Understanding A propane Sketch

How you might write a propane sketch, including the shebang makes it easier to run the sketch using script in the atom editor, but assumes you have jruby available at /usr/bin/jruby or more likely via symbolic link (yet another reason not to use rvm or rbenv since they futz with your environment).

my_sketch.rb

#!/usr/bin/env jruby
# frozen_string_literal: false
require 'propane'

class MyApp < Propane::App
  # load_library :my_library # propane method
  # include_package 'org.package' # JRuby method
  def settings
    size 200, 200 # size 'mode' or fullscreen 'mode' goes here
    # pixel_density(2) # only for HiDpi screens
    # see https://processing.org/reference/pixelDensity_.html
    # smooth # useless unless you enter a figure 2, 3, 4 or 8
    # for default renderer default is 3 for P2D and P3D it is 2
    # see https://processing.org/reference/smooth_.html
  end

  def setup
    sketch_title 'Regular Propane Sketch' # propane method
  end

  def draw
    # draw loop
  end
end

MyApp.new

Structure

You will see that under the hood the structure is like a jruby_art (and ruby-processing) wrapped bare sketch (the only real difference is there’s not the option of starting a sketch with MRI ruby).

# frozen_string_literal: false
require 'propane'
module Propane
  # include_package 'org.package' # JRuby method
  class MyApp < App # App is a subclass of processing.core.PApplet

    # load_library :my_library # propane method

    def settings
      size 200, 200 # size 'mode' go here

    end

    def setup
      sketch_title 'Bare Sketch' # propane method
    end

    def draw
      # draw loop
    end    
  end  
end

# NB: If you use this explicit form need to use Propane::MyApp.new to run sketch

See more at propane github pages