[RFC] Qi Bootmenu

[Marc Andre Tanner]

On Sat, Oct 10, 2009 at 12:14:02AM +1100, Carsten Haitzler wrote:
> On Fri, 9 Oct 2009 13:00:12 +0200 Marc Andre Tanner <openmoko at brain-dump.org>
> said:
> > On Fri, Oct 09, 2009 at 02:35:14PM +1100, Carsten Haitzler wrote:
> > > On Thu, 8 Oct 2009 22:50:00 +0200 Marc Andre Tanner
> > > >  - GUI based on elementary with framebuffer support?
> > > > 
> > > >    In theory this would be the best solution because we would
> > > >    use the same technology as in a normal system just with a 
> > > >    different backend.  This should ensure that it's actually
> > > >    finger friendly. Although text entry remains a problem 
> > > >    because the illume keyboard can't be used. But I hope that
> > > >    text entry won't be necessary anyway (no kernel command line
> > > >    changes through the GUI, sorry ;) In practice I don't know 
> > > >    how mature the framebuffer backend actually is and it has 
> > > >    quite a few dependcies[2]:
> > > > 
> > > >     * eina
> > > >     * eet
> > > >           o zlib
> > > >           o libjpeg
> > > >     * evas
> > > >           o freetype
> > > 
> > > i think you missed fontconfig - though it is optional, all the default
> > > themes for elementary etc. assume fontconfig support for font naming.
> > 
> > Ok now I am confused. Evas actually has support for reading fonts.{dir,alias}
> > files and doesn't require fontconfig for this. Doesn't this work the way I 
> > think it does? 
> 
> oh wait. sorry. fonts.dir and fonts.alias are built-in. they are old x-stile
> font naming schemes. its a simple parser. fontconfig provides things like Sans
> etc. normally. i've actually totally forgotten about that code. it's ancient.
> interesting that it still works! :)

Ok, I have to admit my knowledge about fonts is basically inexistent.

Does this mean the fonts.{dir,alias} files are useless because the mapping for
special styles like bold/italic doesn't work? And I need fontconfig for these?
I probably don't need special styles anyway and I certainly don't find the idea
of storing font configuration in XML that appealing...

> > > >     * ecore
> > > >           o ecore-file
> > > >           o ecore-evas
> > > >           o ecore-input
> > > >           o ecore-job
> > > >           o ecore-txt
> > > >           o libiconv (functionality can be provided by uClibc)
> > > >           o tslib
> > > >     * edje
> > > >           o embryo
> > > >           o lua
> > > >     * libpng
> > > 
> > > nb. u can drop libpng. if all your image data is inside edje files (or u can
> > > put it inot .eet files too) then you won't need this.
> > 
> > I added libpng because I saw that the default elementary themes uses png files
> > and I thought it needs some way to read them, thus libpng.
> 
> the theme does. but its compiled into a .edj file. once there it is no longer
> png :) no need for png.. unless u - un your app, specify png files for things :)
>

Thanks for the clarification I'm starting to understand how this all works. 

So if I want to load an external logo from the SD card I would need a image
library. Since libjpeg is already a dependency of eet I could just require
that the system images provide an jpeg logo and libpng can go away.

Just out of interest: how is the image stored in the .edj file? Since eet 
depends on libjpeg is it reencoded as jpeg? 
 
> > > >    I have cross compiled all this and without any special optimisation
> > > >    (I just disabled everything in ./configure which seemed not critical)
> > > >    the whole system is about 6-7MB large this is without the kernel.
> > > 
> > > indeed.
> > 
> > As a said this is without any optimization, no special compilation flags, 
> > nothing. I should try to link everything statically which has 2 main
> > advantages:
> 
> you will save very little with things like -Os. maybe 5-10%. on a good day.
> that ballpark.

Newer gcc's support whole build optimization that is you basically compile an
entire project with one gcc inovacation. It will use lots of memory at compile
time but because it has more knowledge about the whole project and how the 
different parts work together it can use more advanced optimization techniques
which should result in smaller/more efficient code. Anyway this is the theory
I will see how this works in practice. There are enough other things to
improve before I even want to start with this kind of thing. 
 
