; ----------------------------------------------------------------------
;  Correct the image (un-slant and un-curve).  -tab 19jan2018
;  Also, clean the image first.
;> if not already cleaned
;

pro nsxng_correct_image, IMG, SOP1, SOP2, AVP, SPX, NCP, NoClean, NoHotClean
;  common nsx
  c = nsxng_constants()
  ARCSEC_PER_PIXEL = c.ARCSEC_PER_PIXEL
  
  NoFlat = 1
  
  nc = IMG[0].nc                ;   /* nominal 2048 */
  nr = IMG[0].nr                ;   /* nominal 1024 */

;float *clnimgNFD;   /* clean image with No Flat Division */
;float *fltimg;

  if not ptr_valid(IMG.clnimg) then nsxng_clean_image, IMG, SPX, NoClean, NoHotClean, NCP

; Zero 
  for ii=0,nc-1 do begin
     for jj=0,nr-1 do begin 
        pixno = ii + (jj * long(nc))
        (*IMG.corimg)[pixno] = 0. 
     endfor 
  endfor  
  
; For 2017 calibration, I used 0.2 arcsec per pixel and use nso=3 width. 
  asinc = ARCSEC_PER_PIXEL 
  asnum = SPX[3].numpro - 1
  asmax = asinc * double(asnum)
  print,format='("Correct image using asinc=",F,"  asmax=",F,"  asnum=",I,"")',asinc,asmax,asnum

; Each order. 
  for nso=3,7 do begin
     if (nso eq 7) then ecol=nc/2 else ecol=nc
     jjoff = ((7-nso) * 200) 
     
; Each column (where a 'column' starts at lower edge and then slants up).
     for icol=0L,ecol-1 do begin
        edge = nsx_find_real_image_row( 1, icol, nso ) 
        for as=0.,asmax,asinc do begin

; Select row (offset from edge) boundaries on arcsec scale. 
           rba = edge + nsx_AVPinv( AVP, nso, icol, as, IMG ) 
           rbb = edge + nsx_AVPinv( AVP, nso, icol, as+asinc, IMG ) 
           rbave = (rba + rbb) / 2. 
           rowoff = rbave - edge 

; Column range using actual 'rowoff' value. 
           nsx_slant_boundaries_SOP2, nso, icol, rowoff, SOP1, SOP2, ecol, cb1, cb2 

; Fractional pixel. 
           nsx_fractional_pixel_2D, nc, IMG.clnimg, cb1, cb2, rba, rbb, imgsum    
           nsx_fractional_pixel_2D, nc, clnimgNFD    , cb1, cb2, rba, rbb, imgsumNFD 
           ii = icol 
           jj = jjoff + cnint(( as / asinc )) 
           pixno = ii + (jj * nc) 
           (*IMG.corimg)[pixno]    = imgsum 
           (*IMG.corimgNFD)[pixno] = imgsumNFD 
        endfor ; as
     endfor    ; icol
  endfor    ; nso

; Trim out first 12 columns and last 4 columns of corimg[]. 
  for jj=0,nr-1 do begin
     for ii=0,12-1 do begin
        pixno=ii+(jj*long(nc))
        (*IMG.corimg)[pixno]=0.
        (*IMG.corimgNFD)[pixno]=0.
     endfor
     for ii=nc-4,nc-1 do begin
        pixno=ii+(jj*long(nc))
        (*IMG.corimg)[pixno]=0.
        (*IMG.corimgNFD)[pixno]=0.
     endfor
  endfor

  nsx_write_general_image,"clnimg.fits", IMG[0].clnimg,  nc, nr  
  nsx_write_general_image, "clnimgNFD.fits", clnimgNFD,  nc, nr  
  
  nsx_write_general_image, "corimg.fits", IMG[0].corimg,  nc, nr 
  nsx_write_general_image, "corimgNFD.fits", IMG[0].corimgNFD,  nc, nr 
  
  ptr_free, clnimgNFD
  ptr_free, fltimg

end