Rodolphe VAGNER wrote:
In fact the first tests I've done seem to indicate the contrary :
my uncompressed file is a black area and my CCITT Gr4 or 3, and LWZ
compressed files
are well rendered.
It's bizarre, isn'it ?
What about jimy ? where can I find doc on it ?
Ok, here it goes.
The Jimi home page is
http://java.sun.com/products/jimi/
You can download the whole package there, including
Source, JavaDoc and, most valuable, additional docs
describing supported file and image formats.
For TIFF, the following compression schemes are supported
- Uncompressed images
- CCITT compressed Bi-level images with CCITT RLE, CCITT
Group 3 1D Fax, CCITT Group 3 2D Fax, CCITT Group 4 Fax
- CCITT Class F Fax
- Packbits compressed images (a simple RLE type compression)
- LZW Compressed images
JPEG compression is not supported.
The TIFF spec is available from
http://partners.adobe.com/asn/developer/PDFS/TN/TIFF6.pdf
Compression schemes are
Packbits: run length encoding (Sec. 9)
CCITT G3 Fax (Sec. 10)
CCITT Bilevel (Sec. 11)
LZW (Sec. 13)
JPEG (Sec. 22)
CCITT Class F compression is apparently defined in a RFC,
for example available here:
http://www.zvon.org/tmRFC/RFC2306/Output/chapter3.html
It is also mentioned that Jimi does only understand
black and white (bilevel), grayscale (palette) and RGB
(palette and direct color). CMYK, Cie L*a*b* and YCbCr
color models are not implemented.
It is not mentioned whether compression predictors are
supported, I supposed not (does anybody use them?). It is
also not explicitely noted how Jimi deals with alpha
channels.
If uncompressed TIFF comes out black, probably the color
model or palette size is inconvenient for Jimi.
J.Pietschmann
