kdu_codestream::get_registration

Retrieves component registration information for the indicated image component. The horizontal and vertical registration offsets are returned in crg after scaling by scale and rounding to integers. Samples from this component have horizontal locations (kx + crg.x/scale.x)*subs.x and vertical locations (ky + crg.y/scale.y)*subs.y, where kx and ky are integers ranging over the bounds returned by the get_dims member function and subs.x and subs.y are the sub-sampling factors for this component. The component offset information is recovered from any CRG marker segment in the code-stream; the default offsets of 0 will be used if no such marker segment exists.

The interpretation of the component index is affected by the component range arguments, first_component and max_components supplied in any call to the apply_input_restrictions function. The registration offsets and scale argument are also corrected to account for the effects of any prevailing geometric transformations which may have been applied through a call to the change_appearance member function.

comp_idx [int]

scale [kdu_coords]

crg [kdu_coords &]