[grid="all"]
`------------`-----------------------
*State*         _Idea_
*Date*          _2008-03-06_
*Proposed by*   link:Ichthyostega[]
-------------------------------------


Design the handling of Parameters and Automation
------------------------------------------------
Parameters of Plugin Components and/or Render Nodes play a role at various
levels of the application.
 +
Thus it seems reasonable to do a formal requirements analysis and design prior
to coding.


Description
~~~~~~~~~~~
Regarding components directly participating in the render (which may be
implemented by plugins), we distinguish between *configuration* (static) and
*parameters* (dynamic). The point of reference for this distinction is the
render process: a plugin configuration may well be variable in some manner,
e.g. the plugin may provide different flavours of the same algorithm. But this
choice has to be fixed prior to feeding the corresponding plugin asset to the
builder. Contrary to such fixed configuration setup, the _parameters_ are
considered to be _variable_ during the rendering process. They can be changed
on-the-fly from GUI, and they may be automated. Probably, each Render Node will
have at least one such _parameter_ -- namely a bypass switch.


Tasks
^^^^^

 * we need to work out an introspection mechanism for parameters
   - asses what different types of parameters we need
   - find out how much structured parameters will be (do simple values
     suffice?)
   - define how parameters can be discovered/enumerated
   - define a naming scheme for parameters, so they can be addressed
     unambiguously
 * value parameters have a value range. Work out how to handle this
 * parameters may need a specific presentation in the GUI
   - linear/logarithmic scale, scale reference
   - selecting the right widget

So...

. find out to which extend we need these properties
. find out what parts of the App will have what requirements?
. chose a best fitting implementation based on this information

A closely related issue is the handling of *Automation*. The current draft
calls for an abstract interface "ParamProvider", which just allows the
link:Plugin/RenderComponent[] to pull a current value, without knowing if the
ParamProvider is a GUI widget or an automation data set with interpolation. The
component using the param value should not need to do any interpolation. We
should re-asses and refine this draft as needed. Note: Render Nodes are
stateless; this creates some tricky situations.







Alternatives
^^^^^^^^^^^^
?? (any ideas?)


Rationale
~~~~~~~~~






Comments
--------


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