From npac.syr.edu!paulc Tue Feb  7 10:00:01 EST 1995

Inlined images in HTML
----------------------

HTML only accepts gif format for inlined images. So if you have  
pictures in some other format, e.g. postscript, jpeg, etc, that you
want to include inside a document, you will have to convert it to gif. 
You can still access postscript, jpeg, tiff, etc. images under Mosaic, 
but they will be displayed by external viewers like gs or xv.

xv will let you convert from most common image formats, by displaying the
image, clicking the right mouse button on it to get the control panel,
and then using SAVE to save it in GIF format. 
Note that xv is an incredibly useful program. It will allow you to do
screen capture (GRAB), crop images (autocrop or using GRAB), rotate them, 
change the colors, resize them, etc etc etc.

However xv will not display postscript. Converting postscript to gif can
be done using ghostscript as follows:

If you have a file image.ps, type the following commands:
   
   gs /usr/local/lib/ghostscript/pstoppm.ps
   GS>(image) ppm24run
   GS>quit

ppm24run is for 24-bit color images. If you have greyscale you
could use ppm8run and get a smaller image file, I think. I used
ppm1run on a black-and-white picture and it worked fine.
Note however that some fancy fonts won't be converted properly if you 
have to convert from postscript, since gs doesn't know too many fonts.

This procedure creates a file called image.ppm. Now start up xv:

   xv image.ppm

and with the cursor inside the image, click on the right mouse
button to put up the xv control panel. SAVE the image to gif format.

If the gif of your picture is very large, it may take a long time to 
display it under Mosaic. What you can do in that case is to have a 
thumbnail image in-lined in the document, so that if people click on 
this smaller image, it spawns a viewer (xv or ghostscript) to display 
the large image. (To quit xv type 'q' with the cursor on the image.)
To show an example of how to do this, I have a version of the spin models
project summary that uses a thumbnail image for the graphic. You can 
access this by 

  Mosaic  ~paulc/NPAC/projects/physics/thumbnail.html

A thumbnail image can be created by either resizing under xv, or by
using the postscript to gif conversion procedure described above with
one extra command to set the size of the image:

   gs /usr/local/lib/ghostscript/pstoppm.ps
   GS> 10 10 ppmsetdensity
   GS> (image) ppm24run
   GS>quit


In the computational physics summaries on the experimental NPAC server 
I have some examples of how to present images. There are also some
pretty lame attempts to basically show what should be animations by using 
a series of still pictures. I am working with a few people to try to 
create a "slideshow" functionality under Mosaic. If anyone has any ideas 
on how to do this, or would like to help, please let me know.

Have fun,

InfoPaul