Re: [boost] GIL io_new review

Subject: Re: [boost] GIL io_new review
From: Domagoj Saric (domagoj.saric_at_[hidden])
Date: 2010-12-08 04:45:52

"Phil Endecott" <spam_from_boost_dev_at_[hidden]> wrote in message 
news:1291751283459_at_dmwebmail.dmwebmail.chezphil.org...

> Having said that, I suspect that even with lots of extensions GIL might 
> not really be what I need.  Here's a typical problem that I will have to 
> address in the next few weeks:  I have a 1e12 pixel image - a map - which 
> is supplied as a few thousand 5000x5000 TIFF tiles; I have to join them 
> together, tweak the colours, draw some lines on top, and re-chop it into a 
> few million 256x256 PNG tiles.  The issue of course is that that image 
> can't be held in RAM.  I will do this with my own wrappers around libtiff 
> and libpng, in rows or chunks.

Hi Phil,
if you are willing to try (and can work/test with MSVC on Windows) I think 
io2 should already be able to help you here (partial ROI based access to big 
images) at least with the WIC backend...
The LibTIFF backend is unfortunately still not ready for this as I haven't 
yet implemented full/2D ROI access for it (both because of lack of time and 
because I first wanted to have an open discussion on how it should be done 
for such particular backends, the related LibTIFF issue in question was 
discussed near the end of the "[gil] New IO release" thread)...

Example code demonstrating a possible (skeleton) solution: 
http://codepad.org/WD7CpIJ8 ...

ps. unfortunately I do not have access to such a huge image to test whether 
WIC can actually handle such monster images...

>> - Do you think the extensions should be accepted as a part of Boost.GIL
>> library?
>
> On the grounds that this is better than what is currently there, and on 
> the assumption that Domagoj Saric is not imminently going to post 
> something else that would supersede this, I believe that it should be 
> accepted.

If we've already waited so long, why rush if some of us agree that there are 
still things that need 'polishing'...
You said you already did some LibXXX wrappers of your own...if this is 
so...why not join the effort even if only temporary to make sure you get 
what you want...Christian also seems open for cooperation...

-- 
"What Huxley teaches is that in the age of advanced technology, spiritual
devastation is more likely to come from an enemy with a smiling face than
from one whose countenance exudes suspicion and hate."
Neil Postman