Module: ImageRuby::RubyBitmapModl

Defined in:
lib/imageruby/bitmap/rbbitmap.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#height ⇒ Object (readonly)

Returns the value of attribute height.



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 28

def height
  @height
end

#width ⇒ Object (readonly)

Returns the value of attribute width.



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 27

def width
  @width
end

Instance Method Details

#alpha_data ⇒ Object

returns the alpha data string with the alpha channel information of the pixels

To get the color value of a pixel on given x,y coordinates use image.get_pixel(x,y) or image

Examples

bitmap.pixel_data[(12)*bitmap.width+10] # the alpha value at x=12, y=10
bitmap.pixel_data[(12)*bitmap.width+11] # the alpha value at x=12, y=11
bitmap.pixel_data[(12)*bitmap.width+12] # the alpha value at x=12, y=12



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 103

def alpha_data
  @alpha = 255.chr*(@height * @width) unless @alpha
  @alpha
end

#dup ⇒ Object

Creates a duplicate of the image



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 59

def dup
  ret = super
  ret.initialize_dup(self)
end

#get_pixel(x, y) ⇒ Object

return a Color object of a given x and y coord



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 40

def get_pixel(x,y)
  index = (y*@width + x)
  pointindex = index*3
  Color.from_rgba(
    @array[pointindex+2].ord,
    @array[pointindex+1].ord,
    @array[pointindex].ord,
    @alpha ? @alpha[index].ord : 255
    )

end

#initialize_bitmap_representation(width_, height_, color = nil) ⇒ Object

Initialize the representation of bitmap with the given width and height (used internally)



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 31

def initialize_bitmap_representation(width_, height_, color = nil)

  color ||= Color.from_rgb(0,0,0)

  @width = width_
  @height = height_
  @array = color.to_s*@width*@height
end

#initialize_dup(orig) ⇒ Object 



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 52

def initialize_dup(orig)
  @alpha = orig.alpha_data.dup
  @array = orig.pixel_data.dup
  self
end

#pixel_data ⇒ Object

returns the pixel data string with the RGB information of the pixels

To get the color value (including alpha) of a pixel on given x,y coordinates use image.get_pixel(x,y) or image

Examples

bitmap.pixel_data[(12)*bitmap.width+10] # the red channel at x=12, y=10
bitmap.pixel_data[(12)*bitmap.width+10+1] # the green channel at x=12, y=10
bitmap.pixel_data[(12)*bitmap.width+10+2] # the blue channel at x=12, y=10



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 90

def pixel_data
  @array
end

#set_pixel(x, y, color) ⇒ Object

set a color value for a image



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# File 'lib/imageruby/bitmap/rbbitmap.rb', line 65

def set_pixel(x,y,color)

  index = (y*@width + x)
  pointindex = index*3
  @array[pointindex+2] = color.r.chr
  @array[pointindex+1] = color.g.chr
  @array[pointindex] = color.b.chr

  if color.a != 255 then
    @alpha = 255.chr*(@height * @width) unless @alpha
    @alpha[index] = color.a.chr
  end

  self
end