> >  - the linker should be able to remove any code paths which aren't actually
> >    used.
> 
> not from share libraries. only if you statically compile with executables.

That's what I meant. I would statically compile my bootmenu app and just copy
that over to the rootfs.

> >  - at runtime the dynamic linker doesn't have to load all the libraries 
> >    (less I/O + code relocation) which should speed up the application start. 
> > 
> > > >    I am not familiar with the EFL code base but what I have seen
> > > >    so far seems like it isn't really optimized for size. So there could
> > > >    be some potential although it would require some work and upstream 
> > > >    approval.
> > > > 
> > > >    Maybe the idea to use elementary is overkill but what are the 
> > > >    alternatives? 
> > > 
> > > i'll shime in here. yes. efl has grown over the years, and well - the more
> > > functionality you want, the more space it will take. if you are hell-bent on
> > > smallest size you possibly would just write your own fb gui that is very
> > > simple and ugly (with white/black boxes for example). 
> > 
> > I know that elf provides a lot of features and is rather small for what it
> > does (don't get me started on gtk or qt). But what suprised me for example
> > was that although I had compiled elementary with just the framebuffer backend
> > it nevertheless tried to use the X backend unless it was told to not do so
> > (with ELM_ENGINE=fb). So there apparently is code there which strictly
> > speaking doesn't has to be there.
> 
> x11 engine is the default. thats just how the code is. :) if its not coimpiled
> in you just get stubs trying to use the engine and returning 0 saying they
> cant (ie nothing compiled in) you wont save more than a dozen or 2 bytes by
> trying to remove these stubs entirely. its not worth it.

Ok that's probably true, I was just arguing from the busybox mindset where a few
bytes are actually a worthwhile saving ;)

> > Another thing is the lua/embryo thing. If I am not mistaken they basically do 
> > the same thing so it should be possible to only use one of the two. Lua was
> > added recently and should become the default, right? So embryo will go away in
> > the long run, correct? But I guess it will be needed for backwards
> > compatibility anyway so in my opinion it should be possible to disable lua at
> > compile time.
> 
> there .. no. embryo is there because it is a default feature of edje. lua is as
> of recently also a default feature. it is required because all edje files are
> equally capable. i do not want an edje that "might not work with some edje
> files". it's not going to happen because as policy i want all edje files and
> themes to work the same everywhere. not fail or work stangely because someone
> happend to build without the support somewhere. thus you will need both. note.
> embryo is TINY. its runtime library is on the order of about 40kb. thats the
> footprint. the bits in edje that hook to it might be another 10kb of code at
> worst. lua is much bigger - but we are now using it because it saves us work
> and adds more power. it's not fully up and ready yet, but it will be. so you're
> getting both embryo and lua. one way or another.
> 
> (not embryo script is compiled to bytecode and put into the .edj files. its is
> VERY fast to execute. about 2x faster than java. it wil be many times faster
> than lua to execute the same logic, so as long as you want just simple logic -
> use embryo script. if u want to get more complex and imaginative.. then u want
> lua - so there is a very good reason to keep both. efficiency)

Again thanks for the clarification. I understand your point of view regarding
ejde files which should work everywhere to a certain degree. On the other
hand I think that the peoples who actually use lua could enable it on their own,
or there should at least be the possibility to disable it. Afterall special 
environments like the one we are talking about here don't need it.

I guess I could either use an older svn snapshot before the lua merge (I don't
like this option because it of course means bugs wont be fixed in my version)
or patch it manually out (don't know how complicated that would be). 

