From bryanw@rahul.net Fri Dec 2 21:45:28 1994 Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!concert!inxs.ncren.net!taco.cc.ncsu.edu!lll-winken.llnl.gov!uwm.edu!math.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!hookup!olivea!barrnet.net!rahul.net!a2i!bryanw.a2i!bryanw From: Bryan Woodworth Newsgroups: alt.graphics.pixutils Subject: Graphics Info avail via WWW! Date: 30 Nov 1994 13:13:08 GMT Organization: a2i network Lines: 134 Message-ID: <3bhtp4$dtn@hustle.rahul.net> NNTP-Posting-Host: jive.rahul.net NNTP-Posting-User: bryanw Summary: WWW archive Keywords: www graphics archive [Lastmod: 23.11.94 22:05:44] !!=new info The WWW Graphics Page is now online via the World Wide Web! URL: http://www.rahul.net/bryanw/index.html [Even if you don't have a graphical front-end, you can still access the information. Plain ASCII output (via the program LYNX) is available for those users using dial-up accounts (e.g. Netcom, a2i, Portal, CRL, and many more). You may already have lynx installed online! Enter "lynx" at the shell prompt. If it doesn't exist, just ftp the source and compile it yourself. See .signature at bottom of message for details on obtaining the FAQ via ftp.rahul.net.] !! Are you a Microsoft Windows user who doesn't have SLIP or a SLIP !! emulator (e.g. tia), and wants to see WWW graphics? Have no fear! !! SLIPKNOT is here! ftp to oak.oakland.edu:/pub/win3/internet and get !! slnot*! This great program gives you WWW graphics without need !! for slip or slip emulation! TRY IT TODAY.. Information of the following variety awaits you: o The FAQ desk -- Graphics information * Tom Lane's JPEG faq -- Obtaining viewers and understanding the JPEG image format * A link to the NCSA Mosaic FTP site, for those looking for Mosaic, the famous WWW graphical browser * Jim Howard's alt.binaries.pictures FAQ -- Info on how to decode pictures, posting, and much more * MPEG information: Links to Frank Gadegast's MPEG faq and MPEG homepage; The WWW Graphics Page's very own MPEG faq; The MPEG Standards Homepage (info on MPEG standards, site for MPEG movies, and more); and an MPEG movie archive * A link to the massive Usenet FAQ pages at Ohio State, an outstanding resource * A link to Thomas Boutell's fantastic WWW faq! In living WWW format! (Also availble via FTP from the WWW Graphics Page as a ZIPped Ascii file) Info on WWW browsers for all platforms (even Unix dial-up), writing HTML documents, and more! A M U S T R E A D F O R E V E R Y O N E -- Internet Service FAQ pages * The Internet Services FAQ * FSP (alternative to FTP) FAQ * Internet Gopher FAQ -- Miscellaneous FAQs (selection subject to change) * Howard Stern * Unix X-Windows on Intel Architecture * The MS-DOS Archives * Playboy Enterprises (required reading!) * The alt.supermodels FAQ! Read on for juicy info on your favourite supermodels.. o Computer Support Areas -- Where to obtain programs of a graphical nature for your architecture * Macintosh -- MPEG players, contact sheet makers, dl/gl/fli viewers, etc. * IBM PC -- MPEG players, JPEG viewers, a link to the Xing Technology FTP site, and official QPEG support site for North America (including the latest version of QPEG, along with a link to Oliver Fromme's homepage in Germany) NOW DIVIDED INTO COGENT areas: JPEG/GIF viewers, MPEG viewers, contact sheet makers, AVI viewers, and probably a few other juicy tidbits. * Unix/X-Window -- MPEG source, movies; information on XAnim, a wonderful graphics !! program by Mark Podlipec; pbmplus/netpbm/icontact !! pointers * The QuickTime Support Link. A pointer to Robert A. Lentz's exquisite QuickTime information page, with info on flattening quicktimes and programs and utils for Macintosh, X Window, and Microsoft Windows. A MUST see!! !! * The Archie Support Link. Now! Easy point-and-click !! interface for Archie queries. (Your client must !! support telnet; Lynx has it built-in; information !! on how to get your client to support telnet is ! provided online.) Try it now! o The Tennis Center -- Information on my favorite game, tennis. (I realize this is tangential, but.. so what!) * The rec.sport.tennis FAQ * The Tennis Homepage (In Canada, with links to another tennis homepage) * Want to play tennis? Email! o Favorite Links -- Other sites you should try, and IMMEDIATELY! * Michel Buffa's Video Games Page (3DO, Atari Jaguar, SNES, Sega, Gameboy, etc..) * The UnOfficial Nine Inch Nails Homepage * Jeff's Atari Jaguar Homepage * The Beastie Boys Homepage * The Llama Mailserver (MPEG resource and more!) * The alt.sex.movies Homepage * The Rolling Stones Homepage * The CDnow! homepage -- ordering CDs via WWW * The Playboy Enterprises, Inc. homepage -- now you can explore Playboy's catalog via WWW! The material is presented in a refreshing format, just for YOU! If you have any problems, questions, suggestions for additions, etc, please do not hesitate to send me email. This free service is intended to help YOU find what you NEED and DESERVE! The WWW Graphics Page.. your online WWW resource for Graphics Utilities! Try it today! URL: http://www.rahul.net/bryanw/index.html -- Bryan Woodworth (bryanw@rahul.net) Try The WWW Graphics Page today! URL: http://www.rahul.net/bryanw/index.html Need a WWW browser? FTP to ftp.rahul.net:/pub/bryanw/wwwfaq.zip Info on WWW browsers for all platforms -- even Unix dial-up! From jon@stekt.oulu.fi Fri Dec 2 21:46:16 1994 Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!portal.gmu.edu!europa.eng.gtefsd.com!howland.reston.ans.net!pipex!sunic!news.funet.fi!ousrvr.oulu.fi!news.oulu.fi!jon From: jon@stekt.oulu.fi (Jouni Miettunen) Newsgroups: alt.graphics.pixutils Subject: Re: formats for major file types Date: 01 Dec 1994 00:42:36 GMT Organization: University of Oulu, Department of Electrical Engineering, Finland Lines: 34 Distribution: world Message-ID: References: <3b3t30$3n2@portal.gmu.edu> <3b6aou$qek@grover.jpl.nasa.gov> Reply-To: jon@stekt.oulu.fi NNTP-Posting-Host: stekt9.oulu.fi Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit In-reply-to: tgl@netcom.com's message of Sat, 26 Nov 1994 06:15:03 GMT On Sat, 26 Nov 1994 06:15:03 GMT, tgl@netcom.com (Tom Lane) said: >> You can get most of those by ftp at >> x2ftp.oulu.fi:/pub/msdos/programming/formats >> Of course, it is in Finland... isn't there a mirror for this site in the > I always assumed that that .fi site was a mirror of one of the two > US file-format archives