     xmax = pt.x;
    582 
    583                 if( ymin > pt.y )
    584                     ymin = pt.y;
    585 
    586                 if( ymax < pt.y )
    587                     ymax = pt.y;
    588             }
    589 
    590             v.i = CV_TOGGLE_FLT(xmin); xmin = cvFloor(v.f);
    591             v.i = CV_TOGGLE_FLT(ymin); ymin = cvFloor(v.f);
    592             // because right and bottom sides of the bounding rectangle are not inclusive
    593             // (note +1 in width and height calculation below), cvFloor is used here instead of cvCeil
    594             v.i = CV_TOGGLE_FLT(xmax); xmax = cvFloor(v.f);
    595             v.i = CV_TOGGLE_FLT(ymax); ymax = cvFloor(v.f);
    596         }
    597     }
    598 
    599     return Rect(xmin, ymin, xmax - xmin + 1, ymax - ymin + 1);
    600 }
    601 
    602 
    603 static Rect maskBoundingRect( const Mat& img )
    604 {
    605     CV_Assert( img.depth() <= CV_8S && img.channels() == 1 );
    606 
    607     Size size = img.size();
    608     int xmin = size.width, ymin = -1, xmax = -1, ymax = -1, i, j, k;
    609 
    610     for( i = 0; i < size.height; i++ )
    611     {
    612         const uchar* _ptr = img.ptr(i);
    613         const uchar* ptr = (const uchar*)alignPtr(_ptr, 4);
    614         int have_nz = 0, k_min, offset = (int)(ptr - _ptr);
    615         j = 0;
    616         offset = MIN(offset, size.width);
    617         for( ; j < offset; j++ )
    618             if( _ptr[j] )
    619             {
    620                 have_nz = 1;
    621                 break;
    622             }
    623         if( j < offset )
    624         {
    625             if( j < xmin )
    626                 xmin = j;
    627             if( j > xmax )
    628                 xmax = j;
    629         }
    630         if( offset < size.width )
    631         {
    632             xmin -= offset;
    633             xmax -= offset;
    634             size.width -= offset;
    635             j = 0;
    636             for( ; j <= xmin - 4; j += 4 )
    637                 if( *((int*)(ptr+j)) )
    638                     break;
    639             for( ; j < xmin; j++ )
    640                 if( ptr[j] )
    641                 {
    642                     xmin = j;
    643                     if( j > xmax )
    644                         xmax = j;
    645                     have_nz = 1;
    646                     break;
    647                 }
    648             k_min = MAX(j-1, xmax);
    649             k = size.width - 1;
    650             for( ; k > k_min && (k&3) != 3; k-- )
    651                 if( ptr[k] )
    652                     break;
    653             if( k > k_min && (k&3) == 3 )
    654             {
    655                 for( ; k > k_min+3; k -= 4 )
    656                     if( *((int*)(ptr+k-3)) )
    657                         break;
    658             }
    659             for( ; k > k_min; k-- )
    660                 if( ptr[k] )
    661                 {
    662                     xmax = k;
    663                     have_nz = 1;
    664                     break;
    665                 }
    666             if( !have_nz )
    667             {
    668                 j &= ~3;
    669                 for( ; j <= k - 3; j += 4 )
    670                     if( *((int*)(ptr+j)) )
    671                         break;
    672                 for( ; j <= k; j++ )
    673                     if( ptr[j] )
    674                     {
    675                         have_nz = 1;
    676                         break;
    677                     }
    678             }
    679             xmin += offset;
