aboutsummaryrefslogtreecommitdiff
path: root/noao/rv/fftmode.x
blob: 40e45e449b21aa9fe546af793ce2197f633de4f3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
include <gset.h>
include "rvpackage.h"
include "rvflags.h"
include "rvcomdef.h"
include "rvplots.h"
include "rvfilter.h"


# FFT_COLON - Procedure to process the colon commands defined below.  Most
# commands are for interactive editing of parameters to the task.

int procedure fft_colon (rv, cmdstr)

pointer	rv				#I RV struct pointer
char	cmdstr[SZ_LINE]			#I Command

pointer sp, cmd
int 	strdic()

begin
	call smark (sp)
	call salloc (cmd, SZ_LINE, TY_CHAR)

	call sscan (cmdstr)
	call gargwrd (Memc[cmd], SZ_LINE)

	# Unpack the keyword from the string and look it up in the
	# dictionary.  Switch on command and call the appropriate routines.

        if (strdic(Memc[cmd], Memc[cmd], SZ_LINE, FILT_KEYWORDS) != 0) {
            # Process the FILTERPARS pset commands.
            call filt_colon (rv, cmdstr)

	} else { 
	    # Now process the mode specific colon commands.
	    switch (strdic(Memc[cmd], Memc[cmd], SZ_FNAME, PLOT_KEYWORDS)) {
	    case PLT_FILTER:
	        call cmd_filter (rv)

	    case PLT_FFT_ZOOM:
	        call cmd_fft_zoom (rv)

	    case PLT_LOG_SCALE:
	        call cmd_log_scale (rv)

	    case PLT_ONE_IMAGE:
	        call cmd_one_image (rv)

	    case PLT_OVERLAY:
	        call cmd_overlay (rv)

	    case PLT_PLOT:
	        call cmd_plot (rv)

	    case PLT_SPLIT_PLOT:
	        call cmd_split_plotx (rv)

	    case PLT_WHEN:
	        call cmd_when (rv)

	    default:
	        # Default action
		call rv_mode_prompt (rv)
	        call rv_errmsg ("Type '?' for a list of commands.")
	        call sfree (sp)
	        return (ERR)
	    }
	}

	call sfree (sp)
	return (OK)
end


# FFT_CURSOR - Get the next command from the user in the input cursor loop
# and perform the requested function.

int procedure fft_cursor (rv)

pointer	rv				#I RV struct pointer

pointer	gp, sp, cmd, filt
int	wcs, key
int	ofnpts, rfnpts
real	x, y
char	ckey
bool	prompt

int 	fft_colon(), clgcur(), stridx(), spc_cursor()
int	rv_parent(), fft_pow2(), rv_chk_filter()

define	exit_			99
define	replot_			98

begin
	# Update the mode counter.
	RV_MODES(rv) = (RV_MODES(rv)*10) + FFT_MODE

	call smark (sp)
	call salloc (cmd, SZ_LINE, TY_CHAR)

	# Nab some pointers.
	ofnpts = fft_pow2 (RV_NPTS(rv))
	rfnpts = fft_pow2 (RV_RNPTS(rv))
	gp = RV_GP(rv)


#	if (RVF_LASTKEY(rv) == 'p' && RV_FILTER(rv) != NONE)
#	    key = 'p'
#	else
	    key = 'b'
	repeat {

	    RV_CMD(rv) = key
	    ckey = key
    	    if (stridx(ckey,":?iqrsx") == 0)
	        RVF_LASTKEY(rv) = key
	    prompt = true
replot_     RV_NEWGRAPH(rv) = NO
	    switch (key) { 			# switch on the keystroke
	    case '?':				
	    	# List options
		call gpagefile (gp, FM_HELP, "FFT Mode Options: ")

	    case ':':				
		# Process a colon command.
	    	if (fft_colon(rv,Memc[cmd]) == OK) {
		    if (RV_NEWGRAPH(rv) == YES) {
		        key = RVF_LASTKEY(rv)
		        goto replot_
		    }
		}
		prompt = false

