Fwd: Hello, how is it going?

(Yes, he was OK with forwarding.)


---------- Forwarded message ----------
From: Tor Lillqvist <tml@iki.fi>
Date: 1 June 2012 11:26
Subject: Re: Hello, how is it going?
To: Iain Billett <iainbillett@gmail.com>

(Are you OK if I forward this message also to the list?)

> Am I right in
> saying that DocumentLoader up to now didn't display any output other than a
> title bar?

Yep. (Nor was it expected to; lots of time went into just to get a
working infrastructure and plumbing necessary for a document to load
(into internal data structures etc, without any rendering). Only for a
few weeks had I now then been investigating, experimenting, reading
code and documentation to find out how to get the document to render
into a bitmap. And it turned out to not be that complicated after all.
Sigh.

> I've been thinking about this. A pretty simplistic scheme would be to have a
> 'viewer' for each document type ( This may not be necessary but it seems
> sensible given each doc type has a different logical structure, how is a
> spreadsheet divided?) based on documentLoader which simply provides page
> tiles for rendering in the GUI. Then we could have editors which extend
> viewers.

Yep. One complication is that I don't want to write the same code,
basically, twice: once in Java for Android and once in C++ for iOS
(and potential other software on other platforms where one would want
to use LO code to load documents and render pages into bitmaps). So
need to come up with some suitable way to share code.

> I think it's certainly possible to manage with the Android API but using
> OpenGL should be more flexible which could be useful in the long run.

Yep. And for both Android and iOS, OpenGL is actually the lower level
that everything goes through anyway, isn't it? Actually I am not sure,
but maybe, so even if one would use no "advanced" OpenGL
functionality, using it to just display a texture into which a (part
of a) document page has been rendered, that would bypass several
layers of "normal" Android / iOS GUI library. But I am probably just
talking crack here...

How familiar are you with OpenGL (ES)? Myself, I have never really
used it "for real" on any platform, but I have read/browsed several
books about it over time, and written some occasional throwaway test
programs, so I am definitely not "scared" of it;) Probably the more
traditional OpenGL ES 1.0 will be enough for us, I doubt we will need
shaders.

> There's quite a few examples on how to
> implement scrolling / zoom on this type of layout.

For the "silly test" DocumentLoader I found an open source class
called GestureImageView which was trivial to take into use. But that
is just for that test app, I doubt it is suitable for any "real" app
we work on as part of this GSoC work. (GestureImageView is Apache
licensed, so ideas and code can certainly be borrowed freely from it,
if needed. And as you say, there are lots of other sample code and
tutorials etc.)

> Having said that, from my
> point of view I'd like to get familiar with OpenGL on android, I've only
> really tinkered up to now.

Ah OK, that answers my question above. You are basically in the same
situation as I then, I guess? Or have you used OpenGL "for real" on
other platforms, just not the ES version on Android?

--tml