gistfile1.rb

def histogram(location)
    if !@texplayinit
      init_texplay
    end
    
    histogram_image = TexPlay.create_blank_image(@@Win, 101, 1022)
    img = Gosu::Image.new(@@Win, @imagefilename)
    
    @histopixels = Array.new
    101.times{ |x| 
      @histopixels[x] = 0
    }
    img.each{ |pixel| 
      pixel = grayscale(pixel)
      intensity = (pixel[0].round(2))*100
      @histopixels[intensity] = @histopixels[intensity] + 1
    }
    @xcount = 0
    @histopixels.each{ |p| 
      p.times{ |y| 
        histogram_image.pixel @xcount, y, :color => [1, 0, 1, 1] 
      }
      @xcount = @xcount + 1
    }
    histogram_image.save location
  end