1 files changed, 186 insertions, 2 deletions
diff --git a/servo/components/style/values/computed/basic_shape.rs b/servo/components/style/values/computed/basic_shape.rs
index d39110ec1c..21df7baf93 100644
--- a/servo/components/style/values/computed/basic_shape.rs
+++ b/servo/components/style/values/computed/basic_shape.rs
@@ -7,9 +7,12 @@
 //!
 //! [basic-shape]: https://drafts.csswg.org/css-shapes/#typedef-basic-shape
 
+use crate::values::animated::{Animate, Procedure};
+use crate::values::computed::angle::Angle;
 use crate::values::computed::url::ComputedUrl;
 use crate::values::computed::{Image, LengthPercentage, NonNegativeLengthPercentage, Position};
 use crate::values::generics::basic_shape as generic;
+use crate::values::specified::svg_path::{CoordPair, PathCommand};
 
 /// A computed alias for FillRule.
 pub use crate::values::generics::basic_shape::FillRule;
@@ -21,8 +24,13 @@ pub type ClipPath = generic::GenericClipPath<BasicShape, ComputedUrl>;
 pub type ShapeOutside = generic::GenericShapeOutside<BasicShape, Image>;
 
 /// A computed basic shape.
-pub type BasicShape =
-    generic::GenericBasicShape<Position, LengthPercentage, NonNegativeLengthPercentage, InsetRect>;
+pub type BasicShape = generic::GenericBasicShape<
+    Angle,
+    Position,
+    LengthPercentage,
+    NonNegativeLengthPercentage,
+    InsetRect,
+>;
 
 /// The computed value of `inset()`.
 pub type InsetRect = generic::GenericInsetRect<LengthPercentage, NonNegativeLengthPercentage>;
@@ -35,3 +43,179 @@ pub type Ellipse = generic::Ellipse<Position, NonNegativeLengthPercentage>;
 
