Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 558 insertions, 0 deletions

diff --git a/servo/components/style/values/computed/transform.rs b/servo/components/style/values/computed/transform.rs
new file mode 100644
index 0000000000..d70349ee0f
--- /dev/null
+++ b/servo/components/style/values/computed/transform.rs
@@ -0,0 +1,558 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Computed types for CSS values that are related to transformations.
+
+use super::CSSFloat;
+use crate::values::animated::transform::{Perspective, Scale3D, Translate3D};
+use crate::values::animated::ToAnimatedZero;
+use crate::values::computed::{Angle, Integer, Length, LengthPercentage, Number, Percentage};
+use crate::values::generics::transform as generic;
+use crate::Zero;
+use euclid::default::{Transform3D, Vector3D};
+
+pub use crate::values::generics::transform::TransformStyle;
+
+/// A single operation in a computed CSS `transform`
+pub type TransformOperation =
+    generic::GenericTransformOperation<Angle, Number, Length, Integer, LengthPercentage>;
+/// A computed CSS `transform`
+pub type Transform = generic::GenericTransform<TransformOperation>;
+
+/// The computed value of a CSS `<transform-origin>`
+pub type TransformOrigin =
+    generic::GenericTransformOrigin<LengthPercentage, LengthPercentage, Length>;
+
+/// The computed value of the `perspective()` transform function.
+pub type PerspectiveFunction = generic::PerspectiveFunction<Length>;
+
+/// A vector to represent the direction vector (rotate axis) for Rotate3D.
+pub type DirectionVector = Vector3D<CSSFloat>;
+
+impl TransformOrigin {
+    /// Returns the initial computed value for `transform-origin`.
+    #[inline]
+    pub fn initial_value() -> Self {
+        Self::new(
+            LengthPercentage::new_percent(Percentage(0.5)),
+            LengthPercentage::new_percent(Percentage(0.5)),
+            Length::new(0.),
+        )
+    }
+}
+
+/// computed value of matrix3d()
+pub type Matrix3D = generic::Matrix3D<Number>;
+
+/// computed value of matrix()
+pub type Matrix = generic::Matrix<Number>;
+
+// we rustfmt_skip here because we want the matrices to look like
+// matrices instead of being split across lines
+#[cfg_attr(rustfmt, rustfmt_skip)]
+impl Matrix3D {
+    /// Get an identity matrix
+    #[inline]
+    pub fn identity() -> Self {
+        Self {
+            m11: 1.0, m12: 0.0, m13: 0.0, m14: 0.0,
+            m21: 0.0, m22: 1.0, m23: 0.0, m24: 0.0,
+            m31: 0.0, m32: 0.0, m33: 1.0, m34: 0.0,
+            m41: 0., m42: 0., m43: 0., m44: 1.0
+        }
+    }
+
+    /// Convert to a 2D Matrix
+    #[inline]
+    pub fn into_2d(self) -> Result<Matrix, ()> {
+        if self.m13 == 0. && self.m23 == 0. &&
+           self.m31 == 0. && self.m32 == 0. &&
+           self.m33 == 1. && self.m34 == 0. &&
+           self.m14 == 0. && self.m24 == 0. &&
+           self.m43 == 0. && self.m44 == 1. {
+            Ok(Matrix {
+                a: self.m11, c: self.m21, e: self.m41,
+                b: self.m12, d: self.m22, f: self.m42,
+            })
+        } else {
+            Err(())
+        }
+    }
+
+    /// Return true if this has 3D components.
+    #[inline]
+    pub fn is_3d(&self) -> bool {
+        self.m13 != 0.0 || self.m14 != 0.0 ||
+        self.m23 != 0.0 || self.m24 != 0.0 ||
+        self.m31 != 0.0 || self.m32 != 0.0 ||
+        self.m33 != 1.0 || self.m34 != 0.0 ||
+        self.m43 != 0.0 || self.m44 != 1.0
+    }
+
+    /// Return determinant value.
