Class: FB2Image::FB

Inherits:
Object
  • Object
show all
Defined in:
lib/fb2image.rb

Overview

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Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(src_width, src_height, fb, opts = {}) ⇒ FB

Returns a new instance of FB.



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# File 'lib/fb2image.rb', line 12

def initialize(src_width, src_height, fb, opts={})
  @src_width       = src_width
  @src_height      = src_height
  @fb              = fb
  @thinning_rate   = opts[:thinning_rate] || 1
  @width           = @src_width  / @thinning_rate
  @height          = @src_height / @thinning_rate
  @r_shift         = (opts[:red_shift]   || 0)  / 8
  @g_shift         = (opts[:green_shift] || 8)  / 8
  @b_shift         = (opts[:blue_shift]  || 16) / 8
  @bits_per_pixel  = opts[:bits_per_pixel] || 1
  @bytes_per_pixel = @bits_per_pixel / 8
end

Instance Attribute Details

#fb ⇒ Object

Returns the value of attribute fb.



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# File 'lib/fb2image.rb', line 10

def fb
  @fb
end

#height ⇒ Object

Returns the value of attribute height.



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# File 'lib/fb2image.rb', line 10

def height
  @height
end

#src_height ⇒ Object

Returns the value of attribute src_height.



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# File 'lib/fb2image.rb', line 10

def src_height
  @src_height
end

#src_width ⇒ Object

Returns the value of attribute src_width.



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# File 'lib/fb2image.rb', line 10

def src_width
  @src_width
end

#thinning_rate ⇒ Object

Returns the value of attribute thinning_rate.



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# File 'lib/fb2image.rb', line 10

def thinning_rate
  @thinning_rate
end

#width ⇒ Object

Returns the value of attribute width.



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# File 'lib/fb2image.rb', line 10

def width
  @width
end

Instance Method Details

#write_bmp(dest_path) ⇒ Object 



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# File 'lib/fb2image.rb', line 59

def write_bmp(dest_path)
  image = BitMap.new(@width, @height)
  @height.times do |y|
    @width.times do |x|
      idx = (y * @src_width * @thinning_rate) + (x * @thinning_rate)
      pixel = @fb[idx * @bytes_per_pixel, @bytes_per_pixel]
      r = pixel[@r_shift]
      g = pixel[@g_shift]
      b = pixel[@b_shift]
      image.pset(x, y, r, g, b)
    end
  end
  image.write(dest_path)
end

#write_png(dest_path) ⇒ Object 



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# File 'lib/fb2image.rb', line 26

def write_png(dest_path)
  depth      = 8 #@bits_per_pixel
  color_type = 2
  img_data   = ""

  open(dest_path, "wb") do |f|
    # ファイルシグニチャ
    f.print "\x89PNG\r\n\x1a\n"

    # ヘッダ
    f.print chunk("IHDR", [@width, @height, depth, color_type, 0, 0, 0].pack("NNCCCCC"))

    # 画像データ
    @height.times do |y|
      line = []
      @width.times do |x|
        idx = (y * @src_width * @thinning_rate) + (x * @thinning_rate)
        pixel = @fb[idx * @bytes_per_pixel, @bytes_per_pixel]
        r = pixel[@r_shift, 1]
        g = pixel[@g_shift, 1]
        b = pixel[@b_shift, 1]
        line << [r, g, b]
      end
      img_data << ([0] + line.flatten).pack("C*")
    end

    f.print chunk("IDAT", Zlib::Deflate.deflate(img_data))

    # 終端
    f.print chunk("IEND", "")
  end
end