Add Image rotation support

Co-authored-by: DKolter <68352124+DKolter@users.noreply.github.com>

core/src/image.rs

@@ -173,5 +173,7 @@ pub trait Renderer: crate::Renderer {
         handle: Self::Handle,
         filter_method: FilterMethod,
         bounds: Rectangle,
+        rotation: f32,
+        scale: Size,
     );
 }

core/src/lib.rs

@@ -39,6 +39,7 @@ mod padding;
 mod pixels;
 mod point;
 mod rectangle;
+mod rotation;
 mod shadow;
 mod shell;
 mod size;
@@ -64,6 +65,7 @@ pub use pixels::Pixels;
 pub use point::Point;
 pub use rectangle::Rectangle;
 pub use renderer::Renderer;
+pub use rotation::RotationLayout;
 pub use shadow::Shadow;
 pub use shell::Shell;
 pub use size::Size;

core/src/renderer/null.rs

@@ -171,6 +171,8 @@ impl image::Renderer for () {
         _handle: Self::Handle,
         _filter_method: image::FilterMethod,
         _bounds: Rectangle,
+        _rotation: f32,
+        _scale: Size,
     ) {
     }
 }
@@ -185,6 +187,8 @@ impl svg::Renderer for () {
         _handle: svg::Handle,
         _color: Option<Color>,
         _bounds: Rectangle,
+        _rotation: f32,
+        _scale: Size,
     ) {
     }
 }

core/src/rotation.rs

@@ -0,0 +1,37 @@
+//! Control the rotation of some content (like an image) with the `RotationLayout` within a
+//! space.
+use crate::Size;
+
+/// The strategy used to rotate the content.
+///
+/// This is used to control the behavior of the layout when the content is rotated
+/// by a certain angle.
+#[derive(Debug, Hash, Clone, Copy, PartialEq, Eq)]
+pub enum RotationLayout {
+    /// The layout is kept exactly as it was before the rotation.
+    ///
+    /// This is especially useful when used for animations, as it will avoid the
+    /// layout being shifted or resized when smoothly i.e. an icon.
+    Keep,
+    /// The layout is adjusted to fit the rotated content.
+    ///
+    /// This allows you to rotate an image and have the layout adjust to fit the new
+    /// size of the image.
+    Change,
+}
+
+impl RotationLayout {
+    /// Applies the rotation to the layout while respecting the [`RotationLayout`] strategy.
+    /// The rotation is given in radians.
+    pub fn apply_to_size(&self, size: Size, rotation: f32) -> Size {
+        match self {
+            Self::Keep => size,
+            Self::Change => Size {
+                width: (size.width * rotation.cos()).abs()
+                    + (size.height * rotation.sin()).abs(),
+                height: (size.width * rotation.sin()).abs()
+                    + (size.height * rotation.cos()).abs(),
+            },
+        }
+    }
+}

core/src/svg.rs

@@ -100,5 +100,7 @@ pub trait Renderer: crate::Renderer {
         handle: Handle,
         color: Option<Color>,
         bounds: Rectangle,
+        rotation: f32,
+        scale: Size,
     );
 }