;+ ; NAME: ; LEGEND ; PURPOSE: ; Create an annotation legend for a plot. ; EXPLANATION: ; This procedure makes a legend for a plot. The legend can contain ; a mixture of symbols, linestyles, Hershey characters (vectorfont), ; and filled polygons (usersym). A test procedure, legendtest.pro, ; shows legend's capabilities. Placement of the legend is controlled ; with keywords like /right, /top, and /center or by using a position ; keyword for exact placement (position=[x,y]) or via mouse (/position). ; CALLING SEQUENCE: ; LEGEND [,items][,keyword options] ; EXAMPLES: ; The call: ; legend,['Plus sign','Asterisk','Period'],psym=[1,2,3] ; produces: ; ----------------- ; | | ; | + Plus sign | ; | * Asterisk | ; | . Period | ; | | ; ----------------- ; Each symbol is drawn with a plots command, so they look OK. ; Other examples are given in optional output keywords. ; ; lines = indgen(6) ; for line styles ; items = 'linestyle '+strtrim(lines,2) ; annotations ; legend,items,linestyle=lines ; vertical legend---upper left ; items = ['Plus sign','Asterisk','Period'] ; sym = [1,2,3] ; legend,items,psym=sym ; ditto except using symbols ; legend,items,psym=sym,/horizontal ; horizontal format ; legend,items,psym=sym,box=0 ; sans border ; legend,items,psym=sym,delimiter='=' ; embed '=' betw psym & text ; legend,items,psym=sym,margin=2 ; 2-character margin ; legend,items,psym=sym,position=[x,y] ; upper left in data coords ; legend,items,psym=sym,pos=[x,y],/norm ; upper left in normal coords ; legend,items,psym=sym,pos=[x,y],/device ; upper left in device coords ; legend,items,psym=sym,/position ; interactive position ; legend,items,psym=sym,/right ; at upper right ; legend,items,psym=sym,/bottom ; at lower left ; legend,items,psym=sym,/center ; approximately near center ; legend,items,psym=sym,number=2 ; plot two symbols, not one ; legend,items,/fill,psym=[8,8,8],colors=[10,20,30]; 3 filled squares ; INPUTS: ; items = text for the items in the legend, a string array. ; For example, items = ['diamond','asterisk','square']. ; You can omit items if you don't want any text labels. ; OPTIONAL INPUT KEYWORDS: ; ; linestyle = array of linestyle numbers If linestyle(i) < 0, then omit ; ith symbol or line to allow a multi-line entry. ; psym = array of plot symbol numbers. If psym(i) is negative, then a ; line connects pts for ith item. If psym(i) = 8, then the ; procedure usersym is called with vertices define in the ; keyword usersym. If psym(i) = 88, then use the previously ; defined user symbol ; vectorfont = vector-drawn characters for the sym/line column, e.g., ; ['!9B!3','!9C!3','!9D!3'] produces an open square, a checkmark, ; and a partial derivative, which might have accompanying items ; ['BOX','CHECK','PARTIAL DERIVATIVE']. ; There is no check that !p.font is set properly, e.g., -1 for ; X and 0 for PostScript. This can produce an error, e.g., use ; !20 with PostScript and !p.font=0, but allows use of Hershey ; *AND* PostScript fonts together. ; N. B.: Choose any of linestyle, psym, and/or vectorfont. If none is ; present, only the text is output. If more than one ; is present, all need the same number of elements, and normal ; plot behaviour occurs. ; By default, if psym is positive, you get one point so there is ; no connecting line. If vectorfont(i) = '', ; then plots is called to make a symbol or a line, but if ; vectorfont(i) is a non-null string, then xyouts is called. ; /help = flag to print header ; /horizontal = flag to make the legend horizontal ; /vertical = flag to make the legend vertical (D=vertical) ; box = flag to include/omit box around the legend (D=include) ; clear = flag to clear the box area before