On Feb 20, 2013, at 10:12 AM, Ostap Pochtarenko wrote:
> Hello
>
> Corresponds more how to read tiles using "ImageBuf"? Because I don't
> understand how correctly read (records) images which recorded tiles.
>
I'm not sure I understand your question. But I'm going to take a stab at it
anyway.
There are three easy ways to read a tiled image with OpenImageIO:
1. Read the whole image into your own buffer:
// Allocate and read into a big float buffer
ImageInput *in = ImageInput::open (filename);
std::vector<float> buf (in->spec().image_pixels() *
in->spec().nchannels);
in->read_image (&buf[0], TypeDesc::FLOAT);
in->close ();
delete in;
2. Use an ImageBuf:
ImageBuf ib (filename);
ib.read ();
// now you may access the pixels using ib.getpixel(x,y,&myfloatpixel)
// or ImageBuf::Iterator traversal
// or copy to your own buffer using ib.get_pixels(...)
3. Use ImageCache:
ImageCache *ic = ImageCache::create (); // just do this once
... set up your buffer to the right size ...
ic->get_pixels (ustring(filename), ..., &mybuffer);
All of these work identically for tiled and scanline files.
There's one more option: Like #1, but instead of read_image(), you could call
read_tile() repeatedly to read individual tiles. But that ONLY works for tiled
files, and there is no advantage to doing this versus #1 if you need the whole
image at once -- reading individual tiles is only helpful if your application
needs the individual tiles one-by-one.
--
Larry Gritz
[email protected]
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