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Re: TVIM display routine on 24-bit displays
- Subject: Re: TVIM display routine on 24-bit displays
- From: David Williams <d.williams(at)qub.ac.uk>
- Date: Thu, 11 Jan 2001 18:27:39 +0000
- Newsgroups: comp.lang.idl-pvwave
- Organization: Queen's University of Belfast
- References: <3A5DF8CA.E0BAE1ED@qub.ac.uk>
- Xref: news.doit.wisc.edu comp.lang.idl-pvwave:22906
As an afterthought, I decided to include the actual TVIM routine, just
in case...
As I say, help would be greatly appreciated on this issue.
Dave
;+
; ROUTINE: tvim
;
; USEAGE: tvim,a
;
; tvim,a,scale=scale,range=range,xrange=xrange,yrange=yrange,$
; aspect=aspect,title=title,xtitle=xtitle,ytitle=ytitle,$
; noaxis=noaxis,interp=interp,colors=colors,c_map=c_map,$
; stitle=stitle,rmarg=rmarg,clip=clip,labels=labels,$
;
pcharsize=pcharsize,lcharsize=lcharsize,nbotclr=nbotclr,&
; clevels=clevels,nodata=nodata,rgb_nodata=rgb_nodata,$
;
barwidth=barwidth,position=position,noframe=noframe,rct=rct, $
; subtitle=subtitle
;
; PURPOSE: Display an image with provisions for
;
; 1. numbered color scale
; 2. plot title
; 3. annotated x and y axis
; 4. simplified OPLOT capability
; 5. manual or automatic scaling with smooth or discreet
colors
; 6 special treatment of "invalid data" pixels
;
; INPUT
; a image quantity
;
; Optional keyword input:
;
; title
; plot title
;
; xtitle
; x axis title
;
; ytitle
; y axis title
;
; stitle
; color key title (drawn to the right of color scale)
;
; rmarg
; right margin expansion factor to provide more room for extra wide
; color scale annotation (default=1)
;
; xrange
; array spanning entire x axis range. (default = [0,x_dimension-1])
;
; yrange
; array spanning entire y axis range. (default = [0,y_dimension-1])
;
; NOTE:TVIM only uses min(XRANGE), max(XRANGE), min(YRANGE) and
max(YRANGE).
;
; scale
; if set draw color scale. SCALE=2 causes steped color scale
;
; range
; two or three element vector indicating physical range over which
; to map the color scale. The third element of RANGE, if specified,
; sets the step interval of the displayed color scale. It has no
; effect when SCALE is not set. E.g., RANGE=[0., 1., 0.1] will
; cause the entire color scale to be mapped between the physical
; values of zero and one; the step size of the displayed color
; scale will be set to 0.1.
;
; clip
; specifies a set percentage of pixels which will be left outside
; the color scale. Larger values of CLIP yield images with greater
; contrast. For example if clip=2 then the color scale range will
; be set to include 98% of the pixels and to exclude the brightest
; 1% and the dimmest 1% of the pixel brightness distribution.
; Keyword RANGE overides the effect of CLIP.
;
; If CLIP is a two element vector, the upper and lower percentile
; range can be specified. For example CLIP=[0,95] will exclude the
; top 5%.
;
; An alternative is to set CLIP to a single negative integer. This
; causes the grey scale range to be obtained from the max and min
; value of the image array after it is filtered by a 2-D median
; filter. The radius of the median filter is set to -clip. Median
; filtering is effective in removing "salt and pepper" noise,
; (isolated high or low values). For example, setting clip=-1
; causes the code to check the 9 element superpixel centered at
; each pixel for median values. A single extremely large or small
; value does not affect the final value of the median at each pixel
; point.
;
; aspect
; the x over y aspect ratio of the output image. If not set, aspect
; is set to (size_x/size_y) of the input image.
;
; position
; specifies the lower left and upper right TVIM frame position in
; normal coordinates. When set POSITION overides the setting of
; ASPECT.
