;+
; NAME		cavity_width.pro
;
; FUNCTION	Determine coronal cavity width.
;
; SYNTAX	cavity_width, xdim, ydim, xcen, ycen, pixrs, roll, pos=1
;
;		xdim, ydim	image dimensions
;		xcen, ycen	sun center
;		pixrs		pixels/Rsun
;		roll		angle (deg) of solar north w.r.t. +Y axis.
;		rpos		vector of radius values [Rsun]
;		apos		vector of angle  values [degrees]
;		xpos		vector of x-dimension coordinates. 
;		ypos		vector of y-dimension coordinates. 
;		numpos		number of positions measured
;
;		pos		Optional position number label.
;		pfile		Optional output file name.
;		disp_label	Option to display position number.
;
; PROCEDURES	rcoord		Coordinate conversion: [radius,angle] <--> [x,y]
;
; HISTORY	Andrew L. Stanger   HAO/NCAR    2 Dec 2004
;-

PRO cw, xdim, ydim, xcen, ycen, pixrs, roll,			$
		  rpos, apos, xpos, ypos, ascanmin, ascanmax,		$
		  radtop, angtop, r1, r2,				$
		  numpos, pos=pos, pfile=pfile, disp_label=disp_label

   ;--- Annotation colors:

   white  = 255
   red    = 254
   green  = 253
   blue   = 252
   grey   = 251
   yellow = 250
   black  =   0

   cs = 1.0

;   IF (STRLOWCASE (!version.os) EQ 'irix')    THEN cfac = 1.0 ELSE cfac = 2.0
;   cs = cfac * 1.0

   IF (KEYWORD_SET (pos)) THEN pos_num = pos	$
   ELSE pos_num = 1
   print, 'cavity_width> pos_num: ', pos_num

   ;--- Draw azimuthal arcs at 1/3 & 2/3 of the cavity height.

   print, 'cavity_width> ascanmin/ascanmax: ', ascanmin, ascanmax
   anginc = 0.5
   angrange = 40.0
   angmid = angtop
   angbeg = angtop - angrange * 0.5
   itmax  = 160
   itmax  = FIX (angrange / anginc + 0.5)

   print, 'cavity_width> xcen/ycen: ', xcen, ycen
   print, 'cavity_width> pixrs: ', pixrs
   print, 'cavity_width> radtop/angtop: ', radtop, angtop
   print, 'cavity_width> r1/r2: ', r1, r2

   FOR it = 0, itmax DO		$
   BEGIN ;{
      angle = it * anginc + angbeg
      ierr = rcoord (r1, angle, x1, y1, 1, roll, xcen, ycen, pixrs)
      ierr = rcoord (r2, angle, x2, y2, 1, roll, xcen, ycen, pixrs)
;      print, 'cavity_width> r1/angle: ', r1, angle, '  x1/y1: ', x1, y1
      PLOTS, [x1-1, x1+1], [y1-1, y1+1], /DEVICE, color=green
      PLOTS, [x1-1, x1+1], [y1+1, y1-1], /DEVICE, color=green
      PLOTS, [x2-1, x2+1], [y2-1, y2+1], /DEVICE, color=green
      PLOTS, [x2-1, x2+1], [y2+1, y2-1], /DEVICE, color=green
   END   ;}

   ;--- Create arrays for angle, radius & position values.

   angbuf = FLTARR (100)
   radbuf = FLTARR (100)
   xbuf   = INTARR (100)
   ybuf   = INTARR (100)
   angle  = 0.0
   radius = 0.0

   ;--- Use mouse to identify cavity edges along arcs drawn onto the image.

   TVCRS, xcen, ycen				; Enable cursor

   PRINT, 'Use mouse and click at the left & right edges of the cavity'
   PRINT, 'along BOTH the lower and upper azimuthal arcs.'
   PRINT, 'Click middle mouse button to terminate position measurements.'

   i = 0
   WHILE ( 1 ) DO	$
   BEGIN ;{
      CURSOR, rxcur, rycur, /DEVICE, WAIT=3
      IF (!ERR EQ 2) THEN GOTO, quit		; Done if middle button clicked.

      ierror = rcoord (radius, angle, rxcur, rycur, -1, roll, xcen, ycen, pixrs)

;      PRINT, 'x, y: ', rxcur, rycur, ' radius, angle: ', radius, angle
      PRINT, FORMAT = '("[x,y]: ", i4, i4, "   [r,th]: ", F5.2, " Rsun ", F7.2, " degrees")', $
		      rxcur, rycur, radius, angle
      WAIT,  0.5

      ;--- Write Region information into log file.

;      OPENW, lulog, logfile, /GET_LUN
;      PRINTF, lulog, 'Mouse-Defined Curved Wedge        Region: ',	$
;		      STRING (aoinum, FORMAT='(i3)')
;      PRINTF, lulog, STRING (rmin, FORMAT='(F7.2)'), ' -->	',	$
;	 	      STRING (rmax, FORMAT='(F7.2)'), ' Rsun   ',	$
;                     STRING (angmin, FORMAT='(F7.2)'), ' --> ',	$
;		      STRING (angmax, FORMAT='(F7.2)'), ' degrees'
;      PRINTF, lulog, 'polygon vertices file: ', pvfile
;      CLOSE, lulog
;      FREE_LUN, lulog

      ;--- Write info to screen.

;      PRINT, STRING (rmin, FORMAT='(F7.2)'), ' -->	',	$
;	      STRING (rmax, FORMAT='(F7.2)'), ' Rsun   ',	$
;             STRING (angmin, FORMAT='(F7.2)'), ' --> ',	$
;	      STRING (angmax, FORMAT='(F7.2)'), ' degrees'

      ;--- Draw an "+" to mark cursor position.

      xv = [rxcur - 3, rxcur + 3]
      yv = [rycur,     rycur]
      PLOTS, xv, yv, /DEVICE, color=red
      xv = [rxcur,     rxcur    ]
      yv = [rycur - 3, rycur + 3]
      PLOTS, xv, yv, /DEVICE, color=red

      IF (KEYWORD_SET (disp_label)) THEN	$
       XYOUTS, rxcur+5, rycur, STRTRIM (STRING (pos_num), 2), $
       charsize=cs, /DEVICE, color=red

      ;--- Write information to text file.

      IF (KEYWORD_SET (pfile)) THEN $
      BEGIN
         CLOSE,  21
         OPENU,  21, pfile, /APPEND
         spos_num = STRING (pos_num, FORMAT='(I3)')     
	 sradius  = STRING (radius,  FORMAT='(F6.2)')
	 sangle   = STRING (angle ,  FORMAT='(F8.2)')
	 PRINTF, 21, 'Position #', spos_num, '   radius:', sradius, $
		     '   P.A.:', sangle
         CLOSE,  21
      END

      radbuf [i] = radius
      angbuf [i] = angle
      xbuf   [i] = rxcur
      ybuf   [i] = rycur
      i = i + 1
      pos_num = pos_num + 1
   END ;}

   quit: WAIT, 1.0

   ;--- Copy information to arrays with the correct dimension lengths.

   numpos = i
   rpos = FLTARR (i)
   apos = FLTARR (i)
   xpos = FLTARR (i)
   ypos = FLTARR (i)

   rpos [0:i-1] = radbuf [0:i-1]
   apos [0:i-1] = angbuf [0:i-1]
   xpos [0:i-1] = xbuf   [0:i-1]
   ypos [0:i-1] = ybuf   [0:i-1]

   print, 'cavity_width> numpos: ', numpos
   print, 'cavity_width> rpos  : ', rpos
   print, 'cavity_width> apos  : ', apos

   pos = pos_num

END