	    case 'b':
		# Display power spectra before filtering
		RVP_WHEN(rv) = BEFORE
		RVP_PLOT(rv) = POWER_PLOT
		call fft_plot (rv, RVP_PLOT(rv))

	    case 'f':
		# Display FFT's after filtering.
		if (RV_FILTER(rv) == NONE) {
		    call rv_mode_prompt (rv)
	    	    call rv_errmsg ("Filtering is currently disabled.")
		    prompt = false
		} else {
		    RVP_WHEN(rv) = AFTER
		    RVP_PLOT(rv) = AMPLITUDE_PLOT
		    call fft_plot (rv, RVP_PLOT(rv))
		}

	    case 'g':
		# Display FFT's before filtering.
		RVP_WHEN(rv) = BEFORE
		RVP_PLOT(rv) = AMPLITUDE_PLOT
		call fft_plot (rv, RVP_PLOT(rv))

	    case 'i':
		# Print period trend information.
		call rv_mode_prompt (rv)
		call fft_inverse (rv, x, y, wcs)
	        prompt = false

	    case 'I':
		call error (0, "Interrupt")

	    case 'o':
		# Display filtered and unfiltered object spectrum.
		if (RV_FILTER(rv) == OBJ_ONLY || RV_FILTER(rv) == BOTH) {
		    if (rv_chk_filter(rv, OBJECT_SPECTRUM) != OK) {
		        call rv_mode_prompt (rv)
	    	        call rv_errmsg ("Invalid filter specified.")
		        prompt = false
		    } else {
		        call malloc (filt, ofnpts, TY_REAL)
		        call gclear (gp)
		        if (RV_CONTINUUM(rv)==BOTH || 
			    RV_CONTINUUM(rv)==OBJ_ONLY) {
		        	call amovr (OCONT_DATA(rv,1), Memr[filt], 
				    RV_NPTS(RV))
		                call split_plot (rv, gp, TOP, OCONT_DATA(rv,1),
				    RV_NPTS(rv), OBJECT_SPECTRUM, NORM_PLOT)
		        } else {
		            call amovr (OBJPIXY(rv,1), Memr[filt], RV_NPTS(rv))
		            call split_plot (rv, gp, TOP, OBJPIXY(rv,1), 
				RV_NPTS(rv), OBJECT_SPECTRUM, SPECTRUM_PLOT)
		        }
		        call rv_do_filter (rv, RV_OSAMPLE(rv), Memr[filt], 
			    RV_NPTS(rv), Memr[filt], ofnpts, NO)
	                call split_plot (rv, gp, BOTTOM, Memr[filt], 
			    RV_NPTS(rv), OBJECT_SPECTRUM, FILTER_PLOT)
		        call mfree (filt, TY_REAL)
		    }
		} else {
		    call rv_mode_prompt (rv)
		    call rv_errmsg ("Filtering disabled for object spectrum.")
		    prompt = false
		}

	    case 'p':
		# Display power spectra after filtering.
		if (RV_FILTER(rv) == NONE) {
		    call rv_mode_prompt (rv)
	    	    call rv_errmsg ("Filtering is currently disabled.")
		    prompt = false
		} else {
		    RVP_WHEN(rv) = AFTER
		    RVP_PLOT(rv) = POWER_PLOT
		    call fft_plot (rv, RVP_PLOT(rv))
		}

	    case 'q':				
		# Quit this mode.
		break

	    case 'r':				
		# Replot.
	        if (RVF_LASTKEY(rv) != 'r')
	 	    key = RVF_LASTKEY(rv)
		goto replot_

