#!ruby -Ku
# -*- mode: ruby; coding: utf-8 -*-
# Last updated: <2017/04/08 23:17:51 +0900>
#
# scalenx.rb
#
# pixel scalking , Scale2x, Scale3x
#
# Author: mieki256
# License: GPL
#
# Original algorithm by Andrea Mazzoleni.
# Scale2x
# http://www.scale2x.it/

module ScaleNx

  # pixel scaling, Scale2x
  # @param src [Array<Array>] pixel data array
  # @return [Array<Array>] 2x pixel data array
  def scale2x(src)
    width, height = src[0].size, src.size
    nwidth, nheight = width * 2, height * 2
    dst = Array.new(nheight).map { Array.new(nwidth) }
    dy = 0
    dx = 0
    height.times do |y|
      y0 = (y > 0)? y - 1 : y
      y1 = y
      y2 = (y < height - 1)? y + 1 : y
      ay0 = src[y0]
      ay1 = src[y1]
      ay2 = src[y2]
      width.times do |x|
        x0 = (x - 1 >= 0)? x - 1 : x
        x1 = x
        x2 = (x + 1 < width)? x + 1 : x

        a = ay0[x0]
        b = ay0[x1]
        c = ay0[x2]
        d = ay1[x0]
        e = ay1[x1]
        f = ay1[x2]
        g = ay2[x0]
        h = ay2[x1]
        i = ay2[x2]

        if b != h && d != f
          e0 = (d == b)? d : e
          e1 = (b == f)? f : e
          e2 = (d == h)? d : e
          e3 = (h == f)? f : e
        else
          e0 = e
          e1 = e
          e2 = e
          e3 = e
        end

        dst[dy][dx]         = e0
        dst[dy][dx + 1]     = e1
        dst[dy + 1][dx]     = e2
        dst[dy + 1][dx + 1] = e3
        dx += 2
      end
      dy += 2
      dx = 0
    end
    return dst
  end

  # pixel scaling, Scale3x
  # @param src [Array<Array>] pixel data array
  # @return [Array<Array>] 3x pixel data array
  def scale3x(src)
    width, height = src[0].size, src.size
    nwidth, nheight = width * 3, height * 3
    dst = Array.new(nheight).map { Array.new(nwidth) }
    dx = 0
    dy = 0
    height.times do |y|
      y0 = (y > 0)? y - 1 : y
      y1 = y
      y2 = (y < height - 1)? y + 1 : y
      ay0 = src[y0]
      ay1 = src[y1]
      ay2 = src[y2]
      width.times do |x|
        x0 = (x - 1 >= 0)? x - 1 : x
        x1 = x
        x2 = (x + 1 < width)? x + 1 : x
        a = ay0[x0]
        b = ay0[x1]
        c = ay0[x2]
        d = ay1[x0]
        e = ay1[x1]
        f = ay1[x2]
        g = ay2[x0]
        h = ay2[x1]
        i = ay2[x2]
        if b != h and d != f
          e0 = (d == b)? d : e
          e1 = ((d == b and e != c) or (b == f and e != a))? b : e
          e2 = (b == f)? f : e
          e3 = ((d == b and e != g) or (d == h and e != a))? d : e
          e4 = e
          e5 = ((b == f and e != i) or (h == f and e != c))? f : e
          e6 = (d == h)? d : e
          e7 = ((d == h and e != i) or (h == f and e != g))? h : e
          e8 = (h == f)? f : e
        else
          e0 = e
          e1 = e
          e2 = e
          e3 = e
          e4 = e
          e5 = e
          e6 = e
          e7 = e
          e8 = e
        end
        dst[dy][dx]         = e0
        dst[dy][dx + 1]     = e1
        dst[dy][dx + 2]     = e2
        dst[dy + 1][dx]     = e3
        dst[dy + 1][dx + 1] = e4
        dst[dy + 1][dx + 2] = e5
        dst[dy + 2][dx]     = e6
        dst[dy + 2][dx + 1] = e7
        dst[dy + 2][dx + 2] = e8
        dx += 3
      end
      dy += 3
      dx = 0
    end
    return dst
  end
end

if $0 == __FILE__
  # ----------------------------------------
  # usage sample

  require 'dxruby'
  require 'benchmark'

  include ScaleNx

  # convert DXRuby Image to array
  def conv_image2array(img)
    w, h = img.width, img.height
    data = []
    h.times do |y|
      dt = []
      w.times do |x|
        a, r, g, b = img[x, y]
        dt.push([r, g, b, a])
      end
      data.push(dt)
    end
    return data
  end

  # convert array to DXRuby Image
  def conv_array2image(src)
    w, h = src[0].size, src.size
    img = Image.new(w, h, [0, 0, 0, 0])
    h.times do |y|
      src[y].each_with_index do |v, x|
        r, g, b, a = v
        img[x, y] = [a, r, g, b]
      end
    end
    return img
  end

  imagefile = "hq3x_original.png"

  srcimg = Image.load(imagefile)
  src = conv_image2array(srcimg)

  dst2x = nil
  dst3x = nil
  Benchmark.bm do |x|
    x.report do
      dst2x = scale2x(src)
    end
    x.report do
      dst3x = scale3x(src)
    end
  end
  dstimg2x = conv_array2image(dst2x)
  dstimg3x = conv_array2image(dst3x)

  Window.resize(540, 360)
  Window.minFilter = TEXF_POINT
  Window.magFilter = TEXF_POINT
  Window.scale = 2

  Window.loop do
    break if Input.keyPush?(K_ESCAPE)
    x, y = 0, 0
    Window.draw(0, 0, srcimg)
    x += srcimg.width
    Window.draw(x, y, dstimg2x)
    x = 0
    y += dstimg2x.height
    Window.draw(x, y, dstimg3x)
  end
end