René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Simplify the Object/Display/DisplayViewer type hierarchies","articleBody":"In conjunction with imagej/imagej-common#12, we want to rework how SciJava `Display`s are structured.\n\nThe status quo:\n- You have an `Object`, which gets wrapped in a (UI-agnostic) `Display`. Each `Display` is a _list_ of such `Object`s, rather than only a single `Object`. To visualize that `Display`, you then need a UI-specific `DisplayViewer`, which actually shows the `Display`'s contents to the user somehow.\n- In ImageJ, the type hierarchies are more complex: you have a `Data`, which is wrapped in a `DataView` (e.g., `Dataset` wrapped in `DatasetView`, or `Overlay` wrapped in `OverlayView`). Then an `ImageDisplay`, which is a type of `Display` for `DataView`s.\n\nWe can streamline this. Let's have instead:\n- `View`, which wraps an `Object`, and contains visualization settings. Subtypes of view (e.g., `ImageView`) implemented as needed to encapsulate the appropriate viz settings.\n  - A `ViewService` handles wrapping of `Object`s to the most appropriate `View`.\n  - In the case of images, there would be an `ImageView` which has a position (while its wrapped `Dataset` does not).\n- `Display`, which becomes a _UI-specific_ thing used by the `UIService`.\n  - In other words: `DisplayViewer` gets renamed to `Display`.\n  - The old `Display` no longer exists—we only support a single `View` per `Display`.\n  - We have a `DefaultView` that is used for `Object`s with no particular need for visualization settings.\n- To cover the need for multiple N-dimensional image objects (i.e., `Dataset`s and `Overlay`s) bagged together, we provide `CompositeView`, which composes a list of `View`s in a single composite space.\n  - See also `CombinedInterval` _et. al_ in `imagej-common`, which will facilitate this.\n  - This `CompositeView` would be the closest thing to the current `Display`, but would support recursive nesting of `View`s, so that a proper object hierarchy can exist (see also imagej/imagej-common#12).\n\nThese changes would reduce the amount of names floating around—we would no longer need \"viewers\" but would only have `View`s and `Display`s. It would also help simplify the implementation of new UIs, at least from the perspective of understanding the execution flow.\n","author":{"url":"https://github.com/ctrueden","@type":"Person","name":"ctrueden"},"datePublished":"2015-04-08T17:19:42.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/157/scijava-common/issues/157"}