[comp.graphics] Frequently asked questions - weekly automated posting.

jef@well.UUCP (Jef Poskanzer) (11/13/89)

This message is automatically posted once a week in an effort to cut
down on the repetitive junk in comp.graphics.  If you have answers to
other frequently asked questions that you would like included in this
posting, please send me mail.  If you don't want to see this posting
every week, please add the subject line to your kill file.  Thank you.
---
Jef

      Jef Poskanzer  jef@well.sf.ca.us  {ucbvax, apple, hplabs}!well!jef
                        "...Is this a trick question?"

- - - - - - - - - -

0) General references for graphics questions:

    Fundamentals of Interactive Computer Graphics, J. D. Foley and A. van Dam,
      Addison Wesley, ISBN 0-201-14468-9
    Principles of Interactive Computer Graphics 2nd Ed., Newman and Sproul,
      McGraw Hill, ISBN 0-07-046338-7
    Procedural Elements for Computer Graphics, David F. Rogers, McGraw Hill,
      ISBN 0-07-053534-5
    Mathematical Elements for Computer Graphics 2nd Ed., David F. Rogers and
      J. Alan Adams, McGraw Hill, ISBN 0-07-053530-2
    Applied Concepts in Microcomputer Graphics, Bruce Artwick, Prentice-Hall,
      ISBN 0-13-039322-3


1) Quantizing 24 bit images down to 8 bits.  Find a copy of "Color
Image Quantization for Frame Buffer Display" by Paul Heckbert, SIGGRAPH
'82 Proceedings, page 297.  There are other algorithms, but this one
works well and is fairly simple.


2) Converting color into grayscale.  The NTSC formula is:

    luminosity = .299 red + .587 green + .114 blue


3) Quantizing grayscale to black&white.  The only reference you need
for this stuff is:

    Digital Halftoning, Robert Ulichney, MIT Press, ISBN 0-262-21009-6


4) How to convert from one image format to another.  There are a number
of free toolkits for doing image format conversions, simple image
manipulations such as size scaling, plus the above-mentioned 24 -> 8,
color -> gray, gray -> b&w conversions.  Here are pointers to three of
them:

    Utah RLE Toolkit.  Available via FTP on cs.utah.edu.

    Fuzzy Pixmap Manipulation, by Michael Mauldin.  Version 0.9 was posted
    to comp.sources.unix, and is available from c.s.u archives.  The latest
    version is always available via FTP in nl.cs.cmu.edu:/usr/mlm/ftp.

    PBMPLUS, by Jef Poskanzer.  Version of 13sep89 was posted to
    alt.sources.  The latest version is always available via FTP as
    expo.lcs.mit.edu:contrib/pbmplus.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:

    cs.utah.edu		128.110.4.21
    NL.CS.CMU.EDU	128.2.222.56
    expo.lcs.mit.edu	18.30.0.212

Please do *not* post or mail messages saying "I can't FTP, could
someone mail this to me?" There are a number of sites that archive the
sources newsgroups and make the contents available through an automated
mail query system.

If you bring one of these packages to someplace far away, such as the
West Coast or Europe, consider making it available for FTP from your
site and letting me know so I can add you to this posting.

jef@well.UUCP (Jef Poskanzer) (11/27/89)

This message is automatically posted once a week in an effort to cut
down on the repetitive junk in comp.graphics.  If you have answers to
other frequently asked questions that you would like included in this
posting, please send me mail.  If you don't want to see this posting
every week, please add the subject line to your kill file.  Thank you.
---
Jef

      Jef Poskanzer  jef@well.sf.ca.us  {ucbvax, apple, hplabs}!well!jef
                        "...Is this a trick question?"

- - - - - - - - - -

0) General references for graphics questions:

    Fundamentals of Interactive Computer Graphics, J. D. Foley and A. van Dam,
      Addison Wesley, ISBN 0-201-14468-9
    Principles of Interactive Computer Graphics 2nd Ed., Newman and Sproul,
      McGraw Hill, ISBN 0-07-046338-7
    Procedural Elements for Computer Graphics, David F. Rogers, McGraw Hill,
      ISBN 0-07-053534-5
    Mathematical Elements for Computer Graphics 2nd Ed., David F. Rogers and
      J. Alan Adams, McGraw Hill, ISBN 0-07-053530-2
    Applied Concepts in Microcomputer Graphics, Bruce Artwick, Prentice-Hall,
      ISBN 0-13-039322-3


1) Drawing three-dimensional objects on a two-dimensional screen.  The
simple answer is, you divide by the depth.  For a more verbose explanation,
see any of the above references.


