Add a document method that returns a layer's bounding box (#273)

* Add a document method that returns a layer's bounding box

* Moved `use` to the top of the file

* Add layer local bounding box method

Author: AyeTbk

core/document/src/document.rs

@@ -227,6 +227,16 @@ impl Document {
 		Ok(())
 	}
 
+	pub fn layer_axis_aligned_bounding_box(&self, path: &[LayerId]) -> Result<[DVec2; 2], DocumentError> {
+		let layer = self.layer(path)?;
+		Ok(layer.bounding_box(self.root.transform * layer.transform, layer.style))
+	}
+
+	pub fn layer_local_bounding_box(&self, path: &[LayerId]) -> Result<[DVec2; 2], DocumentError> {
+		let layer = self.layer(path)?;
+		Ok(layer.bounding_box(layer.transform, layer.style))
+	}
+
 	fn mark_as_dirty(&mut self, path: &[LayerId]) -> Result<(), DocumentError> {
 		let mut root = &mut self.root;
 		root.cache_dirty = true;

core/document/src/layers/mod.rs

@@ -6,6 +6,7 @@ pub use ellipse::Ellipse;
 pub mod line;
 use glam::{DMat2, DVec2};
 use kurbo::BezPath;
+use kurbo::Shape as KurboShape;
 pub use line::Line;
 
 pub mod rect;
@@ -100,6 +101,12 @@ impl LayerDataTypes {
 			}
 		}
 	}
+
+	pub fn bounding_box(&self, transform: glam::DAffine2, style: style::PathStyle) -> [DVec2; 2] {
+		let bez_path = self.to_kurbo_path(transform, style);
+		let bbox = bez_path.bounding_box();
+		[DVec2::new(bbox.x0, bbox.y0), DVec2::new(bbox.x1, bbox.y1)]
+	}
 }
 
 #[derive(Serialize, Deserialize)]
@@ -168,6 +175,10 @@ impl Layer {
 		self.data.to_kurbo_path(self.transform, self.style)
 	}
 
+	pub fn bounding_box(&self, transform: glam::DAffine2, style: style::PathStyle) -> [DVec2; 2] {
+		self.data.bounding_box(transform, style)
+	}
+
 	pub fn as_folder_mut(&mut self) -> Result<&mut Folder, DocumentError> {
 		match &mut self.data {
 			LayerDataTypes::Folder(f) => Ok(f),