Sha256: c6cf2e3807ff5f4d881330d85abbf29c76671b06bb5655b795e0447a7dfc7685
Contents?: true
Size: 899 Bytes
Versions: 9
Compression:
Stored size: 899 Bytes
Contents
Spontaneous::Media::Image.define :webp, [82, 73, 70, 70, nil, nil, nil, nil, 87, 69, 66, 80] do |file|
file.seek(12)
format = file.read(4)
height = width = 0
uint24 = proc { |bytes| (bytes + 0.chr).unpack("V").first }
uint14 = proc { |int| int & 0x3fff }
case format
when "VP8 " #simple-file-format-lossy
file.seek(10, IO::SEEK_CUR)
# two 14 bit ints with 2 bits of scaling info
header = file.read(4).unpack("v*")
width, height = header.map(&uint14)
when "VP8L" #simple-file-format-lossless
file.seek(5, IO::SEEK_CUR)
# two consecutive 14 bit ints
header = file.read(4).unpack("v*")
width = uint14[header[0]] + 1
height = (header[0] >> 14) + ((header[1] & 0xfff) << 2) + 1
when "VP8X" #extended-file-format
file.seek(8, IO::SEEK_CUR)
width = uint24[file.read(3)] + 1
height = uint24[file.read(3)] + 1
end
[width, height]
end
Version data entries
9 entries across 9 versions & 1 rubygems