drawing the legend ; clrclear = color of clearing ; delimiter = embedded character(s) between symbol and text (D=none) ; colors = array of colors for plot symbols/lines (D=!color) ; textcolors = array of colors for text (D=!color) ; margin = margin around text measured in characters and lines ; spacing = line spacing (D=bit more than character height) ; pspacing = psym spacing (D=3 characters) ; charsize = just like !p.charsize for plot labels ; charthick = array of char thickness numbers ; thick = array of line thickness numbers, if used, then linestyle ; must also be specified ; position = data coordinates of the /top (D) /left (D) of the legend ; normal = use normal coordinates for position, not data ; device = use device coordinates for position, not data ; number = number of plot symbols to plot or length of line (D=1) ; usersym = 2-D array of vertices, cf. usersym in IDL manual. (D=square) ; /fill = flag to fill the usersym ; /left = flag to place legend snug against left side of plot window (D) ; /right = flag to place legend snug against right side of plot window ; If /right,pos=[x,y], then x is position of RHS and text ; runs right-to-left. ; /top = flag to place legend snug against top of plot window (D) ; /bottom = flag to place legend snug against bottom of plot window ; /top,pos=[x,y] and /bottom,pos=[x,y] produce same positions. ; ; If LINESTYLE, PSYM, VECTORFONT, THICK, COLORS, or TEXTCOLORS are ; supplied as scalars, then the scalar value is set for every line or ; symbol in the legend. ; Outputs: ; legend to current plot device ; OPTIONAL OUTPUT KEYWORDS: ; corners = 4-element array, like !p.position, of the normalized ; coords for the box (even if box=0): [llx,lly,urx,ury]. ; Useful for multi-column or multi-line legends, for example, ; to make a 2-column legend, you might do the following: ; c1_items = ['diamond','asterisk','square'] ; c1_psym = [4,2,6] ; c2_items = ['solid','dashed','dotted'] ; c2_line = [0,2,1] ; legend,c1_items,psym=c1_psym,corners=c1,box=0 ; legend,c2_items,line=c2_line,corners=c2,box=0,pos=[c1(2),c1(3)] ; c = [c1(0)c2(2),c1(3)>c2(3)] ; plots,[c(0),c(0),c(2),c(2),c(0)],[c(1),c(3),c(3),c(1),c(1)],/norm ; Useful also to place the legend. Here's an automatic way to place ; the legend in the lower right corner. The difficulty is that the ; legend's width is unknown until it is plotted. In this example, ; the legend is plotted twice: the first time in the upper left, the ; second time in the lower right. ; legend,['1','22','333','4444'],linestyle=indgen(4),corners=corners ; ; BOGUS LEGEND---FIRST TIME TO REPORT CORNERS ; xydims = [corners(2)-corners(0),corners(3)-corners(1)] ; ; SAVE WIDTH AND HEIGHT ; chdim=[!d.x_ch_size/float(!d.x_size),!d.y_ch_size/float(!d.y_size)] ; ; DIMENSIONS OF ONE CHARACTER IN NORMALIZED COORDS ; pos = [!x.window(1)-chdim(0)-xydims(0) $ ; ,!y.window(0)+chdim(1)+xydims(1)] ; ; CALCULATE POSITION FOR LOWER RIGHT ; plot,findgen(10) ; SIMPLE PLOT; YOU DO WHATEVER YOU WANT HERE. ; legend,['1','22','333','4444'],linestyle=indgen(4),pos=pos ; ; REDO THE LEGEND IN LOWER RIGHT CORNER ; You can modify the pos calculation to place the legend where you ; want. For example to place it in the upper right: ; pos = [!x.window(1)-chdim(0)-xydims(0),!y.window(1)-xydims(1)] ; Common blocks: ; none ; Procedure: ; If keyword help is set, call doc_library to print header. ; See notes in the code. Much of the code deals with placement of the ; legend. The main problem with placement is not being ; able to sense the length of a string before it is output. Some crude ; approximations are used for centering. ; Restrictions: ; Here are some things that aren't implemented. ; - An