Layer snapping

editor/src/consts.rs

@@ -15,6 +15,8 @@ pub const VIEWPORT_SCROLL_RATE: f64 = 0.6;
 
 pub const VIEWPORT_ROTATE_SNAP_INTERVAL: f64 = 15.;
 
+pub const SNAP_TOLERANCE: f64 = 3.;
+
 // TRANSFORMING LAYER
 pub const ROTATE_SNAP_ANGLE: f64 = 15.;
 pub const SCALE_SNAP_INTERVAL: f64 = 0.1;

editor/src/document/document_file.rs

@@ -65,6 +65,7 @@ pub struct DocumentMessageHandler {
 	pub layer_data: HashMap<Vec<LayerId>, LayerData>,
 	movement_handler: MovementMessageHandler,
 	transform_layer_handler: TransformLayerMessageHandler,
+	pub snapping_enabled: bool,
 }
 
 impl Default for DocumentMessageHandler {
@@ -77,6 +78,7 @@ impl Default for DocumentMessageHandler {
 			layer_data: vec![(vec![], LayerData::new(true))].into_iter().collect(),
 			movement_handler: MovementMessageHandler::default(),
 			transform_layer_handler: TransformLayerMessageHandler::default(),
+			snapping_enabled: true,
 		}
 	}
 }
@@ -127,6 +129,7 @@ pub enum DocumentMessage {
 		insert_index: isize,
 	},
 	ReorderSelectedLayers(i32), // relative_position,
+	SetSnapping(bool),
 }
 
 impl From<DocumentOperation> for DocumentMessage {
@@ -308,6 +311,7 @@ impl DocumentMessageHandler {
 			layer_data: vec![(vec![], LayerData::new(true))].into_iter().collect(),
 			movement_handler: MovementMessageHandler::default(),
 			transform_layer_handler: TransformLayerMessageHandler::default(),
+			snapping_enabled: true,
 		}
 	}
 
@@ -772,6 +776,9 @@ impl MessageHandler<DocumentMessage, &InputPreprocessor> for DocumentMessageHand
 				}
 			}
 			RenameLayer(path, name) => responses.push_back(DocumentOperation::RenameLayer { path, name }.into()),
+			SetSnapping(new_status) => {
+				self.snapping_enabled = new_status;
+			}
 		}
 	}
 
@@ -784,6 +791,7 @@ impl MessageHandler<DocumentMessage, &InputPreprocessor> for DocumentMessageHand
 			RenderDocument,
 			ExportDocument,
 			SaveDocument,
+			SetSnapping,
 		);
 
 		if self.layer_data.values().any(|data| data.selected) {

editor/src/tool/mod.rs

@@ -1,3 +1,4 @@
+mod snapping;
 pub mod tool_message_handler;
 pub mod tool_options;
 pub mod tools;