mentioned in the comp.graphics FAQ. No, we don't mirror anyone. Naturally at the beginning most files were >from the two US sites, but since then more formats have been added as they are found in other (small) sites, posted in news or uploaded to incoming dir(s). We don't have only graphics, but all kind of file formats. > On the other hand, if they think it is a subtopic of "msdos", > then maybe not... Hurm.. If you really think _that's_ peculiar, you might be in for a real suprice: we have under "msdos" also unix and Macintosh code, book reviews, files about US copyright law, master's thesis about AI etc. etc. Btw I maintain the site, comments welcome ;) > regards, tom lane > organizer, Independent JPEG Group --jouni -- * Jouni Miettunen jon@stekt.oulu.fi * Oulu * Finland * Europe * ** I do not represent Oulu university * all opinions mine only ** ** x2ftp.oulu.fi * THE pc game graphics sound PROGRAMMING site ** From jef@netcom.com Fri Dec 2 21:46:49 1994 Newsgroups: alt.graphics.pixutils,alt.answers Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!portal.gmu.edu!europa.eng.gtefsd.com!howland.reston.ans.net!ix.netcom.com!netcom.com!jef From: jef@netcom.com (Jef Poskanzer) Subject: (30oct94) Welcome to alt.graphics.pixutils - automated posting. Message-ID: Followup-To: poster Reply-To: Jef Poskanzer Organization: Paratheo-Anametamystikhood of Eris Esoteric Date: Thu, 1 Dec 1994 09:01:20 GMT Approved: jef@netcom.com Expires: Thu, 5 Jan 1995 09:01:20 GMT Lines: 176 Xref: solitaire.cv.nrao.edu alt.graphics.pixutils:7483 alt.answers:5874 Archive-name: pixutils-faq This message is automatically posted once a month to inform new readers and remind old readers of what alt.graphics.pixutils is about. It was last changed on 30oct94. If you don't want to see this posting every month, please add the subject line to your kill file. Thank you. --- Jef Jef Poskanzer jef@netcom.com jef@well.sf.ca.us "...Is this a trick question?" - - - - - - - - - - This newsgroup is for discussion of pixmap utilities. A pixmap is any image composed of pixels, whether it's a one-bit-deep bitmap, a grayscale image, colormapped, or full color. There are dozens of different file formats for storing pixmaps, and there are a number of software packages for converting between formats and displaying formats. Some of these packages are listed in the Frequently Asked Questions posting in comp.graphics - the relevant excerpts are appended below. Discussion of these packages and other similar ones will probably be the main topic here. Posting uuencoded sample pixmaps for some weird format you're trying to decipher is fine, especially if they are small, but mass posting of pixmaps is not welcome. - - - - - - - - - - [from the comp.graphics weekly posting] 7) Free image manipulation software. There are a number of toolkits for converting from one image format to another, doing simple image manipulations such as size scaling, plus the above-mentioned 24 -> 8, color -> gray, gray -> b&w conversions. Here are pointers to some of them: PBMPLUS, by Jef Poskanzer. Comprehensive format conversion and image manipulation package. The latest version is always available via anonymous FTP as ftp.netcom.com:pub/jef/pbmplus*.tar.Z, ftp.ee.lbl.gov:pbmplus*.tar.Z, and wuarchive.wustl.edu:graphics/graphics/packages/pbmplus/pbmplus*.tar.Z. IM Raster Toolkit, by Alan Paeth (awpaeth@watcgl.uwaterloo.ca). Provides a portable and efficient format and related toolkit. The format is versatile in supporting pixels of arbitrary channels, components, and bit precisions while allowing compression and machine byte-order independence. The kit contains more than 50 tools with extensive support of image manipulation, digital halftoning and format conversion. Previously distributed on tape c/o the University of Waterloo, an FTP version will appear someday. Utah RLE Toolkit. Conversion and manipulation package, similar to PBMPLUS. Available via FTP as cs.utah.edu:pub/urt-*, weedeater.math.yale.edu:pub/urt-*, and freebie.engin.umich.edu:pub/urt-*. Fuzzy Pixmap Manipulation, by Michael Mauldin . Conversion and manipulation package, similar to PBMPLUS. Version 1.0 available via FTP as nl.cs.cmu.edu:/usr/mlm/ftp/fbm.tar.Z, ftp.uu.net:pub/fbm.tar.Z, and ucsd.edu:graphics/fbm.tar.Z. Img Software Set, by Paul Raveling . Reads and writes its own image format, displays on an X11 screen, and does some image manipulations. Version 1.3 is available via FTP as venera.isi.edu:pub/img_1.3.tar.Z along with a large collection of color images. Xim, The X Image Manipulator, by Philip Thompson, does essential interactive displaying, editing, filtering, converting images. Available in the X11R4 source tree. A more recent version is available via ftp from gis.mit.edu. Requires X11R4 and the OSF/Motif1.1 toolkit for the interface. This is not a paint package. Xim reads/writes gif, xwd, xbm, tiff, rle, xim, (writes level 2 eps) and other formats. Also has a library and command line utilities for building your owm applications. xloadimage, by Jim Frost . Reads in images in various formats and displays them on an X11 screen. Available in your nearest comp.sources.x archive. TIFF Software, by Sam Leffler . Nice portable library for reading and writing TIFF files, plus a few tools for manipulating them and reading other formats. Available via FTP as ucbvax.berkeley.edu:pub/tiff/*.tar.Z or ftp.uu.net:graphics/tiff.tar.Z xtiff, an X11 tool for viewing a TIFF file. It was written to handle as many different kinds of TIFF files as possible while remaining simple, portable and efficient. xtiff illustrates some common problems with building pixmaps and using different visual classes. It is distributed as part of Sam Leffler's libtiff package and it is also available on ftp.uu.net and comp.sources.x. xtiff 2.0 was announced in 4/91; it includes Xlib and Xt versions. ALV, a Sun-specific image toolkit. Version 2.0.6 posted to comp.sources.sun on 11dec89. Also available via email to alv-users-request@cs.bris.ac.uk. popi, an image manipulation language. Version 2.1 posted to comp.sources.misc on 12dec89. ImageMagick, an X11 package for display and interactive manipulation of images. Includes tools for image conversion, annotation, compositing, animation, and creating montages. ImageMagick can read and write many of the more popular image formats. Available via FTP as ftp.x.org:contrib/applications/ImageMagick/ImageMagick-3.?.tar.gz