From: "Luis A. Florit"

[ . . . ]
My questions: When to use one and when two iterators? Which one should I use for a procedure like the one described in my plugin? Is this indeed faster than the method I implemented based in myblur5.c?

You probably shouldn't do this at all. The gimp_pixel_rgns_process method handles the data tile by tile, which means that it is impossible, or at least quite difficult, to handle interactions that extend across multiple tiles. It is mainly useful -- and very efficient -- for plugins that act on individual pixels. Your plugin, because it needs to look at neighborhoods, does not fall into that category.

-- Bill

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Hi,

On Fri, 2007-03-16 at 10:39 -0700, William Skaggs wrote:

You probably shouldn't do this at all. The gimp_pixel_rgns_process method handles the data tile by tile, which means that it is impossible, or at least quite difficult, to handle interactions that extend across multiple tiles. It is mainly useful -- and very efficient -- for plugins that act on individual pixels. Your plugin, because it needs to look at neighborhoods, does not fall into that category.

Correct. It would be worth nothing though that a plug-in that processes the data row-by-row should make a call to gimp_tile_cache_ntiles() to make sure that tiles can be cached on the plug-in side. With a tile cache that is large enough to hold two rows of tiles, using gimp_pixel_rgn_get_row() and set_row() shouldn't make much a of a difference performance-wise.

Sven