Understanding API openslide_read_region's arguments

[Benjamin Gilbert]

On 11/13/2012 05:41 PM, Sriram Somanchi wrote:
> So if it computes the averages on the fly is the second call (with
> coordinates (2,2) ) slower than the first one (with coordinates (0,0) )?

I assume so?  But I haven't benchmarked it.

For non-integer downsamples (Aperio, Leica, Trestle), you will usually 
not be able to find integer coordinates in level 0 which produce exactly 
0 subpixel translation in level N.  For higher-numbered MIRAX levels, 
even though the downsamples are integers, we have to do a bunch of 
sub-pixel processing regardless of the region alignment.

In general, I wouldn't encourage designing your program around 
assumptions about OpenSlide's performance under different conditions; 
just ask the API for what you need.

--Benjamin Gilbert