Adobe 65007312 - Photoshop Lightroom Programmer's Manual page 48

C 3: Creating Export and Publish Services
HAPTER
This Export Dialog shows three Export Filter Providers, whose actions have all been inserted in the
processing queue. The Export Service Provider for FTP Upload (one of the sample plug-ins included in the
SDK) has been selected.
The post-process actions are always invoked in the order in which they appear in the dialog, but the export
operation traverses the stack several times, either top-to-bottom (blue arrows), or bottom-to-top (red
arrows). In this discussion, the terms upstream and downstream refer to the downward flow; for example,
when photos that have been rendered by the built-in render engine (using information passed up from
the providers) are passed back down to be modified, and finally exported:
An upstream provider means the post-process action immediately above the current one in the dialog,
which provides a rendered photo to the current action for further processing. When there are no more
actions, the final upstream provider is Lightroom's built-in rendering engine.
A downstream consumer means the post-process action immediately below the current one in the
dialog, which receives a rendered photo from the current one, its upstream provider. When there are
no more actions, the final downstream consumer is the Export Service Provider that sends the
rendered photo to the final destination.
When the user starts the export operation by clicking Export, Lightroom constructs an
object with the settings and photos chosen in the dialog.
Adding an export post-process action 48
LrExportSession