Module: Prawn::SVG::Attributes::ClipPath

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

Instance Method Summary collapse

Instance Method Details

#parse_clip_path_attribute_and_call ⇒ Object 



2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
# File 'lib/prawn/svg/attributes/clip_path.rb', line 2

def parse_clip_path_attribute_and_call
  return unless (clip_path = properties.clip_path)
  return if clip_path == 'none'

  clip_path_element = extract_element_from_url_id_reference(clip_path, 'clipPath')

  if clip_path_element.nil?
    document.warnings << 'Could not resolve clip-path URI to a clipPath element'
  else
    clip_calls = clip_path_element.build_clip_calls(self)
    return if clip_calls.nil?

    add_call_and_enter 'save_graphics_state'

    if clip_path_contains_text?(clip_calls)
      # Text in clip paths is implemented using a PDF soft mask. The text
      # renders in white fill inside the mask to define the visible region.
      # This correctly unions multiple text elements, unlike PDF text
      # rendering mode 7 which intersects separate text objects.
      @calls << ['soft_mask', [], {}, clip_calls]
    else
      @calls.concat clip_calls

      # SVG's clip-rule applies per-element (determining each shape's interior),
      # then elements are unioned. PDF's W* applies even-odd to the entire combined
      # path, which incorrectly creates holes between separate shapes. Only use W*
      # when there's a single child element, where self-intersection matters.
      child_elements = clip_path_element.svg_child_elements
      if child_elements.length == 1 && clip_path_element.computed_properties.clip_rule == 'evenodd'
        add_call 'clip', clip_rule: :even_odd
      else
        add_call 'clip'
      end
    end
  end
end