


                               ShowJPG 2.81

        Copyright (c) 1995-2001 by Jan Patera, All Rights Reserved
                           patera@pictview.com

                       Ultra-fast JPEG image viewer
    with capability of displaying and scrolling during decompression.
         Image swapping to XMS when out of conventional memory.



Usage:
   ShowJPG.exe File_name|Memory_address [Width] [-q] [-l] [-c] [-dTime]
     [-tTime] [-e] [-K]

   File_Name  is  the  name  of the file  to  be  viewed, must include an
extension and may include a path.
   If you want to view  an image located just in the memory, not in a fi-
le, you may specify memory address in the conventional memory (below 1MB)
of  the image in the form :SSSSOOOO, where SSSS  is the segment  part and
OOOO is the offset part, both hexadecimal. Maximum image size is 64KB.
   Optional parameter Width is a number saying the width in pixels of the
graphics  mode you  want to  view the  image in.  Your video adapter must
support any graphics  mode with this width (what  a surprise!). This mode
must be 256 color for black-and-white  images and must be HiColor (32k or
64k colors) or TrueColor (16m colors) for color images. If this parameter
is not specified,  ShowJPG chooses the best mode in  that all or possibly
the biggest  part of the  image that can  be displayed. A  TrueColor mode
rather than a HiColor one is chosen for color images .
   Optional  parameter -q  or -Q  commands the  ShowJPG to decompress the
image  preserving the  maximum quality  of the  image. If  specified, the
decompression is slower than if not specified.
   Optional parameter -l or -L allows to use the left mouse button to end
ShowJPG, instead of the default  right button. This is usable for example
in publicly accessible info-boxes with a screen and a simple touchpad.
   Optional parameter -c or -C forces the ShowJPG to clear the screen be-
fore displaying. 
   With optional parametr -d or -D, ShowJPG  delays Time milliseconds be-
fore displaying  the image (or clearing the screen). Note: because of the
granularity  of the DOS timer (55 ms), the time is always rounded to mul-
tiple of 55 ms.
   The  previous two switches  work under Windows 95 only. ShowJPG is too
fast for Windows 95 ;-)) and some video drivers. This speed may result in
missing or partially  displayed parts of images or in remaining  parts of
the previous picture on the screen.
   Optional  parameter -t or -T can  be used for slideshows. ShowJPG will
display  the image for the given time period  and then quit. The user can
exit ShowJPG within this time using the keyboard and mouse.
   Optional parameter -e or -E forces  ShowJPG not clear  the screen when
it exits, the image  will remain  displayed. This  works also with the -t
switch. Usefull for splash screens and slideshows.
   Optional parameter -k or -K will keep the screen unchanged before
displaying the image. This is usefull for slideshows.


Examples:

 ShowJPG parrot.jpg
 ShowJPG :1ef40000  864
 ShowJPG e:girl.jff 1192 -Q
 ShowJPG ..\country\house.jif   1280 -l


   You  may  scroll  the  image  in  all  directions  using  a  mouse and
a keyboard.
   Scrolling is even available during decompression.
Use these keys to scroll:
"Left" - moves the image to the right and displays next part on the left
"Right" - moves the image to the left and displays next part on the right
"Up" - moves the image down and displays next part toward the top
"Dn" - moves the image up and displays next part toward the bottom
"PgUp" - displays the top of the image
"PgDn" - displays the bottom of the image
"Home" - displays the left side of the image
"End" - displays the right side of the image

   Zooming can be  performed by pressing + (plus,  Zoom-in) and - (minus,
Zoom-out) keys on the numeric keypad. Zooming is actually switching among
graphics modes  with  higher or  lower  resolution. On  color images, all
TrueColor  (16m colors),  all HiColor  (32k colors)  and all HiColor (64k
colors)  modes are  looped  cyclically.  Notice that  transformations are
performed when switching among 16m, 32k and 64k color modes. So the image
looses its quality after displaying in any HiColor mode (and it takes so-
me time).

  Viewing can be ended by pressing Esc, Enter or Space or a mouse button.



I would like  to thank Douglas  Bashford for his  careful reading of  all
texts in this package and corrections  of my mistakes. Release of English
version of ShowJPG would be impossible without his effort.
I am also grateful  many Internet users whose positive  feedback keeps me
alive and working on ShowJPG, PictView and other cool software.


If you think that ShowJPG  is something what  you have been looking for a
long time or  if wish to sponsor further development,  do not hesitate to
contact me. Detailed information (addresses...) can be found on the below
indicated websites.