	    case 's':
		# Display the spectra.
		if (rv_parent(rv) == SPEC_MODE) {
		    goto exit_
		} else if (spc_cursor (rv) == QUIT) {
		    RV_MODES(rv) = (RV_MODES(rv) - FFT_MODE) / 10
		    call sfree (sp)
		    return (QUIT)
		} else {
		    key = RVF_LASTKEY(rv)
		    goto replot_
	 	}

	    case 't':
		# Display filtered and unfiltered template spectrum.
		if (RV_FILTER(rv) == TEMP_ONLY || RV_FILTER(rv) == BOTH) {
		    if (rv_chk_filter(rv, REFER_SPECTRUM) != OK) {
		        call rv_mode_prompt (rv)
	    	        call rv_errmsg ("Invalid filter specified.")
		        prompt = false
		    } else {
		        call malloc (filt, rfnpts, TY_REAL)
		        call gclear (gp)
		        if (RV_CONTINUUM(rv)==BOTH || 
			    RV_CONTINUUM(rv)==TEMP_ONLY) {
		                call amovr (RCONT_DATA(rv,1), Memr[filt], 
				    RV_RNPTS(rv))
		                call split_plot (rv, gp, TOP, RCONT_DATA(rv,1),
				    RV_RNPTS(rv), REFER_SPECTRUM, NORM_PLOT)
		        } else {
		            call amovr (REFPIXY(rv,1), Memr[filt], RV_RNPTS(rv))
		            call split_plot (rv, gp, TOP, REFPIXY(rv,1), 
				RV_RNPTS(rv), REFER_SPECTRUM, SPECTRUM_PLOT)
		        }
		        call rv_do_filter (rv, RV_RSAMPLE(rv), Memr[filt], 
			    RV_RNPTS(rv), Memr[filt], rfnpts, NO)
	                call split_plot (rv, gp, BOTTOM, Memr[filt], 
			    RV_RNPTS(rv), REFER_SPECTRUM, FILTER_PLOT)
		        call mfree (filt, TY_REAL)
		    }
		} else {
		    call rv_mode_prompt (rv)
		    call rv_errmsg ("Filtering disabled for template spectrum.")
		    prompt = false
		}

	    case 'x':
		# Return to correlation mode.
		RV_MODES(rv) = (RV_MODES(rv) - FFT_MODE) / 10
		call sfree (sp)
		return (QUIT)

	    default:
	    	# Unknown command.
		call rv_mode_prompt (rv)
		call rv_errmsg ("Type '?' for a list of commands.")
		prompt = false
	    }

	    if (prompt)
	        call rv_mode_prompt (rv)
	    ckey = key
    	    if (stridx(ckey,":?iqrsx") == 0)
	        RVF_LASTKEY(rv) = key

	} until (clgcur("cursor",x,y,wcs,key,Memc[cmd],SZ_LINE) == EOF)

exit_ 	call sfree (sp)
	RV_MODES(rv) = (RV_MODES(rv) - FFT_MODE) / 10
	return (OK)
end


# FFT_PLOT - Do the plotting for the FFT plotting subpackage and determine
# the type of plot to draw.

procedure fft_plot (rv, flags)

pointer	rv				#I RV struct pointer
int	flags				#I Type of plot to draw

begin
        # Get the graphics pointer and clear the workstation.
        if (RV_GP(rv) != NULL)
            call gclear (RV_GP(rv))                             
        else
            return

        # Call the plot primitives.
        switch (flags) {
        case AMPLITUDE_PLOT:
            call fft_fplot (rv, RVP_SPLIT_PLOT(rv))
        case POWER_PLOT:
            call fft_pplot (rv, RVP_SPLIT_PLOT(rv))
        default:
            call error (0, "Invalid FFT plot specification.")
        }
end


