How to use APNGFrame#pixels ?

[dteoh]

Thank you for making this Ruby wrapper!

I'm trying to get each frames' image data so that I can hopefully convert it into MiniMagick::Image object.

How can I convert #<SWIG::TYPE_p_unsigned_char:0x007fd002fde9e8 @__swigtype__="_p_unsigned_char"> into a Ruby binary string?

[Kagetsuki]

Sorry for the late reply. I'm in the middle of moving.

Basically each pixel is encoded as a set of 3 chars (a char being a type with a fixed bit width of 8 bits), such that there is a Red char, followed by a Green char, followed by a Blue char. Obviously these are not actual characters, we're just using this because it's got a fixed bit width of 8 per color for 24 bits per pixel. So, basically, the array is just a long line of RGB sets. To encode it as a Ruby binary string, basically all you need to do is get the numerical value of each char and stack them up in whatever order the MiniMagick::Image object wants the RGB values.

*The alpha channel is encoded the same way in a separate array.

Does this help?

[dteoh]

Thank you for the explanation of the encoding scheme. My problem is that the SWIG::TYPE_p_unsigned_char type has no usable instance or class methods to read the underlying data. I'm not sure if this is a problem with the gem that was built on my machine or just an incomplete wrapper definition. Apart from the standard methods available to Object, there is nothing else :(

I am using version 3.2.0 of the gem.

[Kagetsuki]

Aaaah, this could be due to a few things but I have a feeling it's either an issue with the wrapper or with the version of SWIG you used to build the extension. Can you give me the output of swig -version ?

I'm a bit busy but I'll try and make some time to check this out today or tomorrow. Thanks for your patience.

[dteoh]

No worries, this is not urgent :)

$ swig -version
SWIG Version 3.0.8

Compiled with clang++ [x86_64-apple-darwin14.5.0]

Configured options: +pcre

Please see http://www.swig.org for reporting bugs and further information

$ apngasm
apngasm 3.1.6

Both swig and apngasm were installed using Homebrew on OSX 10.10

[Kagetsuki]

OK, yeah that's definitely up to date. We messed up the wrapper code somewhere. I'll write some specs and put someone on fixing this.