Missing package-level rendition_flow, rendition_orientation, rendition_spread metadata (JSON to shared-js)

[danielweck]

Issue first mentioned in #39
(see comment thread)

[danielweck]

Ah, here's the culprit:
https://github.com/readium/readium-sdk/blob/develop/Platform/Android/src/org/readium/sdk/android/Package.java#L423
As you can see, only rendition_layout is implemented!
Missing: rendition_flow, rendition_orientation, rendition_spread.
@jccr would you mind looking into this JNI code if you have spare cycles? Thank you very much!

[danielweck]

PS: instead of just fetching the value in the toJSON() function, could we store the values locally as it's already done with page-progression-direction (for example):
https://github.com/readium/readium-sdk/blob/develop/Platform/Android/src/org/readium/sdk/android/Package.java#L138

[danielweck]

Note: this is really a follow-up to readium/readium-sdk#128 (where the missing spine-level metadata was added). This separate issue is for the package-level metadata.
PS: I have re-assigned this issue to myself.

[danielweck]

Addressed in feature branch / Pull Request:
readium/readium-sdk#134
#43

[danielweck]

@jccr I implemented support for package-level rendition metadata, which required fixing the spine-level accessor methods (to cascade up into the package, when properties are not explicitly set by spine items). Could you please take a look at the Pull Request (linked above). You'll see that I decided to pass the Package instance directly into the appropriate methods, rather than to store a permanent reference to the Package object at SpineItem construction time. The latter would require modifying the JNI construction code (marshalling of the Package JNI pointer), which felt unnecessarily complicated. However, if you think it is worth the effort, let's refactor this before merging to develop. Thanks :)