Class: FormatParser::DPXParser

Inherits:
Object
  • Object
show all
Includes:
IOUtils
Defined in:
lib/parsers/dpx_parser.rb,
lib/parsers/dpx_parser/dpx_structs.rb

Defined Under Namespace

Classes: DPX

Constant Summary collapse

BE_MAGIC = 
'SDPX'
LE_MAGIC = 
BE_MAGIC.reverse

Instance Method Summary collapse

Methods included from IOUtils

#safe_read, #safe_skip

Instance Method Details

#call(io) ⇒ Object 



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
 
# File 'lib/parsers/dpx_parser.rb', line 22

def call(io)
  io = FormatParser::IOConstraint.new(io)
  magic = safe_read(io, 4)
  return unless [BE_MAGIC, LE_MAGIC].include?(magic)

  io.seek(0)

  dpx_structure = DPX.read_and_unpack(ByteOrderHintIO.new(io, magic == LE_MAGIC))

  w = dpx_structure.fetch(:image).fetch(:pixels_per_line)
  h = dpx_structure.fetch(:image).fetch(:lines_per_element)

  pixel_aspect_w = dpx_structure.fetch(:orientation).fetch(:horizontal_pixel_aspect)
  pixel_aspect_h = dpx_structure.fetch(:orientation).fetch(:vertical_pixel_aspect)
  pixel_aspect = pixel_aspect_w / pixel_aspect_h.to_f

  image_aspect = w / h.to_f * pixel_aspect

  display_w = w
  display_h = h
  if image_aspect > 1
    display_h = (display_w / image_aspect).round
  else
    display_w = (display_h * image_aspect).round
  end

  FormatParser::Image.new(
    format: :dpx,
    width_px: w,
    height_px: h,
    display_width_px: display_w,
    display_height_px: display_h,
    intrinsics: dpx_structure,
  )
end