On Fri, 2 Aug 2024 01:39:11 GMT, Michael Strauß <mstra...@openjdk.org> wrote:
>> This PR completes the CSS Transitions story (see #870) by adding
>> interpolation support for backgrounds and borders, making them targetable by
>> transitions.
>>
>> `Background` and `Border` objects are deeply immutable, but not
>> interpolatable. Consider the following `Background`, which describes the
>> background of a `Region`:
>>
>>
>> Background {
>> fills = [
>> BackgroundFill {
>> fill = Color.RED
>> }
>> ]
>> }
>>
>>
>> Since backgrounds are deeply immutable, changing the region's background to
>> another color requires the construction of a new `Background`, containing a
>> new `BackgroundFill`, containing the new `Color`.
>>
>> Animating the background color using a CSS transition therefore requires the
>> entire Background object graph to be interpolatable in order to generate
>> intermediate backgrounds.
>>
>> More specifically, the following types will now implement `Interpolatable`.
>>
>> - `Insets`
>> - `Background`
>> - `BackgroundFill`
>> - `BackgroundImage`
>> - `BackgroundPosition`
>> - `BackgroundSize`
>> - `Border`
>> - `BorderImage`
>> - `BorderStroke`
>> - `BorderWidths`
>> - `CornerRadii`
>> - `Stop`
>> - `Paint` and all of its subclasses
>> - `Margins` (internal type)
>> - `BorderImageSlices` (internal type)
>>
>> ## Interpolation of composite objects
>>
>> As of now, only `Color`, `Point2D`, and `Point3D` are interpolatable. Each
>> of these classes is an aggregate of `double` values, which are combined
>> using linear interpolation. However, many of the new interpolatable classes
>> comprise of not only `double` values, but a whole range of other types. This
>> requires us to more precisely define what we mean by "interpolation".
>>
>> Mirroring the CSS specification, the `Interpolatable` interface defines
>> several types of component interpolation:
>>
>> | Interpolation type | Description |
>> |---|---|
>> | default | Component types that implement `Interpolatable` are interpolated
>> by calling the `interpolate(Object, double)}` method. |
>> | linear | Two components are combined by linear interpolation such that `t
>> = 0` produces the start value, and `t = 1` produces the end value. This
>> interpolation type is usually applicable for numeric components. |
>> | discrete | If two components cannot be meaningfully combined, the
>> intermediate component value is equal to the start value for `t < 0.5` and
>> equal to the end value for `t >= 0.5`. |
>> | pairwise | Two lists are combined by pairwise interpolation. If the start
>> list has fewer elements than the target list, the...
>
> Michael Strauß has updated the pull request incrementally with two additional
> commits since the last revision:
>
> - fix since tag
> - adjust table styling
Thank you for this contribution!
This is the second batch of code review comments. Will probably have more
after testing.
modules/javafx.graphics/src/main/java/javafx/scene/paint/Stop.java line 162:
> 160: // re-allocating when we run out of space. In general, we expect
> the size of stop lists
> 161: // to be quite small (a single-digit number of stops at most).
> 162: Stop[] stops = new Stop[firstList.size() + secondList.size()];
are there unit tests to cover most of the scenarios, at least using short
sequences?
modules/javafx.graphics/src/test/java/test/javafx/scene/paint/StopListTest.java
line 264:
> 262: new Stop(1, color2)),
> 263: res);
> 264: }
Do you think any other combinations should be added, for completeness sake?
For example, let's consider two lists with 2 points each. We might want to
test scenarios:
--
--
--|
|--
---
---
----|
---|
------
--
|-----
|--
|---|
|---|
|--
--|
---
--
and also have the two lists swapped maybe?
what do you think?
-------------
PR Review: https://git.openjdk.org/jfx/pull/1522#pullrequestreview-2215836542
PR Review Comment: https://git.openjdk.org/jfx/pull/1522#discussion_r1702023646
PR Review Comment: https://git.openjdk.org/jfx/pull/1522#discussion_r1702046900
