Method: PSD::Compose#darken

Defined in:
lib/psd/renderer/compose.rb

#darken(fg, bg, opacity) ⇒ Object

Subtractive blend modes



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# File 'lib/psd/renderer/compose.rb', line 31

def darken(fg, bg, opacity)
  return apply_opacity(fg, opacity) if fully_transparent?(bg)
  return bg if fully_transparent?(fg)

  mix_alpha, dst_alpha = calculate_alphas(fg, bg, opacity)
  new_r = r(fg) <= r(bg) ? blend_channel(r(bg), r(fg), mix_alpha) : r(bg)
  new_g = g(fg) <= g(bg) ? blend_channel(g(bg), g(fg), mix_alpha) : g(bg)
  new_b = b(fg) <= b(bg) ? blend_channel(b(bg), b(fg), mix_alpha) : b(bg)

  rgba(new_r, new_g, new_b, dst_alpha)
end