+    #[inline]
+    pub fn determinant(&self) -> CSSFloat {
+        self.m14 * self.m23 * self.m32 * self.m41 -
+        self.m13 * self.m24 * self.m32 * self.m41 -
+        self.m14 * self.m22 * self.m33 * self.m41 +
+        self.m12 * self.m24 * self.m33 * self.m41 +
+        self.m13 * self.m22 * self.m34 * self.m41 -
+        self.m12 * self.m23 * self.m34 * self.m41 -
+        self.m14 * self.m23 * self.m31 * self.m42 +
+        self.m13 * self.m24 * self.m31 * self.m42 +
+        self.m14 * self.m21 * self.m33 * self.m42 -
+        self.m11 * self.m24 * self.m33 * self.m42 -
+        self.m13 * self.m21 * self.m34 * self.m42 +
+        self.m11 * self.m23 * self.m34 * self.m42 +
+        self.m14 * self.m22 * self.m31 * self.m43 -
+        self.m12 * self.m24 * self.m31 * self.m43 -
+        self.m14 * self.m21 * self.m32 * self.m43 +
+        self.m11 * self.m24 * self.m32 * self.m43 +
+        self.m12 * self.m21 * self.m34 * self.m43 -
+        self.m11 * self.m22 * self.m34 * self.m43 -
+        self.m13 * self.m22 * self.m31 * self.m44 +
+        self.m12 * self.m23 * self.m31 * self.m44 +
+        self.m13 * self.m21 * self.m32 * self.m44 -
+        self.m11 * self.m23 * self.m32 * self.m44 -
+        self.m12 * self.m21 * self.m33 * self.m44 +
+        self.m11 * self.m22 * self.m33 * self.m44
+    }
+
+    /// Transpose a matrix.
+    #[inline]
+    pub fn transpose(&self) -> Self {
+        Self {
+            m11: self.m11, m12: self.m21, m13: self.m31, m14: self.m41,
+            m21: self.m12, m22: self.m22, m23: self.m32, m24: self.m42,
+            m31: self.m13, m32: self.m23, m33: self.m33, m34: self.m43,
+            m41: self.m14, m42: self.m24, m43: self.m34, m44: self.m44,
+        }
+    }
+
+    /// Return inverse matrix.
+    pub fn inverse(&self) -> Result<Matrix3D, ()> {
+        let mut det = self.determinant();
+
+        if det == 0.0 {
+            return Err(());
+        }
+
+        det = 1.0 / det;
+        let x = Matrix3D {
+            m11: det *
+            (self.m23 * self.m34 * self.m42 - self.m24 * self.m33 * self.m42 +
+             self.m24 * self.m32 * self.m43 - self.m22 * self.m34 * self.m43 -
+             self.m23 * self.m32 * self.m44 + self.m22 * self.m33 * self.m44),
+            m12: det *
+            (self.m14 * self.m33 * self.m42 - self.m13 * self.m34 * self.m42 -
+             self.m14 * self.m32 * self.m43 + self.m12 * self.m34 * self.m43 +
+             self.m13 * self.m32 * self.m44 - self.m12 * self.m33 * self.m44),
+            m13: det *
+            (self.m13 * self.m24 * self.m42 - self.m14 * self.m23 * self.m42 +
+             self.m14 * self.m22 * self.m43 - self.m12 * self.m24 * self.m43 -
+             self.m13 * self.m22 * self.m44 + self.m12 * self.m23 * self.m44),
+            m14: det *
+            (self.m14 * self.m23 * self.m32 - self.m13 * self.m24 * self.m32 -
+             self.m14 * self.m22 * self.m33 + self.m12 * self.m24 * self.m33 +
+             self.m13 * self.m22 * self.m34 - self.m12 * self.m23 * self.m34),
+            m21: det *
+            (self.m24 * self.m33 * self.m41 - self.m23 * self.m34 * self.m41 -
