Code review comment for lp:~mir-team/mir/touchspot-renderable

556 + if (buffer.stride().as_uint32_t() * buffer_size.height.as_uint32_t() != size)
557 + BOOST_THROW_EXCEPTION(std::logic_error("Size of pixels is not equal to size of buffer"));

You should just do a line by line copy. You'll be excluding devices with stride.