Module: ImageRuby::PureRubyImageMethods

Defined in:
lib/imageruby/pureruby.rb

Instance Method Summary collapse

Instance Method Details

#[](x, y) ⇒ Object

Returs the color of a pixel locate in the given x and y coordinates or a rectangle section of the image if a range is specified

Example

image[0,0] # return a Color object representing the color of the pixel at 0,0
image[0..20,10..30] # return a image object with the cropped rectagle with x between 0 and 20 and y between 10 and 30
image[0..20,20] # return a image object cropped rectagle with x between 0 and 20 and y equals 15



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# File 'lib/imageruby/pureruby.rb', line 55

def [] (x,y)
  if x.instance_of? Fixnum and y.instance_of? Fixnum
    get_pixel(fixx(x),fixy(y))
  else
    x = (fixx(x)..fixx(x)) if x.instance_of? Fixnum
    y = (fixy(y)..fixy(y)) if y.instance_of? Fixnum

    if x.instance_of? Range
      x = (fixx(x.first)..fixx(x.last))
    end

    if y.instance_of? Range
      y = (fixy(y.first)..fixy(y.last))
    end

    newimg = Image.new(x.last + 1 - x.first, y.last + 1 - y.first)

    width = x.count
    (0..y.count).each do |y_|

      destpointer = y_*width*3
      origpointer = ((y.first + y_)*self.width + x.first)*3

      newimg.pixel_data[destpointer..destpointer+width*3] =
        self.pixel_data[origpointer..origpointer+width*3]
    end

    newimg
  end
end

#[]=(x, y, obj) ⇒ Object

Set the color of a pixel locate in the given x and y coordinates or replace a rectangle section of the image with other image of equal dimensions if a range is specified

Example

image[0,0] = Color.red # set the color of pixel at 0,0 to Color.red
image[0..20,10..30] = other_image # replace the rectagle with x between 0 and 20 and y between 10 and 30 with other_image



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# File 'lib/imageruby/pureruby.rb', line 95

def []= (x,y,obj)
  if x.instance_of? Fixnum and y.instance_of? Fixnum
    set_pixel(x,y,obj)
  else
    x = (x..x) if x.instance_of? Fixnum
    y = (y..y) if y.instance_of? Fixnum

    width = x.count
    (0..y.count-1).each do |y_|
      origpointer = y_*obj.width*3
      destpointer = ((y.first + y_)*self.width + x.first)*3

      self.pixel_data[destpointer..destpointer+obj.width*3-1] =
        obj.pixel_data[origpointer..origpointer+obj.width*3-1]

    end
  end
end

#color_replace(color1, color2) ⇒ Object

Duplicate the image and then call color_replace! method with the given parameters



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# File 'lib/imageruby/pureruby.rb', line 233

def color_replace(color1, color2)

  newimage = self.dup
  newimage.color_replace!(color1,color2)
  newimage
end

#color_replace!(color1, color2) ⇒ Object

Replace the color given in the first argument by the color given in the second with alpha values

Examples

image.color_replace!(Color.red, Color.black) # replace red with black
image.color_replace!(Color.black, Color.coerce([0,0,0,128]) ) # replace black with %50 transparent black



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# File 'lib/imageruby/pureruby.rb', line 246

def color_replace!( color1, color2)
  strcolor1 = color1.to_s
  strcolor2 = color2.to_s

  a = color2.a.chr

  (0..width*height).each do |i|
    if pixel_data[i*3..i*3+2] == strcolor1 then
      pixel_data[i*3..i*3+2] = strcolor2
      alpha_data[i] = a
    end
  end
end

#draw(x, y, image) ⇒ Object

Duplicates the image and draw into the duplicate with the given parameters (by calling draw!)