# FFT_FLTPLOT - Plot the (filtered) spectrum to the screen.

procedure fft_fltplot (rv, gp, vec, npts)

pointer	rv				#I RV struct pointer
pointer	gp				#I graphics descriptor
real	vec[ARB]			#I Data to be plotted
int	npts				#I Npts of data to plot

pointer	sp
pointer	objx, title, idsys
int	i
real	x1, x2, y1, y2
double	dex()

begin
	if (gp == NULL)
	    return

	call smark (sp)
	call salloc (objx, npts, TY_REAL)
	call salloc (idsys, SZ_LINE, TY_CHAR)
	call salloc (title, 4*SZ_LINE, TY_CHAR)

	call gclear (gp)

	# Scale the vector.
	if (RV_DCFLAG(rv) == -1) {
	    do i = 1, npts 
	        Memr[objx+i-1] = real (i)
	} else {
	    do i = 1, npts 
	        Memr[objx+i-1] = dex (RV_OW0(rv) + (i-1) * RV_OWPC(rv))
	}

	# Scale the WCS.
	call gascale (gp, Memr[objx], npts, 1)
	call gascale (gp, vec, npts, 2)

	# Force a pretty Y scaling.
	call ggwind (gp, x1, x2, y1, y2)
	y1 = y1 - (0.02*y1)
	y2 = y2 + (0.02*y2)
	call gswind (gp, x1, x2, y1, y2)
		
	# Do the title and labeling.
	call sysid (Memc[idsys], SZ_LINE)
	call sprintf (Memc[title], 4*SZ_LINE,
	    "%s\nObject='%s' Star='%s'\nnpts=%d aperture=%d")
	         call pargstr (Memc[idsys])
	         call pargstr (IMAGE(rv))
		 call pargstr (OBJNAME(rv))
	         call pargi (npts)
		 call pargi (RV_APNUM(rv))
	call glabax (gp, Memc[title], "wavelength", "intensity")

	# Draw the vectors.
	call gpline (gp, Memr[objx], vec, npts)

	call gflush (gp)
	call sfree (sp)
end


# FFT_GFILTER - Fill an array with the requested filter function so that
# it may be overplotted on the FFT plot.

procedure fft_gfilter (rv, filt, npts, y2)

pointer	rv				#I RV struct pointer
real	filt[npts]			#U FFT data array
int	npts				#I no. elements in fft[]
real	y2				#I Upper limit of plot

pointer	sp, buf
int	i, npts2
real	tmp

begin
	call smark (sp)
	call salloc (buf, 2*npts, TY_REAL)
	call aclrr (Memr[buf], 2*npts)

	npts2 = 2 * npts 			# initializations
	if (RVP_LOG_SCALE(rv) == YES)
	    y2 = 10.0 ** y2
	call amovkr (y2, Memr[buf], npts2)

	# Now apply the filter to get the function.
	call rv_filter (rv, Memr[buf], npts)

	# Now recover the filter function.
	do i = 1, npts {
	    tmp = Memr[buf+i-1]
	    if (RVP_LOG_SCALE(rv) == YES && tmp != 0.0)
	        filt[i] = log10 (tmp) 
	    else
	        filt[i] = tmp
	}
	
	call sfree (sp)
end


# PLOT_OVERLAY - Plot the filter function overlayed on the FFT plot.

procedure fft_fltoverlay (rv, gp, fnpts, y2)

pointer	rv				#I RV struct pointer
pointer	gp				#I Graphics decriptor
int	fnpts				#I Npts in FFT
real	y2				#I Current Y2 of window

pointer	sp, filt
real	startp, endp
int	rv_chk_filter(), fft_pow2()

begin
	if (gp == NULL || RVP_OVERLAY(rv) == NO)
	    return

	# Check for a nonsensical filter specification.
	if (RV_WHERE(rv) == TOP && rv_chk_filter(rv,OBJECT_SPECTRUM) != OK)
	    return
	if (RV_WHERE(rv) == BOTTOM && rv_chk_filter(rv,REFER_SPECTRUM) != OK)
	    return

