jpx_layer_source::get_layer_size

Returns the dimensions of this compositing layer, as they appear on its registration grid. In the absence of any codestream registration (creg) box, there is only one code-stream in each compositing layer and the dimensions of the layer are those of the image region occupied by that code-stream on its high resolution canvas. Where a codestream registration box exists, there may be multiple code-streams, each of which has its high resolution grid adjusted by the sampling factors and offsets returned via get_codestream_registration. In this case, the layer size is determined to be the intersection of the resampled regions associated with each codestream, rounded outwards to a whole number of resampled pixels, as described by the JPX standard (accounting for corrigenda).