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# File 'lib/imageruby/pureruby.rb', line 115

def draw(x,y,image)
  obj = self.dup()
  obj.draw!(x,y,image)
  obj
end

#draw!(x, y, image) ⇒ Object

Draw a given image to the given x and y coordinates (matching left-upper corner of the drawn image) when drawing, the method use the alpha channel of the origin image to properly implement alpha drawing (transparency)

Examples:

image.draw!(0,0,other_image)



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# File 'lib/imageruby/pureruby.rb', line 129

def draw!(x,y,image)

    draw_height = image.height
    draw_width = image.width

    if y+image.height > self.height
      draw_height = self.height - y
    end

    if x+image.width > self.width
      draw_width = self.width - x
    end

    dest_pixel_data = self.pixel_data
    orig_pixel_data = image.pixel_data

    (0..draw_height-1).each do |y_orig|
      y_dest = y_orig + y

      origpointer = y_orig*image.width*3
      destpointer = (y_dest*width+x)*3

      (0..draw_width-1).each do |x_orig|
        color = orig_pixel_data[origpointer..origpointer+2]

          alpha = image.alpha_data[y_orig*image.width+x_orig].ord

            if alpha < 255
              if alpha > 0
                dest_pixel_data[destpointer] =
                  (( orig_pixel_data[origpointer].ord*(alpha) + dest_pixel_data[destpointer].ord*(255-alpha) ) / 255).chr
                  origpointer = origpointer + 1
                  destpointer = destpointer + 1

                dest_pixel_data[destpointer] =
                  (( orig_pixel_data[origpointer].ord*(alpha) + dest_pixel_data[destpointer].ord*(255-alpha) ) / 255).chr
                  origpointer = origpointer + 1
                  destpointer = destpointer + 1

                dest_pixel_data[destpointer] =
                  (( orig_pixel_data[origpointer].ord*(alpha) + dest_pixel_data[destpointer].ord*(255-alpha) ) / 255).chr
                  origpointer = origpointer + 1
                  destpointer = destpointer + 1

              else
                destpointer = destpointer + 3
                origpointer = origpointer + 3
              end
            else
              dest_pixel_data[destpointer..destpointer+2] = color
              destpointer = destpointer + 3
              origpointer = origpointer + 3
            end
      end
    end
end

#each_pixel ⇒ Object

Walks each pixel on the image, block is mandantory to call this function and return as yield block calls x,y and pixel color for each pixel of the image

This function does not allow to modify any color information of the image (use map_pixel for that)

Examples:

image.each_pixel do |x,y,color|
  print "pixel at (#{x},#{y}): #{color.inspect}\n"
end



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# File 'lib/imageruby/pureruby.rb', line 198

def each_pixel
  (0..@width-1).each do |x|
    (0..@height-1).each do |y|
      yield(x,y,get_pixel(x,y))
    end
  end
end

#inspect ⇒ Object 



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# File 'lib/imageruby/pureruby.rb', line 283

def inspect()
  "#<ImageRuby::Image:#{object_id} @width=#{@width}, @height=#{@height}>"
end

#map_pixel ⇒ Object

Creates a new image of same dimensions in which each pixel is replaced with the value returned by the block passed as parameter, the block receives the coordinates and color of each pixel

Example

image_without_red = image.map_pixel{|x,y,color| color.r = 0; color } # remove color channel of all pixels



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# File 'lib/imageruby/pureruby.rb', line 212

def map_pixel
  Image.new(@width, @height) do |x,y|
    yield(x,y,get_pixel(x,y))
  end
end

#map_pixel! ⇒ Object

Replace each pixel of the image with the value returned by the block passed as parameter, the block receives the coordinates and color of each pixel

Example

image.map_pixel!{|x,y,color| color.r = 0; color } # remove color channel of all pixels



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# File 'lib/imageruby/pureruby.rb', line 224

def map_pixel!
  each_pixel do |x,y,color|
    set_pixel(x,y, yield(x,y,get_pixel(x,y)))
  end

  self
end

#mask(color1 = nil) ⇒ Object

Replace a color with %100 transparency, useful for mask drawing

Example

masked = other_image.mask(Color.black)
image.draw(0,0,masked) # draw the image without the black pixels



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# File 'lib/imageruby/pureruby.rb', line 266

def mask(color1 = nil)
  color1 = color1 || Color.from_rgb(255,255,255)
  color2 = color1.dup
  color2.a = 0

  color_replace(color1,color2)
end

#on_chain {|_self| ... } ⇒ Object

For sugar syntax, yield the image and then return self

Example:

Image.from_file("input.bmp").on_chain{|img| img[0,0] = Color.red }.save("output.bmp")

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/imageruby/pureruby.rb', line 279

def on_chain
  yield(self); self
end

#save(path, format) ⇒ Object

Save the image to a given file by path and format

Example

image.save("output.bmp", :bmp)



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# File 'lib/imageruby/pureruby.rb', line 33

def save(path, format)
  FilePersistor.persist(self,path,format)
end