;
; noaxis
; if set do not draw x and y numbered axis around image. Instead
; just draw a box
;
; noframe
; if set no not draw anything around image, not even a box
;
; interp
; TVIM normally uses nearest neighbor sampling to resize the image
; to fill the data window area. If INTERP is set the resizing
; operation uses bilinear interpolation
;
; If INTERP = 2 the interpolation range is adjusted so that there
; is a half pixel border around the plot. This ensures that the
; smoothed image properly represents the cell center values of the
; pixels, but introduces an extrapolation on the outer edges. This
; option has noticeable effects for small (<20) image arrays.
;
; NOTE: When writing to a Postscript file the resizing operation is
; accomplished by changing the pixel size. Thus the INTERP
; parameter has no effect on Postscript output.
;
; pcharsize
; character size of numbers along x and y axis and the title
; (default is !p.charsize if non-zero, 1 otherwise)
;
; NOTE: The character size of the x and y-axis number scale
; annotation may be independently controlled by the !x.charsize or
; !y.charsize system variables. For example, the x and y axis
; number scale characters may be made invisible by setting these
; variables to a very small non-zero number before calling TVIM.
; Remember to restore normal character sizes by setting !x.charsize
; and !y.charsize to 1 or zero after the call to TVIM.
;
; lcharsize
; character size of color key number or labels (default is
; !p.charsize if non-zero, 1 otherwise)
;
; barwidth
; width of color key which appears to right of image when SCALE is
; set. (default=1)
;
; labels
; a vector of strings used to label the color key levels. If not
; set the default color key number labels are used. If the number
; of elements in LABELS is the same as the number of elements in
; COLORS then the labels will appear in the middle of a given
; color band instead of at the boundary between colors. If COLORS
; is not set the number of elements in LABELS should be at least
; as large as the number of color key segments plus one.
;
; colors
; an array of color indicies. When the COLORS array is set TVIM
; will map values of A into the color values specified in COLORS.
; How physical values are assigned to color values depends on how
; the RANGE parameter is set, as shown in this table:
;
; RANGE color_value
; ----- -----------
; 1. not set COLORS(A)
; 2. [amin,amax] COLORS((A-amin)/dinc)
; 3. [amin,amax,inc] COLORS((A-amin)/inc)
;
; where amin, amax and inc are user specified elements of RANGE
; and dinc=(amax-amin)/n_elements(COLORS). In case 1, A is used
; directly as a subscript into COLORS. When RANGE is not set
; legend labels should be used to annotate the color values. In
; case 2, A is scaled so that each color defined in COLORS
; represents a proportionate fraction of the total dynamic range.
; In case 3, amin and inc (and not amax) are used to control which
; colors are associated with given physical values. See examples.
;
; c_map
; TVIM normally rescales the input image to span the entire color
; table range. Setting C_MAP disables this automatic re-scaling.
; This is useful when the image byte values correspond to a
; particular color mapping that could be destroyed by the
; rescaling process (E.G. a gif image).
;
; NOTE: When the number of IDL color table entries is less than
; 256 some colors may be lost. Use a private color map to avoid
; this. See examples.
;
; nbotclr
; number of reserved colors at the bottom of the color
; table. Color values between 0 and nbotclr-1 will not
; be used in the displayed image. This allows the
; bottom of the table to be set to special colors which
; will not be used in the displayed the image. This
; keyword is disabled when either the COLORS or NODATA
; options are used. (default=1)
;
; NOTE: by default the color table indicies used within a TVIM
; image is limited to the range 1 to !d.n_colors-2. In most
; predefined color tables, color index 0 and !d.n_color-1
; correspond to pure black and white, respectively. TVIM uses
; these color indicies as background and foreground colors for
; region blanking and axis annotation. Color tables which do not
; define black and white in these index locatations are not good
; choices for TVIM plots, unless the first and last color table
; entries are redefined as black and white using TVLCT, e.g.,
; tvlct,0,0,0,0 & tvlct,255,255,255,!d.n_colors-1
;
; NOTE: the procedure DCOLORS can be used to load a set
; of discreet colors in the bottom 11 color values
; (0-10). The original color table is resampled to fit
; between color value 11 and the !d.n_colors-1.
;
;
; nodata
; pixel values which are interpreted as invalid data. Pixels
; containing this data value are colored with color RGB_NODATA.
