IOCA

Full Name	IBM IOCA (Image Object Content Architecture)
Format ID	IG_FORMAT_ICA =16
File Extension(s)	.ica, .mod
Data Type	Raster Image
Data Encoding	Binary
Color Profile Support	No
Multi-Page Support	Yes
Alpha Channel Support	No
ImageGear Platforms Support	WIN32, WIN64, Unix, Unix64, .NET, .NET64, MAC

ImageGear Supported Versions:

N/A

ImageGear Supported Features:

IG_FLTR_DETECTSUPPORT - autodetection
IG_FLTR_MPAGEREADPSUPPORT - multi-page file reading
IG_FLTR_PAGEINSERTSUPPORT - single-page file writing
IG_FLTR_PAGEREADSUPPORT - single page file reading

ImageGear Read Support:

IG_COMPRESSION_NONE:
- Indexed RGB: 1, 4, 8 bpp;
- RGB: 24 bpp
IG_COMPRESSION_CCITT_G3:
- Indexed RGB: 1 bpp
IG_COMPRESSION_CCITT_G4:
- Indexed RGB: 1 bpp
IG_COMPRESSION_IBM_MMR:
- Indexed RGB: 1 bpp
IG_COMPRESSION_ABIC_BW:
- Indexed RGB: 1 bpp
IG_COMPRESSION_ABIC_GRAY:
- Indexed RGB: 4bpp
IG_COMPRESSION_JPEG:
- Grayscale: 8 bpp;
- RGB: 24 bpp

ImageGear Write Support:

IG_COMPRESSION_CCITT_G3:
- Indexed RGB: 1 bpp
IG_COMPRESSION_CCITT_G4:
- Indexed RGB: 1 bpp
IG_COMPRESSION_IBM_MMR:
- Indexed RGB: 1 bpp

ImageGear Filter Control Parameters:

Filter Control Parameter	Type	Default Value	Available Values	Description
STITCH_TILES	AT_BOOL	FALSE	TRUE, FALSE	Set to TRUE to enable automatic tile stitching during image loading.

Comments:

IOCA files are most often used for document storage. They are not so unusual from most file formats, except for their naming conventions, which tend to be IBM-specific.

The general structure of an IOCA image file includes a "beginning segment", an "end segment", a header component called "Image Data Parameters", a palette, and the actual image data. Most IOCA images (less than 24-bit) contain a palette. The elements of the bitmap image are referred to as Image Data Elements (IDEs), that are called pixels by most other formats. The "Object Content" refers to the combination of the header and the image data.

IBM uses fields in the header called "self-defining fields". They each contain a type code, the length of the parameter, and then the actual parameter data. They include information as resolution, size, encoding scheme, and bit depth.

There are many optional parameters. Subsets of IOCA parameters are referred to as "function sets" and define different flavors of the IOCA, one being the MO:DCA, also supported by ImageGear. Examples of optional parameters include a tiling parameter, if the image is tiled, and a Band Image parameter, which signifies that the image is saved in "bands" ("bit planes" in other formats).

References Used

Image Object Content Architecture Reference, 2d ed., copyright International Business Machines Corporation, August 1991.