private static Kdu_coords getReferenceExpansion(
int reference_component, Kdu_channel_mapping channels, Kdu_codestream codestream)
throws KduException {
int c;
Kdu_coords ref_subs = new Kdu_coords();
Kdu_coords subs = new Kdu_coords();
codestream.Get_subsampling(reference_component, ref_subs);
Kdu_coords min_subs = new Kdu_coords();
min_subs.Assign(ref_subs);
for (c = 0; c < channels.Get_num_channels(); c++) {
codestream.Get_subsampling(channels.Get_source_component(c), subs);
if (subs.Get_x() < min_subs.Get_x()) min_subs.Set_x(subs.Get_x());
if (subs.Get_y() < min_subs.Get_y()) min_subs.Set_y(subs.Get_y());
}
Kdu_coords expansion = new Kdu_coords();
expansion.Set_x(ref_subs.Get_x() / min_subs.Get_x());
expansion.Set_y(ref_subs.Get_y() / min_subs.Get_y());
for (c = 0; c < channels.Get_num_channels(); c++) {
codestream.Get_subsampling(channels.Get_source_component(c), subs);
if ((((subs.Get_x() * expansion.Get_x()) % ref_subs.Get_x()) != 0)
|| (((subs.Get_y() * expansion.Get_y()) % ref_subs.Get_y()) != 0)) {
Kdu_global.Kdu_print_error(
"The supplied JP2 file contains color channels "
+ "whose sub-sampling factors are not integer "
+ "multiples of one another.");
codestream.Apply_input_restrictions(
0, 1, 0, 0, null, Kdu_global.KDU_WANT_OUTPUT_COMPONENTS);
channels.Configure(codestream);
expansion = new Kdu_coords(1, 1);
}
}
return expansion;
}
