Re: Graphics on a IIgs...

[supertimer@aol.com (Supertimer)]

dalloff@gcfn.org (Dave Althoff Jr) wrote:

>Okay, here's my problem.  Hopefully someone here knows of a good solution...
>
>I have bunches and bunches of neat pictures.  These pictures are presently
>on a Windows '98 machine.  I want to use these pictures on my IIgs.
>
>The pictures are presently obscenely-sized JPEG files.  This is not a
>problem, as I can scale them down to the size I need for the IIgs.  The
>pictures are presently 24-bit color.  This is not a problem either, as I
>can scale the colors to the 4-bit version I need for the IIgs.
>
>So now I have a collection of 320x200 16-color graphics available on the
>Windows machine.  Question is, what format should they be in?
>
>Now, I can leave them as JPEG files, display each one on the GS (each one
>will require several minutes to decompress as my accelerator doesn't work)
>and I can save them as SHR graphics.
>
>I can convert them to GIF files, but the one GIF viewer I have is not very
>good, and doesn't convert to SHR.
>
>I can save them as BMP files, uncompressed, but I have no way of bringing
>those up on my SHR screen.
>
>It seems that the most reasonable thing to do is to make the Windows
>machine (1,000 MHz processor) do the heavy lifting to convert the images to
>something the IIgs (3 MHz processor) can handle.  So the most obvious tool
>to use would be a converter that can convert .BMP-->.SHR on the Windows
>machine.  Anybody know of such a critter?
>
>Or, alternatively, a .BMP->.SHR converter on the IIgs (Convert 3200,
>perhaps?).  But my preference would be to get the files into a
>"GS-friendly" format early on...
>
>Anybody got any ideas?

I used to do this a lot but I could never get good results if I converted to
16 colors on the PC side.  Sure, it might look good ON THE PC because
dithering works best on a high resolution display (the pixels are smaller)
but once converted to the IIGS, it looked terrible.

The best method I have found is to convert the files to 320x200 GIFs
(256 colors) as a batch and use Prism to batch convert these to 3200
color graphics on the IIGS.

If you really wanted to maximize quality on the IIGS, you will want to
do a section by section color reduction on the PC side.  Break the
picture up horizontally and reduce the colors in each section to 256
& save the file as a TIFF file.  On the IIGS, use Prism to convert the
TIFF files to 3200.  This works better than the batch GIF conversion
because each section is drawing from the full PC pallette so the
IIGS can approximate this from its full 4096 color pallete.  3200
color graphics work by maximizing the color range across scan
lines.  Even though each scan line is still 16 colors, overall your
image will have many more of the 4096 possible colors.