module HexaPDF:: ImageLoader:: JPEG
This module is used for loading images in the JPEG
format from files or IO streams.
See: PDF2.0 s7.4.8, ITU T.81 Annex B, ITU T.872
Constants
- APP14_MARKER¶
Adobe uses the marker 0xEE (APPE or APP14) for its purposes. We need to use it for determinig whether we have a CMYK or YCCK image.
- APP14_TRANSFORM_CMYK¶
Value of the 12th byte in an APP14 marker specifying that the image uses CMYK color encoding, with all four colors complemented.
- EOI_MARKER¶
End-of-image marker
- MAGIC_FILE_MARKER¶
The magic marker that tells us if the file/IO contains an image in
JPEG
format.- SOF_MARKERS¶
The various start-of-frame markers that tell us which kind of
JPEG
it is. The marker segment itself contains all the needed information needed for creating thePDF
image object.See: ITU T.81 B1.1.3
- SOS_MARKER¶
Start-of-scan marker