Space & Astronomy/Space and Astronomy (October 1993).iso/mac/VIEWERS/MSDOS/VGA2GIF3.ZIP/VGA2GIF.DOC

Text File | 1988-08-12 | 6KB | 176 lines

                          Capture VGA screens to .GIF files

                           (C)1988 Laurie and Bill Fleisher

                                   4680 Carrick SE
                                  Kentwood, MI 49508
                                    [phone]


          This program consists of two modules.  The first on, VGACAP, is a
          TSR  (memory  resident program)  which  captures the  320x200x256
          (mode 13H) screen and palette to a disk file.  The second module,
          SCR2GIF.EXE, converts this  file into a  .GIF file, which can  be
          displayed with programs like  PICEM  or VGAGIF.   The reason  for
          the split  modules is  to keep  the size  of the  memory resident
          program small.   This prevents competition for memory  space with
          your graphics editor of display program.   Some of these programs
          tend to be memory hogs when displaying mode 13H.  The VGACAP uses
          only 2k of  memory. This should  not interfere with memory  usage
          very much.

          To install the capture program, simply type VGACAP. It will check
          your video adapter, and  install itself if it finds  a compatible
          adapter.   Otherwise  it simply aborts.   In order  to invoke it,
          display the image  you want to capture.  Then press ALT and  C at
          the same time.  After a few seconds of disk activity, a BEEP will
          sound to indicate a successful capture.   VGACAP will check video
          modes to see of 320x200x256 mode is active.  If not, it will exit
          without capture.

          The file created will have a name of VGA-xxx.SCR, where xxx  is a
          three digit decimal  number.  The  program checks the  directory,
          and will use the lowest number not already in use.  You can write
          999 files to a directory  this way (if you don't run  out of disk
          space).
          If  you delete any .SCR files, VGACAP  will fill the blank spaces
          on the next capture before adding to the end of the list.

          Each file consists simply  of a 768 byte area  containing palette
          data  (256x3), followed by 64000 bytes of screen dump.  The total
          size is therfore 64768 bytes.

          It is recommended  you rename the files to  something descriptive
          when  you return  to  DOS unless  you are  going to  convert them
          immediately.

          The SCR2GIF file  is very simple to  use.  There are  three modes
          for using it. The modes are determined by whether no, one, or two
          file  names  are entered  on  the  command line  when  SCR2GIF is
          invoked.

          SCR2GIF        or
          SCR2GIF inputfilename       or
          SCR2GIF inputfilename outputfilename

          MODE 1

          C:>SCR2GIF

          The first way of using it requires that you enter only VGA2GIF on
          the command  line. It will  prompt for both  file names. It  will
          fill in the  suggested input file extension of .SCR. You need not
          enter the  extension if .SCR is  okay. Otherwise, as soon  as you
          type the "." the SCR extension will vanish so you can  enter your
          own extension. If it cannot find your input file name it will ask
          you to reenter.

          The output file name will then be requested. It will present your
          input file name  with the extension changed to "GIF".  If this is
          okay, just  hit  the ENTER  key.  Otherwise, start  entering  the
          filename you want. The  extension will behave as in  entering the
          input file  name described  above.   If the  output file  already
          exists, it  will ask  permission to  overwrite it.   The  default
          (ENTER) is "No, don't overwrite" It will then ask for a new
          file name.


          MODE 2

          C:>SCR2GIF filename.SCR
               or
          C:>SCR2GIF *.SCR

          This mode will  accept wildcards. The  output file names will  be
          the same  as the input  file names  except that the  extension is
          changed to .GIF.
          It will accept  the same wildcards as  DOS (? or *). You  will be
          asked ONCE whether it should overwrite a .GIF if the name happens
          to  be  the same  as  the output  file.  This will  apply  to all
          conversions if a wildcard  is used.  For  instance, if the  input
          file is  VGA-000.SCR and it  finds a  file named VGA-000.GIF   it
          will overwrite it  if you answer  Y. If, however, VGA-000.GIF  is
          protected (Read  only attribute set) it will refuse to over-write
          it and "Permission denied" will be displayed.


          MODE 3

          C:>SCR2GIF inputname.SCR outputname.GIF

          The  third  mode is  intended for  running  from batch  files and
          accepts
          both input and output file names on the command line as:

          SCR2GIF myinput.pic myoutput.mac

          An error message  is generated if it  cannot open the input  file
          (if it  can't find  it for  instance) or  if it  cannot open  the
          output file (if the output file already exists).
          In  any case,  the program will  request whatever  information it
          requires.   If the output file exists  already, you will be asked
          if you want  to overwrite it.   We may provide a  similar package
          for  other screen modes  if people are  interested and  if no one
          else  provides one  first.  If  you like  the program or  find it
          useful,  you don't have to send money, although it might be nice.
          But at least write  and let us know  you like it, don't  like it,
          and let us know we did something useful.