2) Quantizing 24 bit images down to 8 bits.  Find a copy of "Color
Image Quantization for Frame Buffer Display" by Paul Heckbert, SIGGRAPH
'82 Proceedings, page 297.  There are other algorithms, but this one
works well and is fairly simple.


3) Converting color into grayscale.  The NTSC formula is:

    luminosity = .299 red + .587 green + .114 blue


4) Quantizing grayscale to black&white.  The only reference you need
for this stuff is:

    Digital Halftoning, Robert Ulichney, MIT Press, ISBN 0-262-21009-6


5) Image manipulation software.  There are a number of free 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.  Version of 13sep89 was posted to alt.sources.
    The latest version is always available via FTP as
    expo.lcs.mit.edu:contrib/pbmplus.tar.Z.

    Utah RLE Toolkit.  Conversion and manipulation package, similar to
    PBMPLUS.  Available via FTP on cs.utah.edu.

    Fuzzy Pixmap Manipulation, by Michael Mauldin <mlm@nl.cs.cmu.edu>.
    Conversion and manipulation package, similar to PBMPLUS.  Available via
    FTP in nl.cs.cmu.edu:/usr/mlm/ftp, and also in your nearest
    comp.sources.unix archive.

    Img-whatnot, by Paul Raveling <raveling@venera.isi.edu>.  Reads and
    writes its own image format, displays on an X.V11 screen, and does some
    image manipulations.  Available via FTP on venera.isi.edu, along with a
    large collection of color images.

    Xim, by Philip R. Thompson.  Reads and writes its own image format,
    displays on an X.V11 screen, and does some image manipulations.
    Available via FTP in expo.lcs.mit.edu:contrib.

    xloadimage, by Jim Frost <madd@std.com>.  Reads in images in various
    formats and displays them on an X.V11 screen.  Available via FTP in
    expo.lcs.mit.edu:contrib, and in your nearest comp.sources.x archive.

    TIFF Software, by Sam Leffler <sam@okeeffe.berkeley.edu>.  Nice
    portable library for reading and writing TIFF files, plus a few tools
    for manipulating them and reading other formats.  Available via FTP as
    okeeffe.berkeley.edu:pub/tiff.tar.Z.

    HIPS, from the Human Information Processing Laboratory at NYU.  For
    availability contact Michael Landy, Psychology Dept., NYU, 6 Washington
    Place, Room 980, New York NY 10003.  This package is *not* free.

    ALV Toolkit, available via email to alv-users-request@cs.bris.ac.uk.

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:

    expo.lcs.mit.edu		18.30.0.212
    cs.utah.edu			128.110.4.21
    NL.CS.CMU.EDU		128.2.222.56
    venera.isi.edu		128.9.0.32
    okeeffe.berkeley.edu	128.32.130.3

Please do *not* post or mail messages saying "I can't FTP, could
someone mail this to me?" There are a number of sites that archive the
sources newsgroups and make the contents available through an automated
mail query system.

If you bring one of these packages to someplace far away, such as the
West Coast or Europe, consider making it available for FTP from your
site and letting me know so I can add you to this posting.

jef@well.UUCP (Jef Poskanzer) (12/04/89)

This message is automatically posted once a week in an effort to cut
down on the repetitive junk in comp.graphics.  If you have answers to
other frequently asked questions that you would like included in this
posting, please send me mail.  If you don't want to see this posting
every week, please add the subject line to your kill file.  Thank you.
---
Jef

      Jef Poskanzer  jef@well.sf.ca.us  {ucbvax, apple, hplabs}!well!jef
                        "...Is this a trick question?"

