first stab at violin page

Author: Mike Travers

src/data_visualization/violin.clj

@@ -0,0 +1,72 @@
+^{:kindly/hide-code true
+  :clay
+  {:title  "Introduction to Violin Plots with Vega"
+   :quarto {:author      :mt
+            :description "..."
+            :image       "overlayplot.png"
+            :type        :post
+            :date        "2025-11-24"
+            :category    :clojure
+            :tags        [:dataviz :vega-lite]}}}
+
+(ns scicloj.data-visualization.violin
+  (:require
+   [clojure.data.json :as json]
+   [scicloj.kindly.v4.api :as kindly]
+   [scicloj.kindly.v4.kind :as kind]
+   ))
+
+
+;;; Get the movie dataset
+(def movie-data
+  (json/read-str (slurp  "https://vega.github.io/editor/data/movies.json") ))
+
+
+;;; Make a simple boxplot showing US Gross by Genre
+(kind/vega-lite
+ {:mark {:type "boxplot" :tooltip {:content "data"}},
+  :data {:values  movie-data}
+  :encoding
+  {"color" {:field "Major Genre", :type "nominal" :legend false},
+   "y" {:field "Major Genre",
+        :type "nominal"},
+   "x" {:field "US Gross",
+        :type "quantitative"}
+   :tooltip {:field "Title"
+             ;; :type "quantitative"
+             }},
+  :width 800
+  })
+
+
+;; That's nice, but how can we add violins to this?
+(kind/vega-lite
+ {:mark {:type "area"},
+  :data {:values movie-data}
+  :transform [{:density "US Gross"
+               :groupby ["Major Genre"]
+               :extent [0, 200000000]}]
+  :encoding
+  {"color" {:field "Major Genre", :type "nominal" :legend false},
+   "y" {:field "density",
+        :type "quantitative"
+        :stack "center"
+        :axis false
+        },               ;this reflect-doubles the area plot to produce the violin shape
+   "x" {:field "value",
+        :type "quantitative"}
+   "facet" {:field "Major Genre"
+            :type "nominal"
+            :columns 1
+            :spacing 0
+            :legend :left
+            }
+   },
+  :width 800
+  })
+
+
+
+
+
+