"Phil Endecott" <spam_from_boost_dev@chezphil.org> wrote in message news:1292110169238@dmwebmail.dmwebmail.chezphil.org...
why can't you just read individual 5k input tiles and chop each of those into the smaller output PNGs and then move on...yes the 5000%256!=0 issue might require reading up to 4 input tiles and/or remembering some of the edge data for the cross-border input tiles and/or maybe of the input tile which in turn would require a (much) more complex code...but I do not really see the issue with that
I prefer fast and simple code to either fast-and-complex or slow-and-simple.
Khm...I must say I still doubt that that/your approach, considering the inherent RAM and disk thrashing (and the consequential virtually zero locality of reference) can be even nearly as fast as the 'complex code' solution...
So I just want the library to provide the simple open/read-row/write-row/close functionality for the image files, and to supply types that I can use for pixel_t, etc.
Independent of the rest of the discussion/issues, yes I would agree that explicit read/write row would be a valuable part of the interface...
Great.
As mentioned in a recent reply to Mateusz, I've finally cleaned up the code to compile on GCC and Clang as well as added a 'low level interface' (to all backends) that might satisfy your needs: - pixel_size() - row_size() - format() - image_format_id() - can_do_row_access() - can_do_tile_access() - can_do_roi_access() - can_do_vertical_roi_access() - begin_sequential_row_access() - get_native_format<> - global formatted_image_traits<>::supported_pixel_formats_t + libtiff_image specific: - tile_size() - tile_row_size() - tile_dimensions() - begin_sequential_tile_access() Most of these are probably obvious (or will be from examples/code), except maybe for format() - it will return a 'value' that is a backend's internal representation of the loaded image's pixel format and can be used in two ways: whether it matches a format of your target image (whose, backend's internal, format value you retrieve with the get_native_format<> member metafunction) or to convert it to the index in the backend's MPL typelist of supported formats (e.g. formatted_image_traits<libjpeg_image>::supported_pixel_formats_t) by passing it to the image_format_id() static member function... You can find a link with example code in the recent reply to Mateusz: http://lists.boost.org/Archives/boost/2011/01/174907.php ... hope you find it useful... -- "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