kds_metascope [struct]

If this member is true, any window request which intersects with this scope makes the containing kds_metagroup object mandatory for transmission to the client. Such meta-data groups will be transmitted regardless of whether or not the client has supplied a "metareq" JPIP request field, and whether or not a "metareq" request field excludes the transmission of image data. Very little metadata generally requires such a strong classification. However, quite a few entries may require the slightly weaker image_mandatory flag, declared below.

This flag plays the same role as is_mandatory, except that the metadata will not be considered mandatory if a "metareq" request field indicates that no image data or image headers should be returned. Typically, codestream headers, colour space info, etc., should be considered as "image_mandatory", since they will be required by the client if any image data is sent, but will not be necessary otherwise.

This parameter determines the priority with which the meta-data should be sequenced by kdu_serve::generate_increments if the present scope is found to intersect with the client's interests. This sequencing priority is expressed relative to other meta-data and also relative to compressed image elements.

sequence values may be either negative or positive, where data having a smaller sequencing index is sequenced earlier than data with a larger index, when kdu_serve::generate_increments is preparing messages for transmission to a client. For reference, all code-stream header data-bins have an implicit sequence index of 0 and the sequence number for precinct data-bin contributions is equal to the quality layer index of the first packet associated with the data being delivered. Where code-stream and meta-data have identical sequence numbers, the meta-data is sequenced first.

If the scope list associated with a kds_metagroup object has multiple scope entries, the sequencing algorithm finds the smallest sequence value amongst all kds_metascope objects which intersect with the client's interests, using that value to schedule the corresponding meta-data.

If true, the scope is associated with the logical target (file) globally, rather than with any specific codestream. In this case, the first_stream_id, last_stream_id, first_component, last_component, min_size, from_x, from_y, to_x and to_y members are ignored. The whole_stream and whole_image members are also ignored. Note that JPIP "metareq" requests which use the "/g" qualifier refer to metadata entries which have at least one scope in which global is true.

If true, the scope is associated globally with each of the codestreams in the range identified by the first_stream_id and last_stream_id members. In this case, the whole_image, first_component, last_component, min_size, from_x, from_y, to_x and to_y members are ignored. Note that JPIP "metareq" requests which use the "/w" qualifier refer to metadata entries which have at least one scope in which global and whole_stream are both false. JPIP "metareq" requests which use the "/s" qualifier refer to metadata entries which have at least one scope in which global is false, but whole_stream is true.

If true, the scope is associated with the full spatial extent of each image component in the range first_component to last_component, within each code-stream in the range first_stream_id to last_stream_id. In this case, the from_x, from_y, to_x and to_y members are ignored. Otherwise, the scope is restricted to the region specified by the from_x, from_y, to_x and to_y members.

First ID the range of code-stream identifiers to which this scope refers. Ignored if global is true. Must otherwise identify a valid code-stream.

Last ID in the range of code-stream identifiers to which this scope refers. Ignored if global is true. Must otherwise identify a valid code-stream ID, no smaller than last_stream_id.

Index of the first image component to which the scope refers, within each of the code-streams in the range identified by first_stream_id and last_stream_id. Ignored if either global or whole_stream are true.

Index of the last image component to which the scope refers, within each of the code-streams in the range identified by first_stream_id and last_stream_id. Must be at least as large as first_component. Ignored if eiher global or whole_stream are true.

Minimum size for the requested image resolution (not the region) at which this scope becomes valid. The idea is that some meta-data might not be of any interest until the image being requested has sufficiently high resolution. Ignored if either global or whole_stream are true.

Ignored if global, whole_stream or whole_image is true. Otherwise, this member identifies the relative position (in the range 0 to 1) of the left edge of the scope region.

Ignored if global, whole_stream or whole_image is true. Otherwise, this member identifies the relative position (in the range 0 to 1) of the upper edge of the scope region.

Ignored if global, whole_stream or whole_image is true. Otherwise, this member identifies the relative position (in the range 0 to 1) of the right edge of the scope region.

Ignored if global, whole_stream or whole_image is true. Otherwise, this member identifies the relative position (in the range 0 to 1) of the bottom edge of the scope region.

Used to build a linked list of scope records, known as the meta-data scope list.