subroutine tecs_plot(file)

  character(len=*) file

  integer, parameter :: dmax=500, nset=3, nmenu=9, chartfreq=2
  real, parameter :: winmin=60., undef=-65535.0

  real*4 x1,x2,xmin,xmax,ymin(2),ymax(2),window
  real*4 xd(dmax),yd(dmax,nset)
  real*4 ylast1,ylast2,y1,y2
  real*4 ex,ey,fx,fy,hmenu,wmenu,ymenu,ticks
  real*4 xbox(8), ybox(8)
  integer l,j,i,t0,t1,ntot,i1,i2,rl,n,startday,thisday
  integer first,last,tbase,lastj
  integer color(3)/2,4,3/
  character key*1
  character text(nmenu)*12/ &
   'live off','sel. zoom','zoom in','zoom out','show all','n days','n hours','n min','quit'/
  character keys*(nmenu)/'LZ+-XDHMQ'/
  character weekdays(7)*3/'Mon','Tue','Wed','Thu','Fri','Sat','Sun'/
  character buf*8
  external tplot_close
  logical live, xwin, zoom, right
  integer iret, numb

  integer dlog_open_r, dlog_get, dlog_close_r

  data window/1800./

  zoom=.false.
  right=.true.
  call pgopen(" ")
  call pgqinf('TYPE', buf, l)
  if (buf=='NULL') then
    print *,'No PGPLOT-Device defined'
    goto 9
  endif
  xwin=(buf(1:1)=='X')
  live=.not. xwin ! live switched off by default on X-Windows

  call pgask(.false.)
  l=0
  iret=dlog_open_r(file, first, last, tbase)
  if (iret<0) then
    call err_txt('dlog_open_r')
    goto 99
  endif
  xmax=0
  x1=0

1 if (right .or. window==0 .or. live) then
    ntot=dlog_get(dmax, nset, tbase, -window*1.1, 0.0, undef, xd, yd)
    if (ntot<=0) then
      if (ntot<0) then
        call err_txt('dlog_get')
        goto 99
      endif
      x2=last-tbase
    else
      x2=maxval(xd(1:ntot))
    endif
    if (live) then
      if (x1 .eq. 0) then
        x1=max(x2-window,xd(1))
      else
        window=x2-x1
      endif
      x2=max(x1+window,x2+min(window*0.2,max(window*0.01,300.)))
    elseif (window==0) then
      x1=minval(xd(1:ntot))
      window=x2-x1
    else
      x1=x2-window
    endif
  else
    if (.not. zoom) then
      x2=(x1+x2+window)/2
      x1=x2-window
    endif
    ntot=dlog_get(dmax, nset, tbase, x1-window*0.1, x2+window*0.1, undef, xd, yd)
  endif
  if (ntot<0) then
    call err_txt('dlog_get')
    goto 99
  endif
  if (ntot>0) then
    xmin=minval(xd(1:ntot))
    xmax=maxval(xd(1:ntot))
  else
    xmin=x1
    xmax=x2
  endif

  call pgsvp(0.07,0.93,0.1,0.9) ! define window size

  if (xmax<=xmin) then
    xmax=xmin+1
!    l=0
!    print *,'no points found'
!    print *
!    goto 9
  endif
  call pgsch(1.0)
  i1=1
  i2=2
  do rl=1,2
    if (zoom) then
      ymin(1)=y1
      ymax(1)=y2
    else
      ymin(rl)=1e30
      ymax(rl)=-1e30
      ylast1=ymin(rl)
      ylast2=ymax(rl)
      do i=i1,i2
        do j=1,ntot
          if (xd(j) >= x1 .and. xd(j) <= x2 .and. yd(j,i)/=undef) then
            ymin(rl)=min(ymin(rl),yd(j,i))
            ymax(rl)=max(ymax(rl),yd(j,i))
          endif
        enddo
        do j=max(1,ntot-4),ntot
          if (yd(j, i)/=undef) then
            ylast1=min(ylast1,yd(j, i))
            ylast2=max(ylast2,yd(j, i))
          endif
        enddo
      enddo

      ey=(ymax(rl)-ymin(rl))
      fy=abs(ymax(rl))
      if (rl==1) then
        ymax(rl)=ymax(rl)+max(fy*0.0075,ey*0.25)
        ymin(rl)=ymin(rl)-max(fy*0.005,ey*0.01)
      else
        ymax(rl)=ymax(rl)+max(fy*0.1,ey*0.01)
        ymin(rl)=ymin(rl)-max(fy,ey*4)
      endif
      if (live) then
        ymin(rl)=min(ymin(rl),max(0.0,ylast1-ey*0.4))
        ymax(rl)=max(ymax(rl),ylast2+ey*0.4)
      endif
    endif

    if (ymax(rl) .lt. ymin(rl)) then
      ymax(rl)=1
      ymin(rl)=0
    elseif (ymax(rl) .eq. ymin(rl)) then
      ymax(rl)=ymin(rl)+1.0
      ymin(rl)=0
    endif

    zoom=.false.

