X-Git-Url: http://git.maemo.org/git/?p=opencv;a=blobdiff_plain;f=src%2Fcv%2Fcvconvhull.cpp;fp=src%2Fcv%2Fcvconvhull.cpp;h=8ef28785d0e8336f444ebcaf423ae8382f9e1fff;hp=0000000000000000000000000000000000000000;hb=e4c14cdbdf2fe805e79cd96ded236f57e7b89060;hpb=454138ff8a20f6edb9b65a910101403d8b520643 diff --git a/src/cv/cvconvhull.cpp b/src/cv/cvconvhull.cpp new file mode 100644 index 0000000..8ef2878 --- /dev/null +++ b/src/cv/cvconvhull.cpp @@ -0,0 +1,851 @@ +/*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" + +static int +icvSklansky_32s( CvPoint** array, int start, int end, int* stack, int nsign, int sign2 ) +{ + int incr = end > start ? 1 : -1; + /* prepare first triangle */ + int pprev = start, pcur = pprev + incr, pnext = pcur + incr; + int stacksize = 3; + + if( start == end || + (array[start]->x == array[end]->x && + array[start]->y == array[end]->y) ) + { + stack[0] = start; + return 1; + } + + stack[0] = pprev; + stack[1] = pcur; + stack[2] = pnext; + + end += incr; /* make end = afterend */ + + while( pnext != end ) + { + /* check the angle p1,p2,p3 */ + int cury = array[pcur]->y; + int nexty = array[pnext]->y; + int by = nexty - cury; + + if( CV_SIGN(by) != nsign ) + { + int ax = array[pcur]->x - array[pprev]->x; + int bx = array[pnext]->x - array[pcur]->x; + int ay = cury - array[pprev]->y; + int convexity = ay*bx - ax*by;/* if >0 then convex angle */ + + if( CV_SIGN(convexity) == sign2 && (ax != 0 || ay != 0) ) + { + pprev = pcur; + pcur = pnext; + pnext += incr; + stack[stacksize] = pnext; + stacksize++; + } + else + { + if( pprev == start ) + { + pcur = pnext; + stack[1] = pcur; + pnext += incr; + stack[2] = pnext; + } + else + { + stack[stacksize-2] = pnext; + pcur = pprev; + pprev = stack[stacksize-4]; + stacksize--; + } + } + } + else + { + pnext += incr; + stack[stacksize-1] = pnext; + } + } + + return --stacksize; +} + + +static int +icvSklansky_32f( CvPoint2D32f** array, int start, int end, int* stack, int nsign, int sign2 ) +{ + int incr = end > start ? 1 : -1; + /* prepare first triangle */ + int pprev = start, pcur = pprev + incr, pnext = pcur + incr; + int stacksize = 3; + + if( start == end || + (array[start]->x == array[end]->x && + array[start]->y == array[end]->y) ) + { + stack[0] = start; + return 1; + } + + stack[0] = pprev; + stack[1] = pcur; + stack[2] = pnext; + + end += incr; /* make end = afterend */ + + while( pnext != end ) + { + /* check the angle p1,p2,p3 */ + float cury = array[pcur]->y; + float nexty = array[pnext]->y; + float by = nexty - cury; + + if( CV_SIGN( by ) != nsign ) + { + float ax = array[pcur]->x - array[pprev]->x; + float bx = array[pnext]->x - array[pcur]->x; + float ay = cury - array[pprev]->y; + float convexity = ay*bx - ax*by;/* if >0 then convex angle */ + + if( CV_SIGN( convexity ) == sign2 && (ax != 0 || ay != 0) ) + { + pprev = pcur; + pcur = pnext; + pnext += incr; + stack[stacksize] = pnext; + stacksize++; + } + else + { + if( pprev == start ) + { + pcur = pnext; + stack[1] = pcur; + pnext += incr; + stack[2] = pnext; + + } + else + { + stack[stacksize-2] = pnext; + pcur = pprev; + pprev = stack[stacksize-4]; + stacksize--; + } + } + } + else + { + pnext += incr; + stack[stacksize-1] = pnext; + } + } + + return --stacksize; +} + +typedef int (*sklansky_func)( CvPoint** points, int start, int end, + int* stack, int sign, int sign2 ); + +#define cmp_pts( pt1, pt2 ) \ + ((pt1)->x < (pt2)->x || ((pt1)->x <= (pt2)->x && (pt1)->y < (pt2)->y)) +static CV_IMPLEMENT_QSORT( icvSortPointsByPointers_32s, CvPoint*, cmp_pts ) +static CV_IMPLEMENT_QSORT( icvSortPointsByPointers_32f, CvPoint2D32f*, cmp_pts ) + +static void +icvCalcAndWritePtIndices( CvPoint** pointer, int* stack, int start, int end, + CvSeq* ptseq, CvSeqWriter* writer ) +{ + CV_FUNCNAME( "icvCalcAndWritePtIndices" ); + + __BEGIN__; + + int i, incr = start < end ? 1 : -1; + int idx, first_idx = ptseq->first->start_index; + + for( i = start; i != end; i += incr ) + { + CvPoint* ptr = (CvPoint*)pointer[stack[i]]; + CvSeqBlock* block = ptseq->first; + while( (unsigned)(idx = (int)(ptr - (CvPoint*)block->data)) >= (unsigned)block->count ) + { + block = block->next; + if( block == ptseq->first ) + CV_ERROR( CV_StsError, "Internal error" ); + } + idx += block->start_index - first_idx; + CV_WRITE_SEQ_ELEM( idx, *writer ); + } + + __END__; +} + + +CV_IMPL CvSeq* +cvConvexHull2( const CvArr* array, void* hull_storage, + int orientation, int return_points ) +{ + union { CvContour* c; CvSeq* s; } hull; + CvPoint** pointer = 0; + CvPoint2D32f** pointerf = 0; + int* stack = 0; + + CV_FUNCNAME( "cvConvexHull2" ); + + hull.s = 0; + + __BEGIN__; + + CvMat* mat = 0; + CvSeqReader reader; + CvSeqWriter writer; + CvContour contour_header; + union { CvContour c; CvSeq s; } hull_header; + CvSeqBlock block, hullblock; + CvSeq* ptseq = 0; + CvSeq* hullseq = 0; + int is_float; + int* t_stack; + int t_count; + int i, miny_ind = 0, maxy_ind = 0, total; + int hulltype; + int stop_idx; + sklansky_func sklansky; + + if( CV_IS_SEQ( array )) + { + ptseq = (CvSeq*)array; + if( !CV_IS_SEQ_POINT_SET( ptseq )) + CV_ERROR( CV_StsBadArg, "Unsupported sequence type" ); + if( hull_storage == 0 ) + hull_storage = ptseq->storage; + } + else + { + CV_CALL( ptseq = cvPointSeqFromMat( + CV_SEQ_KIND_GENERIC, array, &contour_header, &block )); + } + + if( CV_IS_STORAGE( hull_storage )) + { + if( return_points ) + { + CV_CALL( hullseq = cvCreateSeq( + CV_SEQ_KIND_CURVE|CV_SEQ_ELTYPE(ptseq)| + CV_SEQ_FLAG_CLOSED|CV_SEQ_FLAG_CONVEX, + sizeof(CvContour), sizeof(CvPoint),(CvMemStorage*)hull_storage )); + } + else + { + CV_CALL( hullseq = cvCreateSeq( + CV_SEQ_KIND_CURVE|CV_SEQ_ELTYPE_PPOINT| + CV_SEQ_FLAG_CLOSED|CV_SEQ_FLAG_CONVEX, + sizeof(CvContour), sizeof(CvPoint*), (CvMemStorage*)hull_storage )); + } + } + else + { + if( !CV_IS_MAT( hull_storage )) + CV_ERROR(CV_StsBadArg, "Destination must be valid memory storage or matrix"); + + mat = (CvMat*)hull_storage; + + if( (mat->cols != 1 && mat->rows != 1) || !CV_IS_MAT_CONT(mat->type)) + CV_ERROR( CV_StsBadArg, + "The hull matrix should be continuous and have a single row or a single column" ); + + if( mat->cols + mat->rows - 1 < ptseq->total ) + CV_ERROR( CV_StsBadSize, "The hull matrix size might be not enough to fit the hull" ); + + if( CV_MAT_TYPE(mat->type) != CV_SEQ_ELTYPE(ptseq) && + CV_MAT_TYPE(mat->type) != CV_32SC1 ) + CV_ERROR( CV_StsUnsupportedFormat, + "The hull matrix