- - - - - - - - - -

0) General references for graphics questions:

    Fundamentals of Interactive Computer Graphics, J. D. Foley and A. van Dam,
      Addison Wesley, ISBN 0-201-14468-9
    Principles of Interactive Computer Graphics 2nd Ed., Newman and Sproul,
      McGraw Hill, ISBN 0-07-046338-7
    Procedural Elements for Computer Graphics, David F. Rogers, McGraw Hill,
      ISBN 0-07-053534-5
    Mathematical Elements for Computer Graphics 2nd Ed., David F. Rogers and
      J. Alan Adams, McGraw Hill, ISBN 0-07-053530-2
    Applied Concepts in Microcomputer Graphics, Bruce Artwick, Prentice-Hall,
      ISBN 0-13-039322-3


1) Drawing three-dimensional objects on a two-dimensional screen.  The
simple answer is, you divide by the depth.  For a more verbose explanation,
see any of the above references.


2) Quantizing 24 bit images down to 8 bits.  Find a copy of "Color
Image Quantization for Frame Buffer Display" by Paul Heckbert, SIGGRAPH
'82 Proceedings, page 297.  There are other algorithms, but this one
works well and is fairly simple.


3) Converting color into grayscale.  The NTSC formula is:

    luminosity = .299 red + .587 green + .114 blue


4) Quantizing grayscale to black&white.  The only reference you need
for this stuff is:

    Digital Halftoning, Robert Ulichney, MIT Press, ISBN 0-262-21009-6


5) Image manipulation software.  There are a number of free 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.  Version of 22nov89 was posted to
    comp.sources.misc.  The latest version is always available via FTP
    as expo.lcs.mit.edu:contrib/pbmplus.tar.Z and ftp.ee.lbl.gov:
    pbmplus.tar.Z.  Also available in your nearest X.V11 source tree
    or comp.sources.misc archive.

    Utah RLE Toolkit.  Conversion and manipulation package, similar to
    PBMPLUS.  Available via FTP as cs.utah.edu:pub/toolkit-2.0.tar.Z and
    ucsd.edu:graphics/utah-raster-toolkit.tar.Z.

    Fuzzy Pixmap Manipulation, by Michael Mauldin <mlm@nl.cs.cmu.edu>.
    Conversion and manipulation package, similar to PBMPLUS.  Available via
    FTP as nl.cs.cmu.edu:/usr/mlm/ftp/fbm.tar.Z and ucsd.edu:graphics/
    fbm.tar.Z, and also in your nearest comp.sources.unix archive.

    Img-whatnot, by Paul Raveling <raveling@venera.isi.edu>.  Reads and
    writes its own image format, displays on an X.V11 screen, and does some
    image manipulations.  Available via FTP as expo.lcs.mit.edu:contrib/
    Img.tar.Z, and venera.isi.edu:pub/Img.tar.Z along with a large
    collection of color images.

    Xim, by Philip R. Thompson.  Reads and writes its own image format,
    displays on an X.V11 screen, and does some image manipulations.
    Available via FTP as expo.lcs.mit.edu:contrib/xim3c.tar.Z.

    xloadimage, by Jim Frost <madd@std.com>.  Reads in images in various
    formats and displays them on an X.V11 screen.  Available via FTP as
    expo.lcs.mit.edu:contrib/xloadimage.tar.Z, and in your nearest
    comp.sources.x archive.

    TIFF Software, by Sam Leffler <sam@okeeffe.berkeley.edu>.  Nice
    portable library for reading and writing TIFF files, plus a few tools
    for manipulating them and reading other formats.  Available via FTP as
    okeeffe.berkeley.edu:pub/tiff.tar.Z.

    HIPS, from the Human Information Processing Laboratory at NYU.  For
    availability contact Michael Landy, Psychology Dept., NYU, 6 Washington
    Place, Room 980, New York NY 10003.  This package is *not* free.

    ALV Toolkit, available via email to alv-users-request@cs.bris.ac.uk.

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:

    expo.lcs.mit.edu		18.30.0.212
    ftp.ee.lbl.gov		128.3.254.68
    cs.utah.edu			128.110.4.21
    NL.CS.CMU.EDU		128.2.222.56
    venera.isi.edu		128.9.0.32
    okeeffe.berkeley.edu	128.32.130.3

Please do *not* post or mail messages saying "I can't FTP, could
someone mail this to me?" There are a number of sites that archive the
sources newsgroups and make the contents available through an automated
mail query system.

If you bring one of these packages to someplace far away, such as the
West Coast or Europe, consider making it available for FTP from your
site and letting me know so I can add you to this posting.