**CIGAL Reference Manual, Chapter 3 (Functions): trace**
===== Trace -- Generate vector list by tracing an image intensity contour =====
**usage: numvecs = trace(mode,v0,dir,spacng,loval,hival)**

TRACE follows an intensity contour in an image, generating a list of graphics vectors along its path.
     MODE (octal)
       1     1o   stop at sharp corners or dead ends
       2     2o   store image intensity as vector intensity
       4     4o   for line tracing, draw vectors in center of line
       8    10o   for line tracing, store line width as vector width
      16    20o   trace in bursts with pauses
      32    40o   for closed trace (mode & 1) don't set direction automatically
      64   100o   don't stop when loop is closed
     128   200o   pause at sharp corners or dead ends

For now TRACE returns number of vectors added to VECS list.
Perhaps someday should return VLIST pointer?

**See Also:**\\
[[jvs:cigal:manual:chapter3:sample|SAMPLE(3)]], 
[[jvs:cigal:manual:chapter3:search|SEARCH(3)]], 
[[jvs:cigal:manual:chapter4:simage|SIMAGE(4)]], 
[[jvs:cigal:manual:chapter4:tflag|TFLAG(4)]], 
[[jvs:cigal:manual:chapter4:thi|THI(4)]], 
[[jvs:cigal:manual:chapter4:tlo|TLO(4)]]

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