+             self.m24 * self.m31 * self.m43 + self.m21 * self.m34 * self.m43 +
+             self.m23 * self.m31 * self.m44 - self.m21 * self.m33 * self.m44),
+            m22: det *
+            (self.m13 * self.m34 * self.m41 - self.m14 * self.m33 * self.m41 +
+             self.m14 * self.m31 * self.m43 - self.m11 * self.m34 * self.m43 -
+             self.m13 * self.m31 * self.m44 + self.m11 * self.m33 * self.m44),
+            m23: det *
+            (self.m14 * self.m23 * self.m41 - self.m13 * self.m24 * self.m41 -
+             self.m14 * self.m21 * self.m43 + self.m11 * self.m24 * self.m43 +
+             self.m13 * self.m21 * self.m44 - self.m11 * self.m23 * self.m44),
+            m24: det *
+            (self.m13 * self.m24 * self.m31 - self.m14 * self.m23 * self.m31 +
+             self.m14 * self.m21 * self.m33 - self.m11 * self.m24 * self.m33 -
+             self.m13 * self.m21 * self.m34 + self.m11 * self.m23 * self.m34),
+            m31: det *
+            (self.m22 * self.m34 * self.m41 - self.m24 * self.m32 * self.m41 +
+             self.m24 * self.m31 * self.m42 - self.m21 * self.m34 * self.m42 -
+             self.m22 * self.m31 * self.m44 + self.m21 * self.m32 * self.m44),
+            m32: det *
+            (self.m14 * self.m32 * self.m41 - self.m12 * self.m34 * self.m41 -
+             self.m14 * self.m31 * self.m42 + self.m11 * self.m34 * self.m42 +
+             self.m12 * self.m31 * self.m44 - self.m11 * self.m32 * self.m44),
+            m33: det *
+            (self.m12 * self.m24 * self.m41 - self.m14 * self.m22 * self.m41 +
+             self.m14 * self.m21 * self.m42 - self.m11 * self.m24 * self.m42 -
+             self.m12 * self.m21 * self.m44 + self.m11 * self.m22 * self.m44),
+            m34: det *
+            (self.m14 * self.m22 * self.m31 - self.m12 * self.m24 * self.m31 -
+             self.m14 * self.m21 * self.m32 + self.m11 * self.m24 * self.m32 +
+             self.m12 * self.m21 * self.m34 - self.m11 * self.m22 * self.m34),
+            m41: det *
+            (self.m23 * self.m32 * self.m41 - self.m22 * self.m33 * self.m41 -
+             self.m23 * self.m31 * self.m42 + self.m21 * self.m33 * self.m42 +
+             self.m22 * self.m31 * self.m43 - self.m21 * self.m32 * self.m43),
+            m42: det *
+            (self.m12 * self.m33 * self.m41 - self.m13 * self.m32 * self.m41 +
+             self.m13 * self.m31 * self.m42 - self.m11 * self.m33 * self.m42 -
+             self.m12 * self.m31 * self.m43 + self.m11 * self.m32 * self.m43),
+            m43: det *
+            (self.m13 * self.m22 * self.m41 - self.m12 * self.m23 * self.m41 -
+             self.m13 * self.m21 * self.m42 + self.m11 * self.m23 * self.m42 +
+             self.m12 * self.m21 * self.m43 - self.m11 * self.m22 * self.m43),
+            m44: det *
+            (self.m12 * self.m23 * self.m31 - self.m13 * self.m22 * self.m31 +
+             self.m13 * self.m21 * self.m32 - self.m11 * self.m23 * self.m32 -
+             self.m12 * self.m21 * self.m33 + self.m11 * self.m22 * self.m33),
+        };
+
+        Ok(x)
+    }
+
+    /// Multiply `pin * self`.
