Draft document-rendering tiling API to be called from viewer apps

[Michael Meeks]

On Wed, 2012-06-06 at 17:48 +0300, Tor Lillqvist wrote:
> >        IMHO the decision to render just squares prolly complicates the
> > situation un-necessarily.
> 
> Sure, but on the other hand it makes it simpler in that we don't need
> to figure out the aspect ratio of each page (they can be different)
> beforehand.

	Surely we have to do that in order to present it to the user ? at
least, I assume we would want to end up with a texture that is the
size/shape of the page - it sounds like you have something different in
mind though (?).

> BTW, I didn't mention in the IDL, but I did think that the not only
> would it be a square, but also the side of the square would be a
> power-of-two. Presumably you also want power-of-two for each side?

	Not really; my main concer was to ensure that we could render a region
of the document into a full-screen window ;-) such that we could get
that middle bit of the page (or worse spreadsheet) rendered so we didn't
have to create an humungeous texture of the whole page at a high
resolution and throw most of it away :-) Prolly 'tiling' is the wrong
word to use for that ;-) my bad; the whole thing brings back hideous
memories of the libart_lgpl work / optimisation that turned out to all
be worse than useless on even legacy hardware.

> > Consider an A4 document - 2 x sqrt(2) in
> > dimensions - almost certainly we end up with some 21x17 type ratio and
> > then have to work hard to try to pack squares into it.
> 
> Hmm, but isn't this then an argument *in favour* of keeping the
> rendered area square (and with a power-of-two side)? (Note that this
> would mean that when zoomed in at some level and beyond, some tiles
> will be completely outside of the page area.)

	IMHO the use of the term 'tiles' here is prolly just a misleading
nonsense ;-) my main concern is the ability to render an arbitrary
sub-set of a page to an arbitrarily sized texture.

	HTH,

		Michael.

-- 
michael.meeks at suse.com  <><, Pseudo Engineer, itinerant idiot