;
; rgb_nodata
; an RGB value (a 3 component vector) used to color pixels filled
; with invalid data. (default = [0,0,0])
;
; NOTE: NODATA and RGB_NODATA override the effect of NBOTCLR
;
; rct
; if set, reverse direction of color table. This keyword can be
; used on black & white printers to allow large field values to be
; represented by dark colors.
;
; subtitle
; if used adds a subtitle to the plot. Added by dcjk, QUB, 97.
;
; KEYWORD OUTPUT:
; CLEVELS
; physical values at the color key tic marks. Use this to set
; contour levels in a subsequent call to CONTOUR.
;
; SIDE EFFECTS:
; Setting SCALE=2 changes the color scale using the STEP_CT
; procedure. The color scale may be returned to its original
; state by the command, STEP_CT,/OFF
;
; PROCEDURE:
; TVIM first determines the size of the plot data window with a
; dummy call to PLOT. When the output device is "X", CONGRID is
; used to scale the image to the size of the available data
; window. Otherwise, if the output device is Postscript,
; scaleable pixels are used in the call to TV.
;
; If the input image quantity is not of type byte, TVIM converts
; them to byte by scaleing the input between 0 and !d.n_colors-1.
; If the input is already a byte array and if either the number of
; color table entries is 256 or if C_MAP is set, then no scaling
; is done. This is to ensure consistency with specially defined
; private color tables.
;
; After the the image is drawn TVIM calls PLOT again to draw the x
; and y axis and titles. Finally if scale is set, TVIM calls the
; COLOR_KEY procedure to draw the color scale just to the right of
; the data window.
;
; RESTRICTIONS:
; A stepped color scale (SCALE = 2 option) is not available when
; writing to a black & white postscript file (i.e., when the
; DEVICE color option is not enabled).
;
; DEPENDENCIES: COLOR_KEY, STEP_CT, PRANK
;
; EXAMPLES:
;
;; Plot a GIF image with its own preset RGB
;; table (perhaps from a digitized video image)
;
; window,colors=256 ; set up a private color map
; read_gif,file,im,r,g,b
; tvlct,r,g,b
; tvim,im,/c_map
;;
;;
;; Plot an image with descreet greyscale values to a printer
;; which has its own hard-wired color table.
;
; im=randata(128,128,s=4)
; immx=max(im) & immn=min(im)
; !p.multi=[0,2,2]
; tvim,im,/scale,colors=!p.color*indgen(4)/3.,range=[immn,immx]
; tvim,im,/scale,colors=!p.color*indgen(5)/4.,range=[immn,immx]
; tvim,im,/scale,colors=!p.color*indgen(8)/7.,range=[immn,immx]
; tvim,im,/scale,colors=!p.color*indgen(10)/9.,range=[immn,immx]
;;
;;
;; Display a map of surface types (green=veg, blue=water, red=sand)
;; Notice how RANGE is used to associate physical values with colors.
;; (use im from the previous example)
;
; im=randata(128,128,s=4)
; immx=max(im) & immn=min(im) & delim=immx-immn
;
; tvlct,[0,0,0,255],[0,255,0,0],[0,0,255,0]
; !p.multi=[0,2,2]
; colors=[1,2,3] & labels=[' veg',' water',' sand']
; range=[immn,immx,delim/3]
;
; tvim,im,/scale
;
; tvim,im,colors=colors,range=range,/scale
;
; tvim,im,colors=colors,range=range,/scale,labels=labels,lch=2
;
; !p.multi=0
; range=[immn-.25*delim,immx+.25*delim,delim/2]
; lbl=[' veg!c region 1',' water!c region 2',' sand!c region 3']
;
tvim,im,colors=colors,range=range,/scale,labels=lbl,lch=2,rmarg=2,pchar=1.2
;;
;;
;; Display the image from previous example and overlay a contour plot
;;
; loadct,5
; im=randata(128,128,s=4)
; immx=max(im) & immn=min(im) & delim=immx-immn
; xrange=[-120,-100]
; yrange=[20,50]
; range=[immn,immx]
; xx=findrng(xrange,128)
; yy=findrng(yrange,128)
;
; tvim,im,/scale,xrange=xrange,yrange=yrange,clevels=clevels,range=range
; contour,im,xx,yy,levels=clevels,/overplot
;
;
;; NOTE: You might prefer the results obtained from procedure
CONFILL.