+    #[inline]
+    pub fn pre_mul_point4(&self, pin: &[f32; 4]) -> [f32; 4] {
+        [
+            pin[0] * self.m11 + pin[1] * self.m21 + pin[2] * self.m31 + pin[3] * self.m41,
+            pin[0] * self.m12 + pin[1] * self.m22 + pin[2] * self.m32 + pin[3] * self.m42,
+            pin[0] * self.m13 + pin[1] * self.m23 + pin[2] * self.m33 + pin[3] * self.m43,
+            pin[0] * self.m14 + pin[1] * self.m24 + pin[2] * self.m34 + pin[3] * self.m44,
+        ]
+    }
+
+    /// Return the multiplication of two 4x4 matrices.
+    #[inline]
+    pub fn multiply(&self, other: &Self) -> Self {
+        Matrix3D {
+            m11: self.m11 * other.m11 + self.m12 * other.m21 +
+                 self.m13 * other.m31 + self.m14 * other.m41,
+            m12: self.m11 * other.m12 + self.m12 * other.m22 +
+                 self.m13 * other.m32 + self.m14 * other.m42,
+            m13: self.m11 * other.m13 + self.m12 * other.m23 +
+                 self.m13 * other.m33 + self.m14 * other.m43,
+            m14: self.m11 * other.m14 + self.m12 * other.m24 +
+                 self.m13 * other.m34 + self.m14 * other.m44,
+            m21: self.m21 * other.m11 + self.m22 * other.m21 +
+                 self.m23 * other.m31 + self.m24 * other.m41,
+            m22: self.m21 * other.m12 + self.m22 * other.m22 +
+                 self.m23 * other.m32 + self.m24 * other.m42,
+            m23: self.m21 * other.m13 + self.m22 * other.m23 +
+                 self.m23 * other.m33 + self.m24 * other.m43,
+            m24: self.m21 * other.m14 + self.m22 * other.m24 +
+                 self.m23 * other.m34 + self.m24 * other.m44,
+            m31: self.m31 * other.m11 + self.m32 * other.m21 +
+                 self.m33 * other.m31 + self.m34 * other.m41,
+            m32: self.m31 * other.m12 + self.m32 * other.m22 +
+                 self.m33 * other.m32 + self.m34 * other.m42,
+            m33: self.m31 * other.m13 + self.m32 * other.m23 +
+                 self.m33 * other.m33 + self.m34 * other.m43,
+            m34: self.m31 * other.m14 + self.m32 * other.m24 +
+                 self.m33 * other.m34 + self.m34 * other.m44,
+            m41: self.m41 * other.m11 + self.m42 * other.m21 +
+                 self.m43 * other.m31 + self.m44 * other.m41,
+            m42: self.m41 * other.m12 + self.m42 * other.m22 +
+                 self.m43 * other.m32 + self.m44 * other.m42,
+            m43: self.m41 * other.m13 + self.m42 * other.m23 +
+                 self.m43 * other.m33 + self.m44 * other.m43,
+            m44: self.m41 * other.m14 + self.m42 * other.m24 +
+                 self.m43 * other.m34 + self.m44 * other.m44,
+        }
+    }
+
+    /// Scale the matrix by a factor.
+    #[inline]
+    pub fn scale_by_factor(&mut self, scaling_factor: CSSFloat) {
+        self.m11 *= scaling_factor;
+        self.m12 *= scaling_factor;
+        self.m13 *= scaling_factor;
+        self.m14 *= scaling_factor;
+        self.m21 *= scaling_factor;
+        self.m22 *= scaling_factor;
+        self.m23 *= scaling_factor;
+        self.m24 *= scaling_factor;
+        self.m31 *= scaling_factor;
+        self.m32 *= scaling_factor;
+        self.m33 *= scaling_factor;
+        self.m34 *= scaling_factor;
+        self.m41 *= scaling_factor;
+        self.m42 *= scaling_factor;
+        self.m43 *= scaling_factor;
+        self.m44 *= scaling_factor;
+    }
+
+    /// Return the matrix 3x3 part (top-left corner).