	fnpts = max (fft_pow2 (RV_NPTS(rv)), fft_pow2 (RV_RNPTS(rv)) ) / 2

	# Allocate working space.
	call smark (sp)			
	call salloc (filt, 2*fnpts, TY_REAL)

	# Get the filter to be plotted.
	y2 = y2 - (0.075 * y2)
	call fft_gfilter (rv, Memr[filt], 2*fnpts, y2)

	# Compute the endpoint.
	if (RV_WHERE(rv) == BOTTOM) {
	    startp = 1.
	    endp = real(fnpts) / RVP_FFT_ZOOM(rv)
	} else {
	    startp = 0.
	    endp = (real(fnpts) / RVP_FFT_ZOOM(rv)) / (2. * real(fnpts))
	}
	fnpts = fnpts * 2

	# Now plot the filter function.
	call gseti (gp, G_PLCOLOR, C_RED)
	call gvline (gp, Memr[filt], int(fnpts/RVP_FFT_ZOOM(rv)), startp, endp)
	call gseti (gp, G_PLCOLOR, C_FOREGROUND)

        if (DEBUG(rv)) {
            call d_printf (DBG_FD(rv),"flt_overlay:\tstart=%g end=%g\n")
		call pargr (startp) ; call pargr (endp)
            call d_printf (DBG_FD(rv),"\t\tnew=%d np=%d rnp=%d fnp=%d\n")
		call pargi (fnpts) ;call pargi (RV_NPTS(rv))
		call pargi (RV_RNPTS(rv)) ; call pargi (RV_FFTNPTS(rv)) 
	    call flush (DBG_FD(rv))
	}


	call sfree (sp)
end


# FFT_FPLOT - Plot the (two) Fourier transforms to the screen.

procedure fft_fplot (rv, flag)

pointer	rv				#I RV struct pointer
int	flag				#I Type of flag to print (SINGLE/SPLIT)

pointer	gp
pointer	sp, rfft, title, bp, ylbl
int	fnpts
int	fft_pow2()
real	x1, x2, y1, y2, startp, endp

begin
	gp = RV_GP(rv)
	if (gp == NULL)
	    return

	# Allocate working space.
	call smark (sp)			
	call salloc (rfft, 2*fft_pow2(RV_NPTS(rv)), TY_REAL)
	call salloc (title, 2*SZ_LINE, TY_CHAR)
	call salloc (ylbl, SZ_LINE, TY_CHAR)
	call salloc (bp, SZ_LINE, TY_CHAR)

	# Clear the screen.
	call gclear (gp)

	if (flag == SINGLE_PLOT) {
	    if (RVP_ONE_IMAGE(rv) == OBJECT_SPECTRUM) {
	        if (RV_CONTINUUM(rv) != NONE) {
	            call get_fft (rv,OCONT_DATA(rv,1), RV_NPTS(rv), Memr[rfft],
		        fnpts)
	        } else {
	            call get_fft (rv,OBJPIXY(rv,1), RV_NPTS(rv), Memr[rfft], 
		        fnpts)
	        }
	    } else {
	        if (RV_CONTINUUM(rv) != NONE) {
	            call get_fft (rv,RCONT_DATA(rv,1), RV_RNPTS(rv), Memr[rfft],
		        fnpts)
	        } else {
	            call get_fft (rv,REFPIXY(rv,1), RV_RNPTS(rv), Memr[rfft], 
		        fnpts)
	        }
	    }

	    # Draw the plot to the screen
	    fnpts = max (RV_FFTNPTS(rv), fnpts) / 2
	    call gascale (gp, Memr[rfft], int(fnpts/RVP_FFT_ZOOM(rv)), 2)
	    call ggwind (gp, x1, x2, y1, y2)

	    call get_anplot_title (rv, title)
	    if (RVP_LOG_SCALE(rv) == YES) 
		call strcpy ("log(|G(k)|)", Memc[ylbl], SZ_FNAME)
	    else
		call strcpy ("|G(k)|", Memc[ylbl], SZ_FNAME)

