Module: Prawn::Graphics::BlendMode

Included in:
Prawn::Graphics
Defined in:
lib/prawn/graphics/blend_mode.rb

Overview

The BlendMode module is used to change the way two graphic objects are blended together.

Stable API collapse

Instance Method Details

#blend_mode(blend_mode = :Normal) { ... } ⇒ void

This method returns an undefined value.

Set blend mode. If a block is passed blend mode is restored afterwards.

Passing an array of blend modes is allowed. PDF viewers should blend layers based on the first recognized blend mode.

Valid blend modes since PDF 1.4 include ‘:Normal`, `:Multiply`, `:Screen`, `:Overlay`, `:Darken`, `:Lighten`, `:ColorDodge`, `:ColorBurn`, `:HardLight`, `:SoftLight`, `:Difference`, `:Exclusion`, `:Hue`, `:Saturation`, `:Color`, and `:Luminosity`.

Examples:

pdf.fill_color('0000ff')
pdf.fill_rectangle([x, y + 25], 50, 50)
pdf.blend_mode(:Multiply) do
  pdf.fill_color('ff0000')
  pdf.fill_circle([x, y], 25)
end

Parameters:

  • blend_mode (Symbol, Array<Symbol>) (defaults to: :Normal)

Yields:



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# File 'lib/prawn/graphics/blend_mode.rb', line 31

def blend_mode(blend_mode = :Normal)
  renderer.min_version(1.4)

  save_graphics_state if block_given?
  renderer.add_content("/#{blend_mode_dictionary_name(blend_mode)} gs")
  if block_given?
    yield
    restore_graphics_state
  end
end