File: mng-reco-proposal-20071017 It is proposed to register MNG chunk: ReC0. In this proposal, the new chunk name is shown in private form (second letter lowercase, ReCO). Until the proposal is approved, the private form must be used in any test implementations. It is proposed to document the ReCO chunk in the MNG 1.0 Specification, Version 1.0.1, as follows: A. Change document version to 1.0.1. B. Add paragraph 4.2.12. Simplicity profile in MHDR chunk: Add bit 10: 0: ReCO chunk is not present. 1: ReCO chunk may be present. 4.2.12. ReCO Record current frame The ReCO chunk is useful for accomplishing the equivalent of the GIF "restore-to-previous" disposal method. This chunk is currently not a registered MNG chunk. Registration is being pursued with the PNG Registration Authority. In the meantime, the private form of the chunk name (ReCO, with a lowercase "e"), must be used in any public datastreams. It has two fields Object_id (16-bit unsigned int): Existing object to be used for storing image of frame Mode (byte) 0: Initialize object to transparent and start recording offscreen copy of current frame (including any background layers). 1: Stop recording. 2: Restart recording with existing contents. The object_id must already have been the subject of a DEFI chunk and must still exist. The dimensions and location of the area to be recorded are specified in the DEFI chunk. Each layer that is defined while the ReCO chunk is in recording mode is composited over whatever is in the object. It is permitted to have more than one ReCO object open at the same time. The first ReCO chunk for each object in a segment must have mode 0, and the last ReCO chunk for each object in a segment must have mode 1. C. Add to the Appendix: Revision History * 15 Nov 2007 (version 1.0.1): * Added ReCO chunk.