must have the same type as input or 32sC1 (integers)" ); + + CV_CALL( hullseq = cvMakeSeqHeaderForArray( + CV_SEQ_KIND_CURVE|CV_MAT_TYPE(mat->type)|CV_SEQ_FLAG_CLOSED, + sizeof(contour_header), CV_ELEM_SIZE(mat->type), mat->data.ptr, + mat->cols + mat->rows - 1, &hull_header.s, &hullblock )); + + cvClearSeq( hullseq ); + } + + total = ptseq->total; + if( total == 0 ) + { + if( mat ) + CV_ERROR( CV_StsBadSize, + "Point sequence can not be empty if the output is matrix" ); + EXIT; + } + + cvStartAppendToSeq( hullseq, &writer ); + + is_float = CV_SEQ_ELTYPE(ptseq) == CV_32FC2; + hulltype = CV_SEQ_ELTYPE(hullseq); + sklansky = !is_float ? (sklansky_func)icvSklansky_32s : + (sklansky_func)icvSklansky_32f; + + CV_CALL( pointer = (CvPoint**)cvAlloc( ptseq->total*sizeof(pointer[0]) )); + CV_CALL( stack = (int*)cvAlloc( (ptseq->total + 2)*sizeof(stack[0]) )); + pointerf = (CvPoint2D32f**)pointer; + + cvStartReadSeq( ptseq, &reader ); + + for( i = 0; i < total; i++ ) + { + pointer[i] = (CvPoint*)reader.ptr; + CV_NEXT_SEQ_ELEM( ptseq->elem_size, reader ); + } + + // sort the point set by x-coordinate, find min and max y + if( !is_float ) + { + icvSortPointsByPointers_32s( pointer, total, 0 ); + for( i = 1; i < total; i++ ) + { + int y = pointer[i]->y; + if( pointer[miny_ind]->y > y ) + miny_ind = i; + if( pointer[maxy_ind]->y < y ) + maxy_ind = i; + } + } + else + { + icvSortPointsByPointers_32f( pointerf, total, 0 ); + for( i = 1; i < total; i++ ) + { + float y = pointerf[i]->y; + if( pointerf[miny_ind]->y > y ) + miny_ind = i; + if( pointerf[maxy_ind]->y < y ) + maxy_ind = i; + } + } + + if( pointer[0]->x == pointer[total-1]->x && + pointer[0]->y == pointer[total-1]->y ) + { + if( hulltype == CV_SEQ_ELTYPE_PPOINT ) + { + CV_WRITE_SEQ_ELEM( pointer[0], writer ); + } + else if( hulltype == CV_SEQ_ELTYPE_INDEX ) + { + int index = 0; + CV_WRITE_SEQ_ELEM( index, writer ); + } + else + { + CvPoint pt = pointer[0][0]; + CV_WRITE_SEQ_ELEM( pt, writer ); + } + goto finish_hull; + } + + /*upper half */ + { + int *tl_stack = stack; + int tl_count = sklansky( pointer, 0, maxy_ind, tl_stack, -1, 1 ); + int *tr_stack = tl_stack + tl_count; + int tr_count = sklansky( pointer, ptseq->total - 1, maxy_ind, tr_stack, -1, -1 ); + + /* gather upper part of convex hull to output */ + if( orientation == CV_COUNTER_CLOCKWISE ) + { + CV_SWAP( tl_stack, tr_stack, t_stack ); + CV_SWAP( tl_count, tr_count, t_count ); + } + + if( hulltype == CV_SEQ_ELTYPE_PPOINT ) + { + for( i = 0; i < tl_count - 1; i++ ) + CV_WRITE_SEQ_ELEM( pointer[tl_stack[i]], writer ); + + for( i = tr_count - 1; i > 0; i-- ) + CV_WRITE_SEQ_ELEM( pointer[tr_stack[i]], writer ); + } + else if( hulltype == CV_SEQ_ELTYPE_INDEX ) + { + CV_CALL( icvCalcAndWritePtIndices( pointer, tl_stack, + 0, tl_count-1, ptseq, &writer )); + CV_CALL( icvCalcAndWritePtIndices( pointer, tr_stack, + tr_count-1, 0, ptseq, &writer )); + } + else + { + for( i = 0; i < tl_count - 1; i++ ) + CV_WRITE_SEQ_ELEM( pointer[tl_stack[i]][0], writer ); + + for( i = tr_count - 1; i > 0; i-- ) + CV_WRITE_SEQ_ELEM( pointer[tr_stack[i]][0], writer ); + } + stop_idx = tr_count > 2 ? tr_stack[1] : tl_count > 2 ? tl_stack[tl_count - 2] : -1; + } + + /* lower