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Stored size: 1.83 KB
Contents
class FormatParser::TIFFParser
include FormatParser::IOUtils
include FormatParser::EXIFParser
MAGIC_LE = [0x49, 0x49, 0x2A, 0x0].pack('C4')
MAGIC_BE = [0x4D, 0x4D, 0x0, 0x2A].pack('C4')
HEADER_BYTES = [MAGIC_LE, MAGIC_BE]
TIFF_MIME_TYPE = 'image/tiff'
ARW_MIME_TYPE = 'image/x-sony-arw'
def likely_match?(filename)
filename =~ /\.tiff?$/i
end
def call(io)
io = FormatParser::IOConstraint.new(io)
return unless HEADER_BYTES.include?(safe_read(io, 4))
# Skip over the offset of the IFD,
# EXIFR will re-read it anyway
io.seek(io.pos + 2)
return if cr2?(io)
# The TIFF scanner in EXIFR is plenty good enough,
# so why don't we use it? It does all the right skips
# in all the right places.
exif_data = exif_from_tiff_io(io)
return unless exif_data
w = exif_data.width || exif_data.pixel_x_dimension
h = exif_data.height || exif_data.pixel_y_dimension
format = arw?(exif_data) ? :arw : :tif
mime_type = arw?(exif_data) ? ARW_MIME_TYPE : TIFF_MIME_TYPE
FormatParser::Image.new(
format: format,
width_px: w,
height_px: h,
display_width_px: exif_data.rotated? ? h : w,
display_height_px: exif_data.rotated? ? w : h,
orientation: exif_data.orientation_sym,
intrinsics: {exif: exif_data},
content_type: mime_type,
)
rescue EXIFR::MalformedTIFF
nil
end
def cr2?(io)
io.seek(8)
safe_read(io, 2) == 'CR'
end
# Similar to how exiftool determines the image type as ARW, we are implementing a check here
# https://github.com/exiftool/exiftool/blob/e969456372fbaf4b980fea8bb094d71033ac8bf7/lib/Image/ExifTool/Exif.pm#L929
def arw?(exif_data)
exif_data.compression == 6 && exif_data.new_subfile_type == 1 && exif_data.make == 'SONY'
end
FormatParser.register_parser new, natures: :image, formats: :tif
end
Version data entries
14 entries across 14 versions & 1 rubygems