RFR: 8332895: Support interpolation for backgrounds and borders [v3]

[John Hendrikx]

On Sat, 3 Aug 2024 00:14:23 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> modules/javafx.graphics/src/main/java/com/sun/javafx/util/Utils.java line 183:
>> 
>>> 181:      *     <li>If the intermediate list is shallow-equal to the first list passed into the method (i.e. its
>>> 182:      *         elements are references to the same objects), the existing list is returned.
>>> 183:      *     <li>If a new list is returned, it is unmodifiable.
>> 
>> Well, it's documented, but I'd rather see this return an unmodifiable list in all cases (and not one of the input lists if it was determined to be modifiable).  Perhaps ensure this is compatible with `List.copyOf` so that copies are only made when needed.
>
> In practice, any list that is passed into this method is already unmodifiable. This isn't a general-purpose method, it's tailored towards its usage for `Border` and `Background` interpolation, and the optimization scheme that is used in these classes.

Alright, I get how it works now, and that there is a lot of reference equality checking going on by callers.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1522#discussion_r1703411678