HLFILTS2.LZH 30 Nov 1991 (c) Copyright 1991 J. Edward Hanway Permission is hereby granted to redistribute this archive, provided that the distribution is complete and unmodified. These programs come with no warranty. I disclaim any responsibility for any damages that they may cause, direct or coincidental. ABOUT THIS ARCHIVE This archive adds support for three new file types to the HamLab image conversion utility. jpeg2hl This filter reads "JPEG Interchange Format (JFIF)" files. JPEG files can be 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.) Note that JPEG requires extensive calculations to decompress a picture. Don't panic if your Amiga doesn't seem to be doing anything at first. bmp2hl Reads uncompressed Windows Bitmap (.BMP) files with 1, 4, 8, or 24 bits per pixel. RLE compressed 4- and 8-bit files are not supported. special2hl This filter is a trick program that can be used to convert from any format supported by the PBMPLUS toolkit directly to HAMLAB. It requires AmigaDOS 2.0. ** This filter is sort of a hack. It requires you to obtain the ** PBMPLUS toolkit (available from many sources such as BBS's) and ** set things up with the correct names and assignments. In order ** to get things set up successfully, you should be familiar with both ** HAMLAB and PBMPLUS, as well as the Amiga CLI. ** ** Because this is very dependent on other programs and installation ** details, I can't guarantee it will work in all situations. ** It may also have problems handling errors gracefully. ** For file formats supported by regular HAMLAB filters, this filter ** should not be used. Requirements: * AmigaDOS 2.0x only * The PBMPLUS toolkit. You should install the PBMPLUS programs in a separate directory, then use the Assign command to assign the name "PBMPLUS:" to that directory. * The "special2hl" program must be placed in the HAMLAB filters directory (the one specified in the hamlab.config file). However, it should be named "XXX-2hl" Replace XXX with the same abbreviation that is used for the PBMPLUS program that you with to run. For example, if you want to use the PBMPLUS program named "giftoppm" name the copy of special2hl "gif-2hl" Note the dash before the 2. It must be there. * Use a text editor to add an entry into your hamlab.config file. It should use the "XXX-2hl" name you chose in the last step. The way this works is the "special2hl" program looks at the new name you gave it. It takes the part before the dash, and uses it to find the correct PBMPLUS program to run. If it is named "XXX-2hl" it will try to look for the following programs, in order: PBMPLUS:XXXtopnm PBMPLUS:XXXtoppm PBMPLUS:XXXtopgm PBMPLUS:XXXtopbm Example for GIF files: **EXAMPLE ONLY -- YOU DON'T ** **NEED TO DO THIS FOR GIF ** 1. Assign PBMPLUS: to the directory where you put the PBMPLUS programs. 2. In your HAMLAB filters directory, make a copy of the "special2hl" program. Name it "gif-2hl". 3. Add the following line to your hamlab.config file: Format "GIF" "gif-2hl" 4. That's it. When the filter is run, it should look for the program "giftoppm" in the PBMPLUS: directory. If the PBMPLUS program displays any messages a console window will open to display them. Click the close gadget on the console window to dismiss it. ABOUT HAMLAB HamLab is an interactive program which converts images from various file formats to Amiga HAM and SHAM mode pictures. The pictures can be displayed (and panned on a "virtual screen" if necessary) and saved in IFF format. Translation filters are provided for GIF, TIFF, IFF ILBM, Targa, Atari ST Spectrum 512, MTV, QRT/DKBTrace, PBMPLUS, Sun Raster, and now JPEG and .BMP files. New filters can be added simply by adding a line to a configuration file. HamLab uses 24-bit RGB for nearly all intermediate calculations. It has fast scaling, cropping, and color response controls, and includes six dithering options which significantly improve the quality of some images. Runs under either AmigaDOS 2.0 or 1.3 + ARP. For use in tight memory situations, the PIPE: device (included with AmigaDOS) is recommended. For the best response time, it helps to have a lot of memory and/or a hard disk, but HamLab has configurable options which make it usable on small systems, too. It is possible to convert, but not display at the same time, most 640x480 images on a 1 MEG system at full size, or to scale them to 320x400 and display them, too. (All without using disk files for temporary storage.) *** IMPORTANT NOTE *** The freely-distributable version of HamLab is a demo version. Unlike some demos, I wanted it to be worth your time and expense. The only "crippled" feature is that images larger than 512 pixels wide or tall will be cut off. Otherwise, all features including save are fully implemented. Look for the HamLab demo wherever you got this archive. For a disk with the complete version of HamLab, the latest set of input filters, and example filter source code, send $20.00 U.S. (plus postage for international orders) to: J. Edward Hanway 149 Arborwood Crescent Rochester, NY 14615-3849 SUPPORT BBS A HamLab support BBS is now running: Chromaticity BBS - (716) 647 6396 - 24hrs 1200-14400 Dual Std HST/V.32bis The BBS maintains the latest version of all filters, and is open to all callers. In addition, registered users get access to the restricted support conference where they can download updates to HamLab.