GeezerVison

PR summary

This PR replaces our use of pybind11's buffer_protocol() and def_buffer() with our own functions. This is needed as nanobind does not provide a buffer protocol.

For now, these functions will live in "py_buffer.h". In a future PR, there will be a variant that uses nanobind API and lives in some variant of: "mplutils.h", "mpl_buffer.h", or "mplbuffer.h". Both variants can exist as we adopt nanobind.

Usage

Replace py::buffer_protocol() with py::custom_type_setup(mpl::buffer_setup<TheClass>).

The wrapped class needs to implement a create_buffer_info() function which returns a new mpl::buffer_info:

// FT2Image::create_buffer_info
auto *create_buffer_info() const
{
    using BufferInfo = mpl::buffer_info<uint8_t, mpl::shape<-1, -1>>;
    return new BufferInfo(m_buffer, m_height, m_width);
}

Use set_owner() on the BufferInfo if another PyObject owns the raw buffer:

// FT2Font::create_buffer_info
auto *create_buffer_info() const
{
    using BufferInfo = mpl::buffer_info<uint8_t, mpl::shape<-1, -1>>;
    auto result = new BufferInfo(image.data(), image.shape(0), image.shape(1));
    result->set_owner(image.pyarray().ptr());
    return result;
}

AI Disclosure

• I use AI for web search due to search engines becoming less reliable.
• I used AI to review py_buffer.h

PR quality check

• Use an expressive title, e.g. "Fix title font property precedence"
• New and changed code is tested
• [/] Plotting related features are demonstrated in an example
• [/] New features and API changes have release notes
• [/] Documentation complies with general and docstring guidelines