[PATCH v2 4/5] logo: Enable image format selection for the logo

[Jules Maselbas]

On Thu, Jan 20, 2022 at 09:13:41AM +0100, Sascha Hauer wrote:
> On Mon, Jan 17, 2022 at 03:28:17PM -0800, Trent Piepho wrote:
> > On Mon, Jan 17, 2022 at 3:03 PM Jules Maselbas <jmaselbas at kalray.eu> wrote:
> > >
> > > +choice
> > > +       prompt "Logo image encoding format to be used"
> > > +       default BAREBOX_LOGO_PNG
> > > +
> > > +config BAREBOX_LOGO_PNG
> > > +       bool "png"
> > > +       select PNG
> > > +       help
> > > +         Encode logo with the PNG image format
> > > +
> > > +config BAREBOX_LOGO_BMP
> > > +       bool "bmp"
> > > +       select BMP
> > > +       help
> > > +         Encode logo with the BMP image format
> > 
> > You might say why one might want one format or ther other.  What's the
> > point of adding bmp support?
> 
> The point could be that for a small logo a bmp image + renderer is
> smaller than a better compressed image + a bigger renderer. I don't know
> if that's actually the case though.

bmp images are ~3 times to ~25 times bigger than png, while qoi images
are at most twice as big as png images.

Using the sandbox config (target x86), the final binary, is compared to
using png:
  - bmp: +1.31MB in total file size (~45%)
  - qoi: +44.0KB in total file size (~1%)
         roughly (+55KB from images, -10KB from .text/.rodata)

The intresting part is that qoi image can be futher compressed, using
lz4 or lzop, and have a file size very close (even smaller) than png
images (not further compressed).

best,
Jules