Method: PSD::Compose#normal

Defined in:
lib/psd/compose.rb

#normal(fg, bg, opts = {}) ⇒ Object

Normal composition, delegate to ChunkyPNG



19
20
21
22
23
24
25
26
27
28
29
 
# File 'lib/psd/compose.rb', line 19

def normal(fg, bg, opts={})
  return fg if opaque?(fg) || fully_transparent?(bg)
  return bg if fully_transparent?(fg)

  mix_alpha, dst_alpha = calculate_alphas(fg, bg, DEFAULT_OPTS.merge(opts))
  new_r = blend_channel(r(bg), r(fg), mix_alpha)
  new_g = blend_channel(g(bg), g(fg), mix_alpha)
  new_b = blend_channel(b(bg), b(fg), mix_alpha)

  rgba(new_r, new_g, new_b, dst_alpha)
end