    680             xmax += offset;
    681             size.width += offset;
    682         }
    683         if( have_nz )
    684         {
    685             if( ymin < 0 )
    686                 ymin = i;
    687             ymax = i;
    688         }
    689     }
    690 
    691     if( xmin >= size.width )
    692         xmin = ymin = 0;
    693     return Rect(xmin, ymin, xmax - xmin + 1, ymax - ymin + 1);
    694 }
    695 
    696 }
    697 
    698 cv::Rect cv::boundingRect(InputArray array)
    699 {
    700     Mat m = array.getMat();
    701     return m.depth() <= CV_8U ? maskBoundingRect(m) : pointSetBoundingRect(m);
    702 }
    703 
    704 ////////////////////////////////////////////// C API ///////////////////////////////////////////
    705 
    706 CV_IMPL int
    707 cvMinEnclosingCircle( const void* array, CvPoint2D32f * _center, float *_radius )
    708 {
    709     cv::AutoBuffer<double> abuf;
    710     cv::Mat points = cv::cvarrToMat(array, false, false, 0, &abuf);
    711     cv::Point2f center;
    712     float radius;
    713 
    714     cv::minEnclosingCircle(points, center, radius);
    715     if(_center)
    716         *_center = center;
    717     if(_radius)
    718         *_radius = radius;
    719     return 1;
    720 }
    721 
    722 static void
    723 icvMemCopy( double **buf1, double **buf2, double **buf3, int *b_max )
    724 {
    725     CV_Assert( (*buf1 != NULL || *buf2 != NULL) && *buf3 != NULL );
    726 
    727     int bb = *b_max;
    728     if( *buf2 == NULL )
    729     {
    730         *b_max = 2 * (*b_max);
    731         *buf2 = (double *)cvAlloc( (*b_max) * sizeof( double ));
    732 
    733         memcpy( *buf2, *buf3, bb * sizeof( double ));
    734 
    735         *buf3 = *buf2;
    736         cvFree( buf1 );
    737         *buf1 = NULL;
    738     }
    739     else
    740     {
    741         *b_max = 2 * (*b_max);
    742         *buf1 = (double *) cvAlloc( (*b_max) * sizeof( double ));
    743 
    744         memcpy( *buf1, *buf3, bb * sizeof( double ));
    745 
    746         *buf3 = *buf1;
    747         cvFree( buf2 );
    748         *buf2 = NULL;
    749     }
    750 }
    751 
    752 
    753 /* area of a contour sector */
    754 static double icvContourSecArea( CvSeq * contour, CvSlice slice )
    755 {
    756     CvPoint pt;                 /*  pointer to points   */
    757     CvPoint pt_s, pt_e;         /*  first and last points  */
    758     CvSeqReader reader;         /*  points reader of contour   */
    759 
    760     int p_max = 2, p_ind;
    761     int lpt, flag, i;
    762     double a00;                 /* unnormalized moments m00    */
    763     double xi, yi, xi_1, yi_1, x0, y0, dxy, sk, sk1, t;
    764     double x_s, y_s, nx, ny, dx, dy, du, dv;
    765     double eps = 1.e-5;
    766     double *p_are1, *p_are2, *p_are;
    767     double area = 0;
    768 
    769     CV_Assert( contour != NULL && CV_IS_SEQ_POINT_SET( contour ));
    770 
    771     lpt = cvSliceLength( slice, contour );
    772     /*if( n2 >= n1 )
    773         lpt = n2 - n1 + 1;
    774     else
    775         lpt = contour->total - n1 + n2 + 1;*/
    776 
    777     if( contour->total <= 0 || lpt <= 2 )
    778         return 0.;
    779 
    780     a00 = x0 = y0 = xi_1 = yi_1 = 0;
    781     sk1 = 0;
    782     flag = 0;
    783     dxy = 0;
    784     p_are1 = (double *) cvAlloc( p_max * sizeof( double ));
    785 
    786     p_are = p_are1;
    787     p_are2 = NULL;
    788 
    789     cvStartReadSeq( contour, &reader, 0 );
    790     cvSetSeqReaderPos( &reader, slice.start_index );
    791     CV_READ_SEQ_ELEM( pt_s, reader );
    792     p_ind = 0;
