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From Andre Fischer <>
Subject Re: Why is it so hard to make a Java program appear native?
Date Tue, 12 Aug 2014 07:04:02 GMT
On 11.08.2014 20:25, jan i wrote:
> On 11 August 2014 20:12, Peter Kelly <> wrote:
>> On 11 Aug 2014, at 3:42 pm, Andre Fischer <> wrote:
>> Question: To what extent is the OO UI frontend code separate from the
>> backend editing, file format handling, and rendering code? I'm thinking in
>> particular here of mobile - which demands a completely different approach
>> to user experience design than desktop. Could OO conceivably be adapted to
>> mobile by replacing its UI?
>> Conceivably? Probably.  But the problem is in the details.  AOO has put a
>> lot of effort into separating UI from model and from underlying frameworks.
>>   For example you can use the UNO API to access a lot of functionality
>> without bothering with the UI.  You can run AOO headless (without any UI),
>> and you can run AOO on several different GUI frameworks (Windows, Mac OSX,
>> Linux with a mixture of X11 and Gnome/KDE).  The problem is that there are
>> dependencies between UI and model or framework.  Most of them not designed
>> but "grown" because of convenience or laziness.
>> So, if you wanted to port AOO to another window system with basically the
>> same UI as today you would probably port VCL (the UI abstraction layer of
>> AOO).  That would involve a lot of cursing but it is doable (it has been
>> done for OSX).  For a mobile device you probably don't want the same UI but
>> something that can be operated with larger input devices then the typical
>> mouse pointer (i.e. fingers).  One way to do that would be to write the GUI
>> from scratch and use the UNO API as a backend.   I am not sure that that is
>> possible though.  If you drop VCL, you don't have SFX2 with its view shells
>> (a mix of view and controller) or slots (a mix of remote procedure calls
>> and value passing).  That means that a) a lot of functionality has to be
>> rewritten (not necessarily a bad thing when you consider the quality of the
>> existing implementation) and b) that that might break the UNO API (which
>> would be bad).
>> Maybe we need an experiment to see what is possible?
>> I'll have a look into the code to understand the architecture better and
>> then hopefully be able to contribute some more informed thoughts about it.
>>  From what you've described, it sounds like there is a dependence from the
>> OO codebase to VCL, is that correct? If my initial understanding it is
>> correct, it sounds like it would be possible to port this to iOS/Android
>> with sufficient effort, though I think that writing a from-scratch UI would
>> be needed, as you suggested. That is, largely to address the much smaller
>> screen real estate and touch controls, and the types of UI layouts that are
>> common on phones/tablets.
>> The fact that OO can run in headless mode sounds promising, since the
>> ability to access much of the functionality without any UI implies that a
>> totally different UI could be put in place on top of this.
> I just wonder if the effort pays off. AOO contains tons of very good ideas
> (proven over time) but equally old code. Juergen have multiple times argued
> that it might be more efficient, to pick the ideas and write new code with
> modern tools, i tend to agree to that.
> Please remember AOO is a good mixture of C/C++/Java/Python/Perl (I might
> have missed something), whereas a new codebase would be simpler.
> We might be able to avoid the big bang, by using AOO in headless mode and
> change to new code part by part.
> But I agree with andre that an experiment, just  moving a little part would
> be a nice proof.

Please don't get me wrong.  I did not mean to advocate porting the 
existing code base to iOS or Android.  Only that if one where to try it, 
then start with an experiment to avoid nasty surprises at a later stage.

If we would want to go towards mobile I would prefer a rewrite.  We 
could certainly salvage one or the other idea but I believe that we 
should focus more on the mistakes that where made and try to avoid 
them.  Remember, AOO is based on a "design" that was made 15 to 20 years 
ago.  A lot of bug fixes where made and a lot of features added in the 
meantime.  But many limitations (like VCL providing rendering of UI 
controls, behavior of them, event loop and some other things, or SFX2 
with its slots, items and view shells) still exist.

Therefore I would start fresh with a limited feature set but with a 
better design than before.


> just my 2ct.
> rgds
> jan I.
>> --
>> Dr. Peter M. Kelly
>> Founder, UX Productivity
>> PGP key:
>> (fingerprint 5435 6718 59F0 DD1F BFA0 5E46 2523 BAA1 44AE 2966)

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