    call pgswin(x1,x2,ymin(rl),ymax(rl))

    do i=i1,i2
      call pgsci(color(i))
      n=0
      lastj=1
      do j=1,ntot
        if (yd(j,i)==undef) then
          if (j>lastj) call pgline(j-lastj, xd(lastj), yd(lastj,i))
          lastj=j+1
        endif
      enddo
      if (ntot .gt. lastj) call pgline(ntot+1-lastj, xd(lastj), yd(lastj,i))
    enddo
    i1=3
    i2=3
  enddo
  rl=2
  call pgsci(1)
!  call pgtbox(' ', 0.0, 0, 'CIMST', 0.0, 0)
  ey=ymax(rl)-(ymax(rl)-ymin(rl))*0.20
  call pgsch(0.7)
  call pgaxis('N', x1, ey, x1, ymax(rl), ey, ymax(rl), 0, 0, 0.5, 0.0, 0.0, -1.0, 0.0)
  rl=1
  call pgswin(x1,x2,ymin(rl),ymax(rl))
  ey=ymax(rl)-(ymax(rl)-ymin(rl))*0.21
  call pgsch(1.0)
  call pgaxis('N', x1, ymin(rl), x1, ey, ymin(rl), ey, 0, 0, 0.5, 0.0, 0.5, -1.0, 0.0)
  if (window>50*3600) then
    ticks=8*3600
  elseif (window>25*3600) then
    ticks=4*3600
  else
    ticks=0.0 ! automatic
  endif
  call pgtbox('ZHXYBCINST', ticks, 0, 'CIMST', 0.0, 0)
  call pgmtxt ('L', 2.5, 0.4, 0.5, 'T [K]')
  call pgsci(color(1))
  call pgmtxt ('L', 2.5, 0.2, 0.5, 'Main Sensor')
  call pgsci(color(2))
  call pgmtxt ('L', 2.5, 0.6, 0.5, 'Sample Sensor')
  call pgsci(color(3))
  call pgmtxt ('L', 2.5, 0.9, 0.5, 'Power [W]')
  call pgsci(1)
  call pgsclp(0)
  hmenu=(ymax(rl)-ymin(rl))/15.
  ymenu=ymax(rl)+hmenu*0.5
  wmenu=(x2-x1)/(nmenu+2)
  if (live) then
    text(1)='live off'
  else
    text(1)='live on'    
  endif
  call pgsch(0.7)
  do i=1,nmenu
    xbox(1)=x1+(i-0.7)*wmenu
    ybox(1)=ymenu+hmenu
    xbox(2)=xbox(1)
    ybox(2)=ymenu+hmenu*0.5
    xbox(3)=x1+(i-0.95)*wmenu
    ybox(3)=ybox(2)
    xbox(4)=xbox(3)
    ybox(4)=ybox(1)
    xbox(5)=xbox(1)
    ybox(5)=ybox(1)
    call pgline(5, xbox, ybox)
    call pgptxt(x1+(i-0.9)*wmenu, ymenu+0.65*hmenu, 0.0, 0.0, keys(i:i))
    call pgptxt(x1+(i-0.9)*wmenu, ymenu+0.15*hmenu, 0.0, 0.0, text(i))
  enddo
  call pgmtxt('T', 3.5, 1.0, 1.0, 'any digit to enter n')
  call pgmtxt('T', 2.0, 0.9, 1.0, 'n=')
  thisday=(x1+x2)/2/(24*3600)
  ey=ymin(rl)-hmenu*1.5
  i=max(0,int((x1+12*3600)/(24*3600)))
  do
    ex=(i+0.5)*24*3600
    if (ex>x2) EXIT
    thisday=0
    call pgptxt(ex, ey, 0.0, 0.5, weekdays(mod(i,7)+1))
    ex=ex-12*3600
    if (ex .gt. x1) then
      call pgmove(ex, ey)
      call pgdraw(ex, ey+hmenu/2)
    endif
    ex=ex+24*3600
    if (ex .lt. x2) then
      call pgmove(ex, ey)
      call pgdraw(ex, ey+hmenu/2)
    endif
    i=i+1
  enddo
  if (thisday>0) then
    call pgptxt((x1+x2)/2, ey, 0.0, 0.5, weekdays(mod(thisday,7)+1))
  endif
  call pgsclp(1)

