Implement fill tool (#254)

* Implement fill tool

* Add fill tool shortcut

* Add getters and setters to styles

* Make fill tool act on the topmost layer clicked

* Refactor fill operation

* Refactor and unify selection tolerance

* Add mark_as_dirty function

* Fix getter names

core/document/src/layers/mod.rs

@@ -23,8 +23,6 @@ use crate::LayerId;
 pub use folder::Folder;
 use serde::{Deserialize, Serialize};
 
-pub const SELECTION_TOLERANCE: f64 = 5.0;
-
 pub trait LayerData {
 	fn render(&mut self, svg: &mut String, transform: glam::DAffine2, style: style::PathStyle);
 	fn to_kurbo_path(&self, transform: glam::DAffine2, style: style::PathStyle) -> BezPath;

core/document/src/layers/style/mod.rs

@@ -56,6 +56,24 @@ impl PathStyle {
 	pub fn new(stroke: Option<Stroke>, fill: Option<Fill>) -> Self {
 		Self { stroke, fill }
 	}
+	pub fn fill(&self) -> Option<Fill> {
+		self.fill
+	}
+	pub fn stroke(&self) -> Option<Stroke> {
+		self.stroke
+	}
+	pub fn set_fill(&mut self, fill: Fill) {
+		self.fill = Some(fill);
+	}
+	pub fn set_stroke(&mut self, stroke: Stroke) {
+		self.stroke = Some(stroke);
+	}
+	pub fn clear_fill(&mut self) {
+		self.fill = None;
+	}
+	pub fn clear_stroke(&mut self) {
+		self.stroke = None;
+	}
 	pub fn render(&self) -> String {
 		format!(
 			"{}{}",