Khoros, a huge (~100 meg) graphical development environment based on X11R4. Khoros components include a visual programming language, code generators for extending the visual language and adding new application packages to the system, an interactive user interface editor, an interactive image display package, an extensive library of image and signal processing routines, and 2D/3D plotting packages. Available via FTP as ftp.khoros.unm.edu:pub/khoros1.0.5 or pub/khoros2/0 LaboImage, a SunView-based image processing and analysis package. It includes more than 200 image manipulation, processing and measurement routines, on-line help, plus tools such as an image editor, a color table editor and several biomedical utilities. Available via anonymous FTP as ftp.ads.com:pub/VISION-LIST-ARCHIVE/SHAREWARE/LaboImage_4.0.tar.Z The San Diego Supercomputer Center Image Tools, software tools for reading, writing, and manipulating raster images. Binaries for some machines available via anonymous FTP in sdsc.edu:sdscpub. The Independent JPEG Group has written a package for reading and writing JPEG files. FTP to ftp.uu.net:graphics/jpeg/jpegsrc.v?.tar.Z Don't forget to set binary mode when you FTP tar files. For you MILNET folks who still don't have name servers, the IP addresses are: ftp.ads.com 128.229.36.25 cs.utah.edu 128.110.4.21 ftp.x.org 198.112.44.100 freebie.engin.umich.edu 141.212.68.23 ftp.ee.lbl.gov 128.3.112.20 ftp.uu.net 192.48.96.9 gis.mit.edu 18.80.1.118 nl.cs.cmu.edu 128.2.222.56 ftp.eece.unm.edu 129.24.24.119 sdsc.edu 132.249.20.22 ucbvax.berkeley.edu 128.32.133.1 venera.isi.edu 128.9.0.32 weedeater.math.yale.edu 130.132.23.17 wuarchive.wustl.edu 128.252.135.4 Please do *not* post or mail messages saying "I can't FTP, could someone mail this to me?" There are a number of automated mail servers that will send you things like this in response to a message. See item 13 below for details on some. 8) Format documents for GIF, TIFF, IFF, BIFF, WHIFF, etc. You almost certainly don't need these. Read the above item 7 on free image manipulation software. Get one or more of these packages and look through them. Chances are excellent that the image converter you were going to write is already there. But if you still want one of the format documents, many such files are available by anonymous ftp from zamenhof.cs.rice.edu (128.42.1.75) in directory pub/graphics.formats. These files were collected off the net and are believed to be correct. This archive includes pixel formats, and two- and three-dimensional object formats. Other file format descriptions are welcome, send to Mark Hall . 13) How to FTP by email. There are a number of sites that archive the Usenet sources newsgroups and make them available via an email query system. You send a message to an automated server saying something like "send comp.sources.unix/fbm", and a few hours or days later you get the file in the mail. In addition, there used to be some FTP-by-mail servers, which would accept FTP commands by mail and then mail back the results. Unfortunately, the services were abused, and have been shut down. From cerious@mercury.interpath.net Fri Dec 16 11:00:18 1994 Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!caen!spool.mu.edu!howland.reston.ans.net!news.sprintlink.net!redstone.interpath.net!mercury!cerious From: cerious@mercury.interpath.net (Phillip A Crews -- Cerious Software) Newsgroups: alt.graphics.pixutils Subject: Re: Conversion Photo CD (.pcd) to GIF/JPEG? Date: 15 Dec 1994 17:44:26 GMT Organization: Vnet Internet Access, Inc. - Charlotte, NC. (704) 374-0779 Lines: 26 Message-ID: <3cpv9q$f1p@redstone.interpath.net> References: <3cmkn2$qeu@news.xs4all.nl> NNTP-Posting-Host: mercury.interpath.net X-Newsreader: TIN [version 1.2 PL2] Bram Buitendijk (worf@xs1.xs4all.nl) wrote: : Hello, : I am looking for a program that will convert my digital photos from : .pcd format to gif or jpeg. I should be able to choose which format : (wallet/snapshot/.../poster), and the compression rate for jpeg. : Any pointers to programs of this kind (for dos/windows) are greatly : appreciated. : (I currently export to .bmp, which I can then convert to gif/jpg, : but I want to convert in batch with no manual labor) ThumbsPlus will convert directly from PCD to GIF or JPEG, either a single file at a time, or multiple files in batch. See below for anonymous ftp location! -- \_\_\_ _/_/_/_/_/_/_/_/_/_/_/_/_/_/ =D--- [ Product Plug ] =D--- \_ \_ Phillip Crews / \_ / Try Thumbs+Plus, the best graphic \_ Cerious Voice: (704)529-0200 / file browser for Windows 3.1. \_ Software Internet: cerious@vnet.net / JPEG GIF BMP PCX TGA CDR WMF WPG \_ Compuserve: 71501,2470 / TIFF CGM GEM PSD IFF EPS RAS PCD + \_ \_ America Online: CeriousSW / vnet.net:/pub/cerious/thmpls.exe \_\_\_ --------------------------- Current version: 2.0c From Thorsten_Lemke@pe2.maus.de Sun Dec 18 08:02:38 1994 Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!caen!math.ohio-state.edu!howland.reston.ans.net!Germany.EU.net!nntp.gmd.de!news.rwth-aachen.de!newsserver.rrzn.uni-hannover.de!rz.uni-hildesheim.de!baghira.han.de!h.maus.de!pe2.maus.de!Thorsten_Lemke From: Thorsten_Lemke@pe2.maus.de (Thorsten Lemke) Newsgroups: alt.graphics.pixutils Subject: Re: WMF to GIF converter? Message-ID: <199412141840.a28570@pe2.maus.de> Date: Wed, 14 Dec 94 16:40:00 GMT References: <3bopin$r8f@lll-winken.llnl.gov> Lines: 9 X-Gate: MausGate/News 1.25/h MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Hi! BS> Can anyone tell me where to find software to convert an image stored BS> as a Windows Meta-file (.wmf) to a GIF file (.gif)? A solution that BS> runs on either a Sun or a Mac will be appreciated. You can use my GraphicConverter (for Mac) for this job. The latest version is 2.0.6. Thorsten From Thorsten_Lemke@pe2.maus.de Sun Dec 18 08:02:51 1994 Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!portal.gmu.edu!europa.eng.gtefsd.com!howland.reston.ans.net!Germany.EU.net!nntp.gmd.de!news.rwth-aachen.de!newsserver.rrzn.uni-hannover.de!rz.uni-hildesheim.de!baghira.han.de!h.maus.de!pe2.maus.de!Thorsten_Lemke From: Thorsten_Lemke@pe2.maus.de (Thorsten Lemke) Newsgroups: alt.graphics.pixutils Subject: Re: pict to gif Message-ID: <199412141840.a28571@pe2.maus.de> Date: Wed, 14 Dec 94 16:40:00 GMT References: <3bu9ho$n4p@newsserv.cs.sunysb.edu> Lines: 10 X-Gate: MausGate/News 1.25/h MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Hi! PD> HI, I am looking for a public program that can convert PD> a PICT file, produced from Mac Photoshop and a color scanner, PD> to a gif or jpeg file for UNIX ( sun ) or MS windows. You can use my shareware program GraphicConverter (for the MAC) for this job. The latest version is 2.0.6. Thorsten From blee@media.mit.edu Fri Dec 23 11:11:28 1994 Newsgroups: comp.infosystems.www.users,comp.infosystems.providers,alt.graphics.pixutils,comp.graphics Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!caen!hookup!news.kei.com!bloom-beacon.mit.edu!news.media.mit.edu!news.media.mit.edu.!blee From: blee@media.mit.edu (Brian Patrick Lee) Subject: Answers: Interlacing, Transparency, & Inline Images FAQ Message-ID: Followup-To: poster Sender: news@news.media.mit.edu (USENET News System) Organization: M.I.T. Media Laboratory Distribution: comp,alt Date: Thu, 22 Dec 1994 03:22:32 GMT Lines: 795 Xref: solitaire.cv.nrao.edu comp.infosystems.www.users:11721 alt.graphics.pixutils:7615 comp.graphics:46925 INLINE IMAGES FREQUENTLY ASKED QUESTIONS Version 0.9.1b, updated 20 December, 1994. Maintained by Brian Patrick Lee (blee@media-lab.mit.edu) This FAQ is not currently available online, but should be shortly. This document addresses issues pertaining to inline images as suppord by WWW browsers, including interlacing, transparency, and color mapping problems with true-color and 8-bit graphic systems. Contents * 1. Introduction + 1.1General + 1.2 Inline Images vs. External Viewers * 2. Color Mapping + 2.1 True Color + 2.2 Indexed Color * 3. GIFs + 3.1 Transparency + 3.2 Interlacing * 4. JPEGs * 5. XBMs * 6. WWW Browsers + 6.1 XMosaic + 6.2 MacMosaic + 6.3 Netscape + 6.4 Other Browsers With Inline Images + 6.5 Imageless Browsers + 6.6 Downloading Inline Images * 7. Image Manipulation Tools + 7.1 Photoshop + 7.2 DeBabilizer + 7.3 Freely Distributable Tools o 7.3.1 DOS and Windows o 7.3.2 Macintosh o 7.3.3 OS/2 o 7.3.4 Unix and XWindows o 7.3.5 Other * 8. Inline Image Tips and Tricks * 9. About This Document * 10. Feedback and Help Requested * 11. Credits + 11.1 Citing This Document + 11.2 Copyright Notice 1. Introduction 1.1 GENERAL INTRODUCTION A WWW browser running on a computer with a true-color display could hypothetically display any number of GIFs as inline images with no problems. However, many computers are equipped with 8-bit graphics hardware, which can show severe color mapping problems with multiple inlined images, and many browsers limit and distort inline image palettes, even with true-color displays. The information here is based on problems encountered while developing a WWW server on a Personal DECstation 5000/25 with 8-bit graphics, running Ultrix v4.2 and OSF/Motif v1.2. The WWW browsers used were XMosaic v2.1 on the DECstation and MacMosaic v1.0.3 on an variety of Macs, including an LCIII and a IIvx with 8-bit color graphics. GIFs were manipulated with Adobe Photoshop 2.5 (commercial software) for the Macintosh. All of the examples below are based on the above configurations. Additional contributions were submitted by the people listed in the credits. (Back to Contents) 1.2 INLINE IMAGES VS. EXTERNAL VIEWERS Most WWW browsers will display GIFs and XBMs as inlined images, and will launch external viewers to display JPEGs and other formats. With 8-bit graphics, a maximum of 256 colors can be displayed per window; less if the window doesn't have it's own custom palette. On a true color system, all images could potentially be displayed inline without problems, but many systems don't have true color graphics. With external images, the viewer has the responsibility of rendering the image, and many can be set to use a custom palette and dither true color images. For inline images, however, the browser must do the palette mapping, and browsers vary widely in their ability to display multiple images on page. Browsers also vary widely in their ability to dither images well, even with only one image on a page. This document can help you create pages with images that will look good on most systems. Hopefully, all browsers will support beautiful, fast dithering and image rendering for 8-bit graphics one day, so this document will become obsolete. Even inline JPEGs must be dithered by a client, so JPEGs are not the final answer, unless browsers do as good a job as external viewers do. (Back to Contents) 2. Color Mapping 2.1 TRUE COLOR True color images are stored in a 24-bit RGB format where each pixel in a file can be any one of approximately 16.7 million colors. For example, a 3 x 3 pixel image with the colors red, green, and blue could be represented as: Colors P R G B R G B R G B i 1 255-000-000 000-255-000 000-000-255 x 2 000-255-000 000-000-255 255-000-000 e 3 255-000-000 000-255-000 000-255-000 l (True Color) Each pixel can have a value of 0 to 256 for each of the three colors, so 256 * 256 * 256 = 1577216 possible colors. Each color, therefore, has it's own RGB values as it is stored. (Back to Contents) 2.2 INDEXED COLOR Many systems have 8-bit displays, which are capable of displaying only 256 colors simultaneously. In order to better represent images on these systems, indexed color was developed. With an indexed color table (palette), you still have a palette of 16.7 million colors to choose from, but you can only use up to 256 colors at once (most indexed palettes use 8-bit color or less). Each image has a palette, which represents the colors in the image. The same 3 x 3 image above would look like this as an indexed color image: Indexed Palette C Image o Row I R G B l n 1 255-000-000 l 1 2 3 d 2 000-255-000 u 2 3 1 e 3 000-000-255 m 1 2 2 x n 8-bit graphic display systems use an indexed color table that can hold a maximum of 256 colors. The colors are allocated on a first come, first serve basis for each image, until 256 colors are used up. Any additional graphics displayed on the screen (inlined images, applications windows, etc.) can only use colors that are already allocated, unless a new color table is used. For example, if you have a window with 4 border colors, and an image with 202 colors, you only have 50 other colors to spare for that screen. If you try to load an image with 60 new colors, you will run out of colors; the remaining 10 will not be created. Instead, the closest colors of those already allocated will be used. Macintoshes