Content Comparison

# Open X-Projection mapping
        fdx = open (XPROJ_MAP, READ_ONLY, TEXT_FILE)
        call gs_ingest (fdx, asfx, asfy)

        do i = 0, nslit-2 {
                ndx1 = Memi[bufi+i]
                ndx2 = Memi[bufi+i+1]
                pc1 = PCODE(sdat,ndx1)
                pc2 = PCODE(sdat,ndx2)

# If both are alignment boxes, just go on ...
                if (pc1 == CODE_AS && pc2 == CODE_AS)           # no problem
                        next
......
# We will need to recalculate something ...

                xlow = X2(sdat,ndx1) + SLIT_GAP(indat)
                xupp = X1(sdat,ndx2) - SLIT_GAP(indat)
                xcen = 0.5 * (xlow + xupp)

                yas = Y2(sdat,ndx1)
                dxlow = gseval (asfx, xcen, yas)
                yas = Y1(sdat,ndx2)
                dxupp = gseval (asfx, xcen, yas)
                dxavg = 0.5 * (dxupp + dxlow)
                dxlow = dxlow - dxavg
                dxupp = dxupp - dxavg
call eprintf ("%6.3f %6.3f\n")
call pargr (dxlow)
call pargr (dxupp)

                if (pc1 == CODE_AS) {
                        del1 = 0.
                        del2 = X1(sdat,ndx2) - xlow - (dxupp - dxlow)
                } else if (pc2 == CODE_AS) {
                        del1 =  xupp - X2(sdat,ndx1) + (dxlow - dxupp)
                        del2 = 0.
                } else {
                        del1 = xcen - 0.5*SLIT_GAP(indat) - X2(sdat,ndx1) + dxlow
                        del2 = X1(sdat,ndx2) - (xcen + 0.5*SLIT_GAP(indat)) - dxupp
                }



                X2(sdat,ndx1) = X2(sdat,ndx1) + del1
                if (del1 != 0. && RELPA(sdat,ndx1) != INDEF) {
                        tana = tan (RELPA(sdat,ndx1))
                        Y2(sdat,ndx1) = Y2(sdat,ndx1) + del1 * FLIP * tana
                }

                X1(sdat,ndx2) = X1(sdat,ndx2) - del2
                if (del2 != 0. && RELPA(sdat,ndx2) != INDEF) {
                        tana = tan (RELPA(sdat,ndx2))
                        Y1(sdat,ndx2) = Y1(sdat,ndx2) - del2 * FLIP * tana
                }