pro MakeRGB
;+
; NAME:
;	MakeRGB
; PURPOSE:
;	Uses the standard 256-color IDL tables to patch together a 256-color
;	table
; CATEGORY:
; CALLING SEQUENCE:
; INPUTS:
; OPTIONAL INPUT PARAMETERS:
; OUTPUTS:
; OPTIONAL OUTPUT PARAMETERS:
; CALLS:
;	IsDisplay
; INCLUDE:
;	@skycolors.pro
; SIDE EFFECTS:
; RESTRICTIONS:
; PROCEDURE:
; MODIFICATION HISTORY:
;-
on_error, 2

@skycolors.pro			; Dummy comment for Linux

dname = !d.name			; Save current device

set_plot, !TheTerminal		; Set terminal device

; On the VAX, !d.n_colors is initially set to 256, but drops to 209 when the first
; window is opened. The call to twin is a kludge to get the lower number of
; actually available colors. On the PC this is not necessary: in 256 color mode
; !d.n_colors is immediately set to 236. In 24-bit color mode the system does not
; reserve any colors for itself and !d.n_colors=2^24.

if IsDisplay() then begin
	twin, /show, xsize=5, ysize=5
	TotalColors = !d.n_colors
	twin, /del

endif else	$
	TotalColors = !d.n_colors

; For the time being, stick to 256 colors max

TotalColors = TotalColors < 256

ncolors = 2+2+2+2+2+2+4+5*256+256	; At most needed

rr = bytarr(ncolors, /nozero)
gg = bytarr(ncolors, /nozero)
bb = bytarr(ncolors, /nozero)

; Define a couple of colors; assign two consecutive indices to each color

n = 0L

FirstColor = n

Black = [n,n+1]						; Black
rr[Black] = 0
gg[Black] = 0
bb[Black] = 0

n = n+2							; # colors used = next free index

White = [n,n+1]						; White
rr[White] = 255
gg[White] = 255
bb[White] = 255

n = n+2

Purple = [n,n+1]
rr[Purple] = 252				; purple (2 colors)
gg[Purple] =  76
bb[Purple] = 193

n = n+2

Red = [n,n+1]
rr[Red] = 255				; red (2 colors)
gg[Red] =   0
bb[Red] =   0

n = n+2

Green = [n,n+1]
rr[Green] = 102 ;     0		; green (2 colors)
gg[Green] = 162 ;   255
bb[Green] =   0 ;	 10

n = n+2

Blue = [n,n+1]
rr[Blue] =   0				; blue (2 colors)
gg[Blue] =   0
bb[Blue] = 255

n = n+2

; Read the bitmap earth.bmp. It contains only 4 different colors.

;map = read_bmp( filepath(root=getenv('SYS'),'earthxxx.bmp'),r,g,b)
;write_bmp, filepath(root=getenv('SYS'),'earthxxxtmp.bmp'),	$
;	n+read_bmp(filepath(root=getenv('SYS'),'earthxxxtmp.bmp'),r,g,b), $
;	shift(r,n),shift(g,n),shift(b,n)

Earth = n+lindgen(4)

rr[Earth] = r[0:3]				; 4 colors from Earth
gg[Earth] = g[0:3]
bb[Earth] = b[0:3]
Earth = [Earth[0],Earth[3]]

n = n+4

; Establish four ranges of color indices by extracting from the default IDL 256-color tables
;	greyish, blueish, yellowish, reddish, greenish

; The number of colors extracted using tvlct will be ncolors, but never more than 256.

;istart = 60					; extract starting at istart
;istep  = 4						; extract every istep color
;istart = 100
;istep  = 3
;istart = 159
;istep = 2
;i = 80+3*indgen(40)
;i = 80+4*indgen(40)

k = ((TotalColors-n)/5) < 256		; Maximum # free indices needed for each color range

; Grey, blue, yellow, red, green

nTables = n_elements(iTables)
pTables = lonarr(nTables,/nozero)
eTables = lonarr(nTables,/nozero)

for iT=0,nTables-1 do begin

	loadct, iTables[iT]
	tvlct, /get, r,g,b

	istart = 0
	ilen   = (n_elements(r)-istart) < k
	istep  = n_elements(r)/ilen
	i = istart+istep*lindgen(ilen)

	pTables[iT] = n
	eTables[iT] = pTables[iT]+ilen-1

	rr[pTables[iT]:eTables[iT]] = r[i]
	gg[pTables[iT]:eTables[iT]] = g[i]
	bb[pTables[iT]:eTables[iT]] = b[i]

	n = n+ilen
endfor

LastColor = n-1

; Append the color table that is used to set up the rgbo
; array for Voxel_Proj

;loadct, 33				; Blue-red
loadct, 4				; Blue/green/red/yellow
tvlct, /get, r, g, b

pRgbo = n
eRgbo = n+n_elements(r)-1

rr[pRgbo:eRgbo] = r				; Append predefined 256-color table
gg[pRgbo:eRgbo] = g
bb[pRgbo:eRgbo] = b

rr = rr[0:eRgbo]
gg = gg[0:eRgbo]
bb = bb[0:eRgbo]

; Write to file

openw, /get_lun, iu, filepath(root=getenv('SYS'),'skyrgb.txt')
printf, iu, [transpose(rr),transpose(gg),transpose(bb)]
free_lun, iu

openw, /get_lun, iu, filepath(root=getenv('SYS'),'skyinfo.txt')
printf, iu, 'TotColors:', TotalColors-1,TotalColors-1
printf, iu, cColors, FirstColor,LastColor
printf, iu, cBlack , Black
printf, iu, cWhite , White
printf, iu, cPurple, Purple
printf, iu, cRed   , Red
printf, iu, cGreen , Green
printf, iu, cBlue  , Blue
printf, iu, cEarth , Earth
for i=0,nTables-1 do printf, iu, cTables[i],pTables[i],eTables[i]
printf, iu, cRgbo  , pRgbo,eRgbo
free_lun, iu

set_plot, dname			; Reestablish the saved device

tvlct, rr[0:pRgbo-1], gg[0:pRgbo-1], bb[0:pRgbo-1]	; load the custom table

return  &  end