reserve black and white, so you would have 58 colors left for the Mac. This can be easily demonstrated by spawning new windows in NCSA XMosaic, and selecting the different windows. When you select a window, the system color table is changed to best represent the colors of the window in the foreground. This can cause the windows in the background to have their colors changed to colors that are not correct for that image. Selecting different windows will cause the colors to change back and forth, which is called colormap flashing. The same thing can happen with multiple images on one page in Mosaic, because only one color table can be used per page. One easy way to lessen this problem is to keep the number of other open applications and windows using up your colors to a minimum. When converting from RGB to GIF, the palette must be indexed. Images with more than 256 colors must have their palettes reduced to 256, sacrificing image quality. An adaptive palette, which is a custom palette chosen to best represent the colors in the original image, will usually create a much better representation of the original image than the system palette, which is a representational spread of colors displayable by the given hardware. If you can get away with a palette smaller than 8 bits, do so. For example, a 6-bit image (64 colors) will download 3 times faster than an 8-bit image of the same size (in pixels). Reducing the palette of an inline image can dramatically speed up downloading, and will also create a sharper image in many cases. The relationship between color depth and max colors is as follows: Bits Max Colors 1 2 2 4 3 8 4 16 5 32 6 64 7 128 8 256 (Back to Contents) 3. GIFS GIF is the acronym for Graphic Interchange Format. It was developed by Compuserve as a standard to facilitate the display of downloaded images on different computer platforms. GIF images handle simple images with limited palettes best. A line drawing, for example will be very sharp and compress well as a GIF. The GIF format uses a color table with up to 256 colors. A color table can be global, to be used by all of the GIFs in a data stream, or local, to be used by the GIF immediately following the color table. A local color table supersedes a global table, and if no color table is present, a GIF viewer can use a previously used color table, a system color table, or a color table of its own. (Back to Contents) 3.1 TRANSPARENCY There are two GIF formats: 87a and 89a. Most viewers only support 87a, and Photoshop only produces 87a. 89a has some graphic control extensions, including a Transparency Index, which causes the background color of the display to remain unchanged for the color indexed as transparent. This can creat an image that does not show a rectangular border, like a normal GIF or JPEG would. Transparent GIFs can be used as spacers, to position images evenly, or wherever you want on a page. The best way to do that is to make transparent GIFs that are only 1 pixel high by however many pixels you need in width, so they will download quickly. Using transparent spacers can be very useful to separate images, but when pages are resized or font sizes are changed, the page will be reformatted, so they are not very useful if you want to position an image in an exact, particular way. Many browsers do not support the transparency function. In order to fake transparency, you can make your background color the same as the default background color of your browser of choice, and index that color as transparent also. Many browsers use a neutral gray of 192-192-192 for their background color. If your image is displayed on a browser with that color as a background, it will apprear transparent whether the browser supports transparency or not. Make sure that the color you pick as transparent doesn't occur anywhere in the image besides the background, or your image will have ``holes'' in it! (Back to Contents) 3.2 INTERLACING Interlaced GIFs contain the same information as non-interlaced GIFs, but the rows are arranged differently. Group 1: Every 8th row, starting with row 0. (Pass 1) Group 2: Every 8th row, starting with row 4. (Pass 2) Group 3: Every 8th row, starting with row 2. (Pass 3) Group 4: Every 8th row, starting with row 1. (Pass 4) When an interlaced GIF is decoded by a viewer, either the viewer de-interlaces the image before display, or the interlaced picture is gradually displayed in the order the rows are stored. Row Interlace Pass 0 ------------------------------------ 1 1 ------------------------------------ 4 2 ------------------------------------ 3 3 ------------------------------------ 4 4 ------------------------------------ 2 5 ------------------------------------ 4 6 ------------------------------------ 3 7 ------------------------------------ 4 8 ------------------------------------ 1 9 ------------------------------------ 4 10 ------------------------------------ 3 11 ------------------------------------ 4 12 ------------------------------------ 2 13 ------------------------------------ 4 14 ------------------------------------ 3 15 ------------------------------------ 4 The format was intended to allow users to view an image with a slow viewer, and get a sense of the overall image quickly. Now, interlaced GIFs are very popular because the Netscape WWW browser displays images as they are downloading, so interlaced GIFs are displayed with gradually increasing resolution. Interlacing is not a feature of Netscape, Netscape just displays them differently than the other browsers. Both 87a and 89a GIFs can be interlaced, and the files are about the same size as non-interlaced GIFs. To get more information about the GIF format, see the CompuServe GIF Programming Reference. From a CompuServe account, follow these menus: Graphic Forums, Intro to Go Graphics, Appendices, Download the GIF Specification. (Back to Contents) 4. JPEGs JPEG is a very efficient, true-color, compressed image format. It was designed by The Joint Photographic Experts Group to compress true-color images. JPEG compression works best with photograph-like images, i.e. images that are complex, and have a wide range of colors. An image of a person, for example, usually looks much better, and compresses to a much smaller file size, in the JPEG format, rather than the GIF format. On the other hand, a simple logo or line drawing will usually compress better and come out