+    /// This is used by retrieving the scale and shear factors
+    /// during decomposing a 3d matrix.
+    #[inline]
+    pub fn get_matrix_3x3_part(&self) -> [[f32; 3]; 3] {
+        [
+            [ self.m11, self.m12, self.m13 ],
+            [ self.m21, self.m22, self.m23 ],
+            [ self.m31, self.m32, self.m33 ],
+        ]
+    }
+
+    /// Set perspective on the matrix.
+    #[inline]
+    pub fn set_perspective(&mut self, perspective: &Perspective) {
+        self.m14 = perspective.0;
+        self.m24 = perspective.1;
+        self.m34 = perspective.2;
+        self.m44 = perspective.3;
+    }
+
+    /// Apply translate on the matrix.
+    #[inline]
+    pub fn apply_translate(&mut self, translate: &Translate3D) {
+        self.m41 += translate.0 * self.m11 + translate.1 * self.m21 + translate.2 * self.m31;
+        self.m42 += translate.0 * self.m12 + translate.1 * self.m22 + translate.2 * self.m32;
+        self.m43 += translate.0 * self.m13 + translate.1 * self.m23 + translate.2 * self.m33;
+        self.m44 += translate.0 * self.m14 + translate.1 * self.m24 + translate.2 * self.m34;
+    }
+
+    /// Apply scale on the matrix.
+    #[inline]
+    pub fn apply_scale(&mut self, scale: &Scale3D) {
+        self.m11 *= scale.0;
+        self.m12 *= scale.0;
+        self.m13 *= scale.0;
+        self.m14 *= scale.0;
+        self.m21 *= scale.1;
+        self.m22 *= scale.1;
+        self.m23 *= scale.1;
+        self.m24 *= scale.1;
+        self.m31 *= scale.2;
+        self.m32 *= scale.2;
+        self.m33 *= scale.2;
+        self.m34 *= scale.2;
+    }
+}
+
+#[cfg_attr(rustfmt, rustfmt_skip)]
+impl Matrix {
+    #[inline]
+    /// Get an identity matrix
+    pub fn identity() -> Self {
+        Self {
+            a: 1., c: 0., /* 0      0*/
+            b: 0., d: 1., /* 0      0*/
+            /* 0      0      1      0 */
+            e: 0., f: 0., /* 0      1 */
+        }
+    }
+}
+
+#[cfg_attr(rustfmt, rustfmt_skip)]
+impl From<Matrix> for Matrix3D {
+    fn from(m: Matrix) -> Self {
+        Self {
+            m11: m.a, m12: m.b, m13: 0.0, m14: 0.0,
+            m21: m.c, m22: m.d, m23: 0.0, m24: 0.0,
+            m31: 0.0, m32: 0.0, m33: 1.0, m34: 0.0,
+            m41: m.e, m42: m.f, m43: 0.0, m44: 1.0
+        }
+    }
+}
+
+#[cfg_attr(rustfmt, rustfmt_skip)]
+impl From<Transform3D<CSSFloat>> for Matrix3D {
+    #[inline]
+    fn from(m: Transform3D<CSSFloat>) -> Self {
+        Matrix3D {
+            m11: m.m11, m12: m.m12, m13: m.m13, m14: m.m14,
+            m21: m.m21, m22: m.m22, m23: m.m23, m24: m.m24,
+            m31: m.m31, m32: m.m32, m33: m.m33, m34: m.m34,
+            m41: m.m41, m42: m.m42, m43: m.m43, m44: m.m44
+        }
+    }
+}
+
+impl TransformOperation {
+    /// Convert to a Translate3D.