HISTORY

2.81  - October 2001

  - Scanning for available graphic modes is no more eager as it was
    taking upto 7 seconds and shaking with display (Matrox Millenium II)


2.80  - April 2001

  - Added support of images with subsampling 1x2:1:1 (created by digital
     cameras in portrait mode)
  - Fixed crash on some images with subsampling 4x1:1:1


2.70  - October 2000

  - Added the -K switch
  - Added support of images with subsampling 4x1:1:1


2.63  - March 2000

  - Fixed a bug causing ignoring switch -t if no mouse driver is loaded
  - Fixed a bug causing ignoring the actual value of switch -d
  

2.62  - August 1999

  - Switch -t for timed view (usable for slideshows) added.
  - Switch -e documented after years :-)


2.61  - May 1998

  - Ability of viewing images located in the base memory added.
  - Screen may be cleared under Windows 95 (switch -c added).
  - ShowJPG may delay under Windows 95 before displaying (switch -d
    added).


2.60  - February 1998

  - Decompressing of Progressive Mode JPEGs with subsampling 1:1:1
    and 2:1:1 added.


2.52e - November 1997

  - Decompressing of Progressive Mode JPEGs with no refine scans
    (e.g. created with Adobe Photoshop 4) fixed.


2.52d - October 1997

  - ShowJPG allows to use the left mouse button instead of the right.


2.52c - March 1997

  - Reading of Progressive Mode JPEGs fixed.


2.52, 2.52b - February 1997

  - Images that are too large and they do not fit in any TrueColor mode,
    are automatically displayed in the best HiColor mode to fit on the
    screen now.


2.51 - February 1997

  - Decompressing of Progressive Mode JPEGs with unusual color component
    IDs fixed.


2.50 - January 1997

  - Support of Progressive mode images from the Internet added.
  - Displaying in 32bit TrueColor modes really fixed.
    It really was not fixed in the 2.0 release.
    Why did nobody report this BUG?????????????


2.25 - March 1996

  - Reading of images with 4:1:1 subsampling fixed
  - Reading of some images with 1:1:1 subsampling fixed.


2.2 - February 1996

  - Displaying very wide images fixed.
  - Only a part of the image is displayed if it is too large to fit in
    memory.


2.1 - January 1996

  - Support of MacBinary files with JPEG compression added.


2.0 - November 1995

  - Sped up by 4 times.
  - Option for extra-quality decompression added.
  - Mouse support added.
  - Support of non-standard graphics modes added.
  - Displaying in 32bit TrueColor modes fixed.
  - Choosing of graphics modes by specifying width of the mode rather than
    illogical mode numbers.


1.0 - March 1995 - First public release


ShowJPG  requires:
-386 processor or better
-VGA videoadapter with VESA BIOS

ShowJPG  recommends:
-XMS

ShowJPG supports:
-Progressive Mode JPEG,  Baseline JFIF-JPEG,  Raw JPEG  and MacBinaryJPEG
 images in grayscales and in YCbCr (TrueColor) color scheme
-Subsampling types 1x1:1:1, 2x1:1:1 (2:1:1), 2x2:1:1 (4:1:1), 4x1:1:1
(4:1:1), and 1x2:1:1 (2:1:1) only

Known bugs:
-Upper part of the image might be damaged for huge progressive JPEGs
-Every 8th or 16th line can be damaged for very wide JPEGs
Both bugs are consequences of the 64KB segments in MS-DOS


I have to say that:
-I have  recoded a routine for  Reverse DCT into assembler  directly from
 the source texts by the Independent JPEG Group, Releases 3 and 4,
-I have  borrowed the overview of  the JPEG file structure  from the same
 source.
-I have  borrowed the overview  of the Progressive  Mode JPEG compression
 algorithm from the same source, Release 6.



This software is freeware, so you may use it as freely as you want to and
where you want to, but  all rights are  reserved. No  fees for the author
are required (see notes on sponsoring above and on the web :-)).
You may  not modify ShowJPG  in any way and you have to distribute it al-
ways with the documentation (this file).
If you want to include  ShowJPG into any of your package that you want to
distribute or use internally in your company, please, send me a short no-
tification and a description of your project. This is just for my private
statistics. Thank you.


All  warranties  are  disclaimed,  including  damage  to  hardware and/or
software from use of this product. In  no event will I be held liable for
any damages, including lost profits,  lost savings or other incidental or
consequential damages  arising out of  your use or  inability to use  the
program, or any other claim by any other party.

Please, send  your impressions, suggestions and  reports via the Internet
to:

 support@pictview.com


The newest version can always be downloaded from:

 http://www.pictview.com


Enjoy!
