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Image Alchemy Version 1.4 March 18, 1991 User's Manual TM Image Alchemy was written by Marcos H. Woehrmann Allan N. Hessenflow David Kettmann Copyright (c) 1990-1991 by Handmade Software, Inc. All Rights Reserved 15951 Los Gatos Blvd., Suite 7 Los Gatos, CA 95032 +1 408 356-4143 (Fax) +1 408 358-1292 (Voice) UUCP: hsi@netcom.COM or: apple!netcom!hsi Cserve: 71330,3136 Shareware Fundamentals and Specifics We encourage you to freely copy and distribute the shareware version of Image Alchemy provided that: 1. No fee beyond normal media, duplication, and shipping costs may be charged. 2. Shareware vendors and computer user groups who charge less than $7.00 per disk may distribute Image Alchemy, but Handmade Software must be supplied with a copy of the first catalogue issue offering each new revision of Image Alchemy. 3. Others may only distribute Image Alchemy with the written permission of Handmade Software. In all cases, it must be clearly stated to the purchaser that he or she is receiving an unregistered copy of a shareware product 4. The distribution files must be distributed in their original forms. The unrestricted version may not be distributed. If you received Image Alchemy as shareware (i.e. you downloaded from a bulletin board, you received it from a friend, it came with some hardware you purchased, or you bought a disk from a software library), and if you use it beyond a two week trial period, you must register the program using the accompanying order form. For the $79.95 registration fee, you will receive the current, retail version of Image Alchemy without the 640 by 480 image size restriction. You will be notified of significant upgrades to Image Alchemy, you will be placed on a mailing list to receive information about future products from Handmade Software, and you will be entitled to phone and email support. Registered users are entitled to minor updates for a nominal fee (not to exceed $5.00 for disks or $20.00 for tapes). Registered users are also entitled to major updates at a substantially reduced price. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 2 What is Image Alchemy? Image Alchemy is a software utility that has two functions in life: First, Image Alchemy performs JPEG compression. This is a new standard for image compression that can achieve much higher compression ratios than conventional compression techniques. It achieves this high compression ratio by not entirely preserving the original image (this is referred to as "lossy" compression). For further information see the What is JPEG Compression section below. Image Alchemy is the first shareware program to perform JPEG compression and decompression. Second, Image Alchemy converts between various graphics file formats. Image Alchemy understands a wide variety of file formats including industry standards such as GIF and TIFF. Currently we support 15 different formats, and we are always adding new formats; in fact, our goal is to have Image Alchemy be able to read and write every type of graphic file in the world. Hardware Requirements IBM PC: At least an 80286 IBM PC AT or clone. At least 380k of free memory (Image Alchemy will run much faster if you have more than 400k of memory available). Some conversions and some images require more memory (Alchemy will attempt to use all available system memory, so if you get out of memory errors or warnings try removing as many TSRs as you can). A hard drive with at least as much free space as three times the size of the image being converting (i.e. a 640x480 image will require approximately 1 meg of free space). A VGA or 8514/A board, if you want to view images (tested VGA boards include those with the Paradise, Everex, Trident, Video 7, and the Tseng Labs Chipsets, tested 8514/A boards include IBM and those with the Western Digital Chipset) MS-DOS or PC-DOS 3.x or greater Sun: A SPARC or 680x0 equipped Sun (either a Sun 3, Sun 4, SPARCstation, or SPARCserver). SunOS 4.0.3 or greater Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 3 Introduction To install Image Alchemy copy the file alchemy.exe (for MS-DOS users) or alchemy (for Sun users) to your hard disk. There are no support files or configuration files which need to be copied. Image alchemy comes with a sample JPEG compressed image, sample.jpg. You might want to copy it to your hard drive to follow along with the examples below. To use Image Alchemy: alchemy -option [-option, ...] inputFileName [outputFileName] The inputFileName is any valid file name (including an optional path). The outputFileName is optional; if it is not specified Image Alchemy generates one by substituting an appropriate extension to the input file name. If the outputFileName does not include an extension one will be added (you may prevent this by appending a period "." to the outputFileName). Options are preceded by a dash ("-"). Those options which take a parameter may have it immediately following the option or separated by a space (for example, either -c128 or -c 128 is acceptable). The only option that is required is the output file format (or the viewing option, for IBM PC users). Image Alchemy will make reasonable decisions for all of the other options. The options are documented below. The order of the options is only significant in the case of the -z, -D, and -V options. The options can appear anywhere in the command line (certain options take parameters; in this case the parameters must follow the option). The case of the options is significant. Three options which are unique in their operation are -z, -D, and -V. These options all mean different things depending on how many times they are specified (for example, -D 150, has a different meaning then -D 150 -D 150). This isn't a problem in actual usage, but is something you should be aware of. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 4 Image Alchemy Options Information: -h Help. Display command summary. -? Display about information. Includes support, ordering, and version information. Output file options (details on each of the supported file formats can be found below in the Details on Supported File Formats section): -a compressionType Generate a tArga file. Optionally specify the compression type used to store the file. Compression types supported are: 0:Raw 1:RLE The default is RLE Compression. -e previewType Generate an Encapsulated PostScript file. Optionally specify the preview type. Preview types supported are: 0:None 1:Device Independent The default is Device Independent -g Generate a Gif file. -i Generate an Ilbm file (also known as an Iff file, also known as an LBM file). Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 5 -j[a] quality Generate a Jpeg file. Optionally specify the use of Arithmetic coding and the quality. If you specify an a immediately after the -j (as in - ja), Alchemy will generate a JPEG file compressed using Arithmetic encoding instead of the default Huffman encoding (see the JPEG section in the Supported File Formats section below for more information). Quality may vary between 1 and 100. The default is 32. The higher the number the higher the quality of the image and the lower the compression ratio. Quality factors below 10 will produce images with significant loss of quality. Since JPEG compression was designed for use with continuous tone images (such as produced by a scanner or digitizer), poor results can be expected when compressing line drawings. Alchemy will not compress files which have less than 32 colours in them unless you explicitly override this by using the -O option. -k Generate a PBM/PGM/PPM file. -l Generate a paLette file. -m Generate a Macintosh pict file. -n Generate an SilicoN Graphics Image file -p Generate a Pcx file. -P Generate a PCL file. -r Generate a Raw file. -s Generate a Sun raster file. -t compressionType Generate a Tiff file. Optionally specify the TIFF compression type used to store the file. Compression types supported are: 0:None 1:LZW 2:PackBits 3:Group III Fax 4:Group IV Fax 9:PICIO 10:SGI RLE The default is LZW Compression. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 6 -w compressionType Generate a Windows BMP file. Optionally specify the BMP compression type used to store the file. Compression types supported are: 0:None 1:RLE The default is None. Palette Options: -24 Specify that the output file should be 24 bit (true colour). This is the default for JPEG files (which must be 24 bit) and is not allowed for GIF and PCX files (which must be paletted). The other file formats, which may be either 24 or 8 bit, default to 24 bit if the input file is 24 bit (certain file formats may only be 8 bits if the images are grey scale, in that case Alchemy will automatically switch to true colour for output). -8 Specify that the output file should be paletted (up to 8 bits). This is the default for GIF and PCX files and is not allowed for JPEG files. The actual number of bits is determined by the -c option (below). If the input file is true colour the output file will be quantized and dithered (see the -c and -d options below). -b Specify that the output file should be grayscale. If the input is paletted or a -8 is specified, -c can be used to specify the number of gray levels. -c colours Specify the number of colours for the output file. Only applicable for paletted files (see -8, above). The number of colours may be between 2 and 256. If the input file has a larger number of colours than specified for the output file, the image will be quantized using Heckbert's median cut algorithm and dithered (see -d, below). Converting an image with a large number of colours to a small number of colours (less than 8) may give poor results. For further information on Heckbert's median cut algorithm see the Colour and Dithering section below. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 7 -d ditherType Specifies the type of dithering, if any, to apply to the image. DitherType can be: 0:None 1:Floyd-Steinberg 2:Stucki 3:Jarvis, Judice, & Ninke The default is Floyd-Steinberg. Floyd-Steinberg is the fastest (except for no dithering) and usually produces the best results. Stucki and Jarvis, Judice, & Ninke both tend to cause an image to appear more grainy on low resolution output devices (such as CRTs). However they produce better results than Floyd-Steinberg on high-resolution low colour devices such as laser printers. This option only has an effect if the number of colours is being reduced or the image is being remapped to a new palette. Dithering is used to reduce colour banding in an image caused by the palette not having a perfect match for every colour in the image. However, dithering does take time and can cause the image to look grainy, so it can be disabled. For further information on dithering see the Colour and Dithering section below. -E Convert image for best possible quality viewing using an EGA board and monitor. This option reduces the palette resolution to 2 bits and automatically specifies the following: -8 -c16 -z0 -z1 -z0. The -c16 option can be overridden by using an explicit -cn option (but n has to less than 16). -f filename Match the output to a palette read from a file. The input image will be remapped to use the palette found in the specified filename. This can be useful if you are combining several images into a collage or want to match an image to a pre-existing palette. The resulting image will be dithered (unless you specify no dithering by using the -d option). -F filename False colour an image using the palette from a file. The input image will be changed to use the palette found in the specified filename but no attempt at picking the best match will be done. This feature can be used to add false colour to monochrome images. The output file is not dithered. Only applicable to paletted input files. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 8 -u Use a Uniform Palette. Instead of using the Heckbert median cut algorithm to generate a palette for the image use a palette with entries which are evenly distributed in the RGB colour cube (actually the cube is distorted because the human eye is not equally sensitive to red, green, and blue). The advantage of using a uniform palette is that it's fast because a custom palette need not be generated. However, this is at the expense of image quality since the palette isn't generated based on image content. When just viewing a true colour image on a paletted display a uniform palette is used. The -c option can be used in conjunction with -u to specify the size of the uniform palette; in that case Image Alchemy will generate a palette with not more than the specified number of colours (but not less than 8). The palette size will not necessarily match the specified size, as the actual size must be the product of three integers, and Alchemy will attempt to pick integers that roughly correspond to the sensitivity of the human eye to red, green, and blue (30%, 59%, and 11%). -z sortType (first usage) Sort the image palette. This option only has an effect if the palette is being generated by Image Alchemy using Heckbert's median cut algorithm. SortType can be: 0:None 1:popularity 2:luminance (white to black) 3:rgb 4:luminance (black to white) The default is None. See below for an example of the -z option. -z selectionType (second usage) If you specify a Palette sort parameter you may also specify a palette selection parameter. SelectionType can be: 0:mean 1:median 2:corner The default is mean. See the Colour and Dithering section below for an explanation of these choices. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 9 -z swapType (third usage) If you specify both a Palette sort parameter and a Palette selection parameter you may also specify a palette swap parameter. SwapType can be: 0:None 1:IBM (colour 0 is black, 7 is white) 2:Macintosh (colour 0 is white, 255 is black) 3:Sun (colour 0 is white, 1 is black) The default is based on the file type being written out (IBM for Gif, Macintosh for Mac PICT, Sun for Sun Raster, and None for all others). Example: for the -z option(s): -z4 -z0 -z3 :sort colours by luminance, use the mean of the Heckbert box for the colour, and move the colours around so that the lightest colour is colour 0 and the darkest colour is colour 1. Note that it is not possible to specify a swapType without first specifying both a sortType and a selectionType. See the Colour and Dithering section below for more information. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 10 Misc Options: -D aspectRatio Specify aspect ratio for the output image. The aspect ratio of an image is the ratio of the width of a single pixel to the height of a single pixel. This option lets you specify this ratio when writing a file or displaying an image (the only file types which support aspect ratio are JPEG, TIFF, Raw, Mac PICT, ILBM, and Targa; specifying this option when writing out other files will have no effect). Ordinarily aspect ratio is specified as two numbers separated by a colon, for example 1:1 or 1:1.2. However to simplify the user interface Alchemy expects a single number which is the percentage of the width of a pixel to its height (so to specify 1:1.2 use -D 83, since 100/1.2 is 83). Example: if you are converting a 640x350 IBM EGA PCX image (which has an aspect ratio of 35:48) to a TIFF image you can say -D 73 (73 is 100/48*35) and the TIFF image will have the correct aspect ratio and an intelligent TIFF reader will make use of the information. Alchemy attempts to preserve aspect ratio whenever possible, but since so few file formats have aspect ratio information this hardly ever happens. This option can also be used when displaying an image on an IBM PC. See the Display options section below for more information. -D dotsPerInchX -D dotsPerInchY Specify image resolution in dots per inch. You must specify both dotsPerInchX and dotsPerInchY, even if they are the same. This option is ignored when writing a file format which does not have image resolution (the only have formats which include image resolution are JPEG, Raw, TIFF, and Mac PICT). Reasonable values to use for dotsPerInch include: 72 (the resolution of a 13 inch monitor display 640x480) and 300 (the resolution of a laser printer). Alchemy will preserve this information when converting files whenever possible. Note that it is not possible to specify both an aspect ratio and a dots per inch value for an image. This is because specifying a dots per inch value automatically implies an aspect ratio. And in fact there are no file formats which support independent aspect ratio and dots per inch values. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 11 -o Overwrite output file if it exists. Image Alchemy will not overwrite an existing file unless the -o option is specified. -O Override JPEG compression warning. See the -j option above for information. -q Apply Smoothing when decompressing a JPEG image. Because JPEG compression works on 8x8 pixel blocks there tend to be discontinuities at the edges of these blocks producing block artifacts. Smoothing attempts to reduce these artifacts. Smoothing is really only necessary at very low quality settings (Q less than 10); even then the effects are not particularly significant. -x Display image statistics. Displays image type, size, number of colours, aspect ratio, and compression ratio. Can not be combined with other options. -X pixels Change the horizontal dimension of the image to the specified number of pixels. Currently Alchemy does simple pixel replication or elimination. Future versions will allow more complex types of scaling in both dimensions. -Y pixels Change the vertical dimension of the image to the specified number of pixels. Currently Alchemy does simple pixel replication or elimination. Future versions will allow more complex type of scaling. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 12 Display options (IBM PC only): In addition to the file conversion options listed above Image Alchemy can display images on a VGA or 8514/A equipped IBM PC. The current version of Image Alchemy supports 320x200x256, 640x400x256, and 640x480x256 display modes for VGA and 640x480x256, 1024x768x256, and 1280x1024x256 display modes for 8514/A (the exact resolutions supported depend on the model board installed). Because of various incompatibilities between different VGA boards 640x400x256 and/or 640x480x256 mode is not supported on all boards and has not been tested on all boards that are supported. The 320x200x256 mode is a standard VGA IBM mode and should work on all VGA boards. VGA boards which have been tested for the the higher resolution modes include Paradise, Tseng Labs 3000 & 4000, Video 7, Trident, and Everex chipset based VGA Boards. Support for others is included but has not been tested and may be accessed through the -vv option (see below). Image Alchemy requires AI to be installed to use 8514/A displays which aren't based on the Western Digital chipset (Alchemy should also be able to display on AI compatible boards which are not 8514/A (such as 340x0 based boards), but this has not been tested). For Western Digital based 8514/A boards, no driver is required. Alchemy checks for a display board in the following order: Western Digital 8514/A, AI based 8514/A, extended VGA, standard VGA. Alchemy automatically uses the lowest resolution mode which will display the entire picture. The image will be centered in the display (for images which are larger than the display Alchemy will center the display in the picture). -v horizontalResolution View file using high resolution mode (640x400x256 or 640x480x256 for VGA, up to 1280x1024x256 for 8514/A). If displaying on a Western Digital chipset 8514/A an optional parameter may follow the -v command. This parameter specifies horizontal resolution and may be either 640, 1024, or 1280. The default is to use the lowest resolution which can fit the entire image. If the image is true colour, a uniform palette will be used and the image will be dithered (dithering may be disabled by use of the -d option, see above). See the Colour and Dithering section below. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 13 -vv Force view. If Image Alchemy can identify the VGA board you have installed and has support for it, but has not been tested with it, you will be given the option of rerunning the program with the -vv option instead of the -v option. This will force viewing of the file. Please contact Handmade Software if you use this option and viewing works correctly on your VGA board so that we can add it to the list of tested boards. -V View using 320x200x256 mode. This is a standard VGA mode which works on all VGA boards (including those built-in to PS/2 computers). This command is most useful combined with the -V option below. -V Scale image to fit on monitor and correct aspect ratio. After specifying the view type, -v, -vv, or -V, you may also specify that the image should be scaled to fit on the display by using a second -V option (which means you end up typing -v -V, -vv -V, or -V -V). This command will scale the image and correct the aspect ratio of the image by removing rows and/or columns from the image. Note that this option can also be useful for displaying images which are not larger than the screen but which have an aspect ratio different than the display. Also note that Alchemy assumes that the aspect ratio of a display pixel is 1:1 when in 640x480 mode and 1:1.2 when in 640x400 mode or 320x200 mode. Furthermore Alchemy assumes that the aspect ratio of pixels in 640x400 and 320x200 images is 1:1.2 and the aspect ratio of pixels in 640x350 images is 35:48. You can override any of these assumptions with the -D option (for a further discussion of aspect ratio see the -D command, above). Don't worry if this is confusing; in practice Alchemy deals with everything automatically if you use the second -V option (there is however a problem with display 320x400 IFF and HAM files, see the Answers to Frequently Asked Questions section below for more information). Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 14 Examples To convert the JPEG file sample.jpg to a Targa file called sample.tga use the following command: alchemy -a sample.jpg To convert the 24 bit Targa file sample.tga to a 256 colour Gif file called new.gif: alchemy -g sample.tga new.gif To convert the 256 colour Gif file, new.gif, to a 64 colour PCX file called new.pcx: alchemy -p -c64 new.gif To view the Gif file new.gif (only applicable on IBM PCs with appropriate VGA board): alchemy -v new.gif To convert sample.jpg to a black and white, two colour GIF file use a text editor to create a file called BW.PAL which contains the following: PAL 2 0 0 0 255 255 255 then: alchemy -g sample.jpg -f bw.pal (Or, you could have said alchemy -g sample.jpg -b -c2, but that wouldn't have demonstrated the -f option). To view the resulting file in 320x200x256 mode, scaling the image to fit the display: alchemy -V -V sample.gif Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 15 Details on Supported File Formats Image Alchemy currently has support for the image file formats listed below. Where we know of restrictions or limitations they are listed. If you have trouble reading in and image in one of the file formats we claim to support please contact us (see What if Image Alchemy Messes Up, below). Image Alchemy identifies the type of file being read by checking various magic numbers and other information that varies from format to format. It is possible for Image Alchemy to incorrectly identify a file; if this happens please contact us. .BMP Windows BitMaP Microsoft Corporation Reads and writes 1, 4, 8, and 24 bit files. Reads and writes RGB (raw), RLE4, and RLE8 files. Since no Windows 3.0 software we have (including the Windows 3.0 supplied utilities) can read nor write RLE4 or RLE8 files, writing RLE compressed files is not recommended because that option has not been tested (Alchemy can read RLE files that it wrote, but that isn't a very significant test). .EPI Encapsulated PostScript .EPSI Adobe Systems Incorporated Output only. Writes Encapsulated Postscript files. If the output file is grayscale, it will work with any PostScript device (grayscale output can be forced with the -b and -8 options). If it's truecolour, then the CMYK extensions or a level 2 device is required. For paletted files, a level 2 device is always required. Colour files can be forced to produce EPS files requiring only the CMYK extensions by using the -24 option. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 16 .JPG Handmade Software JPEG Files Handmade Software, Inc. Joint Photographic Experts Group (JPEG) JPEG-8-R8 draft standard. Reads and writes baseline JPEG with YCbCr CCIR-601 colour space, interleaved components, Huffman or Arithmetic encoded. Image Alchemy can read files with any component subsampling up to 4x4; it always writes 2h:1v 1h:1v 1h:1v. For grayscale images, it uses a single component. Image Alchemy can only recognize grayscale files if the input is either paletted or 8 bit grayscale. Image Alchemy Huffman encoded JPEG files comply with the industry standard `JFIF' interchange format. Grayscale images that have been JPEG compressed will decompress as paletted images (with a 256 level grayscale as a palette); others will be 24 bit. JPEG files can be Huffman or Arithmetic encoded. Arithmetic encoding has the advantage of making the file approximately 20% smaller, but has the disadvantage of taking approximately 10% longer to compress and decompress and the resulting file will no longer be JFIF standard. .IFF Interchange File Format/InterLeaved Bit Map .LBM Commodore-Amiga Corp. Reads 1 through 8 bit, 24 bit, and Ham images; writes 1 through 8 bit and 24 bit images. If you're writing an Ilbm file for use on an Amiga, you probably want to write either a paletted file with 32 colours or a 24 bit file. 24 bit Ilbm files can then be converted to one of the Amiga specific display modes with various third-party utilities. .GIF Graphics Interchange Format CompuServe, Incorporated. Reads and writes 1 bit through 8 bit GIF87A files, reads 1 through 8 bit GIF89A files (discarding all but the first image). Reads both non-interleaved and interleaved files; writes non-interleaved files. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 17 .PAL HSI Palette Files Handmade Software, Inc. Contain only Palette Information. Useful in conjunction with the -f option (see above). PAL files are ASCII files which can be edited with a text editor. The PAL file format: the first line contains the letters "PAL", the next line contains an integer indicating the number of palette entries, the rest of the file consists of lines of 3 numbers each (separated by spaces), representing the red, green, and blue values for each of the colours (the numbers vary between 0 and 255; 0 0 0 is black, 255 255 255 is white, 255 0 0 is bright red, etc.). See the Examples section above for a sample PAL file. Converting a .PAL file to another image format is allowed but doesn't make much sense (since there won't be any image data). .PCL HP Printer Command Language Hewlett-Packard Company Reads and writes 1 bit files (PCL files must be 1 bit, black and white; if you attempt to write out any other file type Alchemy will automatically switch to that mode). Only pays attention to raster images in the file; attempts to skip everything else. Due to the enormous number of options allowed in PCL files this option has not been thoroughly tested. See the Answers to Frequently Asked Questions section below for more information. .PCX PC Paintbrush ZSoft Corp. Reads and writes 1, 4, and 8 bit images. PCX format files are often written out incorrectly; Alchemy attempts to figure out what is wrong and make intelligent decisions (things Alchemy can deal with include PCX files without palettes, files missing the last line of image data, and files with illegal (and incorrect) combinations of bits per pixel and planes). Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 18 .PICT Macintosh PICT format .PIC Apple Computer, Inc. Reads 1, 2, 4, 8, 16, and 32 bit images; writes 1, 2, 4, 8, and 32 bit images. Only pays attention to pixMaps in the pict; attempts to skip everything else. Due to the enormous number of options allowed in PICT files this option has not been thoroughly tested. See the Answers to Frequently Asked Questions section below for more information. .PBM Portable BitMap .PGM Portable GrayMap .PPM Portable PixelMap .PNM Portable aNyMap Jef Poskanzer's Portable BitMap Package Reads and writes 1, 8 (grayscale only), and 24 bit RAWBITS (binary) images. For more information on the Portable BitMap Package see the References section below. .RAST Sun Raster Files .RAS Sun Microsystems, Inc. Reads 1, 8, 24, and 32 bit images. Writes 1, 8, and 32 bit images. Supports Standard, BGR, RGB, and Byte Encoded (RLE) files. .RAW HSI Raw Files Handmade Software Inc. Reads and writes 8 and 24 bit images. Used internally by Image Alchemy when converting between certain combinations of other formats. Can also be explicitly read and written. If you are interested in adding HSI Raw support to your software please contact us for more information. .SGI Silicon Graphics Image Files Silicon Graphics, Inc. Reads and writes 1, 8 (grayscale only), and 24 bit files. Reads Verbatim (uncompressed) and RLE files. Write uncompressed files. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 19 .TGA Targa Files Truevision Corp. Reads 8, 15, 16, 24, and 32 bit images, ignoring the alpha channel for 32 bit images; writes 8 and 24 bit images. 8 bit output files are paletted unless the palette is all gray, in which case the output is a grayscale file. .TIFF Tagged Image File Format Files .TIF Microsoft Corp. and Aldus Corp. Reads 1, 4, 8, 24, and 32 bit images (ignoring the alpha channel for 32 bit images); writes 1, 4, 8, and 24 bit images. Can read TIFF class B, G, R, and some P (those with 1, 4, or 8 bits per pixel) files. Writes class B, G, P, and R files, depending on the input file and options specified. 1,4, and 8 bit output files are paletted unless the palette is all gray, in which case the output is a grayscale file. Output compression types supported are raw, LZW, PackBits, Group III fax, Group IV fax, PICIO, and SGI RLE. Input compression types supported are raw, LZW, PackBits, Group III fax, Group IV fax, CCITT RLE (both byte and word aligned), NeXT, Thunderscan, PICIO, and SGI RLE. General Notes: Image Alchemy automatically recognizes and reads MacBinary files (MacBinary files are generated when you accidently leave MacBinary mode on when transferring a file from a Macintosh). Gamma, aspect ratio, and resolution values are preserved whenever possible. Colour correction tables are currently ignored. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 20 Colour and Dithering Colour images are normally stored in one of two ways: as an array of direct colour values (usually red, green, and blue) (referred to as a truecolour file in this document) or as an array of indices into a colourmap which contains red, green, and blue colour values (referred to as a paletted file in this document). The only reason for the existence of paletted images is that they take less memory, so the hardware to display them is cheaper. The dominance of paletted hardware is changing as the price of memory and the processing power it takes to update large amounts of memory at a reasonable speed drops (a Targa 32 board is an example of a truecolour board, a VGA board is an example of a paletted board). However, until truecolour graphics devices become the norm, there's a need to convert images from truecolour to paletted. This conversion is done in two steps: the first is to generate a palette for use by the image; the second is to map the image to the new palette. Image Alchemy supports two methods of generating a palette. The simplest and fastest method is to use a palette containing colours which are uniformly distributed in the RGB cube, referred to as a uniform palette. This has the advantage that it's fast and the same palette can be used for any image; the primary disadvantage is that most images don't contain colours from everywhere in the RGB cube, so this palette wastes entries representing colours that aren't needed for the particular image being converted. Image Alchemy also supports Heckbert's median cut algorithm. This algorithm first builds a three dimensional histogram indicating how popular any given colour in the RGB cube is in the image being converted. It then proceeds to subdivide this histogram cube (by dividing boxes in half) until it has created as many boxes as there are palette entries. The decision as to where to divide a box is based on the distribution of colours within the box. This algorithm attempts to create boxes which have approximately equal popularity in the image. Palette entries are then assigned to represent each box. There are other methods of generating a palette from an image, but Heckbert's algorithm is generally regarded as the best tradeoff between speed and quality. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 21 You can change the method used to select a colour for each box by use of the -z options. The default method is to use the mean of all the colours in the box (this gives the mathematically correct result). However for some images slightly better results can be obtained by using the center of the box (without regard to where the pixels are in the box). For images with a very small number of different colours (less than 16) better results can be obtained by using a corner of the box (the boxes tend to be large when reducing an image to a small number of colours; picking a colour near the center of the box will give you muddy colours, by using the corner of the box you get more saturated colours). The next step is to map the image to the new palette; this is where dithering becomes important. The simplest approach is to map every colour in the original image to the palette entry which is closest to it (which Image Alchemy does if you specify no dithering). However, since the palette entries generally represent several different colours in the original image, this results in colour banding (where areas of smooth colour changes in the original become areas of one solid colour in the paletted version). This can be alleviated by dithering (or modulating) the image data such that any given pixel may not be mapped to it's closest palette entry, but the average over some area of the image will be closer to the correct colour than it would otherwise be. Image Alchemy uses a class of algorithms called "error-diffusion" to do dithering. These algorithms work by using the closest palette entry to a colour and then distributing the error (the difference between the desired colour and the chosen palette entry) to the pixels below and to the right of the current pixel. This process is repeated for every pixel in the image, using the colour values which have been modified due to the error from previous pixels. For more information on Heckbert median cut and dithering see the appropriate reference listed in the References section below. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 22 What is JPEG Compression? J.P.E.G. stands for the "Joint Photographic Experts Group". This is a group of experts who defined a standard compression scheme for still images, commonly called JPEG Compression. Currently the standard is still in draft form. The standard will hopefully be finalized in 1991. JPEG Compression consists of a series of reasonably complex mathematical operations. These include colour space conversion, Discrete Cosine Transform, quantization, and Huffman or Arithmetic encoding. After these steps you end up with an image which takes fewer bits to store than you started out with. However, when you decompress a JPEG compressed image you end up with an image that is not quite the same as the original image (which is why JPEG Compression is referred to as "lossy"). You might well ask why anyone would want to compress an image using a lossy technique? It turns out that lossy compression ratios are much better than lossless compression ratios and the loss is generally very small. And, in fact, every operation of converting an image is lossy (the original photographic or electronic process which captured the image was lossy, scanning or digitizing the image was lossy, displaying the image on a monitor is lossy, and printing the image is lossy). JPEG compression typically involves the following steps: 1. The image is converted to a colourspace with separate luminance and chrominance (Image Alchemy uses CCIR-601 YCbCr). This is done because the luminance information (Y) is far more important to the human eye than the chrominance information (Cb and Cr); by separating them it's possible to compress the chrominance information more than the luminance information. This step is not specified in the JPEG draft (it doesn't discuss colourspace at all), but is standard practice. 2. The luminance and chrominance information are seperately transformed to the frequency domain using a discrete cosine transform acting on 8x8 pixel blocks (the chrominance information may be subsampled first). 3. The transformed data is quantized (which simply means some information is thrown away). The samples representing higher frequencies are generally quantized more than those representing low frequencies. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 23 4. This quantized data is then compressed using an entropy encoder (Huffman and Arithmetic coding are allowed by the draft JPEG standard; only Huffman is allowed by the JFIF standard). This data then corresponds the JPEG Interchange Format and is ready to be stored in a file. However the JPEG Interchange Format does not include enough information to actually be able to convert the file back to an image. Specifically the colourspace used and the aspect ratio or the resolution of the image are not included. Until recently there was no standard way of putting this information in a JPEG file. On March 1, 1991 representatives of several JPEG hardware and software developers (including C-Cube, Radius, NeXT, Storm Tech., the PD JPEG group, Sun, and Handmade Software) got together at C-Cube and established the JPEG File Interchange Format (JFIF). If you would like more information on the JFIF standard please contact us. If you are interested in getting a copy of the the current draft JPEG standard contact: X3 Secretariat Computer and Business Equipment Manufacturers Institute 311 First Street NW, Suite 500 Washington, DC 20001-2178 The last time we talked with them the charge was $8.00, including shipping. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 24 Answers to Freqently Asked Questions Q: When I convert a gray-scale Gif file to a JPEG file and then back to a Gif file the final Gif file is twice the size of the original. Why is this? A: The input Gif file was probably a 16 or 32 colour gray scale file. When you converted it to a JPEG file the number of colours in the file was lost (JPEG gray scale files are always 256 colour). When the JPEG file was converted back to a Gif file Alchemy assumed you wanted 256 colours in the file. And a 256 colour Gif file is bigger than a 16 colour Gif file (because of the way Gif compression works). To prevent this you can use a -c32 option in the command line; this forces Image Alchemy to use that many colours for the output file. Q: Why can't PHIPS read the Targa file I wrote with Image Alchemy? A: Some software which reads Targa files can not handle compressed files. By using -a0 instead of just -a, Image Alchemy will write out an uncompressed Targa file. In addition, some software can read true colour Targa files, but can not read paletted or gray scale files. Image Alchemy can be forced to write out a true colour file by using the -24 option. Q: Why is decompressing or compressing a JPEG image so slow? A: There are a large number of calculations that have to be done during JPEG compression. This is an inherent limitation of JPEG compression. Image Alchemy has been optimized quite a bit to reduce the number of calculations, and we are working to further reduce the number of calculations. If you are transferring files over modems or storing them on slow media (tape) the compression times are usually more than made up for by the decrease in transmission or retrieval times. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 25 Q: Why can't my favorite desktop publishing package read the TIFF file I wrote with Image Alchemy? A: TIFF is an extremely versatile standard; it can handle anything from 1 bit images to full colour images with an alpha channel and TIFF allows many different types of compression. Unfortunately this versatility means that it's difficult for a single piece of software to be able to read in every valid TIFF file. If the software specifies the classes of TIFF it can read, you can force Alchemy to write out a specific TIFF class by using the following options: class B: -8 -b -c2 -t2 (preferred if input is bilevel) class G: -8 -b -t1 (preferred if input is grayscale) class P: -8 -t1 (preferred if input is paletted) class R: -24 -t1 (preferred if input is true colour) If the supported classes are not specified experiment with various combinations of -24, -8, -b, and -cn. In this case it is usually best to use no compression (-t0) while experimenting with the other options, as many TIFF readers have difficulty with compressed files. When you find a set of options that works, then you can try various compression modes to save space. Be aware that using -b will force the output file to be gray scale and you will lose all the colour information in the file (most DTP programs only have support for gray scale TIFF files). You may also have to use the -Dn -Dn option to specify the resolution of the image (this is especially true when converting from a file format which does not have a value for image resolution). You can generally tell if this is necessary because the program you are using to read in the TIFF file will claim that the file is unreasonably large or small. Generally, if you are using a 300 DPI Laser Printer you want to make the TIFF file 300DPIx300DPI (-D 300 -D 300). If you would like further information specific to using Image Alchemy with your word processor or desktop publishing program please contact us; we will be maintaining a list of how to make Alchemy work with other software packages. Similarly if you figure out how to import files into a specific package let us know and we will add your tips to our documentation. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 26 Q: When I convert a 32 bit Targa file to a PCX file and then to a JPEG file it doesn't look nearly as good as if I convert the Targa File directly to the JPEG file. What can I do to maintain high quality in JPEG compressed files? A: When the Targa file was converted to the PCX file Image Alchemy had to reduce the number of colours in the file (the original Targa File had up to 16 Million Colours, PCX files are limited to 256 colours). This step is known as colour quantization (Image Alchemy uses the Heckbert Median Cut method for quantization, see the Colour and Dithering section above). The difficulty with colour quantization is that it leaves artifacts known as colour banding. To reduce this phenomenon Image Alchemy dithers the image (you can see the effect of colour banding by turning off dithering by using the -d option). Unfortunately a dithered image does not JPEG compress very well (dithering adds a lot of high- frequency information to an image; JPEG compression attempts to remove much of that information). In addition JPEG images are always continuous colour images, so when the JPEG file is decompressed it has to be colour quantized and dithered again. Dithering a previously dithered image reduces the quality even more. The solution is to use the best starting quality you can for JPEG compression, ideally a continuous tone image. The compressed image size will be smaller than if you had started with a paletted image and the quality will be better. Q: When I view a JPEG compressed image on my VGA board the quality isn't nearly as good as when I first convert it to a Gif file and then view it. Why is this? A: To save time Alchemy automatically uses a uniform palette when you are just viewing the image. When converting to a different file format Alchemy does Heckbert quantization to generate a palette. The difference in image quality is the difference between using a uniform palette and an optimum palette. See the Colour and Dithering section above for more information on palette generation. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 27 Q: I've converted a Mac PICT file to a Gif file, but the Gif file is missing some or all of the information that was in the PICT file. What happened to it? A: PICT files are a combination of drawing commands (such as lines, rectangles, and circles) and raster areas (called pixMaps). Alchemy can only read the raster portion of the files. Programs such as MacDraw and MacDraft write out files with drawing commands, programs such as MacPaint write out files which are entirely raster areas (pixMaps), and some programs, such as SuperPaint can write out files which are either or a combination of both. If you are using such a program check the documentation on how to write out files in "paint" mode. Q: I've converted an HP PCL file to a Gif file, but the Gif file is missing some or all of the information that was in the PCL file. What happened to it? A: PCL files have the same problem as PICT files (see above); they are a combination of drawing commands (such as lines and rectangles) and raster areas (called rasters) and Alchemy can only convert the raster areas in PCL files. In addition they contain a lot of font and text information, which is also lost. Unfortunately there isn't any general way to preserve this data. One way which works under Microsoft Windows 3.0 is to install Adobe Type Manager (ATM). ATM automatically intercepts any text commands and converts them to rasters. And in fact, the standard Windows 3.0 HP PCL driver only generates rasters. So the file will appear in its entirety when converted by Alchemy. Contact us if you want further information on using Alchemy with Windows 3.0. Q: I keep getting "Out of Memory trying to ..." messages. Help! A: Image Alchemy is running of of memory. First attempt to maximize the amount of memory available by removing as may TSRs as you can. If this doesn't help please contact us with the following information: your computer configuration (amount of available memory, size of hard disk), operating system version, and what you are trying to do (input file information (size of image and type of file) and options specified). Alchemy can generally convert images as large as 2000 pixels across and an infinite number of pixels down. However there are certain conversions which require more memory than others. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 28 Q: Why can't Image Alchemy read in JPEG files produced by Kodak's ColorSqueeze (or Sun's VFCtool)? A: The JPEG standard is still in draft form. Until it is a mature standard various manufacturer's will implement different versions of it. As of March 1, 1991 Image Alchemy currently supports the JFIF format and should work with any other JPEG software which also claims JFIF compatibility. If other software you are using claims to support the JFIF format and you are having trouble please contact us. If the other software does not support JFIF contact the manufacturer and tell them they should send you an update which supports JFIF (you can tell them to contact us if they need a copy of the JFIF standard). Q: I told Alchemy to convert a PCX file to an 8 bit Gif file (using the -8 option). Yet when I get statistics on the file (using -x) Alchemy reports the file has 16 colours? A: Alchemy will always store the file using the smallest bits- per-pixels allowable for the given image (this results in the smallest possible file). In this case the input file only had 16 colours in it. Things can get more unpredictable with formats such as Sun Raster (which require 1 bit files to be black and white) and SGI (which requires 8 bit files to be grayscale). In these cases Alchemy will always do the best it can (giving you a warning message if it does something which may surprise you later). Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 29 Q: I converted a PCX file with 16 colours to a 16 shade gray TIFF file using the -b and -p options. The 16 colour PCX file had some shades of gray in it which were changed in the TIFF file. How can I prevent this? A: The short answer is: you can't. The long answer is: there is a work around. The problem is that gray-scale TIFF files have a uniformly spaced gray palette (this is required as part of the TIFF standard). So if you create a 16 shade gray TIFF file it will have the following shades of gray in it: 0, 17, 34, 51, 68, 85, ..., 255. However the 16 colour PCX file you started with probably didn't have those exact colours in it (for example, PCX files written out by Windows 3.0 Paint have shades of gray which correspond to 0, 128, 192, and 255). So Alchemy did the best it could and matched the input colours to the output colours. The solution is to tell Alchemy to write out a 256 colour gray scale TIFF file (which you do by adding a -c256 to the -b and -t options). This file still has a uniform gray palette; but that palette now contains every colour: 1, 2, 3, 4, ..., 255. So Alchemy can map the colours 128 and 192 to their exact match. This does have the disadvantage of making the resulting 256 colour TIFF file twice as large as the 16 colour TIFF file; but this is the only way to guarantee that Alchemy can find an exact match for all the shades of gray in the input file. Q: Why do you only allow specifying image resolution in Dots Per Inch? Don't you realize that most of the world is metric? A: Yes, we do realize that the entire world, with the exception of the United States and Great Britain, claims to use the metric system exclusively (and Great Britain will presumably change in 1992). However this isn't true. A laser printer manufactured in Japan is still 300 dots per inch (not 11.811... dots per mm) and a 19 inch monitor sold in Europe is called a 19 inch monitor (actually a 19 inch monitor is called a 20 inch monitor in Europe, they measure the total picture tube diagonal, not just the viewing area). And this even applies to non high-tech things: the wheels on my German car are 16 inches in diameter (though the tires I buy for it are 225 mm wide, even in the United States). Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 30 Q: I am using Alchemy to display a 320x400 IFF image created by an Amiga. When I use just the -v option the image comes out tall and skinny. When I use the -v -V option, which is supposed to correct the aspect ratio, instead of things getting better they get worse (the image is even skinnier). What's going on? A: As near as we can tell Amiga software has a different idea of what aspect ratio is than the rest of the world. For displays aspect ratio is defined as the ratio of the width of a single pixel to the height of a single pixel. So if you have square pixels (which you do on a standard monitor in 640x480 mode) the aspect ratio is 1 to 1 (usually written as 1:1). When you change display modes you are generally not changing the height and width of the total display area; what is changing is the width and height of each pixel, so the aspect ratio changes. For example, a 640x400 display has an aspect ratio of 1:1.2 (that means each pixel is 1.2 times as tall as it is wide (which makes sense since 480/400 equals 1.2)). A 640x200 display (remember IBM CGA graphics mode?) has an aspect ratio of 1:2.4 (which is a pretty extreme aspect ratio). Now this is where it gets interesting. The aspect ratio number stored in Amiga IFF files for 320x400 images is 1:1.1, which means the pixels are 1.1 times as tall as they are wide, so therefore the actual image should be the equivalent of a 320x440 image with square pixels. And this is what Alchemy will attempt to display when you use the second -V (actually Alchemy never makes any dimension larger, so the actual image Alchemy displays is 291x400, which is the same ratio as 320x440). However this is obviously wrong, as you can tell when you actually look at an image. As near as we can tell the actual aspect ratio of these images is 5:3 (the math we used to come up with this number is 640/320:480/400). And in fact if you tell Alchemy to override the aspect ratio by using a -D 167 option (167 because 5/3*100 is 166.6666) the image displays correctly. Why Amigas create images which claim they are 1:1.1 remains a mystery. Q: Do you give multiple copy discounts? Do you have site licenses? Are you interested in licensing the source code? A: Yes. Yes. Yes. Contact us for more information. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 31 Version History v1.4 03/18/91 Released for Sun SPARC, Sun 3, and IBM PC. Format changes: Added Arithmetic coding and decoding for JPEG compression. Added 1 bit PCX file support. Added new compression types to Targa. Added PBM/PGM/PPM support. Added GIF89A support for reading. Added SGI support. Added Windows BMP support. Added writing Group III, Group IV, PICIO, and SGI RLE Tiff compression types. Added Encapsulated PostScript output. Added HP PCL support. Display option changes: Added support for Video 7, Trident, Tseng 4000, IBM 8514/A display boards. Added 320x200x256 display mode. Added image scaling during display (which allows display of the entire image on the screen and preserves aspect ratio). Center images on screen during displaying. During display the screen is now cleared to the darkest colour. Misc changes: Added image scaling Added conversion to monochrome images. Preserve and allow specification of aspect ratio or dots per inch. Added false colour palette conversion. Added optimized EGA image generation support. Added support for very large images. Added palette sorting, paletted swapping, and palette selection parameters. Added Stucki and Jarvis, Judice, & Ninke Dithering. Fixed Bugs: Writing certain 1 bit Sun Raster files Reading incorrectly written PCX files Reading 24 bit RLE compressed Sun Raster files Reading incorrectly written ILBM files. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 32 v1.3 02/05/91 Released for Sun SPARC and IBM PC. Added checking for supported VGA boards, warning if board is recognized but not supported. Fixed bug with reading and writing 8 bit Sun Raster files which have an odd width. Temporary files are now removed when program exits because of an error. Added support for reading Sun Run-Length-Encoded (RLE) files. Added reading support for interleaved GIF files. Added 8 bit RAW files. Added optional smoothing on JPEG reading. Added support for any colour component subsampling on JPEG reading. Targa files are now written bottom-up to make other Targa software happy. Added palette matching and PAL files. Made memory use more efficient (requiring less virtual memory on Suns and less overlay swapping on PCs). Numerous miscellaneous performance improvements, (dramatic for some conversions; hardly noticeable for others). v1.2 01/16/91 First release for Sun SPARC systems. Fixed several minor bugs (primarily aesthetic). Made PCX file identifying and reading more robust. v1.1 01/14/91 First release for MS-DOS. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 33 Coming Attractions A better user's manual (yeah!). A Macintosh Version (the Mac version is working except for the GUI (graphical user interface]. Support for GUI (Windows 3.0 for the IBM and OpenLook 2.0 for Suns). Optimum Huffman table generation for JPEG writing. Support for TIFF files containing JPEG compressed data. Faster JPEG File reading and writing. Emphasizing flesh tones during palette generation (for both Uniform palettes and Heckbert generated palettes). Gamma, Brightness, and Contrast Adjustment. Wildcards for input filenames. Display of images on Targa boards on IBM PCs. Use of Expanded and/or Extended memory on IBM PCs for faster operation. Display of large images with scrolling (especially on PCs). Image Resizing (scaling and/or cropping). Binary versions for other machines (we have written what we consider very transportable code (the same source code compiles on IBM PCs, Macs, and Suns), the biggest limitation on generating new binaries is access to machines, if you can provide help in this regard please contact us). New file formats, including: Utah RLE QDV MTV BPX Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 34 What if Image Alchemy Messes Up? We have made every effort to insure that Image Alchemy can read all files in its supported formats. However, because of poorly written standards and non-adherence to standards there are undoubtedly certain files that Image Alchemy does not read correctly. If you come across any files which Image Alchemy has trouble with please contact us with as much of the following information as you have: version of Image Alchemy you are using, type of file, type of computer which generated it, name and version of software which wrote the file, size of image, and the number of colours in image. We may ask you to send us the file so that we can figure out what went wrong. If you send us a file we will attempt to modify Image Alchemy so that it can read the file. And if by some miracle we manage to get it to work, we will send you an updated copy of Image Alchemy. Similarly, if any files that Image Alchemy writes can not be read by other software we want to know that also. Since we do not own a copy of every software package we may ask you to send us a copy of a file that can be read by that package; we will then compare that to a file written out by Image Alchemy to determine what the problem is. By the way, contact us even if you are not a registered user. We figure the best way to get you to register is to be nice to you. Trademarks Image Alchemy is a trademark of Handmade Software, Inc. All other products or services mentioned, including: IBM PC AT, VGA, 8514/A, Paradise, Everex, Trident, Video 7, Tseng Labs, Wester Digital, MS-DOS, PC-DOS, SPARC, Sun, SPARCstation, SPARCserver, SunOS, Targa, PostScript, EPS, Encapsulated PostScript, Gif, ILBM, IFF, Macintosh, Silicon Graphics, SGI, PCX, TIFF, Windows, Windows BitMaP, EGA, PCL, HP, AI, PS/2, HAM, PC Paintbrush, MacBinary, PHIPS, ColorSqueeze, VFCtool, Amiga, CServe, and CompuServe, are trademarks, registered trademarks, or service marks of their respective companies or organizations. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 35 Disclaimer Handmade Software, Inc. makes no warranty of any kind, either expressed or implied, including but not limited to implied warranties of merchantability and fitness for a particular purpose. In no event shall Handmade Software, Inc. be liable for any errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of the Image Alchemy product or documentation. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 36 Credits Sam Leffler Image Alchemy's TIFF I/O is based on libtiff which is Copyright by Sam Leffler and is used with his permission. Libtiff is available by anonymous ftp as ucbvax.berkeley.edu:pub/tiff/*.tar.Z or uunet.uu.net:graphics/tiff.tar.Z. John Bridges Image Alchemy's VGA display routines are based on VGAKIT, originally written by John Bridges. Marc Schneider Who provided assistance with the Sun implementation of Image Alchemy including Beta testing and answering questions about the internal format of Sun Raster files. Jack Waterman Who proofread the manual more times than anyone should have to read anything (any remaining misteaks are because we made changes after he read it for the final time). References Floyd-Steinberg Dithering Floyd-Steinberg, Stucki, and JJN dithering are described in "Digital Halftoning", by Robert Ulichnet, MIT Press. Heckbert Colour Quantization Originally described in "Color Image Quantization for Frame Buffer Display", SIGGRAPH '82 Proceedings, p. 297. Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 37 The following people have written image file conversion software similar to Image Alchemy. Each of their packages is available via anonymous ftp. These programs are only available as source code and generally require UNIX or one of its variants. Michael Mauldin - Fuzzy Pixmap Manipulation (FBM) Available by anonymous ftp as nl.cs.cmu.edu:/usr/mlm/ftp/fbm.tar.Z, uunet.uu.net:pub/fbm.tar.Z, and ucsd.edu:graphics/fbm.tar.Z. Jef Poskanzer - Portable BitMap (PBMPLUS) Available by anonymous ftp as expo.lcs.mit.edu:contrib/pbmplus.tar.Z and ftp.ee.lbl.gov:pbmplus.tar.Z. Jef also maintains the "Frequently Asked Questions" list in comp.graphics, which is a great source of information on graphics. Paul Raveling - Img Software Set Available by anonymous ftp as expo.lcs.mit.edu:contrib/img_1.3.tar.Z and venera.isi.edu:pub/img_1.3.tar.Z Image Alchemy v1.4 Copyright (c) 1990-91 Handmade Software Inc. Page 38 Image Alchemy 1.4 Order Form Qty Description Price Total _____ Image Alchemy for IBM PC AT on 3.5" Disk $79.95 __________ _____ Image Alchemy for IBM PC AT on 5.25" Disk $79.95 __________ _____ Image Alchemy for Sun 4 on 3.5" Disk $79.95 __________ _____ Image Alchemy for Sun 4 on 1/4" Tape $99.95 __________ _____ Image Alchemy for Sun 3 on 1/4" Tape $99.95 __________ Sub-Total: __________ California Residents add applicable sales tax: __________ Shipping and handling ($4 UPS Ground, $8 UPS Second Day): __________ per copy ($15 FedEx, $7 International AirMail) Total: __________ Circle Payment form: Check MC Visa Amex Card #:______________________________________ Exp. Date: ____________ Signature: _____________________________________________________ You must include the address your credit card bill is sent to as the billing address for MC/Visa/Amex orders. Ship to: Bill to: Name: ______________________________ Name: ________________________________ Company: ___________________________ Company: _____________________________ Address: ___________________________ Address: _____________________________ City: ______________________________ City: ________________________________ State: _________ Zip: __________ State: _________ Zip: ____________ Phone: (______) __________________ Fax: (______) ____________________ Mail: Handmade Software, Inc. 15951 Los Gatos Blvd., Suite 7 Los Gatos, CA 95032 Call: +1 408 358 1292 Fax: +1 408 356 4143 email: hsi@netcom.COM email: 71330,3136 (CompuServe)