  call get_key(key, 0, 0) ! purge buffer

  numb=0
7 if (live) then
    if (xwin) then
      call pgmtxt('T', 1.0, 1.0, 1.0, 'LIVE MODE (click on text window before pressing any further key)')
    endif
    call get_key(key, 0, chartfreq)
    do while (key .eq. char(0)) ! no key pressed
      ntot=dlog_get(dmax, nset, tbase, xmax-0.5, 1e10, undef, xd, yd)
      if (ntot<0) then
        call err_txt('dlog_open_r 2')
        goto 99
      endif
      if (ntot .gt. 1) then
        i1=1
        i2=2
        do rl=1,2
          call pgswin(x1,x2,ymin(rl),ymax(rl))
          do i=i1,i2
            call pgsci(color(i))
            n=0
            lastj=1
            do j=1,ntot
              if (yd(j,i)==undef) then
                if (j>lastj) call pgline(j-lastj, xd(lastj), yd(lastj,i))
                lastj=j+1
              elseif (xd(j)>x2 .or. yd(j,i)<ymin(rl) .or. yd(j,i)>ymax(rl)) then
                call pgpage
	        window=x2-x1
                goto 1
              endif
            enddo
            if (ntot .gt. lastj) call pgline(ntot+1-lastj, xd(lastj), yd(lastj,i))
          enddo
          i1=3
          i2=3
        enddo
        xmax=max(xmax,xd(ntot))
      endif
      call get_key(key, 0, chartfreq)
    enddo
  else
    call pgcurs(ex, ey, key)
    call must_purge
  endif
  rl=1
  call pgswin(x1,x2,ymin(rl),ymax(rl))

8 if (key>='a') key=char(ichar(key)-32)
  if (ey>ymenu) then
    i=max(0,min(nmenu,int((ex-x1)/wmenu+1)))
    key=keys(i:i)
    ex=(x1+x2)/2
  endif
  if (key=='-') then
    window=min(window*2, 8*24*3600.)
  elseif (key=='X') then
    window=0
    live=.false.
  elseif (key=='+' .or. key==',') then
    window=max(winmin,window/2)
  elseif (key=='Z') then
    call pgsci(1)
    if (live) then
      call pgmtxt('T', 1.0, 0.0, 0.0, 'click on two opposite corners of a selection rectangle')
      call pgcurs(ex, ey, key)
    else
      call pgmtxt('T', 1.0, 0.3, 0.0, 'click on second corner of selection rectangle')
    endif
    call pgsci(5)
    xmin=x1
    xmax=x2
    call pgmove(xmin, ey)
    call pgdraw(xmax, ey)
    call pgmove(ex, ymin(rl))
    call pgdraw(ex, ymax(rl))
    call pgcurs(fx, fy, key)
    call must_purge
    x1=max(xmin,min(ex,fx))
    x2=min(xmax,max(ex,fx))
    if (x1>=x2) then
      x1=xmin
      x2=xmax
    endif
    window=x2-x1
    y1=max(ymin(1),min(ey,fy))
    y2=min(ymax(1),max(ey,fy))
    if (y1>=y2) then
      y1=ymin(1)
      y2=ymax(1)
    endif
    zoom=.true.
    live=.false.
    right=.false.
  elseif (key .ge. '0' .and. key .le. '9') then
    numb=numb*10+(ichar(key)-ichar('0'))
    if (numb>0) then
      write(buf, '(i8)') numb
      l=1
      do while (buf(l:l)==' ')
        l=l+1
      enddo
      call pgsci(1)
      call pgmtxt('T', 2.0, 0.9, 0.0, buf(l:))
    endif
    if (xwin .and. .not. live) then
      call pgcurs(ex, ey, key)
      call must_purge
    else
      call get_key(key, 2, 10)
    endif
    if (key/=char(0)) goto 8
    goto 7
  elseif (key .eq. 'D') then
    window=min(7*24*3600,24*3600*max(1,numb))
    right=.true.
    x1=0
  elseif (key .eq. 'H') then
    window=min(7*24*3600,3600*max(1,numb))
    right=.true.
    x1=0
  elseif (key .eq. 'M') then
    window=min(7*24*3600,60*max(1,numb))
    right=.true.
    x1=0
  elseif (key .eq. 'L') then
    live=.not. live
    if (live) then
      right=.true.
      x2=xmax
    endif
  elseif (key=='Q' .or. key==char(13)) then
    goto 9
  elseif (live) then
    goto 7
  endif
  numb=0
  call pgpage
  goto 1
99 call tecs_write_error(6)
9 continue
  call tplot_close
  call get_key(key, 0, 0)  ! purge type-ahead-buffer
  print *
end subroutine

subroutine get_key(key, tmo1, tmo2)
  integer tmo1, tmo2
  character key*1
  logical purge/.false./

  key=char(0)
  if (purge) then
    purge=.false.
    call sys_get_key(key, tmo1)
    if (key/=char(0) .and. key/=char(13)) return
  endif
  if (tmo2>0) call sys_get_key(key, tmo2)
  return

entry must_purge
  purge=.true.
end subroutine

subroutine tplot_close
  call pgclos
  call dlog_close_r
end subroutine