editor/src/tool/snapping.rs

@@ -0,0 +1,112 @@
+use glam::DVec2;
+use graphene::LayerId;
+
+use crate::consts::SNAP_TOLERANCE;
+
+use super::DocumentMessageHandler;
+
+#[derive(Debug, Clone)]
+pub struct SnapHandler {
+	snap_targets: Option<(Vec<f64>, Vec<f64>)>,
+}
+impl Default for SnapHandler {
+	fn default() -> Self {
+		Self { snap_targets: None }
+	}
+}
+
+impl SnapHandler {
+	/// Gets a list of snap targets for the X and Y axes in Viewport coords for the target layers (usually all layers or all non-selected layers.)
+	/// This should be called at the start of a drag.
+	pub fn start_snap(&mut self, document_message_handler: &DocumentMessageHandler, target_layers: Vec<Vec<LayerId>>, ignore_layers: &[Vec<LayerId>]) {
+		if document_message_handler.snapping_enabled {
+			// Could be made into sorted Vec or a HashSet for more performant lookups.
+			self.snap_targets = Some(
+				target_layers
+					.iter()
+					.filter(|path| !ignore_layers.contains(path))
+					.filter_map(|path| document_message_handler.graphene_document.viewport_bounding_box(path).ok()?)
+					.flat_map(|[bound1, bound2]| [bound1, bound2, ((bound1 + bound2) / 2.)])
+					.map(|vec| vec.into())
+					.unzip(),
+			);
+		}
+	}
+
+	/// Finds the closest snap from an array of layers to the specified snap targets in viewport coords.
+	/// Returns 0 for each axis that there is no snap less than the snap tolerance.
+	pub fn snap_layers(&self, document_message_handler: &DocumentMessageHandler, selected_layers: &[Vec<LayerId>], mouse_delta: DVec2) -> DVec2 {
+		if document_message_handler.snapping_enabled {
+			if let Some((targets_x, targets_y)) = &self.snap_targets {
+				let (snap_x, snap_y): (Vec<f64>, Vec<f64>) = selected_layers
+					.iter()
+					.filter_map(|path| document_message_handler.graphene_document.viewport_bounding_box(path).ok()?)
+					.flat_map(|[bound1, bound2]| [bound1, bound2, (bound1 + bound2) / 2.])
+					.map(|vec| vec.into())
+					.unzip();
+
+				let closest_move = DVec2::new(
+					targets_x
+						.iter()
+						.flat_map(|target| snap_x.iter().map(move |snap| target - mouse_delta.x - snap))
+						.min_by(|a, b| a.abs().partial_cmp(&b.abs()).expect("Could not compare document bounds."))
+						.unwrap_or(0.),
+					targets_y
+						.iter()
+						.flat_map(|target| snap_y.iter().map(move |snap| target - mouse_delta.y - snap))
+						.min_by(|a, b| a.abs().partial_cmp(&b.abs()).expect("Could not compare document bounds."))
+						.unwrap_or(0.),
+				);
+
+				// Do not move if over snap tolerance
+				let clamped_closest_move = DVec2::new(
+					if closest_move.x.abs() > SNAP_TOLERANCE { 0. } else { closest_move.x },
+					if closest_move.y.abs() > SNAP_TOLERANCE { 0. } else { closest_move.y },
+				);
+
+				clamped_closest_move
+			} else {
+				DVec2::ZERO
+			}
+		} else {
+			DVec2::ZERO
+		}
+	}
+
+	/// Handles snapping of a viewport position, returning another viewport position.
+	pub fn snap_position(&self, document_message_handler: &DocumentMessageHandler, position_viewport: DVec2) -> DVec2 {
+		if document_message_handler.snapping_enabled {
+			if let Some((targets_x, targets_y)) = &self.snap_targets {
+				// For each list of snap targets, find the shortest distance to move the point to that target.
+				let closest_move = DVec2::new(
+					targets_x
+						.iter()
+						.map(|x| (x - position_viewport.x))
+						.min_by(|a, b| a.abs().partial_cmp(&b.abs()).expect("Could not compare document bounds."))
+						.unwrap_or(0.),
+					targets_y
+						.iter()
+						.map(|y| (y - position_viewport.y))
+						.min_by(|a, b| a.abs().partial_cmp(&b.abs()).expect("Could not compare document bounds."))
+						.unwrap_or(0.),
+				);
+
+				// Do not move if over snap tolerance
+				let clamped_closest_move = DVec2::new(
+					if closest_move.x.abs() > SNAP_TOLERANCE { 0. } else { closest_move.x },
+					if closest_move.y.abs() > SNAP_TOLERANCE { 0. } else { closest_move.y },
+				);
+
+				position_viewport + clamped_closest_move
+			} else {
+				position_viewport
+			}
+		} else {
+			position_viewport
+		}
+	}
+
+	pub fn cleanup(&mut self) {
+		self.snap_targets = None;
+	}
+}

editor/src/tool/tools/ellipse.rs

@@ -49,7 +49,6 @@ impl Default for EllipseToolFsmState {
 }
 #[derive(Clone, Debug, Default)]
 struct EllipseToolData {
-	sides: u8,
 	data: Resize,
 }
 
