Re: [Boost-users] [GIL] Problem trying to use scoped_channel_value with copy_and_convert_pixels

Subject: Re: [Boost-users] [GIL] Problem trying to use scoped_channel_value with copy_and_convert_pixels
From: Nate Crookston (nathan.crookston_at_[hidden])
Date: 2015-01-12 14:43:15

Whoops, the diff was cut off.  Here's the full diff, on the off chance you
need it:

diff --git a/include/boost/gil/channel_algorithm.hpp
b/include/boost/gil/channel_algorithm.hpp

index 1361219..1799470 100644

--- a/include/boost/gil/channel_algorithm.hpp

+++ b/include/boost/gil/channel_algorithm.hpp

@@ -51,7 +51,7 @@ template <typename SrcChannelV, typename DstChannelV,
bool SrcLessThanDst, bool

 template <typename UnsignedIntegralChannel>

-struct unsigned_integral_max_value : public
mpl::integral_c<UnsignedIntegralChannel,-1> {};

+struct unsigned_integral_max_value : public
mpl::integral_c<UnsignedIntegralChannel,(1<<sizeof(UnsignedIntegralChannel))-1>
{};

 template <>

 struct unsigned_integral_max_value<uint8_t> : public
mpl::integral_c<uint32_t,0xFF> {};

HTH,

Nate

On Mon, Jan 12, 2015 at 2:04 PM, Nate Crookston <nathan.crookston_at_[hidden]>
wrote:

> Hi Gabriel,
>
> I've successfully done what you're trying to do I think.  I wrote about
> some problems in the following thread:
> https://groups.google.com/forum/#!topic/boost-list/4CqibxPFdUw.  In
> short, I had to specialize a few other metafunctions.  I think we should
> add a scoped_integral_channel_value type which has appropriate
> specializations for people trying to do what you're doing.
>
> I had to make the following change to compile with c++11 clang:
>
> *diff --git a/include/boost/gil/channel_algorithm.hpp
> b/include/boost/gil/channel_algorithm.hpp*
>
> *index 1361219..1799470 100644*
>
> *--- a/include/boost/gil/channel_algorithm.hpp*
>
> *+++ b/include/boost/gil/channel_algorithm.hpp*
>
> @@ -51,7 +51,7 @@ template <typename SrcChannelV, typename DstChannelV,
> bool SrcLessThanDst, bool
>
>
>
>
>
>  template <typename UnsignedIntegralChannel>
>
> -struct unsigned_integral_max_value : public
> mpl::integral_c<UnsignedIntegralChannel,-1> {};
>
> +struct unsigned_integral_max_value : public
> mpl::integral_c<UnsignedIntegralChannel,(1<<sizeof(Un
>
>
>
>  template <>
>
>  struct unsigned_integral_max_value<uint8_t> : public
> mpl::integral_c<uint32_t,0xFF> {};
>
>
> Then I added a couple specializations in your code:
>
>
> #include <boost/gil/gil_all.hpp>
>
> #include <cstdint>
>
>
> using namespace std;
>
> using namespace boost::gil;
>
>
> namespace detail
>
> {
>
>     struct bits14_min { static std::uint16_t apply() { return 0;} };
>
>     struct bits14_max { static std::uint16_t apply() { return 0x3FF;} };
>
> }
>
>
> typedef scoped_channel_value <std::uint16_t, ::detail::bits14_min,
> ::detail::bits14_max> bits14_t;
>
> namespace boost { namespace gil { namespace detail {
>
>   template <> struct unsigned_integral_max_value<bits14_t> : public
> mpl::integral_c<uint32_t,0x3FF> {};
>
>   template <> struct unsigned_integral_num_bits<bits14_t> : public
> mpl::int_<14> {};
>
> }}}
>
>
> typedef pixel<bits14_t, gray_layout_t> Pixel1;
>
> typedef image<Pixel1> Frame1;
>
>
> int main()
>
> {
>
>   bits14_t x = channel_traits<bits14_t>::max_value();
>
>   assert(x == 0x3ff);
>
>   bits16 y = channel_convert<bits16>(x);
>
>   assert(y == 0xffff);
>
>
>   Frame1 image(
>
>       Frame1::point_t(100, 100),
>
>       Frame1::value_type((1 << 14)-1),
>
>       0);
>
>
>   gray16_image_t image2(image.dimensions());
>
>
>   Frame1::view_t view1(view(image));
>
>   gray16_image_t::view_t view2(view(image2));
>
>
>   copy_and_convert_pixels(view1, view2);
>
>   return 0;
>
> }
>
>
> On Thu, Jan 8, 2015 at 4:13 PM, Gabriel Marcano <gabemarcano_at_[hidden]>
> wrote:
>
>> I have been experimenting with Boost.GIL, and I have run into something
>> that I'm not sure if it's a problem on my end or with Boost.GIL. In
>> essence, I'm trying to make a grayscale image with channels limited to
>> 14 bits. I am using scoped_channel_value to do this. The problem
>> happens when I try to convert the 14 bit image to a 16 bit grayscale
>> image I get compilation errors. I am including the code I am using
>> below:
>>
>> //START CODE
>>
>>     #include <boost/gil/gil_all.hpp>
>>     #include <cstdint>
>>
>>     using namespace std;
>>     using namespace boost::gil;
>>
>>     namespace detail
>>     {
>>         struct bits14_min { static std::uint16_t apply() { return 0;} };
>>         struct bits14_max
>>            { static std::uint16_t apply() { return 0x3FF;} };
>>     }
>>
>>     typedef scoped_channel_value
>>         <std::uint16_t,
>>             ::detail::bits14_min, ::detail::bits14_max> bits14_t;
>>
>>     typedef pixel<bits14_t, gray_layout_t> Pixel1;
>>     typedef image<Pixel1> Frame1;
>>
>>     int main()
>>     {
>>         Frame1 image(
>>             Frame1::point_t(100, 100),
>>             Frame1::value_type((1 << 14)-1),
>>             0);
>>
>>         gray16_image_t image2(image.dimensions());
>>
>>         Frame1::view_t view1(view(image));
>>         gray16_image_t::view_t view2(view(image2));
>>
>>         copy_and_convert_pixels(view1, view2);
>>
>>         return 0;
>>     }
>>
>> //END CODE
>>
>> The interesting thing is that the program compiles if change
>>     typedef scoped_channel_value
>>         <std::uint16_t,
>>             ::detail::bits14_min, ::detail::bits14_max> bits14_t;
>> to
>>     typedef scoped_channel_value
>>         <float,
>>             ::detail::bits14_min, ::detail::bits14_max> bits14_t;
>>
>> I think the relevant error in the log is this:
>>     /usr/include/boost/gil/channel_algorithm.hpp:54:8: error:
>>         ‘struct boost::gil::scoped_channel_value<short unsigned
>>         int, detail::bits14_min, detail::bits14_max>’ is not a
>>         valid type for a template non-type parameter
>>          struct unsigned_integral_max_value : public
>>              mpl::integral_c<UnsignedIntegralChannel,-1> {};
>>
>> I am attaching the full compile log to this email. Thank you for any
>> help with this matter!
>>
>> Sincerely,
>>
>> Gabriel E. Marcano
>>
>> _______________________________________________
>> Boost-users mailing list
>> Boost-users_at_[hidden]
>> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>>
>
>