;+ ; NAME: ; violin_plot.pro ; ; PURPOSE: ; This procedure plots violin plots. ; ; CATEGORY: ; Graphics ; ; CALLING SEQUENCE: ; violin_plot, x_pos=x_pos, y_pos=y_pos, pdf_loc=pdf_loc, pdf_amp=pdf_amp ; ; INPUTS: ; COLOR, FILL, ORIENT, PDF_AMP, PDF_LOC, PSYM, THICK, X_POS, Y_POS ; ; KEYWORD PARAMETERS: ; COLOR: An optional scalar integer specifying the color index value of the ; color to use. The default !p.color. ; FILL: If set then the violin shapes are filled. The default is 0, in ; which only the outline is plotted. ; ORIENT: An optional scalar float specifying the orientation of the ; violin plots. The is the angle from the vertical in which increasing ; values of PDF_LOC point. If input then X_POS and YPOS must both be in ; input. ; PDF_AMP: A required float array of size N_LOC,N_PDF specifying the ; amplitudes of the N_PDF density functions at the N_LOC locations. ; The amplitudes are plotted in the direction 90 degrees either side of ; PDF_LOC. ; PDF_LOC: A required float vector of length N_LOC specifying the locations ; at which to plot the density function amplitudies. If ORIENT is ; input, later elements are located in the direction of ORIENT in ; relation to earlier elements. Otherwise this refers to locations ; in the vertical if only X_POS is input, or in the horizontal if only ; Y_POS is input. ; PSYM: An optional scalar integer specifying the plotting symbol to use, ; according to IDL's plot procedure PSYM input. The default is none. ; THICK: An optional scalar integer specifying the thickness of the plotted ; lines when FILL=0. The default is 1.. ; X_POS: An optional float vector of length N_PDF indicating the position ; of the N_PDF violin plots along the horizontal axis. If input and ; Y_POS is not input, then PDF_LOC points in the direction of the ; vertical axis. If all of X_POS, Y_POS, and ORIENT are input then the ; X_POS and Y_POS values are the reference points from which PDF_LOC ; points in the direction of ORIENT. Either X_POS only, Y_POS only, or ; X_POS and Y_POS and ORIENT together must be input. ; Y_POS: An optional float vector of length N_PDF indicating the position ; of the N_PDF violin plots along the vertical axis. If input and X_POS ; is not input, then PDF_LOC points in the direction of the vertical ; axis. If all of X_POS, Y_POS, and ORIENT are input then the X_POS and ; Y_POS values are the reference points from which PDF_LOC points in the ; direction of ORIENT. Either X_POS only, Y_POS only, or X_POS and ; Y_POS and ORIENT together must be input. ; ; USES: ; - ; ; PROCEDURE: ; This procedure plots lines or shapes forming the "violin plot" method of ; plotting density functions. ; ; EXAMPLE: ; ; Generate two density functions, the opposite of each other. ; x_pos = [ 2, 4 ] ; y_pos = [ 1, 2.5 ] ; pdf_loc = [ 0., 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 ] ; pdf_amp = [ [ 0.1, 0.3, 0.8, 0.5, 0.3, 0.1, 0.1, 0.0 ], $ ; [ 0.0, 0.1, 0.1, 0.3, 0.5, 0.8, 0.3, 0.1 ] ] ; ; Plot these pointing toward the top ; plot, [0,5], [0,4], nodata=1, xstyle=1, ystyle=1, isotropic=1 ; violin_plot, x_pos=x_pos, pdf_loc=pdf_loc, pdf_amp=pdf_amp, fill=1 ; ; Plot these pointing toward the right ; plot, [0,5], [0,4], nodata=1, xstyle=1, ystyle=1, isotropic=1 ; violin_plot, y_pos=y_pos, pdf_loc=pdf_loc, pdf_amp=pdf_amp, fill=1 ; ; Plot these pointing toward the top left ; plot, [0,5], [0,4], nodata=1, xstyle=1, ystyle=1, isotropic=1 ; violin_plot, x_pos=x_pos, y_pos=y_pos, pdf_loc=pdf_loc, pdf_amp=pdf_amp, $ ; fill=1, orient=45. ; ; MODIFICATION HISTORY: ; Written by: Daithi A. Stone, (dastone@runbox.com) 2026-09-10 ;- ;*********************************************************************** PRO VIOLIN_PLOT, $ X_POS=x_pos, Y_POS=y_pos, ORIENT=orient, $ PDF_LOC=pdf_loc, PDF_AMP=pdf_amp, $ COLOR=color, $ PSYM=psym, $ THICK=thick, $ FILL=fill_opt ;*********************************************************************** ; Constants and options ; The number of PDFs to plot if not( keyword_set( pdf_amp ) ) then stop n_pdf = n_elements( pdf_amp[0,*] ) ; If the orientation angle has been input if n_elements( orient ) eq 1 then begin ; Ensure reference positions are specified if n_elements( x_pos ) ne n_pdf then stop if n_elements( y_pos ) ne n_pdf then stop ; Copy the orientation orient_use = orient ; If the orientation is defined by the coordinate input endif else begin ; Option to plot amplitudes horizontally if n_elements( x_pos ) eq n_pdf then begin orient_use = -90 if n_elementS( y_pos ) ne 0 then stop ; Option to plot amplitudes vertically endif else if n_elements( y_pos ) eq n_pdf then begin orient_use = 0 ; Unsupported orientation endif else begin stop endelse endelse ; The number of locations in the PDF n_loc = n_elements( pdf_loc ) if n_loc eq 0 then stop if n_elements( pdf_amp[*,0] ) ne n_loc then stop ; The default fill option (none) if not( keyword_set( fill_opt ) ) then fill_opt = 0 ;*********************************************************************** ; Plot violins ; Iterate through PDFs for i_pdf = 0, n_pdf - 1 do begin ; If plotting with a tilted orientation if n_elements( orient ) eq 1 then begin ; Calculate the cosine and sine of the angle ang_cos = cos( orient_use / 180. * !pi ) ang_sin = sin( orient_use / 180. * !pi ) ; Determine the lines to plots temp_x = x_pos[i_pdf] $ + [ ang_cos * pdf_amp[*,i_pdf] - ang_sin * pdf_loc, $ reverse( -ang_cos * pdf_amp[*,i_pdf] - ang_sin * pdf_loc ) ] temp_y = y_pos[i_pdf] $ + [ ang_cos * pdf_loc + ang_sin * pdf_amp[*,i_pdf], $ reverse( ang_cos * pdf_loc - ang_sin * pdf_amp[*,i_pdf] ) ] ; If plotting amplitudes horizontally endif else if orient_use eq -90 then begin ; Set the lines to plot temp_x = x_pos[i_pdf] + [ pdf_amp[*,i_pdf], reverse( -pdf_amp[*,i_pdf] ) ] temp_y = [ pdf_loc, reverse( pdf_loc ) ] ; If plotting amplitudes vertically endif else if orient_use eq 0 then begin temp_x = [ pdf_loc, reverse( pdf_loc ) ] temp_y = y_pos[i_pdf] + [ pdf_amp[*,i_pdf], reverse( -pdf_amp[*,i_pdf] ) ] endif ; If plotting outlines if fill_opt eq 0 then begin plots, [temp_x[2*n_loc-1],temp_x], [temp_y[2*n_loc-1],temp_y], $ color=color, thick=thick, psym=psym ; If plotting filled violins endif else begin polyfill, [temp_x[2*n_loc-1],temp_x], [temp_y[2*n_loc-1],temp_y], $ color=color endelse endfor ;*********************************************************************** ; The end return END