Add `Image` rotation support

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

1 files changed, 37 insertions, 0 deletions

diff --git a/core/src/rotation.rs b/core/src/rotation.rs
new file mode 100644
index 00000000..821aa494
--- /dev/null
+++ b/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(),
+            },
+        }
+    }
+}