kdu_resolution::get_valid_precincts

Returns the range of precinct indices which correspond to the current region of interest. The indices of the first precinct whose code-blocks make any contribution to the region of interest are returned via indices.pos. Note that these may be negative if geometric transformations were specified in any call to kdu_codestream::change_appearance. The number of precincts in each direction whose code-blocks contribute to the region of interest is returned via indices.size.

It is worth stressing the fact that the range of indices returned by this function refers to precincts whose code-blocks contribute to the region of interest during subband synthesis. This does not necessarily mean that the region occupied by the precinct on the canvas actually intersects with the region of interest, since subband synthesis is a spatially expansive operation. This interpretation of the range of valid indices is particularly useful for building servers for interactive client-server applications.

The caller should not attempt to attach any interpretation to the absolute indices retrieved by this function. Instead, it should use these indices to determine which precincts are to be opened using the open_precinct function described below.

indices [kdu_dims &]