more detailed as a GIF. Even with JPEGs, an 8-bit graphics system can only display so many colors, so if many images are on the same page with widely different palettes, the images may get trashed. If an external viewer shows images, most can use a custom palette, so although you'll get some colormap flashing when you go from window to window, the images will each get a custom palette temporarily. If they are inline, it's up to the browser to handle dithering your 256 or less colors to best represent the potential thousands or millions in the multiple JPEGs. Most browsers just limit the number of colors per image as displayed, because colors are allocated in the order the images are downloaded. Although this delays the inevitable, it still leads to the trashing of images once all of the available colors are allocated, and even trashes images if there are still colors left, through palette reduction. (Back to Contents) 5. XBMs X Bit Maps are two color images, usually rendered with the foreground color as the text color, and the background color as transparent, or the text background color. They are much larger than 2 color GIFs, and are not compressed. XBMs are stored as ASCII. They are 3-10 times larger than GIFs because they are not compressed. They are always the text color and transparent. (Back to Contents) WWW Browsers XMOSAIC XMosaic allocates colors in the order the inlined images are displayed. If the first image has 256 colors, and the second image has 256 different colors, the second image will have to use the colors already allocated, and will be messed up. In order to deal with this problem, XMosaic limits inlined images to 50 colors by default. If you load 5 256 color images, each will be reduced to 50 colors, and you will have 5 x 50, or 250 colors. Aside from the 16 colors in the window, and whatever else you have on the screen ``stealing'' colors, it will look pretty okay. XWindows Mosaic does this to reduce the chances of running out of colors with more than one image on a page. This works okay if many images on the same page use different palettes, but looks bad if there are more than 50, but less than 256 colors on a single page. You can change the default 50 color limit by putting: Mosaic*colorPerInlinedImage: # in your .Xdefaults file, where # is a number between 50 and 256 that would suit your needs. Some colors will still be ``near misses'', but it will look a lot better than the default 50 per image. Also, XMosaic will not have to spend CPU time reducing the palette of an image to 50 colors. If you run out of colors with multi-image pages, though, it will look pretty awful. (Back to Contents) 6.2 MACMOSAIC MacMosaic seems to do a much better job with color allocation and dithering than XMosaic does, and has no default 50 color per image limit on 8 bit graphic systems. MacMosaic v1.0.3 doesn't support transparent GIFs, but the background color, which cannot be changed, is white. So, you can just make the color you want to be transparent white, and you'll get the same effect. (Back to Contents) 6.3 NETSCAPE Netscape does a number of things with inline images that make it a very nice browser to use. * It supports inline JPEGs. Hopefully, this feature will be supported by most browsers in the near future. * It displays images as they are downloading, as opposed to waiting until after the whole page, including images, is downloaded. This is what allows for the intersting interlaced GIF display effect. * It shows you how large an image is, and how much of it is downloaded, so you know what you're waiting for if you have a slow link. * It appears to be nearly identical on PCs, Macs, and XWindows. In my opinion, Netscape has shaken things up in a very good way, by showing how fast and slick a browser can be. I hope other browsers soon follow suit. (Back to Contents) 6.4 OTHER BROWSERS WITH INLINE IMAGES I need more information on the following browsers that support inline images, as well as all of the other browsers available. How well do they render images in terms of quality? What types of inline images do they support (JPEGs, interlaced GIFs, transparent GIFs, etc.). How fast are they? What platforms do they run on? Comparisons would be nice. Browser Transparency Interlace JPEG Alt Tag Air Mosaic yes ? ? yes Amiga Mosaic yes no yes ? Chimera ? ? ? ? Emacs W3 ? ? yes ? IBM WebExplorer ? ? ? ? NCSA MacMosaic 2.0a3 yes no no no NCSA WinMosaic 2.0a6 no no no no NCSA XMosaic 2.1 yes no no no Netscape yes yes yes no Spyglass Mosaic ? ? ? yes The Alt Tag column refers to a browsers ability to display the alt text when autoloading of inline images is turned off. (Back to Contents) 6.5 IMAGELESS BROWSERS More people have access to Lynx and the CERN WWW line mode (text based) browsers than the browsers that support inline images. So it's nice not to forget about them when you are creating pages. Seeing [IMAGE] all over the place can get pretty annoying, and can easily be replaced. Instead, use the alt tag: (add angle brackets where appropriate) img src="big-slow-loading-graphic.gif" alt="Text that describes the image, or illuminates the following passage in such a way that the image isn't sorely missed." or img src="big-slow-loading-graphic.gif" alt=" " (so imageless browsers won't see [IMAGE] and feel that they are missing something, especially if it's just decorative.) Some browsers that support inline images, including Spyglass and AIR Mosaic will display the alt text when auto image loading is turned off. This is another feature that will hopefully be implemented by other browsers. (Back to Contents) 6.6 Downloading Inline Images Many inline images are GIF previews (thumbnails) of images, and have links to JPEGs, so they can be downloaded. If the image is displayed by an external viewer, you can save it from the viewer. However, some images are only viewable as inline images. There are a number of ways to do this. Copy it from the temp directory. Figure out where your temp directory is, and copy the image from there. On Unix systems, it's usually /tmp. Use a screen capture. Although it's easy to do a screen capture, you will get a rendered version of the image. In other words, your display system may not display the image with it's full resolution, or there may be colormapping problems, etc. If it's a JPEG, you won't get the high-quality compressed version, and if it's a GIF, you