    793     cvSetSeqReaderPos( &reader, slice.end_index );
    794     CV_READ_SEQ_ELEM( pt_e, reader );
    795 
    796 /*    normal coefficients    */
    797     nx = pt_s.y - pt_e.y;
    798     ny = pt_e.x - pt_s.x;
    799     cvSetSeqReaderPos( &reader, slice.start_index );
    800 
    801     while( lpt-- > 0 )
    802     {
    803         CV_READ_SEQ_ELEM( pt, reader );
    804 
    805         if( flag == 0 )
    806         {
    807             xi_1 = (double) pt.x;
    808             yi_1 = (double) pt.y;
    809             x0 = xi_1;
    810             y0 = yi_1;
    811             sk1 = 0;
    812             flag = 1;
    813         }
    814         else
    815         {
    816             xi = (double) pt.x;
    817             yi = (double) pt.y;
    818 
    819 /****************   edges intersection examination   **************************/
    820             sk = nx * (xi - pt_s.x) + ny * (yi - pt_s.y);
    821             if( (fabs( sk ) < eps && lpt > 0) || sk * sk1 < -eps )
    822             {
    823                 if( fabs( sk ) < eps )
    824                 {
    825                     dxy = xi_1 * yi - xi * yi_1;
    826                     a00 = a00 + dxy;
    827                     dxy = xi * y0 - x0 * yi;
    828                     a00 = a00 + dxy;
    829 
    830                     if( p_ind >= p_max )
    831                         icvMemCopy( &p_are1, &p_are2, &p_are, &p_max );
    832 
    833                     p_are[p_ind] = a00 / 2.;
    834                     p_ind++;
    835                     a00 = 0;
    836                     sk1 = 0;
    837                     x0 = xi;
    838                     y0 = yi;
    839                     dxy = 0;
    840                 }
    841                 else
    842                 {
    843 /*  define intersection point    */
    844                     dv = yi - yi_1;
    845                     du = xi - xi_1;
    846                     dx = ny;
    847                     dy = -nx;
    848                     if( fabs( du ) > eps )
    849                         t = ((yi_1 - pt_s.y) * du + dv * (pt_s.x - xi_1)) /
    850                             (du * dy - dx * dv);
    851                     else
    852                         t = (xi_1 - pt_s.x) / dx;
    853                     if( t > eps && t < 1 - eps )
    854                     {
    855                         x_s = pt_s.x + t * dx;
    856                         y_s = pt_s.y + t * dy;
    857                         dxy = xi_1 * y_s - x_s * yi_1;
    858                         a00 += dxy;
    859                         dxy = x_s * y0 - x0 * y_s;
    860                         a00 += dxy;
    861                         if( p_ind >= p_max )
    862                             icvMemCopy( &p_are1, &p_are2, &p_are, &p_max );
    863 
    864                         p_are[p_ind] = a00 / 2.;
    865                         p_ind++;
    866 
    867                         a00 = 0;
    868                         sk1 = 0;
    869                         x0 = x_s;
    870                         y0 = y_s;
    871                         dxy = x_s * yi - xi * y_s;
    872                     }
    873                 }
    874             }
    875             else
    876                 dxy = xi_1 * yi - xi * yi_1;
    877 
    878             a00 += dxy;
    879             xi_1 = xi;
    880             yi_1 = yi;
    881             sk1 = sk;
    882 
    883         }
    884     }
    885 
    886     xi = x0;
    887     yi = y0;
    888     dxy = xi_1 * yi - xi * yi_1;
    889 
    890     a00 += dxy;
    891 
    892     if( p_ind >= p_max )
    893         icvMemCopy( &p_are1, &p_are2, &p_are, &p_max );
