[Gimp-developer] Proposal for composition rendering

[yahvuu]

hi all,

here's a (totally unbiased ;-) summary from the previous "composition rendering"
thread, intended as a discussion base:


1. Rendering happens on demand:
   a) when a composition gets displayed on screen (of course)
   b) on export. Here usually the full resolution gets rendered.

   => no rendering happens on saving. Only the necessary data gets written.
      Exceptions can be defined according to 3.)


2. A persistent disk cache of configurable size eliminates expensive re-calculations.
   (a cross-session cache is feasible with reasonable effort?!?)

   Use case: Exporting an expensive composition for a second time should
             not cause re-rendering, unless the disk cache got overwritten
             in the meantime.


3. "Render Hint" operations can be inserted anywhere in a composition.
   These operations have only one option: "render full resolution when saving".

   This way, the user can mark intermediate results from a composition for
   getting cached inside the saved composition file. These Render Hints have
   no effect during editing time.


   Use case: Adding a "Render Hint" operation on top of the composition makes shure
             that a bitmap of the fully rendered composition gets included on saving.

   Use case: A Render Hint after an expensive operation (e.g. denoise) protects
             the invested CPU time once the composition has been saved.



greetings,
peter