won't preserve it's attributes, such as interlacing and transparency. You'll also have to crop the image after the caure. Download it with a URL. If you are using an imageless client, you can download images if they have a link, but how do you see the inline images? If you view the HTML source for the page, you can find the tag for displaying the image. For example, if you see this in the html: (angle brackets omitted) img alt=" " src="directory/path/image-you-want.gif" You can use the following URL to dowload the image directly: http://www.machine.name/directory/path/image-you-want.gif" If you are grabbing someone else's images, be courteous about it, because you don't want to violate copyrights. Don't just steal them to put on your page; get permission or design your own images. (Back to Contents) 7. Image Manipulation Tools 7.1 PHOTOSHOP To create the best GIF images for display on systems with 8 bit graphics, using Adobe Photoshop on a Macintosh for image manipulation: * Combine all of the images that will appear on one page into one large image. This image will be used to generate a palette. * Convert it to an 8 bit indexed color image with an adaptive palette. Photoshop will keep that palette in memory. Do not use dithering, because it will prevent browsers with intelligent color-management and/or dithering schemes from doing their job well. If there is a particular area of the image that you would like to preserve the quality of, Photoshop will favor an area that is selected when it picks an adaptive palette. * Open the original individual images for that page. This will give better results than just chopping up the combined images. * Convert them to 8 bit indexed color images with the Previous Palette option, so they will all have the same adaptive palette (from the combined image) for the whole page. Do not use dithering. * Save the converted images as GIFs. This will look great on any color Mac. A default XWindows Mosaic client will reduce each image to 50 colors, but as long as you don't have more than 256 colors on a page, it should look okay. For display with XWindows Mosaic with the 50 color per image default: * For up to 5 images per page: + Convert each image to an indexed color adaptive palette with 50 colors per image, with up to 5 such images per page, to stay within the 256 color limit. (5 images x 50 colors=250.) Do not use dithering. If you select an area, Photoshop will favor it for adaptive palette color selection. + Save the converted images as GIFs. * For more than 5 images per page: + Combine similar images into a large image. + Convert it to an indexed color image with a 50 color adaptive palette, to get a palette for that set of images. Do not use dithering. Select an area for adaptive palette favoring if you so desire. + Open the original individual images in the similar set. + Convert them to indexed color images with the Previous Palette option, so they will have the same palette per set. Do not use dithering. + Save the converted images as GIFs. + Don't use more than 5 such 50 color *palettes* per page. In other words, you could use 4 images with one 50 color palette, 3 images with another 50 color palette, 1 with another 50 color palette, etc., for up to 5 palettes. Since colors are allocated in the order displayed, you can reserve colors by simply making sure that they are displayed first. For example, if you have buttons at the bottom of a page that show palette mapping problems, a ``quick and dirty'' solution is to put an insignia or bullet with the same colors at the top of the page. This may not work correctly, however, if someone uses the back button or a link to get to the middle of the page, in which case the top of the page might not be displayed before the buttons. (Back to Contents) 7.2 DEBABILIZER DeBabilizer is an image manipulation tool that can create a super-palette for a set of images, alter the bit depth, and convert each individual image to use that palette. It also supports scripting to automate the process. It's available from MacConnection for $295.00 for the Macintosh. (Back to Contents) 7.3 FREELY DISTRIBUTABLE TOOLLS This section is very incomplete. Many tools are not listed here, and I don't have addresses and features of some that are listed. If you'd like to contribute information to this section, it would be most appreciated. 7.3.1 DOS and Windows GIFtrans for Windows does tranparency and is available at ftp.rz.uni-karlsruhe.de in /pub/net/www/tools/giftrans.exe Graphic Workshop for Windows and DOS is available at http://uunorth.north.net:8000/alchemy/html/alchemy.html LView Pro for Windows does 87a, 89a, and reads JPEGs and is available at oak.oakland.edu in /pub/msdos/windows3 Paint Shop Pro 2.0 for Windows does 89a, interlacing, reads many formats and is available at ftp://oak.oakland.edu/pub/msdos/windows3/psp20.zip PicLab does interlacing and some manipulation of GIFs TransGIF for DOS is available at http://melmac.corp.harris.com/transparent_images.html WinGIF does interlacing 7.3.2 Macintosh GIFConverter will interlace GIFs. Transparency is available at http://www.med.cornell.edu/~giles/projects.html#transparency 7.3.3 OS/2 PMJPeg converts BMPs, GIFs, JPEGs, and more, and is available at ftp.cdrom.com in /pub/os2/...? 7.3.4 Unix and XWindows ImageMagick is available at ftp://ftp.x.org/contrib/applications/ImageMagick/ImageMagick-3. 3.tar.gz giftool is available at http://www.homepages.com/tools/ TransGIF for Unix is available at http://melmac.corp.harris.com/transparent_images.html netpbm is a set of graphic manipulation and conversion programs available at ftp://ftp.cs.ubc.ca/pub/archive/netpbm/netpbm-1mar1994.tar.gz and ftp://ftp.cs.umn.edu/.arthive0/X/R5contrib/netpbm-1mar1994.tar. gz xv use arguments -ownmcap and -perfect to display images with a custom palette on 8-bit graphic systems. Other XMosaic palette mapping problems and solutions, including Unix image manipulation tools, are available at http://rugmd4.chem.rug.nl/hoesel/expo/part2.html or http://nearnet.gnn.com/mag/1_94/articles/hassel/image-proc.html 7.3.5 Other GD is a graphics library that you compile for your platform, and can be found at http://siva.cshl.org/gd/gd.html DOS, Windows, Mac, Unix, and XWindows graphic tools can be found at http://www2.ncsu.edu/bae/people/faculty/walker/hotlist/graphics .html (Back to Contents) 8. Inline Image Tricks and Tips * Use