> > > to reduce complexity i would even remove fonts. what i'd do is:
> > >
> > > 1. every bootable os provides as well as kernel in /boot/zImage (or
> > > wherever), it provides a /boot/bootIcon - this is a simple zlib compressed
> > > (see zlib docs on how to simply give it a chunk of data to compress, or
> > > decompress). you could avoid compression if u want, but i think this would
> > > be worthwhile. lets say the icon data is RGBA (lets use a universal format
> > > to account for different devices with different screen depths/formats).
> > > aany bootable os must provide this file or it wont be listed. (yes it's an
> > > added requirementm but moving work to the bootable os's i takes it out of
> > > the qui boot image)
> > > 2. within the qui boot fs u include some /boot/wallpaper file - same format
> > > as icons.
> > > 3. you load wallpaper, convert to screen depth in the simplest/dumbest way
> > > (speed isnt important. you are not doing realtime ui rendering). eg for
> > > 16bpp this would be:
> > > 
> > > unsigned int *inpix;
> > > unsigned short *outpix;
> > > 
> > > *outpix = (((*inpix & 0xff0000) >> 19) << 11) | (((*inpix & 0xff00) >> 10)
> > > <<
> > > 5) | ((*inpix & 0xff) >> 3);
> > > 
> > > i'll leave it up to you to handle other screen formats (32, 24, 18, 15, 12,
> > > 8bpp etc.). but one per format.
> > > 
> > > now blend the icons u find (u'll probably just want to blend agaibnst the
> > > original rgba wallpaper image and then convert thr result to screen format
> > > like above - see google for alpha blending math. its rather simple. it's
> > > easy to do, its much more work to do FAST. here speed isnt important as u
> > > are just going to render this once and put it up - no realtime ui), one at
> > > a time on the screen eg:
> > > 
> > > +-------------+
> > > |             |
> > > | [ 1 ] [ 2 ] |
> > > |             |
> > > | [ 3 ] [ 4 ] |
> > > |             |
> > > | [ 5 ] [ 6 ] |
> > > |             |
> > > +-------------+
> > > ... etc.
> > > 
> > > as many as the screen fits - the icons themselves can just be an image (eg a
> > > penguin) or image + text. u'll probably want to use tslib and get coords
> > > when u press to see if up press on one of them - then boot that. you should
> > > adjust the layout based on screen size. eg for landscape:
> > > 
> > > +-------------------+
> > > |                   |
> > > | [ 1 ] [ 2 ] [ 3 ] |
> > > |                   |
> > > | [ 4 ] [ 5 ] [ 6 ] |
> > > |                   |
> > > +-------------------+
> > > 
> > > this will provide all you need for a grahical boot. it wont be smooth. it
> > > wont scroll or animate. it wont let you add much more complexity without a
> > > lot of work (eg configuration panels or more than the above hyper-simple
> > > boot), but it will function and be very small.
> > 
> > Thanks for your insight. I think it's a little to low level for me right now,
> > afterall I have a limited amount of time I can spend on this. The key is
> > probably to get the right balance between the amount of work and usability /
> > performance. For now I will leave some abstraction layers in and see how
> > small/fast this can be made. 
> >  
> > > of course it's easy for me to say this. i've done all this kind of stuff
> > > before. many times. in fact deep down inside efl are semblances of some of
> > > this, as just a subset of all that efl does. but it does so much more so
> > > it's not small. in return for that footprint you get a small mountain of
> > > features. but as i said - easy for me to say the above. i can do it in my
> > > sleep - it'sw hat i do, but it's up to you to decide if you are up to doing
> > > it at this low level or not. for any reasonable app you'd end up using
> > > enough of efl's features to make it worth carrying along its size. it'd be
> > > worth the expense, but... for you i don't know if you will ever use all
> > > those features. it may simply not be worth it. as long as u use efl your
> > > image is not going to be that small. then again you are adding dropbear and
> > > thus also enough network config tools to set up usbnet
> > 
> > This should be covered by busybox i hope.
> 
> hopefully, but every busybox feature added is more space. 
> 
> > > - what about wifi? wireless tools too? how much is the
> > 
> > Not going to happen (at least not by me). The network support is just to
> > provide a kind of minimal rescue system to ssh in over usb, mount the sd card
> > and then chroot into the regular system to fix something. It's not intended
> > to get some kernel + root filesystem from a NFS server over wifi. Anyway if
> > the usb network support should be the few KBs which make it to large/slow
> > then I will probably drop them. 
> 
> ok.
> 
> > > image size when you remove any of the ui bits - all your other parts (libc,
> > > busybox, dropbear, network tools to bring up usbnet and/or wifi, wireless
> > > tools, dhclient if u have wifi... etc. first see how big that is. how big is
> > > it? then relative to that, look at ui.
> > 
> > I agree that this is the right approach. Antoher interesting thing is how much
> > an aditional MB actually costs in terms of speed (copy from NAND to RAM).
> 
> oh true. though it might work best as a real jffs or cramfs fs instead of
> initrd - it's flash. you have no seek overhead so a linear read isnt going to
> be much better than a sparse fetch of whats needed from jffs2 or cramfs. in
> fact chancges are u'll be better off as u fecth "on demand" as opposed to read
> everything even though some of it isnt needed. my suggestion might be cramfs as
> its going to compress best. :)