half */ + { + int *bl_stack = stack; + int bl_count = sklansky( pointer, 0, miny_ind, bl_stack, 1, -1 ); + int *br_stack = stack + bl_count; + int br_count = sklansky( pointer, ptseq->total - 1, miny_ind, br_stack, 1, 1 ); + + if( orientation != CV_COUNTER_CLOCKWISE ) + { + CV_SWAP( bl_stack, br_stack, t_stack ); + CV_SWAP( bl_count, br_count, t_count ); + } + + if( stop_idx >= 0 ) + { + int check_idx = bl_count > 2 ? bl_stack[1] : + bl_count + br_count > 2 ? br_stack[2-bl_count] : -1; + if( check_idx == stop_idx || (check_idx >= 0 && + pointer[check_idx]->x == pointer[stop_idx]->x && + pointer[check_idx]->y == pointer[stop_idx]->y) ) + { + /* if all the points lie on the same line, then + the bottom part of the convex hull is the mirrored top part + (except the exteme points).*/ + bl_count = MIN( bl_count, 2 ); + br_count = MIN( br_count, 2 ); + } + } + + if( hulltype == CV_SEQ_ELTYPE_PPOINT ) + { + for( i = 0; i < bl_count - 1; i++ ) + CV_WRITE_SEQ_ELEM( pointer[bl_stack[i]], writer ); + + for( i = br_count - 1; i > 0; i-- ) + CV_WRITE_SEQ_ELEM( pointer[br_stack[i]], writer ); + } + else if( hulltype == CV_SEQ_ELTYPE_INDEX ) + { + CV_CALL( icvCalcAndWritePtIndices( pointer, bl_stack, + 0, bl_count-1, ptseq, &writer )); + CV_CALL( icvCalcAndWritePtIndices( pointer, br_stack, + br_count-1, 0, ptseq, &writer )); + } + else + { + for( i = 0; i < bl_count - 1; i++ ) + CV_WRITE_SEQ_ELEM( pointer[bl_stack[i]][0], writer ); + + for( i = br_count - 1; i > 0; i-- ) + CV_WRITE_SEQ_ELEM( pointer[br_stack[i]][0], writer ); + } + } + +finish_hull: + CV_CALL( cvEndWriteSeq( &writer )); + + if( mat ) + { + if( mat->rows > mat->cols ) + mat->rows = hullseq->total; + else + mat->cols = hullseq->total; + } + else + { + hull.s = hullseq; + hull.c->rect = cvBoundingRect( ptseq, + ptseq->header_size < (int)sizeof(CvContour) || + &ptseq->flags == &contour_header.flags ); + + /*if( ptseq != (CvSeq*)&contour_header ) + hullseq->v_prev = ptseq;*/ + } + + __END__; + + cvFree( &pointer ); + cvFree( &stack ); + + return hull.s; +} + + +/* contour must be a simple polygon */ +/* it must have more than 3 points */ +CV_IMPL CvSeq* +cvConvexityDefects( const CvArr* array, + const CvArr* hullarray, + CvMemStorage* storage ) +{ + CvSeq* defects = 0; + + CV_FUNCNAME( "cvConvexityDefects" ); + + __BEGIN__; + + int i, index; + CvPoint* hull_cur; + + /* is orientation of hull different from contour one */ + int rev_orientation; + + CvContour contour_header; + union { CvContour c; CvSeq s; } hull_header; + CvSeqBlock block, hullblock; + CvSeq *ptseq = (CvSeq*)array, *hull = (CvSeq*)hullarray; + + CvSeqReader hull_reader; + CvSeqReader ptseq_reader; + CvSeqWriter writer; + int is_index; + + if( CV_IS_SEQ( ptseq )) + { + if( !CV_IS_SEQ_POINT_SET( ptseq )) + CV_ERROR( CV_StsUnsupportedFormat, + "Input sequence is not a sequence of points" ); + if( !storage ) + storage = ptseq->storage; + } + else + { + CV_CALL( ptseq = cvPointSeqFromMat( + CV_SEQ_KIND_GENERIC, array, &contour_header, &block )); + } + + if( CV_SEQ_ELTYPE( ptseq ) != CV_32SC2 ) + CV_ERROR( CV_StsUnsupportedFormat, + "Floating-point coordinates are not supported here" ); + + if( CV_IS_SEQ( hull )) + { + int hulltype = CV_SEQ_ELTYPE( hull ); + if( hulltype != CV_SEQ_ELTYPE_PPOINT && hulltype != CV_SEQ_ELTYPE_INDEX ) + CV_ERROR( CV_StsUnsupportedFormat, + "Convex hull must represented as a sequence " + "of indices or sequence of pointers" ); + if( !storage ) + storage = hull->storage; + } + else + { + CvMat* mat = (CvMat*)hull; + + if( !CV_IS_MAT( hull )) + CV_ERROR(CV_StsBadArg, "Convex hull is neither sequence nor matrix"); + + if( (mat->cols != 1 && mat->rows != 1) || + !CV_IS_MAT_CONT(mat->type) || CV_MAT_TYPE(mat->type) != CV_32SC1 ) + CV_ERROR( CV_StsBadArg, + "The matrix should be 1-dimensional and continuous array of int's" ); + + if( mat->cols + mat->rows - 1 > ptseq->total ) + CV_ERROR( CV_StsBadSize, "Convex hull is larger than the point sequence" ); + + CV_CALL( hull = cvMakeSeqHeaderForArray( + CV_SEQ_KIND_CURVE|CV_MAT_TYPE(mat->type)|CV_SEQ_FLAG_CLOSED, + sizeof(CvContour), CV_ELEM_SIZE(mat->type), mat->data.ptr, + mat->cols + mat->rows - 1, &hull_header.s, &hullblock )); + } + + is_index = CV_SEQ_ELTYPE(hull) == CV_SEQ_ELTYPE_INDEX; + + if( !storage ) + CV_ERROR( CV_StsNullPtr, "NULL storage pointer" ); + + CV_CALL( defects = cvCreateSeq( CV_SEQ_KIND_GENERIC, sizeof(CvSeq), + sizeof(CvConvexityDefect), storage )); + + if( ptseq->total < 4 || hull->total < 3) + { + //CV_ERROR( CV_StsBadSize, + // "point seq size must be >= 4, convex hull size must be >= 3" ); + EXIT; + } + + /* recognize co-orientation of ptseq and its hull */ + { + int sign = 0; + int index1, index2, index3; + + if( !is_index ) + { + CvPoint* pos = *CV_SEQ_ELEM( hull, CvPoint*, 0 ); + CV_CALL( index1 = cvSeqElemIdx( ptseq, pos )); + + pos = *CV_SEQ_ELEM( hull, CvPoint*, 1 ); + CV_CALL( index2 = cvSeqElemIdx( ptseq, pos )); + + pos = *CV_SEQ_ELEM( hull, CvPoint*, 2 ); + CV_CALL( index3 = cvSeqElemIdx( ptseq, pos )); + } + else + { + index1 = *CV_SEQ_ELEM( hull, int, 0 ); + index2 = *CV_SEQ_ELEM( hull, int, 1 ); + index3 = *CV_SEQ_ELEM( hull, int, 2 ); + } + + sign += (index2 > index1) ? 1 : 0; + sign += (index3 > index2) ? 1 : 0; + sign += (index1 > index3) ? 1 : 0; + + rev_orientation = (sign == 2) ? 0 : 1; + } + + cvStartReadSeq( ptseq, &ptseq_reader, 0 ); + cvStartReadSeq( hull, &hull_reader, rev_orientation ); + + if( !is_index ) + { + hull_cur = *(CvPoint**)hull_reader.prev_elem; + index = cvSeqElemIdx( ptseq, (char*)hull_cur, 0 ); + } + else + { + index = *(int*)hull_reader.prev_elem; + hull_cur = CV_GET_SEQ_ELEM( CvPoint, ptseq, index ); + } + cvSetSeqReaderPos( &ptseq_reader, index ); + cvStartAppendToSeq( defects, &writer ); + + /* cycle through ptseq and hull with computing defects */ + for( i = 0; i < hull->total; i++ ) + { + CvConvexityDefect defect; + int is_defect = 0; + double dx0, dy0; + double depth = 0, scale; + CvPoint* hull_next; + + if( !is_index ) + hull_next = *(CvPoint**)hull_reader.ptr; + else + { + int t = *(int*)hull_reader.ptr; + hull_next = CV_GET_SEQ_ELEM( CvPoint, ptseq, t ); + } + + dx0 = (double)hull_next->x - (double)hull_cur->x; + dy0 = (double)hull_next->y - (double)hull_cur->y; + assert( dx0 != 0 || dy0 != 0 ); + scale = 1./sqrt(dx0*dx0 + dy0*dy0); + + defect.start = hull_cur; + defect.end = hull_next; + + for(;;) + { + /* go through ptseq to achieve next hull