[haiku-development] Re: [PATCH] Add 8-bit indexed colour support to boot splash

2008/7/29 Axel Dörfler <axeld@xxxxxxxxxxxxxxxx>:
> Spacing of the function calls is wrong - it's always fprintf("") not
> fprintf ("") nor fprintf( "" ) :-)
> Also, looking at the end of the patch, the output looks wrong, too, as
> there is an additional tab before the last '};'.
> Other than that, the patch looks good to me.

Do you want me to fix those issues and re-submit the patch, or should
I fix them later?

> Grayscale is probably enough for the moment. You could do a simple
> palette replacement algorithm instead of a real color conversion,
> though -- dunno if that would look better, though.
> If we just do a simple conversion like this, I would actually prefer to
> do it "live" in the boot loader, though; at least it should consume
> less space, and should still be pretty much instant.

Since posting the patch, I've been working on the generate_boot_screen
program, and I've managed to add "Gervautz-Purgathofer octree quantization"
to the program, which means that it can now generate an optimized 256 colour
palette. (It's a open source implementation that I've tweaked, I
wouldn't want to
take credit for stuff that isn't mine)

I've also added a nearest-colour mapping, which gives pretty good result
for an indexed colour image. I'm currently working on applying a
dither algorithm to the image
to make it look even better, though I may submit a patch without the dither, as
it's a significant improvement on the greyscale image anyhow.

The upshot of all of that is that the colour image in 8-bit mode looks
really good,
however the genereate_boot_screen can take a second or two to run with the
colour quantization, and probably longer once I get dithering to work,
so I don't
think it would be a good idea to include those algorithms in the bootloader to
do it "live" as there would be a noticable speed penalty.


David Powell.

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