orientation keyword would allow lines at angles in the legend. ; - An array of usersyms would be nice---simple change. ; - An order option to interchange symbols and text might be nice. ; - Somebody might like double boxes, e.g., with box = 2. ; - Another feature might be a continuous bar with ticks and text. ; - There are no guards to avoid writing outside the plot area. ; - There is no provision for multi-line text, e.g., '1st line!c2nd line' ; Sensing !c would be easy, but !c isn't implemented for PostScript. ; A better way might be to simply output the 2nd line as another item ; but without any accompanying symbol or linestyle. A flag to omit ; the symbol and linestyle is linestyle(i) = -1. ; - There is no ability to make a title line containing any of titles ; for the legend, for the symbols, or for the text. ; Side Effects: ; Modification history: ; write, 24-25 Aug 92, F K Knight (knight@ll.mit.edu) ; allow omission of items or omission of both psym and linestyle, add ; corners keyword to facilitate multi-column legends, improve place- ; ment of symbols and text, add guards for unequal size, 26 Aug 92, FKK ; add linestyle(i)=-1 to suppress a single symbol/line, 27 Aug 92, FKK ; add keyword vectorfont to allow characters in the sym/line column, ; 28 Aug 92, FKK ; add /top, /bottom, /left, /right keywords for automatic placement at ; the four corners of the plot window. The /right keyword forces ; right-to-left printing of menu. 18 Jun 93, FKK ; change default position to data coords and add normal, data, and ; device keywords, 17 Jan 94, FKK ; add /center keyword for positioning, but it is not precise because ; text string lengths cannot be known in advance, 17 Jan 94, FKK ; add interactive positioning with /position keyword, 17 Jan 94, FKK ; allow a legend with just text, no plotting symbols. This helps in ; simply describing a plot or writing assumptions done, 4 Feb 94, FKK ; added thick, symsize, and clear keyword Feb 96, W. Landsman HSTX ; David Seed, HR Wallingford, d.seed@hrwallingford.co.uk ; allow scalar specification of keywords, Mar 96, W. Landsman HSTX ; Converted to IDL V5.0 W. Landsman September 1997 ;- pro legend,help=help,items,linestyle=linestyle,psym=psym,vectorfont=vectorfont $ ,horizontal=horizontal,vertical=vertical,box=box,margin=margin $ ,delimiter=delimiter,spacing=spacing,charsize=charsize,pspacing=pspacing $ ,position=position,number=number,colors=colors,textcolors=textcolors $ ,fill=fill,usersym=usersym,corners=corners $ ,left=left,right=right,top=top,bottom=bottom,center=center $ ,data=data,normal=normal,device=device,charthick=charthick $ ,symsize=symsize,thick=thick,clear=clear,clrclear=clrclear ; ; =====>> HELP ; on_error,2 if keyword_set(help) then begin & doc_library,'legend' & return & endif ; ; =====>> SET DEFAULTS FOR SYMBOLS, LINESTYLES, AND ITEMS. ; ni = n_elements(items) np = n_elements(psym) nl = n_elements(linestyle) nth = n_elements(thick) nv = n_elements(vectorfont) nlpv = max([np,nl,nv]) n = max([ni,np,nl,nv]) ; NUMBER OF ENTRIES strn = strtrim(n,2) ; FOR ERROR MESSAGES if n eq 0 then message,'No inputs! For help, type legend,/help.' if ni eq 0 then begin items = replicate('',n) ; DEFAULT BLANK ARRAY endif else begin szt = size(items) if (szt[szt[0]+1] ne 7) then message,'First parameter must be a string array. For help, type legend,/help.' if ni ne n then message,'Must have number of items equal to '+strn endelse symline = (np ne 0) or (nl ne 0) ; FLAG TO PLOT SYM/LINE if (np ne 0) and (np ne n) and (np NE 1) then message, $ 'Must have 0, 1 or '+strn+' elements in PSYM array.' if (nl ne 0) and (nl ne n) and (nl NE 1) then message, $ 'Must have 0, 1 or '+strn+' elements in LINESTYLE array.' if (nth ne 0) and (nth ne n) and (nth NE 1) then message, $ 'Must have 0, 1 or '+strn+' elements in THICK array.' if nl EQ 0 then linestyle = intarr(n) else $ D=SOLID if nl EQ 1 then linestyle = intarr(n) + linestyle if nth EQ 0 then thick = intarr(n) + 1 else $ if nth EQ 1 then thick = intarr(n) + thick if np EQ 0 then psym = intarr(n) else $ ; D=SOLID if np EQ 1 then psym = intarr(n) + psym if nv EQ 0 then vectorfont = replicate('',n) else $ if nv EQ 1 then vectorfont = replicate(vectorfont,n) ; ; =====>> CHOOSE VERTICAL OR HORIZONTAL ORIENTATION. ; if n_elements(horizontal) eq 0 then begin ; D=VERTICAL if n_elements(vertical) eq 0 then vertical = 1 endif else begin if n_elements(vertical) eq 0 then vertical = not horizontal endelse ; ; =====>> SET DEFAULTS FOR OTHER OPTIONS. ; if n_elements(box) eq 0 then box = 1 if n_elements(clear) eq 0 then clear = 0 if n_elements(clrclear) eq 0 then cclr = -1 else cclr=clrclear(0) if n_elements(charthick) eq 0 then chthk= 1 else chthk=charthick(0) if n_elements(margin) eq 0 then margin = 0.5 if n_elements(delimiter) eq 0 then delimiter = '' if n_elements(charsize) eq 0 then charsize = !p.charsize if charsize eq 0 then charsize = 1 if (n_elements (symsize) eq 0) then symsize= charsize + intarr(n) if n_elements(number) eq 0 then number = 1 if n_elements(colors) eq 0 then colors = !P.color + intarr(n) else $ if N_elements(colors) EQ 1 then colors = colors + intarr(n) if n_elements(textcolors) eq 0 then textcolors = !P.color + intarr(n) else $ if N_elements(textcolors) EQ 1 then textcolors = textcolors + intarr(n) fill = keyword_set(fill) if n_elements(usersym) eq 0 then usersym = 2*[[0,0],[0,1],[1,1],[1,0]]-1 ; ; =====>> INITIALIZE SPACING ; if n_elements(spacing) eq 0 then spacing = 1.2 if n_elements(pspacing) eq 0 then pspacing = 3 xspacing = !d.x_ch_size/float(!d.x_size) * (spacing > charsize) yspacing = !d.y_ch_size/float(!d.y_size) * (spacing > charsize) ltor = 1 ; flag for left-to-right if n_elements(left) eq 1 then ltor = left eq 1 if n_elements(right) eq 1 then ltor = right ne 1 ttob = 1 ; flag for top-to-bottom if n_elements(top) eq 1 then ttob = top eq 1 if n_elements(bottom) eq 1 then ttob = bottom ne 1 xalign = ltor ne 1 ; x alignment: 1 or 0 yalign = -0.5*ttob + 1 ; y alignment: 0.5 or 1 xsign = 2*ltor - 1 ; xspacing direction: 1 or -1 ysign = 2*ttob - 1 ; yspacing direction: 1 or -1 if not ttob then yspacing = -yspacing if not ltor then xspacing = -xspacing ; ; =====>> INITIALIZE POSITIONS: FIRST CALCULATE X OFFSET FOR TEXT ; xt = 0 if nlpv gt 0 then begin ; SKIP IF TEXT ITEMS ONLY. if vertical then begin ; CALC OFFSET FOR TEXT START for i = 0,n-1 do begin if (psym[i] eq 0) and (vectorfont[i] eq '') then num = (number + 1) > 3 else num = number if psym[i] lt 0 then num = number > 2 ; TO SHOW CONNECTING LINE if psym[i] eq 0 then expand = 1 else expand = 2 thisxt = (expand*pspacing*(num-1)*xspacing) if ltor then xt = thisxt > xt else xt = thisxt < xt endfor endif ; NOW xt IS AN X OFFSET TO ALIGN ALL TEXT ENTRIES. endif ; ; =====>> INITIALIZE POSITIONS: SECOND LOCATE BORDER ; if !x.window[0] eq !x.window[1] then begin plot,/nodata,xstyle=4,ystyle=4,[0],/noerase endif ; next line takes care of weirdness with small windows pos = [min(!x.window),min(!y.window),max(!x.window),max(!y.window)] case n_elements(position) of 0: begin if ltor then px = pos[0] else px = pos[2] if ttob then py = pos[3] else py = pos[1] if keyword_set(center) then begin if not keyword_set(right) and not keyword_set(left) then $ px = (pos[0] + pos[2])/2. - xt if not keyword_set(top) and not keyword_set(bottom) then $ py = (pos[1] + pos[3])/2. + n*yspacing