Skip adding/accumulating ClipRect values which corresponding rect offset is auto.
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This is a PR for https://bugzilla.mozilla.org/show_bug.cgi?id=1390352
This patch will skip adding/accumulating the values which corresponding rect offset is auto, and make Servo_AnimationValues_ComputeDistance return negative value instead of 0.0 when the function fails to distinguish its failure.
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There are already these tests in dom/smil/tests of gecko, this PR will enable these tests.
For detail, see https://bugzilla.mozilla.org/show_bug.cgi?id=1390352.
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stylo: Bug 1390039 - Implement compute_distance for mismatched transform lists.
Implement ComputeSquaredDistance for mismatched transform lists.
In order to do this, we have to convert a transform list into a 3d matrix,
so I move the code from layout module into style module for reusing it.
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- [X] These changes do not require tests because this is a Gecko feature and I add many tests in Gecko already.
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The trait ToAnimatedZero now supports it, and it now applies to things with generics,
avoiding the trait bounds for field types of the variant on which it applies.
We could use this method to convert a TransformList into a Matrix, and
use this matrix for computing distance for Stylo and rendering the transform
for Servo.
This is an equivalent of nsStyleTransformMatrix::ReadTransforms in Gecko.
This patch will skip add_weighted() when self_portion + other_portion not equal
to zero. (i.e. adding or accumulating).
Gecko does same behavior since we can't add two auto value.
For now, only #[animation(error)] is supported on variants and it makes
both #[derive(Animate)] and #[derive(ComputeSquaredDistance)] ignore
this particular variant.
The implementation of 2d matrix decomposition in Servo matches that in
spec, but its result is really different from that in Gecko, so the
visual results on the main thread and on the compositor thread are
really different and we got many test failures. Therefore, let's write a
different algorithm of decomposition of 2d matrix for Stylo, and keep
the original one for Servo.
The output of new implemented 2d matrix decomposition is a Decomposed3DMatrix,
so we can reuse the interpolation and re-composition code. (Just like
what we do in Gecko.)
Let's see the example: "rotatex(360deg)" to "none".
While we do interpolation between "rotatex" and "none", the original code
path is:
1. Build an identity transform for none and always use (0, 0, 1) as the
direction vector, i.e. Rotate(0, 0, 1, 0deg).
2. Do interpolation between rotatex (i.e. Rotate(1, 0, 0, 360deg)) and
Rotate(0, 0, 1, 0deg). Because their direction vectors are different,
so we do matrix decomposition/interpolation/recomposition on both
functions. The problem is, matrix decomposition makes the 360deg
disappear, so it looks like "rotatex(0deg)".
3. Obviously, we are trying to interpolate from rotatex(0deg) to none, so
the interpolated matrix is always an identity matrix.
I think rotatex, rotatey, and rotatez are special cases which should
really rotate according to the angle, so we should build the identity
transform for them according to the normalized direction vector, and so we do
interpolation on the angle, instead of converting them into matrix.
Replacing build_identity_transform_list() with
add_weighted_transform_lists(list, list, 0, 0) might be another solution;
However, I didn't do that because build_identity_transform_list() is
much simpler.
stylo: Bug 1362896 - Implement ComputeSquaredDistance for TransformList
We implement ComputeSquaredDistance for TransformList.
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- [X] These changes fix [Bug 1362896](https://bugzilla.mozilla.org/show_bug.cgi?id=1362896).
- [X] These changes do not require tests because Gecko has related tests.
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We need to use enum instead of Either since we can't interpolate stroke-* between
unitless length and unit length(e.g. '5' -> '10px').
This coomit make following:
* Introduce SVGLengthOrPercentageOrNumber on computed and specified values.
* Make SVGLengthOrPercentageOrNumber animatable.
* Make stroke-dasharray not-accumulate.
In SMIL we don't expect the 'none' value of the 'fill' property to be
additive and hence the following animation should have no effect:
<rect width="100" height="100" y="100" fill="blue">
<animate attributeName="fill" dur="3s" from="red" by="none"/>
</rect>
Although SMIL doesn't make this entirely clear, [1] says that "by
animation" and "from-by animation" may only be used "with attributes
that support addition (e.g. most numeric attributes)" and [2] says that
<paint>s are "only additive if each value can be converted to an RGB
color". As a result, the animation above should have no effect.
By extrapolation, animating from 'none' by 'none' should also have no
effect:
<rect width="100" height="100" y="100" fill="blue">
<animate attributeName="fill" dur="3s" from="none" by="none"/>
</rect>
However, in Servo's interpolation of <paint>s we special case the
interpolation and addition of 'none' such that if both values are 'none'
it is allowed.
We should disallow this in order to produce the expected behavior and in
order to match Gecko's behavior.
[1] https://www.w3.org/TR/smil-animation/#AnimFuncValues
[2] https://www.w3.org/TR/SVG11/animate.html#AnimationAttributesAndProperties
For CSS Transitions we want this case to return Err() so we know that the two
values are not interpolable.
For CSS Animations/Web Animations we implement discrete animation as the
fallback behavior when Err() is returned.
We convert a perspective function into a ComputedMatrix, but we apply the
perspective length to a wrong matrix item. We should put it into m34,
instead of m43. m43 is for translate parameter Z.
