On Fri, 7 Aug 2020 14:18:31 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> modules/javafx.graphics/src/main/java/javafx/scene/Node.java line 5523:
>>
>>> 5522: * Defines the {@code ObservableList} of {@link Transform}
>>> objects to be applied to this {@code Node}. The
>>> transforms in this list 5523: * are applied in the <i>reverse</i>
>>> order of which they are specified as per matrix
>>> multiplication rules. This list of transforms 5524: * is applied
>>> before scaling ({@link #scaleXProperty scaleX},
>>> {@link #scaleYProperty scaleY} and {@link #scaleZProperty scaleZ}),
>>
>> `The transforms in this list are applied in the <i>reverse</i> order of
>> which they are specified as per matrix
>> multiplication rules`
>> To apply transformations in a specific order their respective matrices
>> should be multiplied in reverse order. So just
>> the order of multiplication is reverse but the transformation are applied in
>> same order as they are added into the
>> `getTransforms()`. I think phrasing it as 'the transforms are applied in
>> reverse order...' would not be accurate and
>> confusing to reader.
>
> In reading the existing doc carefully, it is both wrong and confusing. It has
> the wrong ordering of transform, scale
> and rotate. It is also confusing given that no distinction is made between
> matrix multiplication order and the observed
> effect on the geometry of the node. You have fixed the part about it being
> wrong, but the confusion remains, especially
> since you made a point of saying that the transforms list is applied in the
> reverse order. The matrices are multiplied
> in the following order: 1. layoutX/Y + translateX/Y/Z
> 2. rotate
> 3. scale
> 4. transforms[0]
> 5. transforms[1]
> ...
>
> We need to both list the actual matrix multiplication order, and then
> describe that the object is transformed from
> object coordinates to local coordinates of the node, to parent coordinated,
> etc., by first applying the transforms in
> the list in reverse order, then scale, rotate, translate+layout. I don't
> think that the `transforms` list is the place
> to do that (it belongs in the Transformations section). This doesn't seem
> like something we can sort out for JavaFX
> 15, so I would split this out and defer it.
So should I revert all the changes about the transforms and leave it for 16, or
do part of it now and part later?
The changes are in the docs for the `Node` class, the `getTransforms()` method
and the `boundsInParentProperty()`
method.
-------------
PR: https://git.openjdk.java.net/jfx/pull/276
