Restructure project directories (#333)

`/client/web` -> `/frontend`
`/client/cli` -> *delete for now*
`/client/native` -> *delete for now*
`/core/editor` -> `/editor`
`/core/document` -> `/graphene`
`/core/renderer` -> `/charcoal`
`/core/proc-macro` -> `/proc-macros` *(now plural)*

editor/src/tool/tools/rectangle.rs

@@ -0,0 +1,119 @@
+use crate::input::keyboard::Key;
+use crate::input::InputPreprocessor;
+use crate::tool::{DocumentToolData, Fsm, ToolActionHandlerData};
+use crate::{document::DocumentMessageHandler, message_prelude::*};
+use glam::DAffine2;
+use graphene::{layers::style, Operation};
+
+use super::resize::*;
+
+#[derive(Default)]
+pub struct Rectangle {
+	fsm_state: RectangleToolFsmState,
+	data: RectangleToolData,
+}
+
+#[impl_message(Message, ToolMessage, Rectangle)]
+#[derive(PartialEq, Clone, Debug, Hash)]
+pub enum RectangleMessage {
+	DragStart,
+	DragStop,
+	Resize { center: Key, lock_ratio: Key },
+	Abort,
+}
+
+impl<'a> MessageHandler<ToolMessage, ToolActionHandlerData<'a>> for Rectangle {
+	fn process_action(&mut self, action: ToolMessage, data: ToolActionHandlerData<'a>, responses: &mut VecDeque<Message>) {
+		self.fsm_state = self.fsm_state.transition(action, data.0, data.1, &mut self.data, data.2, responses);
+	}
+	fn actions(&self) -> ActionList {
+		use RectangleToolFsmState::*;
+		match self.fsm_state {
+			Ready => actions!(RectangleMessageDiscriminant; DragStart),
+			Dragging => actions!(RectangleMessageDiscriminant; DragStop, Abort, Resize),
+		}
+	}
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum RectangleToolFsmState {
+	Ready,
+	Dragging,
+}
+
+impl Default for RectangleToolFsmState {
+	fn default() -> Self {
+		RectangleToolFsmState::Ready
+	}
+}
+#[derive(Clone, Debug, Default)]
+struct RectangleToolData {
+	sides: u8,
+	data: Resize,
+}
+
+impl Fsm for RectangleToolFsmState {
+	type ToolData = RectangleToolData;
+
+	fn transition(
+		self,
+		event: ToolMessage,
+		document: &DocumentMessageHandler,
+		tool_data: &DocumentToolData,
+		data: &mut Self::ToolData,
+		input: &InputPreprocessor,
+		responses: &mut VecDeque<Message>,
+	) -> Self {
+		let mut shape_data = &mut data.data;
+		use RectangleMessage::*;
+		use RectangleToolFsmState::*;
+		if let ToolMessage::Rectangle(event) = event {
+			match (self, event) {
+				(Ready, DragStart) => {
+					shape_data.drag_start = input.mouse.position;
+					responses.push_back(DocumentMessage::StartTransaction.into());
+					shape_data.path = Some(vec![generate_hash(&*responses, input, document.document.hash())]);
+					responses.push_back(DocumentMessage::DeselectAllLayers.into());
+
+					responses.push_back(
+						Operation::AddRect {
+							path: shape_data.path.clone().unwrap(),
+							insert_index: -1,
+							transform: DAffine2::ZERO.to_cols_array(),
+							style: style::PathStyle::new(None, Some(style::Fill::new(tool_data.primary_color))),
+						}
+						.into(),
+					);
+
+					Dragging
+				}
+				(state, Resize { center, lock_ratio }) => {
+					if let Some(message) = shape_data.calculate_transform(center, lock_ratio, input) {
+						responses.push_back(message);
+					}
+
+					state
+				}
+				(Dragging, DragStop) => {
+					// TODO: introduce comparison threshold when operating with canvas coordinates (https://github.com/GraphiteEditor/Graphite/issues/100)
+					match shape_data.drag_start == input.mouse.position {
+						true => responses.push_back(DocumentMessage::AbortTransaction.into()),
+						false => responses.push_back(DocumentMessage::CommitTransaction.into()),
+					}
+
+					shape_data.path = None;
+					Ready
+				}
+				(Dragging, Abort) => {
+					responses.push_back(DocumentMessage::AbortTransaction.into());
+					shape_data.path = None;
+
+					Ready
+				}
+				_ => self,
+			}
+		} else {
+			self
+		}
+	}
+}