1 files changed, 124 insertions, 0 deletions
diff --git a/rust/crates/animation/src/channel_layout.rs b/rust/crates/animation/src/channel_layout.rs
new file mode 100644
index 00000000..59bbc3f6
--- /dev/null
+++ b/rust/crates/animation/src/channel_layout.rs
@@ -0,0 +1,124 @@
+use scene::ParamValue;
+use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
+
+use crate::color::{LinearRgba, parse_color_to_linear_rgba};
+use crate::types::AnimationInterpolation;
+
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, Eq, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub enum ChannelValueKind {
+    Scalar,
+    Discrete,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ChannelComponentDefinition {
+    pub key: String,
+    pub value_kind: ChannelValueKind,
+    pub default_interpolation: AnimationInterpolation,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum ChannelLayout {
+    Leaf(ChannelComponentDefinition),
+    Composite(Vec<ChannelComponentDefinition>),
+}
+
+impl ChannelLayout {
+    pub fn components(&self) -> &[ChannelComponentDefinition] {
+        match self {
+            ChannelLayout::Leaf(component) => std::slice::from_ref(component),
+            ChannelLayout::Composite(components) => components,
+        }
+    }
+
+    pub fn decompose(&self, value: &ParamValue) -> Option<BTreeMap<String, ParamValue>> {
+        match self {
+            ChannelLayout::Leaf(component) => {
+                let mut values = BTreeMap::new();
+                values.insert(component.key.clone(), value.clone());
+                Some(values)
+            }
+            ChannelLayout::Composite(_) => {
+                let ParamValue::String(color) = value else {
+                    return None;
+                };
+                let LinearRgba { r, g, b, a } = parse_color_to_linear_rgba(color)?;
+                let mut values = BTreeMap::new();
+                values.insert("r".to_string(), ParamValue::Number(r));
+                values.insert("g".to_string(), ParamValue::Number(g));
+                values.insert("b".to_string(), ParamValue::Number(b));
+                values.insert("a".to_string(), ParamValue::Number(a));
+                Some(values)
+            }
+        }
+    }
+}
+
+pub fn number_channel_layout() -> ChannelLayout {
+    ChannelLayout::Leaf(ChannelComponentDefinition {
+        key: "value".to_string(),
+        value_kind: ChannelValueKind::Scalar,
+        default_interpolation: AnimationInterpolation::Linear,
+    })
+}
+
+pub fn boolean_channel_layout() -> ChannelLayout {
+    ChannelLayout::Leaf(ChannelComponentDefinition {
+        key: "value".to_string(),
+        value_kind: ChannelValueKind::Discrete,
+        default_interpolation: AnimationInterpolation::Hold,
+    })
+}
+
+pub fn string_channel_layout() -> ChannelLayout {
+    ChannelLayout::Leaf(ChannelComponentDefinition {
+        key: "value".to_string(),
+        value_kind: ChannelValueKind::Discrete,
+        default_interpolation: AnimationInterpolation::Hold,
+    })
+}
+
+pub fn color_channel_layout() -> ChannelLayout {
+    let component = |key: &str| ChannelComponentDefinition {
+        key: key.to_string(),
+        value_kind: ChannelValueKind::Scalar,
+        default_interpolation: AnimationInterpolation::Linear,
+    };
+    ChannelLayout::Composite(vec![
+        component("r"),
+        component("g"),
+        component("b"),
+        component("a"),
+    ])
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn leaf_decompose_wraps_value_under_component_key() {
+        let layout = number_channel_layout();
+        let values = layout.decompose(&ParamValue::Number(3.0)).unwrap();
+        assert_eq!(values.get("value"), Some(&ParamValue::Number(3.0)));
+    }
+
+    #[test]
+    fn color_decompose_parses_hex_into_linear_components() {
+        let layout = color_channel_layout();
+        let values = layout
+            .decompose(&ParamValue::String("#ff0000".to_string()))
+            .unwrap();
+        assert_eq!(values.get("r"), Some(&ParamValue::Number(1.0)));
+        assert_eq!(values.get("g"), Some(&ParamValue::Number(0.0)));
+        assert_eq!(values.get("a"), Some(&ParamValue::Number(1.0)));
+        assert!(
+            layout
+                .decompose(&ParamValue::Number(1.0))
+                .is_none()
+        );
+    }
+}