PRO VSYM, Nvert, STAR=star, SKELETON=skeleton, POLYGON=polygon, \$ FILL=fill, ROT=rot, THICK=thick ;+ ; NAME: ; VSYM ; ; PURPOSE: ; Create "Mongo"-like polygonal plot symbols ; EXPLANATION: ; This procedure generates a subset of Mongo-like plot symbols. ; The symbols are the rotationally symmetric ones that have ; a specified number of vertices and are either open or filled. ; (The half-filled symbols are not included.) After defining the ; plot symbol with VSYM, make the call to PLOT (or PLOTS or OPLOT) with ; PSYM=8. ; ; CATEGORY: ; Graphics ; ; CALLING SEQUENCE: ; VSYM, Nvert ; ; INPUT POSITIONAL PARAMETERS: ; Nvert: Number of vertices in plot symbol. Maximum value ; used is 24. ; ; INPUT KEYWORD PARAMETERS: ; STAR: Set this flag to get a star. E.g., ; vsym, 5,/star gets you a pentagram. ; SKELETON: Set this flag to get an asterisk-like symbol, where ; the center is connected to each vertex. E.g., ; vsym, 4, /skel gets you an X. ; POLYGON: Set this flag to get a regular polygon. This is ; the default symbol type. ; FILL: Set this flag to get filled symbol. Default=open ; ROT: Rotation of symbol about center, in degrees. ; E.g., vsym, 4, rot=45 gets you a diamond, whereas ; vsym, 4 gets you a square. ; THICK: Line thickness of symbol. Default=!P.thick ; ; MODIFICATION HISTORY: ; Written by: R. S. Hill, RITSS, 2 Oct 98 ;- On_error, 0 IF n_elements(nvert) LT 1 THEN nvert=4 IF nvert GT 24 THEN \$ message,/info,'More than 24 vertices requested; 24 used' nv = nvert < 24 vangle = (nv-2.)/nv*180. st = keyword_set(star) sk = keyword_set(skeleton) po = keyword_set(polygon) fi = keyword_set(fill) rt = keyword_set(rot) IF n_elements(thick) LT 1 THEN thick=!P.thick rot_zero = -0.5*vangle if rt then rot_zero = rot_zero + 180./nvert IF st + sk + po GT 1 THEN message, 'More than one symbol type specified' IF st + sk + po EQ 0 THEN po=1 angles = indgen(nv+1)/float(nv) * 2 * !pi + rot_zero/180.0*!pi x = cos(angles) & y = sin(angles) inv2 = indgen(nv+1)*2 inv2_1 = indgen(nv)*2 + 1 IF po THEN BEGIN usersym, x, y, fill=fi, thick=thick ENDIF ELSE IF sk THEN BEGIN xx = fltarr(2*nv+1) & yy = xx xx[inv2] = x yy[inv2] = y usersym, xx, yy, thick=thick ENDIF ELSE IF st THEN BEGIN rot2 = rot_zero + 180./nv inner_angles = \$ indgen(nv)/float(nv) * 2 * !pi + rot2/180.0*!pi inner_x = cos(inner_angles)*0.32 inner_y = sin(inner_angles)*0.32 xx = fltarr(2*nv+1) & yy = xx xx[inv2] = x xx[inv2_1] = inner_x yy[inv2] = y yy[inv2_1] = inner_y usersym, xx, yy, fill=fi, thick=thick ENDIF RETURN END