    894 
    895     p_are[p_ind] = a00 / 2.;
    896     p_ind++;
    897 
    898     // common area calculation
    899     area = 0;
    900     for( i = 0; i < p_ind; i++ )
    901         area += fabs( p_are[i] );
    902 
    903     if( p_are1 != NULL )
    904         cvFree( &p_are1 );
    905     else if( p_are2 != NULL )
    906         cvFree( &p_are2 );
    907 
    908     return area;
    909 }
    910 
    911 
    912 /* external contour area function */
    913 CV_IMPL double
    914 cvContourArea( const void *array, CvSlice slice, int oriented )
    915 {
    916     double area = 0;
    917 
    918     CvContour contour_header;
    919     CvSeq* contour = 0;
    920     CvSeqBlock block;
    921 
    922     if( CV_IS_SEQ( array ))
    923     {
    924         contour = (CvSeq*)array;
    925         if( !CV_IS_SEQ_POLYLINE( contour ))
    926             CV_Error( CV_StsBadArg, "Unsupported sequence type" );
    927     }
    928     else
    929     {
    930         contour = cvPointSeqFromMat( CV_SEQ_KIND_CURVE, array, &contour_header, &block );
    931     }
    932 
    933     if( cvSliceLength( slice, contour ) == contour->total )
    934     {
    935         cv::AutoBuffer<double> abuf;
    936         cv::Mat points = cv::cvarrToMat(contour, false, false, 0, &abuf);
    937         return cv::contourArea( points, oriented !=0 );
    938     }
    939 
    940     if( CV_SEQ_ELTYPE( contour ) != CV_32SC2 )
    941         CV_Error( CV_StsUnsupportedFormat,
    942         "Only curves with integer coordinates are supported in case of contour slice" );
    943     area = icvContourSecArea( contour, slice );
    944     return oriented ? area : fabs(area);
    945 }
    946 
    947 
    948 /* calculates length of a curve (e.g. contour perimeter) */
    949 CV_IMPL  double
    950 cvArcLength( const void *array, CvSlice slice, int is_closed )
    951 {
    952     double perimeter = 0;
    953 
    954     int i, j = 0, count;
    955     const int N = 16;
    956     float buf[N];
    957     CvMat buffer = cvMat( 1, N, CV_32F, buf );
    958     CvSeqReader reader;
    959     CvContour contour_header;
    960     CvSeq* contour = 0;
    961     CvSeqBlock block;
    962 
    963     if( CV_IS_SEQ( array ))
    964     {
    965         contour = (CvSeq*)array;
    966         if( !CV_IS_SEQ_POLYLINE( contour ))
    967             CV_Error( CV_StsBadArg, "Unsupported sequence type" );
    968         if( is_closed < 0 )
    969             is_closed = CV_IS_SEQ_CLOSED( contour );
    970     }
    971     else
    972     {
    973         is_closed = is_closed > 0;
    974         contour = cvPointSeqFromMat(
    975                                     CV_SEQ_KIND_CURVE | (is_closed ? CV_SEQ_FLAG_CLOSED : 0),
    976                                     array, &contour_header, &block );
    977     }
    978 
    979     if( contour->total > 1 )
    980     {
    981         int is_float = CV_SEQ_ELTYPE( contour ) == CV_32FC2;
    982 
    983         cvStartReadSeq( contour, &reader, 0 );
    984         cvSetSeqReaderPos( &reader, slice.start_index );
    985         count = cvSliceLength( slice, contour );
    986 
    987         count -= !is_closed && count == contour->total;
    988 
    989         // scroll the reader by 1 point
    990         reader.prev_elem = reader.ptr;
    991         CV_NEXT_SEQ_ELEM( sizeof(CvPoint), reader );
    992 
    993         for( i = 0; i < count; i++ )
    994         {
    995             float dx, dy;
    996 
    997             if( !is_float )
    998             {
    999                 CvPoint* pt = (CvPoint*)reader.ptr;