This would require that the kernel partition in NAND is formated as a 
filesystem but then Qi couldn't read from it. Or am missing something obvious
here?

> > Below is a listing of my current initramfs files sorted by size. Now that I
> > compare them to my SHR system I see that they are a lot larger. For example 
> > libevas-* is only 687K on my SHR. I will have to investigate if this is just
> > because of the missing optimization flags in my $CFLAGS or what causes this. 
> 
> ok. for option 1, u can nuke libpng. thats 224k gone. libecore_con should be
> able to go. i can't think of a reason you need it.

I enabled it because it seemed like ecore-file was going to need it. I will
recheck this.

> another 44k gone. the
> evas jpeg image loader can go. another 20k. 

I guess I will need this if I want to load logo's from the SD card.

> all the saver modules for evas can go 

I didn't find a way to disable them during ./configure should I just not copy
them over to the rootfs?

> and the png loader. thats a total of 32k gone.

Yay!

> now elementary's default them
> can be very much trimmed. it has images - a fair few in it. if you used fewer
> images and smaller ones that were much simpler and re-used a lot, it'd make it
> smaller. you could get that default theme down to maybe 50-100k without much
> trouble. 

As my designer skills are < 0 I will leave this as is for now.

>also you use DejaVuSans.ttf - its HUGE. 

Yes I just used it to test the font issue thing I posted about on e-devel.

> it has lots of chars for all
> sorts of international text (outside of latin/western european). the standard
> and much smaller Vera.ttf  is only 72k. (DejaVu was a modified Vera with all
> these extra chars added). so you could save 512k by using plain old vera
> instead (this i think has western european accented chars like ö and é œ ß etc.
> so u could even handle that, but for a bootloader i suspect normal
> lasting/ascii is just fine. right?).

Of course plain ascii is enough. I will switch to Vera.ttf.

> so.. lets see. for your #1 i can find 224+44+20+32+512k of savings without
> changing any functionality or doing any real work except deleting files. that's
> 832k to squeeze out there. you can add another probably 250k of savings if u
> spend time in making a very lean theme. so we're about 1.1mb now to lose (of
> uncomrpessed files - and of course this is rounding up all files to 4k blocks
> of savings may be a little less).
> 
> now if u did option #2 and did a lower level ui with no text (text in the
> icons) just with evas + ecore-evas, you could save an extra (on top of the
> total savings above) if you put png loader back but remove eet (this means u
> dont need libjpeg anymore), so... +224 -272 -108 -648 -72 -384 -78 -44 -8 +8
> (trust me on this) ... another 1382k of savings on top of the reduction in #1.
> 
> in #2 efl itself will have a footrpint of 928+448+224+168+100+84+28+24+24+16+16
> +32+8+8+8+8+4+4+4+4... 2100kb. so thats efl's footprint (approximately) in
> addition to a minimal core os. thats whgat it costs you in space for efl to
> save you work for #2 - of course #1 will cost an extra 1382kb on top of this

Thanks for the calculations :) So for now I hope that those 1382kb won't have
that much of an impact.  

> so that is about the best i can do for you. note these numebers are
> uncomrpessed. comrprssed expect the numebrs to about halve. ie efl costs u
> about 1mb of "storage" as after compression thats what u'll get. elementary,
> edje and friends will cost u another about 700k on top. based on your numbers
> below. :) that's not a hell of a lot.

I agree for what it does that's not a lot at all.