only the resolution necessary for your images. If your site is an art gallery, JPEGs would be most appropriate. If you intersperse your text with decorative images, GIFs with a few colors should work just fine. If they are accents or incidental, make them small. * Thumbnail-sized inline GIF images are best to preview and link to a high quality JPEG image. The thumbnail GIF will download fast, and the viewer will have a preview before downloading a high quality jpeg. * Check the file size and quality of GIF vs. JPEG for your images. * Experiment with reducing the palette to reduce the file size. * Be careful about putting style over substance; enough WWW sites are already sorely lacking in both! Good GIFs on a WWW site are not really that impressive; many supermarket tabloids have better resolution and more colors. * A picture should certainly be worth a thousand words, especially if the file size is a thousands of kilobytes! How much is it worth if no one is willing to wait for it to download? * Since so many people have slow connections, it is most corteous to go easy on the graphics for your homepage, and list the file size of your larger files. This way, users with slow connections will not spend a long time waiting before knowing what they are getting. * Colormap reduction will not only make your pages look better on a wider variety of platforms, it also saves bandwidth and time. * Hang on to your original images. Eventually, most browsers will support inline JPEGs, so you may want to reconvert some of your original images to that format. * The screen capture function is an easy way to put nicely formatted tables and such on your page as an inline image. Just capture whatever you want and convert it to a GIF. * Balance your images andToo much text on a page can lead to lead to endless scrolling and boredom. On the other hand, you should make sure that your pages are useable without images, where possible (i.e. not an art gallery.) (Back to Contents) 9. ABOUT THIS DOCUMENT AND ITS CREATION Dan Lottero and I were working on a project called The Computer Clubhouse Online Art Gallery at The Computer Museum in Boston. (It's not quite online yet.) The Clubhouse is an informal educational environment for 10 to 16 year-olds from underserved communities, where they learn to use computer technology creatively. The gallery features art created by Clubhouse members with Adobe Photoshop. Many of the images have thousands of colors, and had to be reduced to 256 color GIFs to be displayed as inlined images. We decided to go with inlined images for speed and simplicity, and to use the Mosaic window as a ``frame'' for the work. We noticed that the Macintoshes on our network were displaying the images very nicely, even the Macs with 8 bit displays, but they looked horrible on XWindows mosaic. This document is the result of our looking into this problem. (Back to Contents) 10. FEEDBACK AND CONTRIBUTIONS Please send comments, corrections, and additional information to: Brian Patrick Lee (blee@media-lab.mit.edu) This FAQ brings up more questions than answers, so I need some help in the following areas: * All Browsers How do they deal with color mapping? o Dithering? o User control over dithering? o User control over palette mapping? + Inline image features supported o Interlacing? o Transparency? o JPEGs? o Other image formats? + Displaying alt text when autoloading of images is off? * Graphic Tools + Tools not listed here + Addresses for all tools + Features for all tools I also welcome any comments, criticism, suggestions, etc. (Back to Contents) 11. Credits I'd like to thank Dan Lottero for his indispensible help with this document, The Computer Clubhouse Online Art Gallery, and Unix; Dan Ellis for help with XWindows, Unix, and HTTPD; Stina Cooke, Sam Christy, Noah Southall, and the Clubhouse Members for making my job fun and rewarding; and David Greschler for approving and supporting The Computer Clubhouse Online Art Gallery project. I'd also like to thank the individuals who contributed via email: Dwight Hare (dwight.hare@eng.sun.com) Kee Hinckley (nazgul@wraith.utopia.com) Frerk Meyer (frerk@educat.hu-berlin.de) Kyle Shannon (kyle@indienet.com) Jim Seidman (jim@spyglass.com) Eric W. Sink (eric@spyglass.com) Bjoern Stabell (bjoerns@acm.org) (Back to Contents) 11.1 CITING THIS DOCUMENT If you want to cite this FAQ for some reason, please use the following format: Brian Patrick Lee, ``Inline Images FAQ'', version number 0.9.1b, December 20, 1994. It would be nice if you let me know about it, also. (Back to Contents) 11.2 COPYRIGHT NOTICE Copyright (c) 1994 by Brian Patrick Lee. All rights reserved. This FAQ may be freely redistributed, as long as it is posted in its entirety and includes this copyright notice. This FAQ may not be distributed for financial gain, or incorporated into commercial documents or compilations without the express permission of the author. This FAQ is provided as is, without any express or implied warranty. (Back to Contents) From drh7511@gold.acns.fsu.edu Sat Dec 31 22:41:39 1994 Path: solitaire.cv.nrao.edu!hearst.acc.Virginia.EDU!caen!math.ohio-state.edu!howland.reston.ans.net!gatech!mailer.acns.fsu.edu!gold!drh7511 From: drh7511@gold.acns.fsu.edu (Josh Hillman) Newsgroups: alt.graphics.pixutils Subject: Re: GIF89 -> JPEG conversion Date: 29 Dec 1994 23:54:53 GMT Organization: Florida State University Lines: 30 Distribution: world Message-ID: <3dvi8d$cha@mailer.fsu.edu> References: NNTP-Posting-Host: gold.acns.fsu.edu X-Newsreader: TIN [version 1.2 PL2] Marc Plaisant (mp0@schooner.cis.ufl.edu) wrote: : I've been trying to save space by converting GIF to JPEG, however : when a GIF89 file is converted, the JPEG version is BIGGER than the GIF : version. Why, how, who, what, when, where? 'Normal' GIF files convert : just fine. : Can someone please point me in the direction of the conversion utility : that'll do the job ([share,free]ware only please), or otherwise could : someone explain why the JPEG files end up being larger than the GIF89 : files. : Thanks, Marc I don't know if these programs will do it properly or not, but they work pretty well with lots of other things: PaintShop Pro (latest version 2.01???) Lview Pro (latest version 1.9) both are for windows (not requiring win32s) -- _/_/_/ _/_/_/ _/ _/ _/ _/ _/ _/ _/_/ _/_/_/ _/ _/ SEMINOLES!!!!!!!!!!!!!!!!! _/ _/ _/ _/ _/ _/_/_/ _/_/_/