Module: Prawn::SVG::Attributes::Opacity

Included in:
Elements::Base
Defined in:
lib/prawn/svg/attributes/opacity.rb

Instance Method Summary collapse

Instance Method Details

#parse_opacity_attributes_and_call ⇒ Object 



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# File 'lib/prawn/svg/attributes/opacity.rb', line 2

def parse_opacity_attributes_and_call
  # The opacity property is not inherited, but the opacity applies to all children underneath the element.
  #
  # Having an opacity property on a parent, and again on a child, multiplies the parent and child's opacities
  # when drawing the children.
  #
  # The fill-opacity and stroke-opacity properties are inherited, but children which have a different value
  # are displayed at that opacity rather than multiplying the parent's fill/stroke opacity with the child's.
  #
  # opacity and fill/stroke opacity can both be applied to the same element, and they multiply together.

  opacity = computed_properties.opacity&.to_f&.clamp(0, 1)
  fill_opacity = computed_properties.fill_opacity.to_f.clamp(0, 1)
  stroke_opacity = computed_properties.stroke_opacity.to_f.clamp(0, 1)

  state.opacity *= opacity if opacity

  fill_opacity = (fill_opacity || 1) * state.opacity
  stroke_opacity = (stroke_opacity || 1) * state.opacity

  fill_opacity = stroke_opacity = 0 if computed_properties.visibility != 'visible'

  if state.last_fill_opacity != fill_opacity || state.last_stroke_opacity != stroke_opacity
    state.last_fill_opacity = fill_opacity
    state.last_stroke_opacity = stroke_opacity
    add_call_and_enter 'transparent', fill_opacity, stroke_opacity
  end
end