etch length-measuring functions

Greetings all,

In the past I've had need of  getting the length of a trace, whether that trace be a segment (CLINESEG), path (CLINE) or of an entire net. "show elements" on the trace yields the desired value but I want the value to be available within a SKILL routine.  So I wrote my own set of functions to calculate the value for me.  Here they are:

;----------------------------------------
; length-finding utility functions
; written by: Chris Walters
;
;
; These functions will find the length of an etch trace
; for a given segment, path, or entire net, respectively
;
; Revision History
;    2006/12/13      Chris Walters
;                        Initial release
;----------------------------------------
procedure( cdw_findSegLength( seg_db)
prog((seglength pt1 pt2 pt3 chordlength rradius aangle xproduct)

seglength = 0.0

pt1 =  car( seg_db->startEnd)
pt2 = cadr( seg_db->startEnd)

pt1.x = xCoord( pt1)
pt1.y = yCoord( pt1)
pt2.x = xCoord( pt2)
pt2.y = yCoord( pt2)

if( seg_db->objType == "arc" then
    pt3 = seg_db->xy
    pt3.x = xCoord( pt3)
    pt3.y = yCoord( pt3)
    chordlength = sqrt( (pt2.x - pt1.x)*(pt2.x - pt1.x) + (pt2.y - pt1.y)*(pt2.y - pt1.y) )
    rradius = seg_db->radius

    ;determine angle formed by pt1 and pt2 with center at rradius
    aangle = 2 * asin( chordlength / (2 * rradius))    ; in radians

    ;determine whether arc is major or minor 
    xproduct = (pt2.x - pt1.x)*(pt3.y - pt1.y) - (pt3.x - pt1.x)*(pt2.y - pt1.y) ; 2D cross-product

    cond(
        ( !seg_db->isClockwise && xproduct  
            seglength =  (6.283185 - aangle) * rradius
        )
        ( !seg_db->isClockwise && xproduct >= 0.0         ; minor arc
            seglength =  aangle * rradius
        )
        (  seg_db->isClockwise && xproduct  
            seglength =  aangle * rradius
        )
        (  seg_db->isClockwise && xproduct >= 0.0         ; major arc
            seglength =  (6.283185 - aangle) * rradius
        )
    );end-cond
else
    seglength = sqrt( (pt2.x - pt1.x)*(pt2.x - pt1.x) + (pt2.y - pt1.y)*(pt2.y - pt1.y) )
);end-if

return( seglength)

);end-prog
);end-procedure

;----------------------------------------
procedure( cdw_findPathLength( path_db)
prog(( pathlength)

pathlength = 0.0

foreach( seg_db path_db->segments
    pathlength = pathlength + cdw_findSegLength( seg_db)
);end-foreach
    
return( pathlength)

);end-prog
);end-procedure

;----------------------------------------
procedure( cdw_findNetLength( net_db)
prog(( netlength)

netlength = 0.0

foreach( net_br net_db->branches
    foreach( child_db net_br->children
        if( child_db->objType == "path"  then
            netlength = netlength + cdw_findPathLength( child_db)
        );end-if
    );end-foreach
);end-foreach
    
return( netlength)

);end-prog
);end-procedure


Merry Christmas!


Chris Walters
local Cadence guru
()