Welcome to propane

Requirements

jruby-9.3.1.0, open jdk11 or [Oracle jdk11][oraclejvm]

If you arrive here from rubygems math_demo you may well have installed propane as a requirement

math_demo # is the executable to run from the command line for the demo, but there's much more

Alternative

If you are familiar with the original ruby-processing (deprecated since January 2017) you may prefer to use JRubyArt instead. However like ruby-processing it depends on a vanilla processing install however currently and for foreseable future, this is the only option for Windows users.

Installing

For more info on how to get the most out of JRubyArt see the propane website and my JRubyArt blog. File all bugs/feature requests at propane issues.

Using

Create sketch from template

propane -c my_sketch 200 200 # creates `my_sketch.rb` with class `MySketch`

Run sketches

jruby my_sketch.rb

Example Sketch:-

#!/usr/bin/env jruby -v -W2
# frozen_string_literal: true
require 'propane'
# Iconic ruby-processing example for Propane
class JWishy < Propane::App
  load_library :control_panel

  attr_reader :alpha, :back_color, :bluish, :hide, :magnitude, :panel
  attr_reader :x_wiggle, :y_wiggle, :go_big, :shape

  def settings
    size 600, 600  
  end

  def setup
    sketch_title 'Wishy Worm'
    control_panel do |c|
      c.title'Control Panel'
      c.look_feel 'Nimbus'
      c.slider :bluish, 0.0..1.0, 0.5
      c.slider :alpha,  0.0..1.0, 0.5
      c.checkbox :go_big, false
      c.button :reset
      c.menu :shape, %w(oval square triangle), 'oval'
      @panel = c
    end
    @hide = false
    @x_wiggle, @y_wiggle = 10.0, 0
    @magnitude = 8.15
    @back_color = [0.06, 0.03, 0.18]
    color_mode RGB, 1
    ellipse_mode CORNER
    smooth
  end

  def draw_background
    back_color[3] = alpha
    fill(*back_color.to_java(:float))
    rect 0, 0, width, height
  end

  def reset
    @y_wiggle = 0
  end

  def draw
    # only make control_panel visible once, or again when hide is false
    unless hide
      @hide = true
      panel.set_visible(hide)
    end
    draw_background
    # Seed the random numbers for consistent placement from frame to frame
    srand(0)
    horiz, vert, mag = x_wiggle, y_wiggle, magnitude
    if go_big
      mag *= 2
      vert /= 2
    end
    blu = bluish
    x, y = (width / 2), -27
    c = 0.0
    64.times do
      x += cos(horiz) * mag
      y += log10(vert) * mag + sin(vert) * 2
      fill(sin(y_wiggle + c), rand * 0.2, rand * blu, 0.5)
      s = 42 + cos(vert) * 17
      args = [@shape, x - s / 2, y - s / 2, s, s]
      draw_shape(args)
      vert += rand * 0.25
      horiz += rand * 0.25
      c += 0.1
    end
    @x_wiggle += 0.05
    @y_wiggle += 0.1
  end

  def mouse_pressed
    return unless hide
    @hide = false
  end

  def draw_shape(args)
    case args[0]
    when 'triangle'
      draw_triangle(args)
    when 'square'
      rect(args[1], args[2], args[3], args[4])
    else
      ellipse(args[1], args[2], args[3], args[4]) # oval for Shoes
    end
  end

  def draw_triangle(args)
    x2 = args[1] + (args[3] * 0.6)
    y0 = args[2] + (args[4] * 0.396)
    y1 = args[2] - (args[4] * 0.792)
    y2 = args[2] + (args[4] * 0.396)
    triangle(args[1] - (args[3] * 0.6), y0, args[1], y1, x2, y2)
  end
end

JWishy.new