@@ -59,7 +58,7 @@ impl Fsm for EllipseToolFsmState {
 	fn transition(
 		self,
 		event: ToolMessage,
-		_document: &DocumentMessageHandler,
+		document: &DocumentMessageHandler,
 		tool_data: &DocumentToolData,
 		data: &mut Self::ToolData,
 		input: &InputPreprocessor,
@@ -71,7 +70,7 @@ impl Fsm for EllipseToolFsmState {
 		if let ToolMessage::Ellipse(event) = event {
 			match (self, event) {
 				(Ready, DragStart) => {
-					shape_data.drag_start = input.mouse.position;
+					shape_data.start(document, input.mouse.position);
 					responses.push_back(DocumentMessage::StartTransaction.into());
 					shape_data.path = Some(vec![generate_uuid()]);
 					responses.push_back(DocumentMessage::DeselectAllLayers.into());
@@ -89,7 +88,7 @@ impl Fsm for EllipseToolFsmState {
 					Dragging
 				}
 				(state, Resize { center, lock_ratio }) => {
-					if let Some(message) = shape_data.calculate_transform(center, lock_ratio, input) {
+					if let Some(message) = shape_data.calculate_transform(document, center, lock_ratio, input) {
 						responses.push_back(message);
 					}
 
@@ -102,12 +101,12 @@ impl Fsm for EllipseToolFsmState {
 						false => responses.push_back(DocumentMessage::CommitTransaction.into()),
 					}
 
-					shape_data.path = None;
+					shape_data.cleanup();
 					Ready
 				}
 				(Dragging, Abort) => {
 					responses.push_back(DocumentMessage::AbortTransaction.into());
-					shape_data.path = None;
+					shape_data.cleanup();
 
 					Ready
 				}

editor/src/tool/tools/line.rs

@@ -1,6 +1,7 @@
 use crate::consts::LINE_ROTATE_SNAP_ANGLE;
 use crate::input::keyboard::Key;
 use crate::input::{mouse::ViewportPosition, InputPreprocessor};
+use crate::tool::snapping::SnapHandler;
 use crate::tool::{DocumentToolData, Fsm, ToolActionHandlerData, ToolOptions, ToolType};
 use crate::{document::DocumentMessageHandler, message_prelude::*};
 use glam::{DAffine2, DVec2};
@@ -53,6 +54,7 @@ struct LineToolData {
 	angle: f64,
 	weight: u32,
 	path: Option<Vec<LayerId>>,
+	snap_handler: SnapHandler,
 }
 
 impl Fsm for LineToolFsmState {
@@ -61,7 +63,7 @@ impl Fsm for LineToolFsmState {
 	fn transition(
 		self,
 		event: ToolMessage,
-		_document: &DocumentMessageHandler,
+		document: &DocumentMessageHandler,
 		tool_data: &DocumentToolData,
 		data: &mut Self::ToolData,
 		input: &InputPreprocessor,
@@ -72,7 +74,9 @@ impl Fsm for LineToolFsmState {
 		if let ToolMessage::Line(event) = event {
 			match (self, event) {
 				(Ready, DragStart) => {
-					data.drag_start = input.mouse.position;
+					data.snap_handler.start_snap(document, document.all_layers_sorted(), &[]);
+					data.drag_start = data.snap_handler.snap_position(document, input.mouse.position);
+
 					responses.push_back(DocumentMessage::StartTransaction.into());
 					data.path = Some(vec![generate_uuid()]);
 					responses.push_back(DocumentMessage::DeselectAllLayers.into());
@@ -95,15 +99,16 @@ impl Fsm for LineToolFsmState {
 					Dragging
 				}
 				(Dragging, Redraw { center, snap_angle, lock_angle }) => {
-					data.drag_current = input.mouse.position;
+					data.drag_current = data.snap_handler.snap_position(document, input.mouse.position);
 
 					let values: Vec<_> = [lock_angle, snap_angle, center].iter().map(|k| input.keyboard.get(*k as usize)).collect();
 					responses.push_back(generate_transform(data, values[0], values[1], values[2]));
 