endif position = [px,py] + [xspacing,-yspacing] end 1: begin ; interactive message,/inform,'Place mouse at upper left corner and click any mouse button.' cursor,x,y,/normal position = [x,y] end 2: begin ; convert upper left corner to normal coordinates if keyword_set(data) then $ position = convert_coord(position,/to_norm) $ else if keyword_set(device) then $ position = convert_coord(position,/to_norm,/device) $ else if not keyword_set(normal) then $ position = convert_coord(position,/to_norm) end else: message,'Position keyword can have 0, 1, or 2 elements only. Try legend,/help.' endcase yoff = 0.25*yspacing*ysign ; VERT. OFFSET FOR SYM/LINE. x0 = position[0] + (margin)*xspacing ; INITIAL X & Y POSITIONS y0 = position[1] - margin*yspacing + yalign*yspacing ; WELL, THIS WORKS! ; ; =====>> OUTPUT TEXT FOR LEGEND, ITEM BY ITEM. ; =====>> FOR EACH ITEM, PLACE SYM/LINE, THEN DELIMITER, ; =====>> THEN TEXT---UPDATING X & Y POSITIONS EACH TIME. ; =====>> THERE ARE A NUMBER OF EXCEPTIONS DONE WITH IF STATEMENTS. ; for iclr = 0,clear do begin y = y0 ; STARTING X & Y POSITIONS x = x0 if ltor then xend = 0 else xend = 1 ; SAVED WIDTH FOR DRAWING BOX if ttob then ii = [0,n-1,1] else ii = [n-1,0,-1] for i = ii[0],ii[1],ii[2] do begin if vertical then x = x0 else y = y0 ; RESET EITHER X OR Y x = x + xspacing ; UPDATE X & Y POSITIONS y = y - yspacing if nlpv eq 0 then goto,TEXT_ONLY ; FLAG FOR TEXT ONLY if (psym[i] eq 0) and (vectorfont[i] eq '') then num = (number + 1) > 3 else num = number if psym[i] lt 0 then num = number > 2 ; TO SHOW CONNECTING LINE if psym[i] eq 0 then expand = 1 else expand = 2 xp = x + expand*pspacing*indgen(num)*xspacing if (psym[i] gt 0) and (num eq 1) and vertical then xp = x + xt/2. yp = y + intarr(num) if vectorfont[i] eq '' then yp = yp + yoff if psym[i] eq 0 then begin xp = [min(xp),max(xp)] ; TO EXPOSE LINESTYLES yp = [min(yp),max(yp)] ; DITTO endif if psym[i] eq 8 then usersym,usersym,fill=fill,color=colors[i] ;; extra by djseed .. psym=88 means use the already defined usersymbol if psym[i] eq 88 then psym[i] =8 if vectorfont[i] ne '' then begin ; if (num eq 1) and vertical then xp = x + xt/2 ; IF 1, CENTERED. xyouts,xp,yp,vectorfont[i],width=width,color=colors[i] $ ,size=charsize,align=xalign,/norm xt = xt > width xp = xp + width/2. endif else begin if symline and (linestyle[i] ge 0) then plots,xp,yp,color=colors[i] $ ,/normal,linestyle=linestyle[i],psym=psym[i],symsize=symsize[i], $ thick=thick[i] endelse if vertical then x = x + xt else if ltor then x = max(xp) else x = min(xp) if symline then x = x + xspacing TEXT_ONLY: xyouts,x,y,delimiter,width=width,/norm,color=textcolors[i],size=charsize,align=xalign x = x + width*xsign if width ne 0 then x = x + 0.5*xspacing xyouts,x,y,items[i],width=width,/norm,color=textcolors[i],size=charsize,align=xalign,charthick=chthk x = x + width*xsign if not vertical and (i lt (n-1)) then x = x+2*xspacing; ADD INTER-ITEM SPACE xfinal = (x + xspacing*margin) if ltor then xend = xfinal > xend else xend = xfinal < xend ; UPDATE END X endfor if (iclr lt clear ) then begin ; =====>> CLEAR AREA x = position[0] y = position[1] if vertical then bottom = n else bottom = 1 ywidth = - (2*margin+bottom-0.5)*yspacing corners = [x,y+ywidth,xend,y] polyfill,[x,xend,xend,x,x],y + [0,0,ywidth,ywidth,0],/norm,color=cclr ; plots,[x,xend,xend,x,x],y + [0,0,ywidth,ywidth,0],thick=2 endif else begin ; ; =====>> OUTPUT BORDER ; x = position[0] y = position[1] if vertical then bottom = n else bottom = 1 ywidth = - (2*margin+bottom-0.5)*yspacing corners = [x,y+ywidth,xend,y] if box then plots,[x,xend,xend,x,x],y + [0,0,ywidth,ywidth,0],/norm return endelse endfor end