trait based event system

packages/html/src/events/image.rs

@@ -1,11 +1,91 @@
 use dioxus_core::Event;
 
 pub type ImageEvent = Event<ImageData>;
-#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
-#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ImageData {
-    #[cfg_attr(feature = "serialize", serde(default))]
-    pub load_error: bool,
+    inner: Box<dyn HasImageData>,
+}
+
+impl<E: HasImageData> From<E> for ImageData {
+    fn from(e: E) -> Self {
+        Self { inner: Box::new(e) }
+    }
+}
+
+impl std::fmt::Debug for ImageData {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("ImageData")
+            .field("load_error", &self.load_error())
+            .finish()
+    }
+}
+
+impl PartialEq for ImageData {
+    fn eq(&self, other: &Self) -> bool {
+        self.load_error() == other.load_error()
+    }
+}
+
+impl ImageData {
+    /// If the renderer encountered an error while loading the image
+    pub fn load_error(&self) -> bool {
+        self.inner.load_error()
+    }
+
+    pub fn downcast<T: 'static>(&self) -> Option<&T> {
+        self.inner.as_any().downcast_ref::<T>()
+    }
+}
+
+#[cfg(feature = "serialize")]
+#[derive(serde::Serialize, serde::Deserialize)]
+struct SerializedImageData {
+    load_error: bool,
+}
+
+#[cfg(feature = "serialize")]
+impl From<&ImageData> for SerializedImageData {
+    fn from(data: &ImageData) -> Self {
+        Self {
+            load_error: data.load_error(),
+        }
+    }
+}
+
+#[cfg(feature = "serialize")]
+impl HasImageData for SerializedImageData {
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+
+    fn load_error(&self) -> bool {
+        self.load_error
+    }
+}
+
+#[cfg(feature = "serialize")]
+impl serde::Serialize for ImageData {
+    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        SerializedImageData::from(self).serialize(serializer)
+    }
+}
+
+#[cfg(feature = "serialize")]
+impl<'de> serde::Deserialize<'de> for ImageData {
+    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        let data = SerializedImageData::deserialize(deserializer)?;
+        Ok(Self {
+            inner: Box::new(data),
+        })
+    }
+}
+
+/// A trait for any object that has the data for an image event
+pub trait HasImageData: std::any::Any {
+    /// If the renderer encountered an error while loading the image
+    fn load_error(&self) -> bool;
+
+    /// return self as Any
+    fn as_any(&self) -> &dyn std::any::Any;
 }
 
 impl_event! [