+    ///
+    /// Must be called on a Translate function
+    pub fn to_translate_3d(&self) -> Self {
+        match *self {
+            generic::TransformOperation::Translate3D(..) => self.clone(),
+            generic::TransformOperation::TranslateX(ref x) => {
+                generic::TransformOperation::Translate3D(
+                    x.clone(),
+                    LengthPercentage::zero(),
+                    Length::zero(),
+                )
+            },
+            generic::TransformOperation::Translate(ref x, ref y) => {
+                generic::TransformOperation::Translate3D(x.clone(), y.clone(), Length::zero())
+            },
+            generic::TransformOperation::TranslateY(ref y) => {
+                generic::TransformOperation::Translate3D(
+                    LengthPercentage::zero(),
+                    y.clone(),
+                    Length::zero(),
+                )
+            },
+            generic::TransformOperation::TranslateZ(ref z) => {
+                generic::TransformOperation::Translate3D(
+                    LengthPercentage::zero(),
+                    LengthPercentage::zero(),
+                    z.clone(),
+                )
+            },
+            _ => unreachable!(),
+        }
+    }
+
+    /// Convert to a Rotate3D.
+    ///
+    /// Must be called on a Rotate function.
+    pub fn to_rotate_3d(&self) -> Self {
+        match *self {
+            generic::TransformOperation::Rotate3D(..) => self.clone(),
+            generic::TransformOperation::RotateZ(ref angle) |
+            generic::TransformOperation::Rotate(ref angle) => {
+                generic::TransformOperation::Rotate3D(0., 0., 1., angle.clone())
+            },
+            generic::TransformOperation::RotateX(ref angle) => {
+                generic::TransformOperation::Rotate3D(1., 0., 0., angle.clone())
+            },
+            generic::TransformOperation::RotateY(ref angle) => {
+                generic::TransformOperation::Rotate3D(0., 1., 0., angle.clone())
+            },
+            _ => unreachable!(),
+        }
+    }
+
+    /// Convert to a Scale3D.
+    ///
+    /// Must be called on a Scale function
+    pub fn to_scale_3d(&self) -> Self {
+        match *self {
+            generic::TransformOperation::Scale3D(..) => self.clone(),
+            generic::TransformOperation::Scale(x, y) => {
+                generic::TransformOperation::Scale3D(x, y, 1.)
+            },
+            generic::TransformOperation::ScaleX(x) => {
+                generic::TransformOperation::Scale3D(x, 1., 1.)
+            },
+            generic::TransformOperation::ScaleY(y) => {
+                generic::TransformOperation::Scale3D(1., y, 1.)
+            },
+            generic::TransformOperation::ScaleZ(z) => {
+                generic::TransformOperation::Scale3D(1., 1., z)
+            },
+            _ => unreachable!(),
+        }
+    }
+}
+
+/// Build an equivalent 'identity transform function list' based
+/// on an existing transform list.
+/// http://dev.w3.org/csswg/css-transforms/#none-transform-animation
+impl ToAnimatedZero for TransformOperation {
+    fn to_animated_zero(&self) -> Result<Self, ()> {
+        match *self {
+            generic::TransformOperation::Matrix3D(..) => {
+                Ok(generic::TransformOperation::Matrix3D(Matrix3D::identity()))
+            },
+            generic::TransformOperation::Matrix(..) => {
+                Ok(generic::TransformOperation::Matrix(Matrix::identity()))
+            },
+            generic::TransformOperation::Skew(sx, sy) => Ok(generic::TransformOperation::Skew(
+                sx.to_animated_zero()?,
+                sy.to_animated_zero()?,
+            )),
+            generic::TransformOperation::SkewX(s) => {
+                Ok(generic::TransformOperation::SkewX(s.to_animated_zero()?))
+            },
+            generic::TransformOperation::SkewY(s) => {
+                Ok(generic::TransformOperation::SkewY(s.to_animated_zero()?))
