JPEG - JPEG File Interchange Format
[File Formats]
- ISO/IEC 10918 (1994, 1995, 1997, 1999)
http://www.jpeg.org/
- Access to the JPEG file format uses libJPEG version 6b.
http://www.ijg.org
Copyright (C) 1991-1998, Thomas G. Lane
from the Independent JPEG Group.
- Access to the EXIF attributes uses libEXIF version 0.6.12.
http://sourceforge.net/projects/libexif
Copyright (C) 2001-2003, Lutz Müller
Data Types: Byte
Color Spaces: Gray, RGB, CMYK and YCbCr (Binary Saved as Gray)
Compressions:
JPEG - ISO JPEG [default]
Only one image.
No alpha channel.
Internally the components are always packed.
Internally the lines are arranged from top down to bottom.
Handle(1) returns jpeg_decompress_struct* when reading, and
jpeg_compress_struct* when writing (libJPEG structures).
Attributes:
AutoYCbCr IM_INT (1) (controls YCbCr auto conversion) default 1
JPEGQuality IM_INT (1) [0-100, default 75] (write only)
ResolutionUnit (string) ["DPC", "DPI"]
XResolution, YResolution IM_FLOAT (1)
Interlaced (same as Progressive) IM_INT (1 | 0) default 0
Description (string)
(lots of Exif tags)
Changes to libJPEG:
jdatadst.c - fflush and ferror replaced by macros JFFLUSH and JFERROR.
jinclude.h - standard JFFLUSH and JFERROR definitions, and new macro HAVE_JFIO.
jmorecfg.h - changed definition of INT32 to JINT32 for better compatibility.
jdhuf.c - added support for OJPEG_SUPPORT in libTIFF.
new file created: jconfig.h
Changes to libEXIF:
new file config.h
changed "exif-tag.c" to add new function
changed "exif-entry.c" to improve exif_entry_initialize
fixed small bug in "mnote-pentax-tag.h".
Comments:
Other APPx markers are ignored.
No thumbnail support.
RGB images are automatically converted to YCbCr when saved.
Also YcbCr are converted to RGB when loaded. Use AutoYCbCr=0 to disable this behavior.
