Converting any image file to Degas pi3 file

[Plymouth]

Hi,

Does anyone know of a program that can convert most (preferably all ) picture/screen images to a Degas pi3 file please?

TIA

[techie_alison]

Paint Shop Pro 4 will save .IFF (Amiga) and .PCX files. These can then be read in to one of the various ST packages of the day.

PSP4 is tiny too, and fast. I still use it as my main photo program. Erm like, 4MBytes-v-400MBytes.

This is like 10-years+ old and it's super fast.

[Plymouth]

Thanks Allison, but I'm afraid your suggested solution won't work...

Paint Shop Pro runs on Windows .

I should have explained , I've escaped the clutches of Microshaft, and use Linux

[simonsunnyboy]

Netpbm can convert to PI1 so maybe they have a program to convert from and PI3 as well.

[ppera]

There are some Atari programs for such conversions - at least can convert from GIF and BMP.
But, as I saw, they are not freewares.
Little googling can solve it...

[Desty]

Also XnView / nconvert which seems to be freeware. I remember Picswitch and ehh... Gemview on the Atari itself working pretty well.

[Paolo]

... and note that nconvert works on Atari. (and Mac, and windoze, and Linux, and ...)

[daeghnao]

Thanks Allison, but I'm afraid your suggested solution won't work...

Paint Shop Pro runs on Windows .

I should have explained , I've escaped the clutches of Microshaft, and use Linux

For ultimate control, make sure you have netpbm, then for something like a png picture, this commandline is the general kind of thing you need:

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pngtopnm image.png | pnmscale -xysize 640 400 | ppmtopgm | pgmtopbm | pbmtopi3 > image.pi3

You can mess with levels, dithering and so on at appropriate stages along the way.

[Lautreamont]

It looks like my 'pi1' saver for Gimp can also write 'pi3' (and 'pi2') pictures.

Download the Degas v2.04 plug-in from Markus Oberhumer if you don't have it yet,
and patch it with the attached file (the patch is as big as the original file).

Install it with "$ gimptool --install degas.c".
You'll have to restart Gimp.

It's not finished, but you should be able to save degas pictures with Gimp now.

I also have a question about 'PI3' files (I've never used them on Atari):
The loader from Markus makes the first index of the palette appear white on screen and the second black.
The problem is that when you're drawing a picture and convert it to a 2-colour palette, Gimp orders the indexes rather randomly.
When you reload your picture, the loader can show it with its colours reversed!

So I wonder if it's a rule for 'PI3' files that the first index is white, would an Atari display a 'PI3' file like the loader ?


And another question about colour conversion between [0..255] and [0..7]:

Markus's loader uses the following table, to make 7 look as bright as possible:

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0 ->   0
1 ->  36
2 ->  73
3 -> 109
4 -> 146
5 -> 182
6 -> 219
7 -> 255

roughly steps of 36 (255 / 7).

My saver uses steps of 32 (256 / 8) to write the Atari palette.

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  0-31  -> 0
 32-63  -> 1
 64-95  -> 2
 96-127 -> 3
128-159 -> 4
160-191 -> 5
192-223 -> 6
224-255 -> 7

I believe it's easier to draw a picture with my method, with steps of 32 in mind rather than with the values from Markus,
but steps of 32 would show a darker picture if used in the loader.

I believe it's safe to keep both, but maybe someone has a clever way to do the conversion ?