■ [画像処理]簡単な畳み込みフィルタリングのつもり

だったはずなのだが、Ruby/SDL上のSurfaceをいじる処理云々で色々手間取って妙に時間がかかってしまった。 一応左下から順に移動平均フィルタ、ラプラシアンフィルタ、先鋭化フィルタを使った結果。

require 'sdl'

auto_lock = true
SDL.init(SDL::INIT_EVERYTHING)

def filtering(surface, filter)
  p = SDL::Surface.new(SDL::HWSURFACE ||
                               SDL::SRCALPHA, surface.w, surface.h, 32,
                               0xff000000, 0x00ff0000, 0x0000ff00, 0x000000ff)

  1.upto(surface.h-2) do |h|
    1.upto(surface.w-2) do |w|
      r = 0
      g = 0
      b = 0

      pix = surface.format.getRGBA(surface[w-1, h-1])
      r += (pix[0]*filter[0][0]).round
      g += (pix[1]*filter[0][0]).round
      b += (pix[2]*filter[0][0]).round

      pix = surface.format.getRGBA(surface[w  , h-1])
      r += (pix[0]*filter[0][1]).round
      g += (pix[1]*filter[0][1]).round
      b += (pix[2]*filter[0][1]).round

      pix = surface.format.getRGBA(surface[w+1, h-1])
      r += (pix[0]*filter[0][2]).round
      g += (pix[1]*filter[0][2]).round
      b += (pix[2]*filter[0][2]).round

      pix = surface.format.getRGBA(surface[w-1, h])
      r += (pix[0]*filter[1][0]).round
      g += (pix[1]*filter[1][0]).round
      b += (pix[2]*filter[1][0]).round

      pix = surface.format.getRGBA(surface[w  , h])
      r += (pix[0]*filter[1][1]).round
      g += (pix[1]*filter[1][1]).round
      b += (pix[2]*filter[1][1]).round

      pix = surface.format.getRGBA(surface[w+1, h])
      r += (pix[0]*filter[1][2]).round
      g += (pix[1]*filter[1][2]).round
      b += (pix[2]*filter[1][2]).round

      pix = surface.format.getRGBA(surface[w-1, h+1])
      r += (pix[0]*filter[2][0]).round
      g += (pix[1]*filter[2][0]).round
      b += (pix[2]*filter[2][0]).round

      pix = surface.format.getRGBA(surface[w  , h+1])
      r += (pix[0]*filter[2][1]).round
      g += (pix[1]*filter[2][1]).round
      b += (pix[2]*filter[2][1]).round

      pix = surface.format.getRGBA(surface[w+1, h+1])
      r += (pix[0]*filter[2][2]).round
      g += (pix[1]*filter[2][2]).round
      b += (pix[2]*filter[2][2]).round

      p[w,h] = [r,g,b,255]
    end
  end

  return p
end

graphics = Array.new
graphics.push(SDL::Surface.load("AngelFish.png"))

graphics.push(filtering(graphics[0],
                      [[0.11, 0.11, 0.11], [0.11, 0.11, 0.11], [0.11, 0.11, 0.11]]))
graphics.push(filtering(graphics[0],
                      [[   0,  1.0,    0], [ 1.0, -4.0,  1.0], [   0,  1.0,    0]]))
graphics.push(filtering(graphics[0],
                      [[   0, -1.0,    0], [-1.0,  5.0, -1.0], [   0, -1.0,    0]]))

screen = SDL::Screen.open(graphics[0].w * 2, graphics[0].h * 2, 32, 0)

while true

    while event = SDL::Event2.poll

      case event
        when SDL::Event2::Quit
          exit

        when SDL::Event2::KeyDown
          exit if event.sym == SDL::Key::ESCAPE

        when SDL::Event2::KeyUp

      end
    end

    screen.put(graphics[0], 0, 0)
    screen.put(graphics[1], graphics[1].w, 0)
    screen.put(graphics[2], 0, graphics[2].h)
    screen.put(graphics[3], graphics[3].w, graphics[3].h)
    screen.updateRect(0,0,0,0)
end