[Boost-users] [GIL] bits8* to gray8_ptr_t without reinterpret_cast?

You might have also seen this question on SO: http://stackoverflow.com/questions/6103252/boostgil-bits8-to-gray8-ptr-t-wit... Trying to work by the design guidelines for GIL, I use |bits__| for my channel data types. I often have external data I'm wrapping into GIL image views. However, even using the |bits__| types for data pointers, I have to add in a reinterpret_cast before I can create my image views. Take the following code |int width= 3; int height= 2; boost::gil::bits8 data8[] = {0, 1, 100, 200, 50, 51}; boost::gil::bits8* pBits8= data8; boost::gil::gray8_ptr_t pGray8= pBits8; boost::gil::gray8_view_t v= interleaved_view(width, height, pGray8, width* sizeof(boost::gil::bits8)); | Results in the error on line 6 "error C2440: 'initializing' : cannot convert from 'boost::gil::bits8 *' to 'boost::gil::gray8_ptr_t' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast" Delving into the source code as much as I can, it appears these types really are unreleated. bits8 is just |unsigned char|, but |gray8_ptr_t| is a pointer to a |struct pixel|. The only element of this struct is a single bits8, so a reinterpret_cast looks safe. It also works fine for the tests I've thrown at it. However, I wrap external data into image views quite often, and having a reinterpret_cast in every place feels problematic. Is there a safer way of constructing a pixel pointer for use in GIL? My current workaround is to create a template specialized cast that only compiles for known safe casts. |template Dest gil_safe_ptr_cast(Src src) { // this cast is unsafe, use reinterpret_cast BOOST_STATIC_ASSERT(false); } template<> boost::gil::gray8_ptr_t gil_safe_ptr_cast(boost::gil::bits8* pBits8) { return reinterpret_castboost::gil::gray8_ptr_t(pBits8); } boost::gil::bits8* pBits8= data8; boost::gil::gray8_ptr_t pGray8= gil_safe_ptr_castboost::gil::gray8_ptr_t(pBits8); // works boost::gil::bits16* pBits16= NULL; boost::gil::gray8_ptr_t pGray82= gil_safe_ptr_castboost::gil::gray8_ptr_t(pBits16); // compile error as expected | If this is the best current solution, I'd be glad to clean it up and pack it into typedefs.hpp for grayscale types. Thoughts?