	    # Draw the top axis labels
	    startp = 0.0
	    endp = (real(fnpts) / RVP_FFT_ZOOM(rv)) / (2. * real(fnpts))
	    call gseti (gp, G_WCS, 1)
	    call gsview (gp, 0.115, 0.95, 0.125, 0.8)
	    call gswind (gp, startp, endp, y1, y2)
	    call gseti (gp, G_XDRAWAXES, 2)
	    call glabax (gp, "", "", Memc[ylbl])

	    # Draw the bottom axis labels
	    startp = 1.0
	    endp = real(fnpts) / RVP_FFT_ZOOM(rv)
	    call gseti (gp, G_WCS, 2)
	    call gsview (gp, 0.115, 0.95, 0.125, 0.8)
	    call gswind (gp, startp, endp, y1, y2)
	    call gseti (gp, G_XDRAWAXES, 1)
	    call gseti (gp, G_YDRAWAXES, 3)
	    call glabax (gp, "", "Wavenumber", Memc[ylbl])

	    # Do the plot title
	    call gseti (gp, G_WCS, 3)
	    call gsview (gp, 0.115, 0.95, 0.125, 0.845)
	    call gswind (gp, startp, endp, y1, y2)
	    call gseti (gp, G_XDRAWAXES, 0)
	    call gseti (gp, G_YDRAWAXES, 0)
	    call glabax (gp, Memc[title], "", "")
	    call gsview (gp, 0.115, 0.95, 0.125, 0.8)

	    call gvline (gp, Memr[rfft], int(fnpts/RVP_FFT_ZOOM(rv)), 
		startp, endp)

	    # Lastly, annotate ther plot so we know what we're looking at.
	    call gctran (gp, 0.73, 0.73, x1, y1, 0, 1)
	    call gseti (gp, G_TXCOLOR, RV_TXTCOLOR(rv))
	    if (RVP_ONE_IMAGE(rv) == OBJECT_SPECTRUM)
	        call gtext (gp, x1, y1, "Object FFT", "")
	    else
	        call gtext (gp, x1, y1, "Template FFT", "")
	    call gctran (gp, 0.73, 0.69, x1, y1, 0, 1)
            if (RV_FILTER(rv) == BOTH || RV_FILTER(rv) == OBJ_ONLY) {
	        call fft_fltoverlay (rv, gp, fnpts*2, y2)
                if (RVP_WHEN(rv) == BEFORE)
                    call gtext (gp, x1, y1, "Before Filter", "")
                else 
                    call gtext (gp, x1, y1, "After Filter", "")
            }
	    call gseti (gp, G_TXCOLOR, C_FOREGROUND)
	    call gseti (gp, G_XDRAWAXES, 3)		# reset gio flags
 
	} else if (flag == SPLIT_PLOT) {

	    # Plot the Object power stectrum along the top.
	    if (RV_CONTINUUM(rv) == OBJ_ONLY || RV_CONTINUUM(rv) == BOTH) {
	        call split_plot (rv, gp, TOP, OCONT_DATA(rv,1), RV_NPTS(rv), 
	            OBJECT_SPECTRUM, FOURIER_PLOT)
	    } else {
	        call split_plot (rv, gp, TOP, OBJPIXY(rv,1), RV_NPTS(rv), 
	            OBJECT_SPECTRUM, FOURIER_PLOT)
	    }

	    # Template power spectrum along the bottom.
	    if (RV_CONTINUUM(rv) == TEMP_ONLY || RV_CONTINUUM(rv) == BOTH) {
	        call split_plot (rv, gp, BOTTOM, RCONT_DATA(rv,1), 
	            RV_RNPTS(rv), REFER_SPECTRUM, FOURIER_PLOT)
	    } else {
	        call split_plot (rv, gp, BOTTOM, REFPIXY(rv,1), 
	            RV_RNPTS(rv), REFER_SPECTRUM, FOURIER_PLOT)
	    }
		
