Hi Zach, thanks a lot for review.
It is generally very good, modulo a few bugs (see below).
What means "modulo a few bugs"?
There are some specific problems with the tests, though. For instance, png_read_test.cpp takes an image file, reads it, then writes it to a temporary file, then re-reads it from the temp file, and compares the two read-in images for equality. This strikes me as a bad test. It is quite possible to read an image, get the wrong results, then write those wrong results to disk, re-read them, and then have the re-read results compare equal to the original read results. There may be other tests with a similar organization; I did not check.
This would assume that both png reader and writer have some bugs in common. I consider that less probable. This test is not perfect, I agree, but I cannot just do a byte compare between the original and copy since the header information might different. If both file have the exact pixel values, that's a good indicator that writing and reading does something right. But I agree with you that testing image writing and reading can be problematic when the same library is used. Maybe I should use ImageMagick as the reference reader and my own lib as the writer in this case.
- What is your evaluation of the documentation?
I was unable to build the docs. I'm actually surprised that the review manager allowed this to go to review without pre-generated, web-accessible docs.
I'm working on it. It turns out that building quickbook is too complicated for me. There are several threads on the boost-user and boost-build mailing lists to overcome my troubles. In case my proposal is accepted I'll make sure I can build the documentation before I add anything to boost. Sorry for inconvenience.
- Did you try to use the extensions? With what compiler? Did you have any problems?
I only evaluated the PNG loading code, in an existing library that already uses (a modified) GIL for image file loading. My library's modified copy of GIL has numerous fixes to the PNG loading code. When I substituted gil.io_new, I found that several files were again unreadable.
I just did a quick test with space_elevator.png you mention below. May it be that you forgot to set the BOOST_GIL_IO_ENABLE_GRAY_ALPHA symbol? The following code works just fine: #define BOOST_GIL_IO_ENABLE_GRAY_ALPHA 1 #include <boost/gil/gil_all.hpp> #include <boost/gil/extension/io_new/png_read.hpp> using namespace boost; using namespace gil; int main() { gray_alpha8_image_t img; read_image( "C:\\chhenning\\zach\\art\\icons\\tech\\space_elevator.png" , img , png_tag() ); return 0; } Regards, Christian