module Prawn::Graphics::BlendMode

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

Public Instance Methods

blend_mode (blend_mode = :Normal) { || ... }

Source

# 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

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`.

@example

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

@param blend_mode [Symbol, Array<Symbol>] @yield @return [void]