	}

	call sfree (sp)
end


# FFT_INVERSE - Print the inverse of the X-axis of the current plot.  The intent
# of this routine is to provide an easy mechanism for users to translate the
# frequency of a point on the power spectrum into a period trend in the data.
# It may also be used to translate wavelengths into approximate wavenumbers.

procedure fft_inverse (rv, x, y, wcs)

pointer	rv					#I RV struct pointer
real	x, y					#I Current cursor (x,y)
int	wcs					#I WCS of cursor read

pointer	gp
real	period
real	x1, x2, y1, y2, xx, yy
int	fnpts, fft_pow2()

begin
	gp = RV_GP(rv)
	if (gp == NULL)
	    return

	# Switch based on the plot flags.
	call ggview (gp, x1, x2, y1, y2)
	call gctran (gp, x, y, x, y, wcs, 1)
	call gctran (gp, x, y, xx, yy, 1, 0)

	fnpts = fft_pow2 (max(RV_NPTS(rv),RV_RNPTS(rv))) / 2
	if (xx < x1 || xx > x2) {		# outside plot window
	    call printf ("Period trend in the data = INDEF.")
	    return
	} else {
	    period = (1. / x) * real(fnpts * 2.)
	    call printf (
		"Period trend in the data = %.2f pixels (K = %d, f = %.3f).")
		    call pargr (period)
		    call pargi (int(x))
		    call pargr (x/real(fnpts))
	} 
end


# FFT_PPLOT - Plot the (two) Fourier power spectra to the screen.

procedure fft_pplot (rv, flag)

pointer	rv				#I RV struct pointer
int	flag				#I Type of flag to print (SINGLE/SPLIT)

pointer	gp
pointer	sp, rfft, title, bp, xlbl, ylbl
int	fnpts
int	fft_pow2()
real	startp, endp
real	x1, x2, y1, y2

begin
	gp = RV_GP(rv)
	if (gp == NULL)
	    return

	# Allocate working space.
	call smark (sp)			
	call salloc (bp, SZ_LINE, TY_CHAR)
	call salloc (xlbl, SZ_LINE, TY_CHAR)
	call salloc (ylbl, SZ_LINE, TY_CHAR)
	call salloc (title, 3*SZ_LINE, TY_CHAR)
	call salloc (rfft, fft_pow2(RV_NPTS(rv)), TY_REAL)

	# Clear the screen.
	call gclear (gp)

	if (flag == SINGLE_PLOT) {
	    if (RVP_ONE_IMAGE(rv) == OBJECT_SPECTRUM) {
	        if (RV_CONTINUUM(rv) != NONE) {
	            call get_fft (rv,OCONT_DATA(rv,1), RV_NPTS(rv), Memr[rfft],
		        fnpts)
	        } else {
	            call get_fft (rv,OBJPIXY(rv,1), RV_NPTS(rv), Memr[rfft], 
		        fnpts)
	        }
	    } else {
	        if (RV_CONTINUUM(rv) != NONE) {
	            call get_fft (rv,RCONT_DATA(rv,1), RV_RNPTS(rv), Memr[rfft],
		        fnpts)
	        } else {
	            call get_fft (rv,REFPIXY(rv,1), RV_RNPTS(rv), Memr[rfft], 
		        fnpts)
	        }
	    }

            # Draw the plot to the screen
            fnpts = max (RV_FFTNPTS(rv), fnpts) / 2
            call gascale (gp, Memr[rfft], int(fnpts/RVP_FFT_ZOOM(rv)), 2)
            call ggwind (gp, x1, x2, y1, y2)

            call get_anplot_title (rv, title)
            if (RVP_LOG_SCALE(rv) == YES)
                call strcpy ("log(|G(k)|)", Memc[ylbl], SZ_FNAME)
            else
                call strcpy ("|G(k)|", Memc[ylbl], SZ_FNAME)

