Conway's Game of Life Glimmer Sample

# From: https://github.com/AndyObtiva/glimmer-dsl-swt/blob/master/docs/reference/GLIMMER_SAMPLES.md#game-of-life

require 'glimmer-dsl-swt'

require_relative 'game_of_life/model/grid'

class GameOfLife
  include Glimmer::UI::CustomShell

  WIDTH = 20
  HEIGHT = 20
  CELL_WIDTH = 25
  CELL_HEIGHT = 25

  before_body do
    @grid = GameOfLife::Model::Grid.new(WIDTH, HEIGHT)
  end

  body {
    shell {
      row_layout :vertical
      text "Conway's Game of Life (Glimmer Edition)"

      canvas {
        layout_data {
          width WIDTH*CELL_WIDTH
          height HEIGHT*CELL_HEIGHT
        }
        (0...HEIGHT).each do |row_index|
          (0...WIDTH).each do |column_index|
            rectangle(column_index*CELL_WIDTH, row_index*CELL_HEIGHT, CELL_WIDTH, CELL_HEIGHT) {
              background <= [@grid.cell_rows[row_index][column_index], "alive", on_read: ->(a) {a ? :black : :white}]

              on_mouse_down {
                @grid.cell_rows[row_index][column_index].toggle_aliveness!
              }
            }
          end
        end
      }

      composite {
        row_layout(:horizontal) {
          margin_width 0
        }

        button {
          text 'Step'
          enabled <= [@grid, :playing, on_read: :! ]

          on_widget_selected {
            @grid.step!
          }
        }

        button {
          text 'Clear'
          enabled <= [@grid, :playing, on_read: :! ]

          on_widget_selected {
            @grid.clear!
          }
        }

        button {
          text <= [@grid, :playing, on_read: ->(p) { p ? 'Stop' : 'Play' }]

          on_widget_selected {
            @grid.toggle_playback!
          }
        }

        label {
          text 'Slower'
        }

        scale {
          minimum 1
          maximum 100
          selection <=> [@grid, :speed]
        }

        label {
          text 'Faster'
        }

      }
    }
  }
end

GameOfLife.launch