🎉 Render drop shadows (wasm) (#5693)

Co-authored-by: Belén Albeza <belen@hey.com>

render-wasm/src/shapes/shadows.rs

@@ -0,0 +1,86 @@
+use skia_safe::{self as skia, image_filters};
+
+use super::Color;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum ShadowStyle {
+    Drop,
+    Inner,
+}
+
+impl From<u8> for ShadowStyle {
+    fn from(value: u8) -> Self {
+        match value {
+            0 => Self::Drop,
+            1 => Self::Inner,
+            _ => Self::default(),
+        }
+    }
+}
+
+impl Default for ShadowStyle {
+    fn default() -> Self {
+        Self::Drop
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Shadow {
+    color: Color,
+    blur: f32,
+    spread: f32,
+    offset: (f32, f32),
+    style: ShadowStyle,
+    hidden: bool,
+}
+
+// TODO: create shadows out of a chunk of bytes
+impl Shadow {
+    pub fn new(
+        color: Color,
+        blur: f32,
+        spread: f32,
+        offset: (f32, f32),
+        style: ShadowStyle,
+        hidden: bool,
+    ) -> Self {
+        Self {
+            color,
+            blur,
+            spread,
+            offset,
+            style,
+            hidden,
+        }
+    }
+
+    pub fn style(&self) -> ShadowStyle {
+        self.style
+    }
+
+    pub fn hidden(&self) -> bool {
+        self.hidden
+    }
+
+    pub fn to_paint(&self, dilate: bool, scale: f32) -> skia::Paint {
+        let mut paint = skia::Paint::default();
+        let mut filter = image_filters::drop_shadow_only(
+            (self.offset.0 * scale, self.offset.1 * scale),
+            (self.blur * scale, self.blur * scale),
+            self.color,
+            None,
+            None,
+            None,
+        );
+
+        if dilate {
+            filter =
+                image_filters::dilate((self.spread * scale, self.spread * scale), filter, None);
+        }
+
+        paint.set_image_filter(filter);
+        paint.set_anti_alias(true);
+
+        paint
+    }
+}