   1000                 CvPoint* prev_pt = (CvPoint*)reader.prev_elem;
   1001 
   1002                 dx = (float)pt->x - (float)prev_pt->x;
   1003                 dy = (float)pt->y - (float)prev_pt->y;
   1004             }
   1005             else
   1006             {
   1007                 CvPoint2D32f* pt = (CvPoint2D32f*)reader.ptr;
   1008                 CvPoint2D32f* prev_pt = (CvPoint2D32f*)reader.prev_elem;
   1009 
   1010                 dx = pt->x - prev_pt->x;
   1011                 dy = pt->y - prev_pt->y;
   1012             }
   1013 
   1014             reader.prev_elem = reader.ptr;
   1015             CV_NEXT_SEQ_ELEM( contour->elem_size, reader );
   1016             // Bugfix by Axel at rubico.com 2010-03-22, affects closed slices only
   1017             // wraparound not handled by CV_NEXT_SEQ_ELEM
   1018             if( is_closed && i == count - 2 )
   1019                 cvSetSeqReaderPos( &reader, slice.start_index );
   1020 
   1021             buffer.data.fl[j] = dx * dx + dy * dy;
   1022             if( ++j == N || i == count - 1 )
   1023             {
   1024                 buffer.cols = j;
   1025                 cvPow( &buffer, &buffer, 0.5 );
   1026                 for( ; j > 0; j-- )
   1027                     perimeter += buffer.data.fl[j-1];
   1028             }
   1029         }
   1030     }
   1031 
   1032     return perimeter;
   1033 }
   1034 
   1035 
   1036 CV_IMPL CvBox2D
   1037 cvFitEllipse2( const CvArr* array )
   1038 {
   1039     cv::AutoBuffer<double> abuf;
   1040     cv::Mat points = cv::cvarrToMat(array, false, false, 0, &abuf);
   1041     return cv::fitEllipse(points);
   1042 }
   1043 
   1044 /* Calculates bounding rectagnle of a point set or retrieves already calculated */
   1045 CV_IMPL  CvRect
   1046 cvBoundingRect( CvArr* array, int update )
   1047 {
   1048     CvRect  rect;
   1049     CvContour contour_header;
   1050     CvSeq* ptseq = 0;
   1051     CvSeqBlock block;
   1052 
   1053     CvMat stub, *mat = 0;
   1054     int calculate = update;
   1055 
   1056     if( CV_IS_SEQ( array ))
   1057     {
   1058         ptseq = (CvSeq*)array;
   1059         if( !CV_IS_SEQ_POINT_SET( ptseq ))
   1060             CV_Error( CV_StsBadArg, "Unsupported sequence type" );
   1061 
   1062         if( ptseq->header_size < (int)sizeof(CvContour))
   1063         {
   1064             update = 0;
   1065             calculate = 1;
   1066         }
   1067     }
   1068     else
   1069     {
   1070         mat = cvGetMat( array, &stub );
   1071         if( CV_MAT_TYPE(mat->type) == CV_32SC2 ||
   1072             CV_MAT_TYPE(mat->type) == CV_32FC2 )
   1073         {
   1074             ptseq = cvPointSeqFromMat(CV_SEQ_KIND_GENERIC, mat, &contour_header, &block);
   1075             mat = 0;
   1076         }
   1077         else if( CV_MAT_TYPE(mat->type) != CV_8UC1 &&
   1078                 CV_MAT_TYPE(mat->type) != CV_8SC1 )
   1079             CV_Error( CV_StsUnsupportedFormat,
   1080                 "The image/matrix format is not supported by the function" );
   1081         update = 0;
   1082         calculate = 1;
   1083     }
   1084 
   1085     if( !calculate )
   1086         return ((CvContour*)ptseq)->rect;
   1087 
   1088     if( mat )
   1089     {
   1090         rect = cv::maskBoundingRect(cv::cvarrToMat(mat));
   1091     }
   1092     else if( ptseq->total )
   1093     {
   1094         cv::AutoBuffer<double> abuf;
   1095         rect = cv::pointSetBoundingRect(cv::cvarrToMat(ptseq, false, false, 0, &abuf));
   1096     }
   1097     if( update )
   1098         ((CvContour*)ptseq)->rect = rect;
   1099     return rect;
   1100 }
   1101 
   1102 
   1103 /* End of file. */
   1104