 					Dragging
 				}
 				(Dragging, DragStop) => {
-					data.drag_current = input.mouse.position;
+					data.drag_current = data.snap_handler.snap_position(document, input.mouse.position);
+					data.snap_handler.cleanup();
 
 					// TODO; introduce comparison threshold when operating with canvas coordinates (https://github.com/GraphiteEditor/Graphite/issues/100)
 					match data.drag_start == input.mouse.position {
@@ -116,6 +121,7 @@ impl Fsm for LineToolFsmState {
 					Ready
 				}
 				(Dragging, Abort) => {
+					data.snap_handler.cleanup();
 					responses.push_back(DocumentMessage::AbortTransaction.into());
 					data.path = None;
 					Ready

editor/src/tool/tools/pen.rs

@@ -1,4 +1,5 @@
 use crate::input::InputPreprocessor;
+use crate::tool::snapping::SnapHandler;
 use crate::tool::{DocumentToolData, Fsm, ToolActionHandlerData, ToolOptions, ToolType};
 use crate::{document::DocumentMessageHandler, message_prelude::*};
 use glam::DAffine2;
@@ -52,6 +53,7 @@ struct PenToolData {
 	next_point: DAffine2,
 	weight: u32,
 	path: Option<Vec<LayerId>>,
+	snap_handler: SnapHandler,
 }
 
 impl Fsm for PenToolFsmState {
@@ -67,7 +69,6 @@ impl Fsm for PenToolFsmState {
 		responses: &mut VecDeque<Message>,
 	) -> Self {
 		let transform = document.graphene_document.root.transform;
-		let pos = transform.inverse() * DAffine2::from_translation(input.mouse.position);
 
 		use PenMessage::*;
 		use PenToolFsmState::*;
@@ -78,6 +79,11 @@ impl Fsm for PenToolFsmState {
 					responses.push_back(DocumentMessage::DeselectAllLayers.into());
 					data.path = Some(vec![generate_uuid()]);
 
+					data.snap_handler.start_snap(document, document.all_layers_sorted(), &[]);
+					let snapped_position = data.snap_handler.snap_position(document, input.mouse.position);
+
+					let pos = transform.inverse() * DAffine2::from_translation(snapped_position);
+
 					data.points.push(pos);
 					data.next_point = pos;
 
@@ -89,6 +95,9 @@ impl Fsm for PenToolFsmState {
 					Dragging
 				}
 				(Dragging, DragStop) => {
+					let snapped_position = data.snap_handler.snap_position(document, input.mouse.position);
+					let pos = transform.inverse() * DAffine2::from_translation(snapped_position);
+
 					// TODO: introduce comparison threshold when operating with canvas coordinates (https://github.com/GraphiteEditor/Graphite/issues/100)
 					if data.points.last() != Some(&pos) {
 						data.points.push(pos);
@@ -100,6 +109,8 @@ impl Fsm for PenToolFsmState {
 					Dragging
 				}
 				(Dragging, PointerMove) => {
+					let snapped_position = data.snap_handler.snap_position(document, input.mouse.position);
+					let pos = transform.inverse() * DAffine2::from_translation(snapped_position);
 					data.next_point = pos;
 
 					responses.extend(make_operation(data, tool_data, true));
@@ -117,13 +128,15 @@ impl Fsm for PenToolFsmState {
 
 					data.path = None;
 					data.points.clear();
+					data.snap_handler.cleanup();
 
 					Ready
 				}
 				(Dragging, Abort) => {
 					responses.push_back(DocumentMessage::AbortTransaction.into());
 					data.points.clear();
 					data.path = None;
+					data.snap_handler.cleanup();
 
 					Ready
 				}