# Demonstrates the syntax for creating a two-dimensional (2D) array, # fromfunction (actually a block) using MDArray (for jruby). # Values in a 2D array are accessed through two index values. # 2D arrays are useful for storing images. In this example, each dot # is colored in relation to its distance from the center of the image. require 'mdarray' WIDTH=640 HEIGHT=360 SKIP=10 def setup size WIDTH, HEIGHT background 0 stroke_weight 2 max_distance = ( (WIDTH / 2 - WIDTH)**2 + (HEIGHT / 2 - HEIGHT)**2 )**0.5 distances = MDArray.fromfunction("float", [WIDTH, HEIGHT]) do |x, y| 255 * ( (WIDTH / 2 - x)**2 + (HEIGHT / 2 - y)**2 )**0.5 / max_distance end (SKIP ... WIDTH).step(SKIP) do |x| (SKIP ... HEIGHT).step(SKIP) do |y| stroke distances[x, y] point x, y end end end
According to the limited documentation it might be more efficient to use the accessor to "get" data rather than using bare array access see below. For actual image manipulation in ruby-processing we might be in a bind, we require external jruby to access the gem, but that appears not to work with PImage sketches?