The image converter no longer works for me:
c64.superdefault.com/

Perhaps it's because now browsers require https to upload files? Tested on both Firefox and Chrome...

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Anyone knows an offline image converter? It's for... work.

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@codewiz When I was searching for one, I ended up instead looking at instructions on how to accomplish that with gimp: reducing resolution and the colours does it. Should also be doable with Imagemagick.

@globalc I'm trying with ImageMagick:

convert bernie-thumb-square.jpg -scale 160x160 -dither FloydSteinberg -remap c64_palette.png out.png

but the result looks too "good" for the :

In part, it's because nobody was doing Floyd–Steinberg dithering back in the day (ImageMagick doesn't have a lot of options).

In part, it's also because the was constrained to 4 colors per character cell in multicolor mode.

@globalc @root

@globalc @root Without dithering at all, it also looks wrong (any artist would have used some dithering):

@codewiz @root
First result looks to me already like from a c64 demo. Maybe shirt sticks out a bit - mastodon cuts that off at the preview of the pic.

@globalc @root I could make an animgif version using 60hz flickering to create intermediate color shades!

@codewiz @root
Would be a nice hack, but effectively blow up file size, and look like a much smaller version of the image with the direct intermediate colors..

@globalc @codewiz Finding someone who uses c64 dithering is harder than I expected. it's a lost art... There's no reason to use one-dimensional error diffusion anymore. Resetting the error for each line seems funny these days

@root @globalc Maybe there's some C64 image viewer that can read and display a bmp or gif file?

If I can find a good one, I'll use it to load my mugshot and then take a screenshot 😏

@codewiz @root
I was thinking the same.. or maybe there was an "established" picture format for the c64, aimed at efficiency for the c64, converting to that could also help.
bmp spends 3 byte per pixel, that's crazily much for what the c64 can actually do.

First time I hear of this SuperCPU... it's an accelerator card for the C64 based on a 20MHz 8/16-bit processor with a 6502 backwards-compatibility mode:
en.wikipedia.org/wiki/SuperCPU

@globalc @root @mike @patrick

@codewiz @root
btw, this reminded me of that quote I got from somewhere, "the whole moon landing was done with less computing power than 2 c64 deliver.."

@codewiz That's awesome!
I was just thinking if there were also some "typical c64 colors", one could mass-grab c64 game screenshots for that from the net and look at the used colors.. but your result here is already great!

@codewiz You could try with cutting down resolution a bit more. Cutting down colors might be harder.

@codewiz We didn’t have error diffusion algorithms like FloydSteinberg, got anything cruder?

@codewiz @globalc The VIC-II has more restrictions than just the palette. https://mcdraw.xyz/ takes care of all that and you can manipulate dithering and color handling live until you like the result.
@codewiz @globalc @root @mike "for Multicolor". It doesn't seem to support hires mode (twice the horizontal pixels, but only 2 colors in each 8x8 block instead of 4).

@codewiz Ahh, now that’s an era appropriate dither. Very nice.

@root I tried this one too, but it only outputs c64 file formats (or executables), and the result isn't great:

@codewiz

The converter we used for 'trouwfuif' ( csdb.dk/release/?id=208435 ) is convertron3000 by fieserwolf; csdb.dk/release/?id=155606 . It outputs koala (multicolor) or hires, though I did not use hires. I tried a preview and after initial promising results, "oh yeah that was before color collision removal, hmm, yes, this is very... not the same thing."

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