LibWeb: Add a few Animation/AnimationEffect getters

Author: https://github.com/mattco98
Commit: 145ae54718
Pull-request: https://github.com/SerenityOS/serenity/pull/23257

Userland/Libraries/LibWeb/Animations/Animation.cpp

@@ -298,6 +298,15 @@ Bindings::AnimationPlayState Animation::play_state() const
     return Bindings::AnimationPlayState::Running;
 }
 
+// https://www.w3.org/TR/web-animations-1/#animation-relevant
+bool Animation::is_relevant() const
+{
+    // An animation is relevant if:
+    // - Its associated effect is current or in effect, and
+    // - Its replace state is not removed.
+    return (m_effect->is_current() || m_effect->is_in_effect()) && replace_state() != Bindings::AnimationReplaceState::Removed;
+}
+
 // https://www.w3.org/TR/web-animations-1/#replaceable-animation
 bool Animation::is_replaceable() const
 {

Userland/Libraries/LibWeb/Animations/Animation.h

@@ -50,6 +50,8 @@ public:
 
     Bindings::AnimationPlayState play_state() const;
 
+    bool is_relevant() const;
+
     bool is_replaceable() const;
     Bindings::AnimationReplaceState replace_state() const { return m_replace_state; }
 

Userland/Libraries/LibWeb/Animations/AnimationEffect.cpp

@@ -7,6 +7,7 @@
 #include <LibJS/Runtime/VM.h>
 #include <LibWeb/Animations/Animation.h>
 #include <LibWeb/Animations/AnimationEffect.h>
+#include <LibWeb/Animations/AnimationTimeline.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/DOM/Element.h>
 #include <LibWeb/WebIDL/ExceptionOr.h>
@@ -264,6 +265,46 @@ Optional<double> AnimationEffect::active_time_using_fill(Bindings::FillMode fill
     return {};
 }
 
+// https://www.w3.org/TR/web-animations-1/#in-play
+bool AnimationEffect::is_in_play() const
+{
+    // An animation effect is in play if all of the following conditions are met:
+    // - the animation effect is in the active phase, and
+    // - the animation effect is associated with an animation that is not finished.
+    return is_in_the_active_phase() && m_associated_animation && !m_associated_animation->is_finished();
+}
+
+// https://www.w3.org/TR/web-animations-1/#current
+bool AnimationEffect::is_current() const
+{
+    // An animation effect is current if any of the following conditions are true:
+
+    // - the animation effect is in play, or
+    if (is_in_play())
+        return true;
+
+    if (auto animation = m_associated_animation) {
+        auto playback_rate = animation->playback_rate();
+
+        // - the animation effect is associated with an animation with a playback rate > 0 and the animation effect is
+        //   in the before phase, or
+        if (playback_rate > 0.0 && is_in_the_before_phase())
+            return true;
+
+        // - the animation effect is associated with an animation with a playback rate < 0 and the animation effect is
+        //   in the after phase, or
+        if (playback_rate < 0.0 && is_in_the_after_phase())
+            return true;
+
+        // - the animation effect is associated with an animation not in the idle play state with a non-null associated
+        //   timeline that is not monotonically increasing.
+        if (animation->play_state() != Bindings::AnimationPlayState::Idle && animation->timeline() && !animation->timeline()->is_monotonically_increasing())
+            return true;
+    }
+
+    return false;
+}
+
 // https://www.w3.org/TR/web-animations-1/#in-effect
 bool AnimationEffect::is_in_effect() const
 {

Userland/Libraries/LibWeb/Animations/AnimationEffect.h

@@ -104,6 +104,9 @@ public:
     double active_duration() const;
     Optional<double> active_time() const;
     Optional<double> active_time_using_fill(Bindings::FillMode) const;
+
+    bool is_in_play() const;
+    bool is_current() const;
     bool is_in_effect() const;
 
     double before_active_boundary_time() const;

Userland/Libraries/LibWeb/Animations/AnimationTimeline.cpp

@@ -23,7 +23,6 @@ void AnimationTimeline::set_current_time(Optional<double> value)
     }
 
     m_current_time = value;
-
     for (auto& animation : m_associated_animations)
         animation->notify_timeline_time_did_change();
 }