+            },
+            generic::TransformOperation::Translate3D(ref tx, ref ty, ref tz) => {
+                Ok(generic::TransformOperation::Translate3D(
+                    tx.to_animated_zero()?,
+                    ty.to_animated_zero()?,
+                    tz.to_animated_zero()?,
+                ))
+            },
+            generic::TransformOperation::Translate(ref tx, ref ty) => {
+                Ok(generic::TransformOperation::Translate(
+                    tx.to_animated_zero()?,
+                    ty.to_animated_zero()?,
+                ))
+            },
+            generic::TransformOperation::TranslateX(ref t) => Ok(
+                generic::TransformOperation::TranslateX(t.to_animated_zero()?),
+            ),
+            generic::TransformOperation::TranslateY(ref t) => Ok(
+                generic::TransformOperation::TranslateY(t.to_animated_zero()?),
+            ),
+            generic::TransformOperation::TranslateZ(ref t) => Ok(
+                generic::TransformOperation::TranslateZ(t.to_animated_zero()?),
+            ),
+            generic::TransformOperation::Scale3D(..) => {
+                Ok(generic::TransformOperation::Scale3D(1.0, 1.0, 1.0))
+            },
+            generic::TransformOperation::Scale(_, _) => {
+                Ok(generic::TransformOperation::Scale(1.0, 1.0))
+            },
+            generic::TransformOperation::ScaleX(..) => Ok(generic::TransformOperation::ScaleX(1.0)),
+            generic::TransformOperation::ScaleY(..) => Ok(generic::TransformOperation::ScaleY(1.0)),
+            generic::TransformOperation::ScaleZ(..) => Ok(generic::TransformOperation::ScaleZ(1.0)),
+            generic::TransformOperation::Rotate3D(x, y, z, a) => {
+                let (x, y, z, _) = generic::get_normalized_vector_and_angle(x, y, z, a);
+                Ok(generic::TransformOperation::Rotate3D(
+                    x,
+                    y,
+                    z,
+                    Angle::zero(),
+                ))
+            },
+            generic::TransformOperation::RotateX(_) => {
+                Ok(generic::TransformOperation::RotateX(Angle::zero()))
+            },
+            generic::TransformOperation::RotateY(_) => {
+                Ok(generic::TransformOperation::RotateY(Angle::zero()))
+            },
+            generic::TransformOperation::RotateZ(_) => {
+                Ok(generic::TransformOperation::RotateZ(Angle::zero()))
+            },
+            generic::TransformOperation::Rotate(_) => {
+                Ok(generic::TransformOperation::Rotate(Angle::zero()))
+            },
+            generic::TransformOperation::Perspective(_) => Ok(
+                generic::TransformOperation::Perspective(generic::PerspectiveFunction::None),
+            ),
+            generic::TransformOperation::AccumulateMatrix { .. } |
+            generic::TransformOperation::InterpolateMatrix { .. } => {
+                // AccumulateMatrix/InterpolateMatrix: We do interpolation on
+                //     AccumulateMatrix/InterpolateMatrix by reading it as a ComputedMatrix
+                //     (with layout information), and then do matrix interpolation.
+                //
+                // Therefore, we use an identity matrix to represent the identity transform list.
+                // http://dev.w3.org/csswg/css-transforms/#identity-transform-function
+                Ok(generic::TransformOperation::Matrix3D(Matrix3D::identity()))
+            },
+        }
+    }
+}
+
+impl ToAnimatedZero for Transform {
+    #[inline]
+    fn to_animated_zero(&self) -> Result<Self, ()> {
+        Ok(generic::Transform(
+            self.0
+                .iter()
+                .map(|op| op.to_animated_zero())
+                .collect::<Result<crate::OwnedSlice<_>, _>>()?,
+        ))
+    }
+}
+
+/// A computed CSS `rotate`
+pub type Rotate = generic::GenericRotate<Number, Angle>;
+
+/// A computed CSS `translate`
+pub type Translate = generic::GenericTranslate<LengthPercentage, Length>;
+
+/// A computed CSS `scale`
+pub type Scale = generic::GenericScale<Number>;