API to determine if a timeline clip has "Scale to Frame Size" enabled
Currently, there is no way for a CEP panel to know if "Scale to Frame Size" is enabled, which means that it's missing crucial information about clip transformations that is highly relevant if the panel needs to adjust position or scale or, indeed, know anything about the dimensions of the clip.
Per a discussion on the forums, it is unlikely this will be added before UXP. This is a request to be sure to add this capability to UXP, but also, that it should be considered a critical enough omission in the Extendscript/CEP architecture that it be added there as well.
See this discussion on the forums: https://community.adobe.com/t5/premiere-pro/how-to-find-out-if-a-clip-was-quot-scaled-to-frame-size-quot-in-a-cep-extension/td-p/11781911
While we understand the desire, and plan to provide this functionality once PPro moves to UXP-based extensibility, It’s unlikely that this feature will make it into ExtendScript extensibility.