opencv/samples/octave/delaunay.m

#! /usr/bin/env octave

## the script demostrates iterative construction of
## delaunay triangulation and voronoi tesselation

## Original Author (C version): ?
## Converted to Python by: Roman Stanchak
## Converted to Octave by: Xavier Delacour

cv;
highgui;

function draw_subdiv_point( img, fp, color )
  global CV_FILLED;
  cvCircle( img, cvPoint(cvRound(fp.x), cvRound(fp.y)), 3, color, \
	   CV_FILLED, 8, 0 );
endfunction

function draw_subdiv_edge( img, edge, color )
  global CV_AA;

  org_pt = cvSubdiv2DEdgeOrg(edge);
  dst_pt = cvSubdiv2DEdgeDst(edge);

  if (org_pt && dst_pt )
    
    org = org_pt.pt;
    dst = dst_pt.pt;

    iorg = cvPoint( cvRound( org.x ), cvRound( org.y ));
    idst = cvPoint( cvRound( dst.x ), cvRound( dst.y ));

    cvLine( img, iorg, idst, color, 1, CV_AA, 0 );
  endif
endfunction


function draw_subdiv( img, subdiv, delaunay_color, voronoi_color )
  
  total = subdiv.edges.total;
  elem_size = subdiv.edges.elem_size;

  for edge in subdiv.edges,
    edge_rot = cvSubdiv2DRotateEdge( edge, 1 );

    if( CV_IS_SET_ELEM( edge ))
      draw_subdiv_edge( img, edge_rot, voronoi_color );
      draw_subdiv_edge( img, edge, delaunay_color );
    endif
  endfor
endfunction


function locate_point( subdiv, fp, img, active_color )

  [res, e0, p] = cvSubdiv2DLocate( subdiv, fp );

  if (e0)
    e = e0
    while (true)
      draw_subdiv_edge( img, e, active_color );
      e = cvSubdiv2DGetEdge(e,CV_NEXT_AROUND_LEFT);
      if (e == e0)
        break
      endif
    endwhile
  endif

  draw_subdiv_point( img, fp, active_color );
endfunction

function draw_subdiv_facet( img, edge )

  t = edge;
  count = 0;

  ## count number of edges in facet
  while (count == 0 || t != edge)
    count+=1;
    t = cvSubdiv2DGetEdge( t, CV_NEXT_AROUND_LEFT );
  endwhile

  buf = []

  ## gather points
  t = edge;
  for i=0:count-1,
    assert t>4
    pt = cvSubdiv2DEdgeOrg( t );
    if (! pt)
      break;
    endif
    buf.append( cvPoint( cvRound(pt.pt.x), cvRound(pt.pt.y) ) );
    t = cvSubdiv2DGetEdge( t, CV_NEXT_AROUND_LEFT );
  endfor

  if( len(buf)==count )
    pt = cvSubdiv2DEdgeDst( cvSubdiv2DRotateEdge( edge, 1 ));
    cvFillConvexPoly( img, buf, CV_RGB(randint(0,255),randint(0,255),randint(0,255)), CV_AA, 0 );
    cvPolyLine( img, [buf], 1, CV_RGB(0,0,0), 1, CV_AA, 0);
    draw_subdiv_point( img, pt.pt, CV_RGB(0,0,0));
  endif
endfunction

function paint_voronoi( subdiv, img )
  total = subdiv.edges.total;
  elem_size = subdiv.edges.elem_size;

  cvCalcSubdivVoronoi2D( subdiv );

  for edge in subdiv.edges,

    if( CV_IS_SET_ELEM( edge ))
      ## left
      draw_subdiv_facet( img, cvSubdiv2DRotateEdge( edge, 1 ));

      ## right
      draw_subdiv_facet( img, cvSubdiv2DRotateEdge( edge, 3 ));
    endif
  endfor
endfunction

win = "source";
rect = cvRect( 0, 0, 600, 600 );

active_facet_color = CV_RGB( 255, 0, 0 );
delaunay_color  = CV_RGB( 0,0,0);
voronoi_color = CV_RGB(0, 180, 0);
bkgnd_color = CV_RGB(255,255,255);

img = cvCreateImage( cvSize(rect.width,rect.height), 8, 3 );
cvSet( img, bkgnd_color );

cvNamedWindow( win, 1 );

storage = cvCreateMemStorage(0);
subdiv = cvCreateSubdivDelaunay2D( rect, storage );

printf("Delaunay triangulation will be build now interactively.\n");
printf("To stop the process, press any key\n");

for i=0:200-1,
  fp = cvPoint2D32f(  int32(rand()*(rect.width-10)+5), int32(rand()*(rect.height-10)+5) )

  locate_point( subdiv, fp, img, active_facet_color );
  cvShowImage( win, img );

  if( cvWaitKey( 100 ) >= 0 )
    break;
  endif

  cvSubdivDelaunay2DInsert( subdiv, fp );
  cvCalcSubdivVoronoi2D( subdiv );
  cvSet( img, bkgnd_color );
  draw_subdiv( img, subdiv, delaunay_color, voronoi_color );
  cvShowImage( win, img );

  if( cvWaitKey( 100 ) >= 0 )
    break;
  endif
endfor


cvSet( img, bkgnd_color );
paint_voronoi( subdiv, img );
cvShowImage( win, img );

cvWaitKey(0);

cvDestroyWindow( win );