20160815

Creating Logos for u-boot images

The Default Logo: Tux

By default, Das U-boot uses a penguin logo when it first starts up. This default looks something like this

While it's cool to have this for Linux users, FreeBSD users would like to see something more relevant. I recently got a pcDuino 3 board that I wanted to get FreeBSD running on. When I saw Tux still greeting me, I knew I had to do something. If nothing else, we should be branding the images made by the project with project logos and not the default which advertises a competitor.

The Quest

So, I set off on a quest to find the logo that would be best. It turns out to be not as simple a question as I thought jumping into this as I thought.

Logo vs Mascot

Traditionally, FreeBSD has had both the logo and the mascot as part of its boot sequence. The FreeBSD daemon that was used was based on artwork from the Walnut Creek CDROM which in turn was based on artwork drawn for Kirk McKusick by Lassiter. I realized that I'd have to do both. I'd make the logo the default, but also make it possible to have the mascot. While the Lassiter image appears to be the official mascot of the project, the Walnut Creek CDROM image is more widely viewed as the mascot of the FreeBSD project, so I had to select which one to use, or add yet another option.

Finding Good Artwork

The needs of u-boot is simple. Generally, you have an 80x80 image that's splashed up on the screen. While there is some wiggle room for the size of the icon, irregular sized icons just look sloppy in comparison to the default (there's several in the u-boot distribution to choose from, so I tried each one and was left dissatisfied each time).

A few web searches later, I found the best three examples to work from that I could: one with the FreeBSD logo, one with the Lassiter image, and a decent one of the Walnut Creek CDROM cd inserts and various books on FreeBSD (the older image from the 2.0 CDROM, not the newer one with daemon walking out of the CD that was used after).

The Lassiter image was by far the worst of the lot, but it was the best I could find. It proved too difficult to work with, so I eliminated it from my work. The logo and the Walnut Creek daemons would have to do.

Creating BMP images

Turns out this is harder than I would have thought.

To do the FreeBSD-associated daemon, I grabbed a copy from wikipedia's BSD daemon article and did the following:
convert freebsd-daemon.jpg -bordercolor white -channel RGBA -fuzz 20% -fill black -floodfill +0+0 white -resize 80x80\! -colors 200 -alpha off -type palette -compress none freebsd-daemon-1.bmp
To do the FreeBSD logo, I grabbed a copy from the FreeBSD web site and did the following:

convert logo-full.png -crop 172x172+2+2\! -resize 80x80 -colors 200 -alpha off -type palette -compress none -transparent-color black logo-full.bmp

This astute observer will notice a few things here. First, both images were 80x80. That's the default size. The u-boot tool, even with my fixes, only works with widths that are an even multiple of 4. I did 200 colors, but the limit is 240 (256 - 16).  Due to the way that uboot encodes the images, more than around 100 colors isn't going to have a big impact for either of these images (it takes the upper nibble from R G and B value that, and only that, so nuanced differences in colors don't matter). There's likely some fancy mode to optimize color generation in ImageMagick (where the convert program comes from), but I stopped before finding it.

Fixing U-Boot to have it join the 21st century

Turns out the bmp_logo utility that comes with u-boot has some serious limitations. First, it won't detect when you have a width that isn't a multiple of 4, and will generate a bad file instead that you won't discover is bad until you boot the box. Next, it doesn't check to see if the bmp is a compressed one or not with the same result. Ditto for number of colors. Same result. Those are all annoying, but the worst thing of all is that it won't handle any BMP that's newer than Windows 95. The BMP format has a field in a header that tells it how big the image hader is. bmp_logo, as distributed, assumes this length (40), but that only works for win95 and older (but not too old, super-antient BMPs likely would fail too). Any modern tool will generate the newer format (like ImageMagick does).

I've fixed the bmp_logo program locally, and merged a copy of the diffs into FreeBSD's repo for the sysutils/u-boot-olimex-a20-som-evb port (so all a20 and newer allwinner ports). I'm working to get this upstreamed.

The Results

Logo

Here's a slightly blurry shot of the logo I settled on. https://people.freebsd.org/~imp/20160814_104146.jpg

[update]
http://people.freebsd.org/~imp/20160815_234153.jpg uses the newest FreeBSD Foundation recommended logo...

The Daemon Formerly Known as Chuckie

Here's a blurry shot of the Walnut Creek daemon.  https://people.freebsd.org/~imp/20160814_124703.jpg

u-boot changes

I've created patches for the A20 Allwinnner ports. They will be committed shortly. I'll also be working to get these upstream into u-boot.

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