Module: Idml::Render::Blending

Defined in:
lib/idml/render/blending.rb

Overview

Maps an Elements::BlendingSetting to the keyword arguments that Pdfrb::Content::Canvas#with_transparency expects. IDML stores opacity as 0–100 (percentage); pdfrb wants 0.0–1.0 alpha. Blend mode names line up directly with PDF BM names; unknown modes fall back to Normal.

Constant Summary collapse

PDF_BLEND_MODES = 
%w[
  Normal Multiply Screen Overlay SoftLight HardLight Darken Lighten
  ColorDodge ColorBurn Difference Exclusion Hue Saturation Color
  Luminosity
].freeze

Class Method Summary collapse

Class Method Details

.args_for(setting) ⇒ Object 



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# File 'lib/idml/render/blending.rb', line 17

def self.args_for(setting)
  return nil unless setting&.blending_setting

  build_args(setting.blending_setting)
end

.wrap(canvas, setting) ⇒ Object

Wraps the given block in Canvas#with_transparency when the page item has a BlendingSetting, otherwise yields directly.



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# File 'lib/idml/render/blending.rb', line 34

def self.wrap(canvas, setting, &)
  args = args_for(setting)
  if args
    canvas.with_transparency(**args, &)
  else
    yield
  end
end