;
; confill,im,xx,yy,/asp,levels=clevels
;;
;;
;; Display a grey scale image and annotate certain points in color
;;
; loadct,0
; dcolors
; tvim,im,/scale,nbotclr=11
; xx=interpolate([40,80],randomu(iseed,10))
; yy=interpolate([40,80],randomu(iseed,10))
; plots,xx,yy,psym=2,color=1+indgen(10)
;
;;
;;
;; Display a grey scale image and show nodata values in red
;;
; loadct,0
; im=randata(100,100,s=4.5)
; im(randomu(iseed,50)*9999)=-999.
; tvim,im,/scale,nodata=-999.,rgb_nodata=[255,0,0]
;
;;
;;
;; Postscript output with a reversed color scale. Because the
;; background color is always RGB=(255,255,255) you must set the
;; default color, !p.color, to a dark color if you want good contrast
;; between the axis labels and the white paper. According to
;; Didier's reversed color table a color index of 255 should produce
;; black, but for some reason !p.color=255 doesn't work right.
;; I think IDL is iterpreting !p.color=255 in some special way.
;; So instead use !p.color=254; this seems to work fine.
;;
; toggle,/color
; loadct,28
; !p.color=254 ; don't use 255, don't ask me why
; tvim,dist(20),/scale
; toggle
;
;;
;; display data defined on a regular LAT-LON grid onto a given map
;; projection. USE MAP_SET and MAP_IMAGE to create the map projection
;; and to warp the image. Then use BOXPOS to position the TVIM frame
;; to correctly register the map and image
;
; IMAGE = sin(!pi*findrng(0,24,200))#sin(!pi*findrng(0,12,200))
; !p.multi=[0,1,2]
; map_set,45,0,/ortho,/advance,pos=boxpos(/aspect)
;
newimage=map_image(image,/bilin,latmin=-90,latmax=90,lonmin=-180,lonmax=180)
; tvim,newimage,title='Warped data',pos=boxpos(/get),/scale
; map_set,45,0,/ortho,pos=boxpos(/get),/grid,/cont,/noerase ; draw map
; tvim,image,xrange=[-180,180],yrange=[-90,90],/scale, $
; title='Unwarped data',xtitle='Longitude',ytitle='Latitude'
; map_set,0,0,/cyl,pos=boxpos(/get),/grid,/cont,/noerase ; draw map
;
;; use MAP_SET2 to mask out land areas. Note that the example below is
;; unusual. MAP_SET2 doesn't always produce such nicely filled land
areas.
;; Typically one must run MAP_SET2 with /SAVE
;; to create a ascii file containing the continental boundary lat-lon
;; coordinates. Then use an editor to group the continental coordinates
;; line segments to form closed contours which POLYFILL can understand
;; (the call to POLYFILL is enabled by setting con_color).
;;
;
; image=randata(256,256,s=2.5)
; tvim,image
;
map_set2,-64,-64,/cont,limit=[-65.1,-64.5,-64,-62],/ortho,con_col=100,$
; pos=boxpos(/get),/noerase,/grid
;;
; AUTHOR: Paul Ricchiazzi oct92
; Earth Space Research Group, UCSB
;
; REVISIONS:
; 28jan93: switched from PUT_COLOR_SCALE to COLOR_KEY
; 11feb93: added INTERP keyword
; 11feb93: added C_MAP keyword
; 11feb93: added STITLE keyword
; 20apr93: added RMARG keyword, centered image in plot window
; 23apr93: call COLOR_KEY before TV. Now stepped color scales copy to PS
file
; 10sep93: deal with perfectly flat images. No more math error when a=0
