Module: GoldenFrill

Defined in:
lib/golden_frill.rb,
lib/golden_frill/version.rb

Constant Summary collapse

GoldenRatio = 
1.618
VERSION = 
"0.1.2"

Class Method Summary collapse

Class Method Details

.darken_color(c, scale = 0.8) ⇒ Object 



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

def self.darken_color(c, scale = 0.8)
  r, g, b = %w{r g b}.map{|x| (ChunkyPNG::Color.send(x, c).to_f * scale).to_i}
  ChunkyPNG::Color.rgb(r,g,b)
end

.run!(opts) ⇒ Object

Requires:

output_path : the path at which to output the requested image
width: the width the rectangle above the frill
height: the height of the rectangle above the frill
base_color: the color of the rectangle above the frill

Optional:

frill_color: the color of the frill. If not provided, will be a darker color than the base



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

def self.run!(opts)
  width, height, base_color, output_path = opts[:width].to_i, opts[:height].to_i, opts[:base_color], opts[:output_path]
  
  bot_height = height.to_i + (width.to_f * GoldenRatio).to_i
  png = ChunkyPNG::Image.new(width.to_i, bot_height)
  
  rc = ChunkyPNG::Color.from_hex(base_color)
  (1..(height - 1)).each do |h|
    (1..(width - 1)).each do |w|
      png[w,h] = rc
    end
  end
  
  ribbon_color = if opts[:frill_color]
    ChunkyPNG::Color.from_hex(opts[:frill_color])
  else
    self.darken_color(rc)
  end
  
  slope = (height - bot_height).to_f / (1 - width).to_f
  
  (height..(bot_height - 1)).each do |h|
    (1..(width - 1)).each do |w|
      on_line_slope = (w * slope) + height
      next if on_line_slope.to_i + 1 < h
      
      alpha_scale = case (on_line_slope.to_i + 1) - h
      when 1 then 0.8
      when 0 then 0.5
      else 
        1.0
      end
      a = (0xff.to_f * alpha_scale).to_i
      
      new_color = ((w + 3) - (width - 1)).times.inject(ribbon_color){|rc, fade|
        darken_color(rc, 0.95)
      }
      new_color = ChunkyPNG::Color.fade(new_color, a) 
      
      # fade the color to a black gradient if in the last couple pixels of the ribbon
      png[w,h] = new_color
    end
  end
  
  png.save(output_path)
end