Implement viewport selection (#178)

* Begin implementing viewport selection

* Implement viewport click and drag selection for ellipse and rectangle

* Begin implementing line selection

* Remove debug prints

* Run cargo format

* Use DVec2 instead of kurbo::Point

* Line and polyline intersection

* Run cargo format

* Add fix for missing layer panel update

* Replace point selection with box selection

* Formatting

Co-authored-by: Keavon Chambers <keavon@keavon.com>

core/document/src/document.rs

@@ -1,4 +1,4 @@
-use glam::DAffine2;
+use glam::{DAffine2, DVec2};
 
 use crate::{
 	layers::{self, style::PathStyle, Folder, Layer, LayerDataTypes, Line, PolyLine, Rect, Shape},
@@ -64,6 +64,19 @@ impl Document {
 		svg
 	}
 
+	/// Checks whether each layer under `path` intersects with the provided `quad` and adds all intersection layers as paths to `intersections`.
+	pub fn intersects_quad(&self, quad: [DVec2; 4], path: &mut Vec<LayerId>, intersections: &mut Vec<Vec<LayerId>>) {
+		self.document_folder(path).unwrap().intersects_quad(quad, path, intersections);
+		return;
+	}
+
+	/// Checks whether each layer under the root path intersects with the provided `quad` and returns the paths to all intersecting layers.
+	pub fn intersects_quad_root(&self, quad: [DVec2; 4]) -> Vec<Vec<LayerId>> {
+		let mut intersections = Vec::new();
+		self.intersects_quad(quad, &mut vec![], &mut intersections);
+		intersections
+	}
+
 	fn is_mounted(&self, mount_path: &[LayerId], path: &[LayerId]) -> bool {
 		path.starts_with(mount_path) && self.work_mounted
 	}