; 14sep93: added CLIP keyword
; 11feb94: added PCHARSIZE,LCHARSIZE,LABELS, and COLORS keywords
; 18feb94: added NBOTCLR keyword
; 16mar94: added INTERP=2 option and adjusted centering of pixels
; 08Jul94: added NODATA and RGB_NODATA keywords
; 04Aug94: added BARWIDTH keyword
; 04Aug94: defaulted PCHARSIZE and LCHARSIZE to !P.CHARSIZE if non-zero
; 02Mar95: added POSITION keyword
; 31Mar95: added NOAXIS keyword
; 24may95: initial sizing includes allowance for PCHARSIZE > 1
; 06sep95: color indecies used in plot now run from 1 to !d.ncolors-2
; 24jul96: do a REFORM(a) to allow tvim,a(1,*,*)
;-
pro tvim,a,scale=scale,range=range,xrange=xrange,yrange=yrange,$
aspect=aspect,title=title,xtitle=xtitle,ytitle=ytitle,$
noframe=noframe,noaxis=noaxis,interp=interp,colors=colors,c_map=c_map,$
stitle=stitle,rmarg=rmarg,clip=clip,labels=labels,clevels=clevels,$
pcharsize=pcharsize,lcharsize=lcharsize,nbotclr=nbotclr,nodata=nodata,$
rgb_nodata=rgb_nodata,barwidth=barwidth,position=position,rct=rct, $
subtitle=subtitle
if n_params() eq 0 then begin
xhelp,'tvim'
return
endif
if keyword_set(pcharsize) eq 0 then begin
if !p.charsize eq 0 then pcharsize=1 else pcharsize=!p.charsize
endif
if keyword_set(lcharsize) eq 0 then begin
if !p.multi(1)>!p.multi(2) gt 2 then lcharsize=.5*pcharsize $
else lcharsize=pcharsize
endif
sz=size(reform(a))
nx=sz(1)
ny=sz(2)
nxm=nx-1
nym=ny-1
plot, [0,1],[0,1],/nodata,xstyle=4,ystyle=4,charsize=pcharsize
px=!x.window*!d.x_vsize
py=!y.window*!d.y_vsize
xsize=px(1)-px(0)
ysize=py(1)-py(0)
if keyword_set(scale) or keyword_set(rmarg) then begin
if keyword_set(rmarg) eq 0 then rmarg=1.
xmarg=!d.x_ch_size*(4+4*lcharsize)
if keyword_set(stitle) then xmarg=xmarg+2*!d.y_ch_size*lcharsize
xsize=xsize-rmarg*xmarg
endif
oxs=xsize
oys=ysize
if keyword_set(aspect) eq 0 then aspect=float(nx)/ny
if xsize gt ysize*aspect then xsize=ysize*aspect else ysize=xsize/aspect
if xsize lt oxs then px(0)=px(0)+.5*(oxs-xsize)
if ysize lt oys then py(0)=py(0)+.5*(oys-ysize)
px(1)=px(0)+xsize
py(1)=py(0)+ysize
if keyword_set(position) then begin
px=position([0,2])*!d.x_vsize
py=position([1,3])*!d.y_vsize
xsize=px(1)-px(0)
ysize=py(1)-py(0)
endif
pos=[px(0),py(0),px(1),py(1)]
;
;max_color=!d.n_colors-1
max_color=!d.n_colors-2
;
if keyword_set(title) eq 0 then title=''
if keyword_set(subtitle) eq 0 then subtitle=''
amax=float(max(a))
amin=float(min(a))
;print, 'a min and max ', amin,amax
num_range=n_elements(range)
if n_elements(nodata) then begin
if n_elements(rgb_nodata) eq 0 then rgb_nodata=[0,0,0]
iinodata=where(a eq nodata,ncnd)
iidata=where(a ne nodata,ncgd)
if ncgd gt 0 then begin
amin=float(min(a(iidata)))
amax=float(max(a(iidata)))
tvlct,rgb_nodata(0),rgb_nodata(1),rgb_nodata(2),1
nbotclr=2
endif
endif else begin
iinodata=-1
endelse
if num_range eq 1 then message,'must specify either 2 or 3 elements of
RANGE'
if num_range eq 0 then begin
if amin eq amax then begin
case 1 of
amax eq 0.: rng=[-1,1.]
