jpx_composition

Manages the information associated with the composition box (box-type = comp) which may be found in a JPX file. At most one composition box may be found in a JPX file, describing the generation of composited and/or animated images from the various compositing layers.

The object provides an interface which is more natural than simply supplying or retrieving compositing instructions to or from the JPX composition box. This means that the object may need to do quite a bit of work to make things look simple for you. There are some ways to abuse this so that a seemingly simple animation ends up being extremely costly to encode into a JPX composition box. The main thing to watch out for is that you should avoid describing animations in which the composition layers are played backwards. The JPX composition box is designed with the idea of using layers one after the other, with possible re-use of layers at later points in the animation. It is possible to describe animations in which the layers are played from the last one back to the first one, but such a description will not be efficient and may not be handled efficiently by some JPX readers (should not affect Kakadu readers, if they are based on the kdu_region_compositor object).

Objects of this class are merely interfaces to an internal object, which cannot be directly created by an application. Use jpx_source::access_composition or jpx_target::access_composition to obtain a non-empty interface.

jpx_composition (2 forms)

exists {Java: Exists}

operator!

copy {Java: Copy}

get_global_info {Java: Get_global_info}

get_next_frame

get_prev_frame

get_frame_info

get_last_persistent_frame

get_instruction

add_frame

add_instruction

set_loop_count {Java: Set_loop_count}