            # Draw the bottom axis labels
            startp = 1.0
            endp = real(fnpts) / RVP_FFT_ZOOM(rv)
            call gseti (gp, G_WCS, 2)
            call gsview (gp, 0.115, 0.95, 0.125, 0.8)
            call gswind (gp, startp, endp, y1, y2)
            call gseti (gp, G_XDRAWAXES, 1)
            call gseti (gp, G_YDRAWAXES, 3)
            call glabax (gp, "", "Wavenumber", Memc[ylbl])
 
            # Draw the top axis labels
            startp = 0.0
            endp = (real(fnpts) / RVP_FFT_ZOOM(rv)) / (2. * real(fnpts))
            call gseti (gp, G_WCS, 1)
            call gsview (gp, 0.115, 0.95, 0.125, 0.8)
            call gswind (gp, startp, endp, y1, y2)
            call gseti (gp, G_XDRAWAXES, 2)
            call glabax (gp, "", "", Memc[ylbl])

            # Do the plot title
            call gseti (gp, G_WCS, 3)
            call gsview (gp, 0.115, 0.95, 0.125, 0.845)   
            call gswind (gp, startp, endp, y1, y2)
            call gseti (gp, G_XDRAWAXES, 0)
            call gseti (gp, G_YDRAWAXES, 0)
            call glabax (gp, Memc[title], "", "")
	    call gsview (gp, 0.115, 0.95, 0.125, 0.8)
 
	    call gvline (gp, Memr[rfft], int(fnpts/RVP_FFT_ZOOM(rv)), 
		startp, endp)

	    # Lastly, annotate the plot so we know what we're looking at.
	    call gctran (gp, 0.73, 0.73, x1, y1, 0, 1)
	    call gseti (gp, G_TXCOLOR, RV_TXTCOLOR(rv))
	    if (RVP_ONE_IMAGE(rv) == OBJECT_SPECTRUM)
	        call gtext (gp, x1, y1, "Object PS", "")
	    else
	        call gtext (gp, x1, y1, "Template PS", "")
	    call gctran (gp, 0.73, 0.69, x1, y1, 0, 1)
            if (RV_FILTER(rv) == BOTH || RV_FILTER(rv) == OBJ_ONLY) {
	        call fft_fltoverlay (rv, gp, fnpts*2, y2)
                if (RVP_WHEN(rv) == BEFORE)
                    call gtext (gp, x1, y1, "Before Filter", "")
                else 
                    call gtext (gp, x1, y1, "After Filter", "")
            }
	    call gseti (gp, G_TXCOLOR, C_FOREGROUND)
	    call gseti (gp, G_XDRAWAXES, 3)		# reset gio flags

	} else if (flag == SPLIT_PLOT) {

	    # Plot the Object power stectrum along the top.
	    if (RV_CONTINUUM(rv) == OBJ_ONLY || RV_CONTINUUM(rv) == BOTH) {
	        call split_plot (rv, gp, TOP, OCONT_DATA(rv,1), RV_NPTS(rv), 
	            OBJECT_SPECTRUM, PS_PLOT)
	    } else {
	        call split_plot (rv, gp, TOP, OBJPIXY(rv,1), RV_NPTS(rv), 
	            OBJECT_SPECTRUM, PS_PLOT)
	    }

	    # Template power spectrum along the bottom.
	    if (RV_CONTINUUM(rv) == TEMP_ONLY || RV_CONTINUUM(rv) == BOTH) {
	        call split_plot (rv, gp, BOTTOM, RCONT_DATA(rv,1), 
	            RV_RNPTS(rv), REFER_SPECTRUM, PS_PLOT)
	    } else {
	        call split_plot (rv, gp, BOTTOM, REFPIXY(rv,1), 
	            RV_RNPTS(rv), REFER_SPECTRUM, PS_PLOT)
	    }
		
	}

	call sfree (sp)
end