amax gt 0.: rng=[0,2*amax]
amax lt 0.: rng=[2*amax,0]
endcase
endif else BEGIN
CASE n_elements(clip) OF
1:if clip ge 0 then begin
rng=prank(a,[clip,100-clip])
endif else begin
clp=-2*clip+1
ix1=-clip & ix2=nx+clip
iy1=-clip & iy2=ny+clip
rng=[min((median(a,clp))(ix1:ix2,iy1:iy2),max=mx),mx]
endelse
2:rng=prank(a,clip)
else:rng=[amin,amax]
endcase
endelse
endif else begin
rng=range(0:1)
if num_range eq 3 then inc=range(2) else inc=0
endelse
ncolors=n_elements(colors)
case 1 of
ncolors ne 0 : begin
case num_range of
0:begin
aa=colors(fix(reform(a)))
rng=[0,ncolors]
inc=1
end
2:begin
clrinc=(rng(1)-rng(0))/ncolors
aa=colors(fix((reform(a)-range(0))/clrinc))
end
3:begin
aa=colors(fix((reform(a)-range(0))/range(2)))
inc=range(2)
rng=[range(0),range(0)+ncolors*inc]
end
endcase
end
keyword_set(c_map) eq 1 : begin
aa=byte(reform(a))
rng(0)=0
rng(1)=max_color
end
else: begin
; if keyword_set(nbotclr) eq 0 then nbotclr=0 else nbotclr=nbotclr
if keyword_set(nbotclr) eq 0 then nbotclr=1 else nbotclr=nbotclr
max_color=max_color-nbotclr
aa=nbotclr+max_color*((float(reform(a))-rng(0))/(rng(1)-rng(0)) > 0.
< 1.)
end
endcase
if keyword_set(rct) then begin
aamin=min(aa,max=aamax)
aa=aamax+aamin-aa
endif else begin
rct=0
endelse
;
posbar=[px(1)+!d.x_ch_size,py(0)]
if keyword_set(scale) then begin
if scale eq 2 then step=1 else step=0
if not keyword_set(barwidth) then barwidth=1
if ncolors eq 0 then begin
color_key,pos=posbar,ysize=ysize,range=rng,inc=inc,step=step,$
title=stitle,charsize=lcharsize,labels=labels,nbotclr=nbotclr,$
clevels=clevels,barwidth=barwidth,rct=rct
endif else begin
color_key,pos=posbar,ysize=ysize,range=rng,inc=inc,title=stitle,$
charsize=lcharsize,colors=colors,labels=labels,clevels=clevels,$
barwidth=barwidth,rct=rct
endelse
endif
if not keyword_set(interp) then interp=0
if iinodata(0) ne -1 then aa(iinodata)=1
if !d.name eq 'X' then begin
mone=interp
if interp lt 2 then begin
tv,congrid(aa,xsize,ysize,interp=interp,minus_one=mone),px(0),py(0)
endif else begin
tv,interpolate(aa,nx*findgen(xsize)/(xsize-1)-.5,$
ny*findgen(ysize)/(ysize-1)-.5,/grid),px(0),py(0)
endelse
endif else begin
tv,aa,px(0),py(0),xsize=xsize,ysize=ysize,/device
endelse
;
if keyword_set(xtitle) eq 0 then xtitle=''
if keyword_set(ytitle) eq 0 then ytitle=''
if not keyword_set(xrange) then xrng=[0,nxm] $
else xrng=[min(xrange), max(xrange)]
if not keyword_set(yrange) then yrng=[0,nym] $
else yrng=[min(yrange), max(yrange)]
case 1 of
keyword_set(noframe):plot,[0,0],[0,0],xstyle=5,ystyle=5,position=pos,$
title=title, subtitle=subtitle,/device,
charsize=pcharsize, $
xrange=xrng,yrange=yrng,/noerase,/nodata
keyword_set(noaxis): plot,[0,0],[0,0],/xstyle,/ystyle,position=pos,$
title=title,xtitle=xtitle,ytitle=ytitle,/device, $
xrange=xrng,yrange=yrng,/noerase,/nodata,$
charsize=pcharsize,xticks=1,yticks=1,$
xtickname=[" "," "],ytickname=[" "," "], $
subtitle=subtitle
else:
plot,[0,0],[0,0],/xstyle,/ystyle,title=title,/nodata,$
xtitle=xtitle,ytitle=ytitle,xrange=xrng,yrange=yrng,$
position=pos,/noerase,/device,charsize=pcharsize, $
subtitle=subtitle
endcase
;
end