make image-orientation animatable

components/style/properties/gecko.mako.rs

@@ -4546,6 +4546,31 @@ fn static_assert() {
     pub fn reset_image_orientation(&mut self, other: &Self) {
         self.copy_image_orientation_from(other)
     }
+
+    pub fn clone_image_orientation(&self) -> longhands::image_orientation::computed_value::T {
+        use gecko_bindings::structs::{nsStyleImageOrientation_Bits, nsStyleImageOrientation_Angles};
+        use properties::longhands::image_orientation::computed_value::{Orientation, T};
+
+        let gecko_orientation = self.gecko.mImageOrientation.mOrientation;
+        if gecko_orientation & nsStyleImageOrientation_Bits::FROM_IMAGE_MASK as u8 != 0 {
+            T::FromImage
+        } else {
+            const ANGLE0: u8 = nsStyleImageOrientation_Angles::ANGLE_0 as u8;
+            const ANGLE90: u8 = nsStyleImageOrientation_Angles::ANGLE_90 as u8;
+            const ANGLE180: u8 = nsStyleImageOrientation_Angles::ANGLE_180 as u8;
+            const ANGLE270: u8 = nsStyleImageOrientation_Angles::ANGLE_270 as u8;
+
+            let flip = gecko_orientation & nsStyleImageOrientation_Bits::FLIP_MASK as u8 != 0;
+            let orientation = match gecko_orientation & nsStyleImageOrientation_Bits::ORIENTATION_MASK as u8 {
+                ANGLE0 => Orientation::Angle0,
+                ANGLE90 => Orientation::Angle90,
+                ANGLE180 => Orientation::Angle180,
+                ANGLE270 => Orientation::Angle270,
+                _ => unreachable!()
+            };
+            T::AngleWithFlipped(orientation, flip)
+        }
+    }
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="InheritedTable"

components/style/properties/longhand/inherited_box.mako.rs

@@ -59,7 +59,7 @@ ${helpers.single_keyword("image-rendering",
 // Image Orientation
 <%helpers:longhand name="image-orientation"
                    products="gecko"
-                   animation_value_type="none"
+                   animation_value_type="discrete"
     spec="https://drafts.csswg.org/css-images/#propdef-image-orientation, \
       /// additional values in https://developer.mozilla.org/en-US/docs/Web/CSS/image-orientation">
     use std::fmt;