point */ + CV_NEXT_SEQ_ELEM( sizeof(CvPoint), ptseq_reader ); + + if( ptseq_reader.ptr == (schar*)hull_next ) + break; + else + { + CvPoint* cur = (CvPoint*)ptseq_reader.ptr; + + /* compute distance from current point to hull edge */ + double dx = (double)cur->x - (double)hull_cur->x; + double dy = (double)cur->y - (double)hull_cur->y; + + /* compute depth */ + double dist = fabs(-dy0*dx + dx0*dy) * scale; + + if( dist > depth ) + { + depth = dist; + defect.depth_point = cur; + defect.depth = (float)depth; + is_defect = 1; + } + } + } + if( is_defect ) + { + CV_WRITE_SEQ_ELEM( defect, writer ); + } + + hull_cur = hull_next; + if( rev_orientation ) + { + CV_PREV_SEQ_ELEM( hull->elem_size, hull_reader ); + } + else + { + CV_NEXT_SEQ_ELEM( hull->elem_size, hull_reader ); + } + } + + defects = cvEndWriteSeq( &writer ); + + __END__; + + return defects; +} + + +CV_IMPL int +cvCheckContourConvexity( const CvArr* array ) +{ + int flag = -1; + + CV_FUNCNAME( "cvCheckContourConvexity" ); + + __BEGIN__; + + int i; + int orientation = 0; + CvSeqReader reader; + CvContour contour_header; + CvSeqBlock block; + CvSeq* contour = (CvSeq*)array; + + if( CV_IS_SEQ(contour) ) + { + if( !CV_IS_SEQ_POINT_SET(contour)) + CV_ERROR( CV_StsUnsupportedFormat, + "Input sequence must be polygon (closed 2d curve)" ); + } + else + { + CV_CALL( contour = cvPointSeqFromMat( + CV_SEQ_KIND_CURVE|CV_SEQ_FLAG_CLOSED, array, &contour_header, &block )); + } + + if( contour->total == 0 ) + EXIT; + + cvStartReadSeq( contour, &reader, 0 ); + + flag = 1; + + if( CV_SEQ_ELTYPE( contour ) == CV_32SC2 ) + { + CvPoint *prev_pt = (CvPoint*)reader.prev_elem; + CvPoint *cur_pt = (CvPoint*)reader.ptr; + + int dx0 = cur_pt->x - prev_pt->x; + int dy0 = cur_pt->y - prev_pt->y; + + for( i = 0; i < contour->total; i++ ) + { + int dxdy0, dydx0; + int dx, dy; + + /*int orient; */ + CV_NEXT_SEQ_ELEM( sizeof(CvPoint), reader ); + prev_pt = cur_pt; + cur_pt = (CvPoint *) reader.ptr; + + dx = cur_pt->x - prev_pt->x; + dy = cur_pt->y - prev_pt->y; + dxdy0 = dx * dy0; + dydx0 = dy * dx0; + + /* find orientation */ + /*orient = -dy0 * dx + dx0 * dy; + orientation |= (orient > 0) ? 1 : 2; + */ + orientation |= (dydx0 > dxdy0) ? 1 : ((dydx0 < dxdy0) ? 2 : 3); + + if( orientation == 3 ) + { + flag = 0; + break; + } + + dx0 = dx; + dy0 = dy; + } + } + else + { + assert( CV_SEQ_ELTYPE(contour) == CV_32FC2 ); + + CvPoint2D32f *prev_pt = (CvPoint2D32f*)reader.prev_elem; + CvPoint2D32f *cur_pt = (CvPoint2D32f*)reader.ptr; + + float dx0 = cur_pt->x - prev_pt->x; + float dy0 = cur_pt->y - prev_pt->y; + + for( i = 0; i < contour->total; i++ ) + { + float dxdy0, dydx0; + float dx, dy; + + /*int orient; */ + CV_NEXT_SEQ_ELEM( sizeof(CvPoint2D32f), reader ); + prev_pt = cur_pt; + cur_pt = (CvPoint2D32f*) reader.ptr; + + dx = cur_pt->x - prev_pt->x; + dy = cur_pt->y - prev_pt->y; + dxdy0 = dx * dy0; + dydx0 = dy * dx0; + + /* find orientation */ + /*orient = -dy0 * dx + dx0 * dy; + orientation |= (orient > 0) ? 1 : 2; + */ + orientation |= (dydx0 > dxdy0) ? 1 : ((dydx0 < dxdy0) ? 2 : 3); + + if( orientation == 3 ) + { + flag = 0; + break; + } + + dx0 = dx; + dy0 = dy; + } + } + + __END__; + + return flag; +} + + +/* End of file. */