 /// The computed value of `ShapeRadius`.
 pub type ShapeRadius = generic::GenericShapeRadius<NonNegativeLengthPercentage>;
+
+/// The computed value of `shape()`.
+pub type Shape = generic::Shape<Angle, LengthPercentage>;
+
+/// The computed value of `ShapeCommand`.
+pub type ShapeCommand = generic::GenericShapeCommand<Angle, LengthPercentage>;
+
+/// The computed value of `PathOrShapeFunction`.
+pub type PathOrShapeFunction = generic::GenericPathOrShapeFunction<Angle, LengthPercentage>;
+
+/// The computed value of `CoordinatePair`.
+pub type CoordinatePair = generic::CoordinatePair<LengthPercentage>;
+
+/// Animate from `Shape` to `Path`, and vice versa.
+macro_rules! animate_shape {
+    (
+        $from:ident,
+        $to:ident,
+        $procedure:ident,
+        $from_as_shape:tt,
+        $to_as_shape:tt
+    ) => {{
+        // Check fill-rule.
+        if $from.fill != $to.fill {
+            return Err(());
+        }
+
+        // Check the list of commands. (This is a specialized lists::by_computed_value::animate().)
+        let from_cmds = $from.commands();
+        let to_cmds = $to.commands();
+        if from_cmds.len() != to_cmds.len() {
+            return Err(());
+        }
+        let commands = from_cmds
+            .iter()
+            .zip(to_cmds.iter())
+            .map(|(from_cmd, to_cmd)| {
+                $from_as_shape(from_cmd).animate(&$to_as_shape(to_cmd), $procedure)
+            })
+            .collect::<Result<Vec<ShapeCommand>, ()>>()?;
+
+        Ok(Shape {
+            fill: $from.fill,
+            commands: commands.into(),
+        })
+    }};
+}
+
+impl Animate for PathOrShapeFunction {
+    #[inline]
+    fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
+        // Per spec, commands are "the same" if they use the same command keyword, and use the same
+        // <by-to> keyword. For curve and smooth, they also must have the same number of control
+        // points. Therefore, we don't have to do normalization here. (Note that we do
+        // normalization if we animate from path() to path(). See svg_path.rs for more details.)
+        //
+        // https://drafts.csswg.org/css-shapes-2/#interpolating-shape
+        match (self, other) {
+            (Self::Path(ref from), Self::Path(ref to)) => {
+                from.animate(to, procedure).map(Self::Path)
+            },
+            (Self::Shape(ref from), Self::Shape(ref to)) => {
+                from.animate(to, procedure).map(Self::Shape)
+            },
+            (Self::Shape(ref from), Self::Path(ref to)) => {
+                // Animate from shape() to path(). We convert each PathCommand into ShapeCommand,
+                // and return shape().
+                animate_shape!(
+                    from,
+                    to,
+                    procedure,
+                    (|shape_cmd| shape_cmd),
+                    (|path_cmd| ShapeCommand::from(path_cmd))
+                )
+                .map(Self::Shape)
+            },
+            (Self::Path(ref from), Self::Shape(ref to)) => {
+                // Animate from path() to shape(). We convert each PathCommand into ShapeCommand,
+                // and return shape().
+                animate_shape!(
+                    from,
+                    to,
+                    procedure,
+                    (|path_cmd| ShapeCommand::from(path_cmd)),
+                    (|shape_cmd| shape_cmd)
+                )
+                .map(Self::Shape)
+            },
+        }
+    }
+}
+
+impl From<&PathCommand> for ShapeCommand {
+    #[inline]
+    fn from(path: &PathCommand) -> Self {
+        use crate::values::computed::CSSPixelLength;
+        match path {
+            &PathCommand::Close => Self::Close,
+            &PathCommand::Move { by_to, ref point } => Self::Move {
+                by_to,
+                point: point.into(),
+            },
+            &PathCommand::Line { by_to, ref point } => Self::Move {
+                by_to,
+                point: point.into(),
+            },
+            &PathCommand::HLine { by_to, x } => Self::HLine {
+                by_to,
+                x: LengthPercentage::new_length(CSSPixelLength::new(x)),
+            },
+            &PathCommand::VLine { by_to, y } => Self::VLine {
+                by_to,
+                y: LengthPercentage::new_length(CSSPixelLength::new(y)),
+            },
+            &PathCommand::CubicCurve {
+                by_to,
+                ref point,
+                ref control1,
+                ref control2,
+            } => Self::CubicCurve {
+                by_to,
+                point: point.into(),
+                control1: control1.into(),
+                control2: control2.into(),
+            },
+            &PathCommand::QuadCurve {
+                by_to,
+                ref point,
+                ref control1,
+            } => Self::QuadCurve {
+                by_to,
+                point: point.into(),
+                control1: control1.into(),
+            },
+            &PathCommand::SmoothCubic {
+                by_to,
+                ref point,
+                ref control2,
+            } => Self::SmoothCubic {
+                by_to,
+                point: point.into(),
+                control2: control2.into(),
+            },
+            &PathCommand::SmoothQuad { by_to, ref point } => Self::SmoothQuad {
+                by_to,
+                point: point.into(),
+            },
+            &PathCommand::Arc {
+                by_to,
+                ref point,
+                ref radii,
+                arc_sweep,
+                arc_size,
+                rotate,
+            } => Self::Arc {
+                by_to,
+                point: point.into(),
+                radii: radii.into(),
+                arc_sweep,
+                arc_size,
+                rotate: Angle::from_degrees(rotate),
+            },
+        }
+    }
+}
+
+impl From<&CoordPair> for CoordinatePair {
+    #[inline]
+    fn from(p: &CoordPair) -> Self {
+        use crate::values::computed::CSSPixelLength;
+        Self::new(
+            LengthPercentage::new_length(CSSPixelLength::new(p.x)),
+            LengthPercentage::new_length(CSSPixelLength::new(p.y)),
+        )
+    }
+}