Picasso

• This project is used in Notebook , but the library can be used independently.
• Data structures from clojure/clojurescript have to be converted to some kind of visual repesentation so that the notebook can render them
• For all clojure/clojurescript datatypes default renderers are defined here
• Custom data-types can implement the renderable protocol
• The notebook receives the render-datastructure and renders it to the notebook cell.

This are the core concepts in picasso:

render (used in nrepl middleware)

(defprotocol Renderable
  (render [self]))

paint (used in notebook-ui)

(defmulti paint :type)

Clojure/Clojurescript Data => (render) => Picasso DataStructure => (paint) => Notebook

Clojure/Clojurescript type based rendering

• All clj/cljs datatypes have default renderers that will be selected based on the type of the data.

Syntactic sugar for librarys that need visualization

• Goal is to use meta-data to trigger rendering of function output.
• Say we want a function that creates a vega spec to be rendered with a vega renderer:

(defn timeseries-plot 
  "timeseries-plot creates vega spec for a timeseries plot"
  [data] 
  ^{:render-with :p/vega} vega-spec)

• The user would then use this with:

[:div [:h1 "demo"]
      (timeseries-plot data)]

• the rendering system would then internally convert this to:

[:div [:h1 "demo"]
      [:p/vega (timeseries-plot data)]]

• This saves the library author from writing a wrapper.

Unit Tests

Clojure:

lein test

Clojurescript:

npm install
lein test-js

Licence

This code is licensed to you under the MIT licence. See LICENCE.txt for details.