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1992-09-05
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HAMLAB PLUS 2.0.8
FILTER AND EXPORTER REFERENCE
(c) Copyright 1990-1992 J. E. Hanway. All rights reserved.
IN THIS DOCUMENT:
INPUT FILTERS SUPPORTED
EXPORTERS SUPPORTED
ACKNOWLEDGEMENTS
INPUT FILTERS SUPPORTED
GIF (Graphics Interchange Format)
GIF versions GIF87a and GIF89a are both supported. (GIF89 features
are ignored.)
Only the first image in the file is used.
Non-interlaced GIF files require much less memory to convert than
interlaced GIF files. NOTE: This "interlace" has nothing to do with
the Amiga display. An "interlaced" GIF file stores the lines of
the image in scrambled order, rather than top-to-bottom, so that,
in theory, you can see the overall picture sooner while it is
being displayed. Most GIF files are not interlaced.
Interlaced files, when opened, will also go through an extra step
during which a progress indicator will display "Buffering..."
During this time their line order is unscrambled.
TIFF (Tag Image File Format)
Supports black&white or gray scale images with 1, 4, or 8 bit
planes.
Supports RGB color images with 3, 12, or 24 bit planes.
Images must either be uncompressed or use PackBits compression
(type 32773).
SPECTRUM 512
Normal, compressed (.SPC) files supported. Uncompressed (.SPU) and
.SPS files are not supported.
PBMPLUS
Black&white (PBM), gray scale (PGM), and color (PPM) files are all
supported. Both ASCII and RAW (binary) formats are supported.
MTV
The RAYSHADE ray tracer by Craig E. Kolb can also write images in
this format.
QRT, DKBTrace
Although both the QRT and DKBTrace ray tracers use the same file
format, QRT uses only 21 bits of information per pixel while
DKBTrace uses 24 bits. With default settings, DKBTrace pictures
will look correct, while QRT pictures will be too dark, but this
can be compensated by increasing the brightness. (The easiest way
to do this is to load the color control settings from the
"QRT_color_response" file supplied.)
SUN RASTERFILES
Black&white, 8-bit mapped color, and 24-bit color images are
supported.
Both uncompressed and run-length compressed raster files are
supported.
IFF ILBM (and HAM-E)
Supports normal, color-mapped, interleaved bit map images with one
to eight bit planes, plus HAM and HALFBRITE images.
Also supports SHAM (sliced HAM), Dynamic HAM, Dynamic Hi-res, and
PCHG (multi-palette) files. All versions of PCHG (12-bit and
24-bit, compressed and uncompressed) are supported.
This filter will detect a HAM-E image and handle it properly.
Both the HAM and REG modes of the HAM-E are supported.
18-bit and 24-bit IFF files are also supported. However, note that
in this release, any CLUT (Color Look-Up Table) chunks in the
file will be skipped. In order to use the information in the
CLUTs, you may load them as color response curves.
Targa
Reads Truevision Targa file types 1, 2, 9, and 10, with 16, 24, or
32 bits per pixel.
JPEG (Joint Photographic Experts Group)
Supports JFIF, the JPEG File Interchange Format.
JPEG files can use two kinds of compression: Huffman coding and
arithmetic coding. Because supporting arithmetic coding would
require licensing a patent from IBM, it is not supported.
(Probably for this reason, Huffman coded JPEG images are much more
common.)
BMP (Windows bitmap, aka "Wallpaper" files)
Reads uncompressed Windows Bitmap (.BMP) files with 1, 4, 8, or 24
bits per pixel.
RLE compressed 4- and 8-bit BMP files are not supported.
GL (GRASP)
This filter was contributed by John Bickers. It reads .PIC and
.CLP files (types C, J, L, and M) which can be extracted from
MS-DOS GRASP (.GL) files using his GLSplit program.
EXPORTERS SUPPORTED
HamLab Temporary File Format
Writes a simple, uncompressed 24-bit format.
Args:
none
24-bit IFF
Writes 24-bit IFF files.
Args:
none
EPS (Encapsulated PostScript)
Writes a single page Encapsulated PostScript file. The file may
be printed directly or imported into a publishing program that
supports EPS.
Can create either a gray scale or full color PostScript image.
Note: your printer must support the PostScript "colorimage"
operator in order to print HL+'s color postscript output.
Args:
BW gray scale output (default is color)
JPEG
Writes JFIF (Jpeg File Interchange Format) files.
The amount of compression done in a JPEG file varies depending
on how much loss of quality you're willing to put up with. The
JPEG exporter uses a quality setting of 1-100, where 100 is
the best quality (virtually lossless) and is the worst. In
general, any setting above 95 is not a good idea bacause the
resulting file may be large. Any setting below 10 is practically
unrecognizable, and some baseline JPEG readers may not be able
to read images with a quality of less than 25.
The default quality setting is 75. Whenever the filter is run,
it displays a requester allowing this to be changed. The
requester may be suppressed by supplying the argument below
when the exporter is run. (To do this, edit the HamLab.config
file or run the exporter from an AREXX command.)
Args:
QUALITY=<qual>
Sets the quality (and suppresses the requester normally
used for entering the quality manually.)
ACKNOWLEDGEMENTS
The GL (GRASP) filter was contributed by John Bickers.
PostScript is a registered trademark of Adobe Systems, Inc.
The Graphics Interchange Format(c) is the Copyright property of
CompuServe Incorporated. GIF(sm) is a Service Mark property of
CompuServe Incorporated.
Rayshade ray tracer by Craig E. Kolb.
MTV ray tracer by Mark Vanderwetting.
QRT ray tracer by Steve Koren.
DKBTrace ray tracer by David K. Buck.
PBMPLUS by Jef Poskanzer.
The JPEG functionality is based on work by the Independent JPEG
Group.