[snip file sizes]

> > > one thing i can suggest. you can drop edje and elementary and do this in
> > > just ecore_evas + evas. you could even drop eet here. just 1 image format
> > > loader (eg libpng), and you'd be able to i think have a subset of ecore
> > > (ecore, ecore_evas, ecore_input, ecore_fb), and just evas + buffer,
> > > software_generic and fb engine and just png loader module. no savers
> > > modules.
> > > 
> > > now you'd need to create all your own "widgets" - but you could stick to a
> > > simple design as above just an array of icons. load the icon files (now u
> > > can make them .png files in the boot dirs of the os's) and put them on the
> > > screen. you can now easily add callbacks for the mouse down (or up really)
> > > on each icon and boot the appropriate os. wallpaper can also be a png file
> > > in the qui boot fs. you will be using efl at a lower level. you handle the
> > > callbacks directly and place the objects yourself (and handle canvas
> > > resizes - yes it can happen even on the fb. eg a resolution change, but in
> > > general handling this right just handles the inital fb size right anyway).
> > > this will mean you donthave to handle rendering code and different screen
> > > formats, image loading or tslib interfacing etc. it should have you a much
> > > reduced efl footprint. but keep you from the lowest ugliest bits. hell if
> > > you keep all the "os info for the ui" inside the png font handling is moot.
> > > u will still need freetype - but u just put name of the os image into the
> > > icon itself (nothing 10 seconds in gimp cant do).
> > > 
> > > so to repeat
> > > 
> > > 1. either full efl, elementary etc. - but this will be a big footprint.
> > > always
> > > 2. subset of efl and keep your ui simple eg as i described above and punt
> > > off all the os identification to a png icon as i described above and
> > > justddumbly display it and handle events when the user presses it. smaller
> > > than full efl but not totally minimal.
> > > 3. do it all yourself at the lowest levesl. as small as it will get but by
> > > far the most amount of work for you.
> > 
> > Thanks for this nice overview.
> > 
> > I would like to try it in that order and see how useable it is speed wise and
> > if it's too slow then move to the next variant and remove one layer of 
> > abstraction.
> > 
> > For now I am working with option 1. As I said in my first mail it would be
> > nice to use the same technology just with a different backend and therefore
> > reuse all the work you and others have put into it.
> > 
> > Option 3 (although probably not as low level as you described it) is what 
> > kexecboot does. It would therefore be an option to add touchscreen support to 
> > kexecboot. I would probably not be as pretty as an elementary based solution
> > if there are people who actually care about the optical aspect of the thing. 
> 
> sure. as i said. options. #3 is by far the most work with the least visual
> appealing results. #2 is probably a nice half-way-house. :)
> 
> > > > Proof of Concept
> > > > ================
> > > > 
> > > > As a proof of concept I started to write a simple shell script (well
> > > > in the beginning it was simple in the meantime it evolved in kind of 
> > > > mini build system, maybe something like OpenWRT could be used but I
> > > > wanted a simple solution where I actually understand what's going on) 
> > > > which downloads and cross compiles everything with an uclibc based 
> > > > toolchain.
> > > > 
> > > > So far I have cross compiled all the components mentioned in this 
> > > > post the result is about 6-7MB large.
> > > > 
> > > > I then tried to run the elementary dialog application from the 
> > > > elementary wiki page[3] in a chrooted system and this works
> > > > (although there seems to be a problem with the touchscreen which
> > > > doesn't quite work right and sometimes even causes a segfault).
> > > 
> > > do you have ts calibration working? 
> > 
> > Don't know yet, I have just copied over the ts.conf from SHR so that it at
> > least uses the same/right modules. Touchscreen calibration is the next thing
> > I need to look into. Because I tested this in a chroot from within a SHR
> > system I thought the touchscreen would already be in a redy-to-use state (i.e
> > calibrated) is this a wrong assumption? 
> 
> ok. chances are a pre-calibrated file will be ok. but if u want to work on
> multiple devices (not just a freerunner and in the end this is a goal you
> should have in mind as there will be more devices with different sized screens,
> etc. etc. and its good to plan ahead).

True.

Thanks,
Marc 

-- 
 Marc Andre Tanner >< http://www.brain-dump.org/ >< GPG key: CF7D56C0