Transform shapes

lightningbeam-ui/Cargo.lock

@@ -2737,6 +2737,7 @@ dependencies = [
 name = "lightningbeam-core"
 version = "0.1.0"
 dependencies = [
+ "egui",
  "kurbo 0.11.3",
  "serde",
  "serde_json",

lightningbeam-ui/lightningbeam-core/Cargo.toml

@@ -7,6 +7,9 @@ edition = "2021"
 serde = { workspace = true }
 serde_json = { workspace = true }
 
+# UI framework (for Color32 conversion)
+egui = "0.29"
+
 # Geometry and rendering
 kurbo = { workspace = true }
 vello = { workspace = true }

lightningbeam-ui/lightningbeam-core/src/action.rs

@@ -64,6 +64,13 @@ impl ActionExecutor {
         &self.document
     }
 
+    /// Get mutable access to the document
+    /// Note: This should only be used for live previews. Permanent changes
+    /// should go through the execute() method to support undo/redo.
+    pub fn document_mut(&mut self) -> &mut Document {
+        &mut self.document
+    }
+
     /// Execute an action and add it to the undo stack
     ///
     /// This clears the redo stack since we're creating a new timeline branch.

lightningbeam-ui/lightningbeam-core/src/actions/add_shape.rs

@@ -0,0 +1,191 @@
+//! Add shape action
+//!
+//! Handles adding a new shape and object to a vector layer.
+
+use crate::action::Action;
+use crate::document::Document;
+use crate::layer::AnyLayer;
+use crate::object::Object;
+use crate::shape::Shape;
+use uuid::Uuid;
+
+/// Action that adds a shape and object to a vector layer
+///
+/// This action creates both a Shape (the path/geometry) and an Object
+/// (the instance with transform). Both are added to the layer.
+pub struct AddShapeAction {
+    /// Layer ID to add the shape to
+    layer_id: Uuid,
+
+    /// The shape to add (contains path and styling)
+    shape: Shape,
+
+    /// The object to add (references the shape with transform)
+    object: Object,
+
+    /// ID of the created shape (set after execution)
+    created_shape_id: Option<Uuid>,
+
+    /// ID of the created object (set after execution)
+    created_object_id: Option<Uuid>,
+}
+
+impl AddShapeAction {
+    /// Create a new add shape action
+    ///
+    /// # Arguments
+    ///
+    /// * `layer_id` - The layer to add the shape to
+    /// * `shape` - The shape to add
+    /// * `object` - The object instance referencing the shape
+    pub fn new(layer_id: Uuid, shape: Shape, object: Object) -> Self {
+        Self {
+            layer_id,
+            shape,
+            object,
+            created_shape_id: None,
+            created_object_id: None,
+        }
+    }
+}
+
+impl Action for AddShapeAction {
+    fn execute(&mut self, document: &mut Document) {
+        let layer = match document.get_layer_mut(&self.layer_id) {
+            Some(l) => l,
+            None => return,
+        };
+
+        if let AnyLayer::Vector(vector_layer) = layer {
+            // Add shape and object to the layer
+            let shape_id = vector_layer.add_shape_internal(self.shape.clone());
+            let object_id = vector_layer.add_object_internal(self.object.clone());
+
+            // Store the IDs for rollback
+            self.created_shape_id = Some(shape_id);
+            self.created_object_id = Some(object_id);
+        }
+    }
+
+    fn rollback(&mut self, document: &mut Document) {
+        // Remove the created shape and object if they exist
+        if let (Some(shape_id), Some(object_id)) = (self.created_shape_id, self.created_object_id) {
+            let layer = match document.get_layer_mut(&self.layer_id) {
+                Some(l) => l,
+                None => return,
+            };
+
+            if let AnyLayer::Vector(vector_layer) = layer {
+                // Remove in reverse order: object first, then shape
+                vector_layer.remove_object_internal(&object_id);
+                vector_layer.remove_shape_internal(&shape_id);
+            }
+
+            // Clear the stored IDs
+            self.created_shape_id = None;
+            self.created_object_id = None;
+        }
+    }
+
+    fn description(&self) -> String {
+        "Add shape".to_string()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::layer::VectorLayer;
+    use crate::shape::ShapeColor;
+    use vello::kurbo::{Circle, Rect, Shape as KurboShape};
+
+    #[test]
+    fn test_add_shape_action_rectangle() {
+        // Create a document with a vector layer
+        let mut document = Document::new("Test");
+        let vector_layer = VectorLayer::new("Layer 1");
+        let layer_id = document.root.add_child(AnyLayer::Vector(vector_layer));
+
+        // Create a rectangle shape
+        let rect = Rect::new(0.0, 0.0, 100.0, 50.0);
+        let path = rect.to_path(0.1);
+        let shape = Shape::new(path).with_fill(ShapeColor::rgb(255, 0, 0));
+        let object = Object::new(shape.id).with_position(50.0, 50.0);
+
+        // Create and execute action
+        let mut action = AddShapeAction::new(layer_id, shape, object);
+        action.execute(&mut document);
+
+        // Verify shape and object were added
+        if let Some(AnyLayer::Vector(layer)) = document.get_layer(&layer_id) {
+            assert_eq!(layer.shapes.len(), 1);
+            assert_eq!(layer.objects.len(), 1);
+
+            let added_object = &layer.objects[0];
+            assert_eq!(added_object.transform.x, 50.0);
+            assert_eq!(added_object.transform.y, 50.0);
+        } else {
+            panic!("Layer not found or not a vector layer");
+        }
+
+        // Rollback
+        action.rollback(&mut document);
+
+        // Verify shape and object were removed
+        if let Some(AnyLayer::Vector(layer)) = document.get_layer(&layer_id) {
+            assert_eq!(layer.shapes.len(), 0);
+            assert_eq!(layer.objects.len(), 0);
+        }
+    }
+
+    #[test]
+    fn test_add_shape_action_circle() {
+        let mut document = Document::new("Test");
+        let vector_layer = VectorLayer::new("Layer 1");
+        let layer_id = document.root.add_child(AnyLayer::Vector(vector_layer));
+
+        // Create a circle shape
+        let circle = Circle::new((50.0, 50.0), 25.0);
+        let path = circle.to_path(0.1);
+        let shape = Shape::new(path)
+            .with_fill(ShapeColor::rgb(0, 255, 0));
+        let object = Object::new(shape.id);
+
+        let mut action = AddShapeAction::new(layer_id, shape, object);
+
+        // Test description
+        assert_eq!(action.description(), "Add shape");
+
+        // Execute
+        action.execute(&mut document);
+
+        if let Some(AnyLayer::Vector(layer)) = document.get_layer(&layer_id) {
+            assert_eq!(layer.shapes.len(), 1);
+            assert_eq!(layer.objects.len(), 1);
+        }
+    }
+
+    #[test]
+    fn test_add_shape_action_multiple_execute() {
+        let mut document = Document::new("Test");
+        let vector_layer = VectorLayer::new("Layer 1");
+        let layer_id = document.root.add_child(AnyLayer::Vector(vector_layer));
+
+        let rect = Rect::new(0.0, 0.0, 50.0, 50.0);
+        let path = rect.to_path(0.1);
+        let shape = Shape::new(path);
+        let object = Object::new(shape.id);
+
+        let mut action = AddShapeAction::new(layer_id, shape, object);
+
+        // Execute twice (should add duplicate)
+        action.execute(&mut document);
+        action.execute(&mut document);
+
+        if let Some(AnyLayer::Vector(layer)) = document.get_layer(&layer_id) {
+            // Should have 2 shapes and 2 objects
+            assert_eq!(layer.shapes.len(), 2);
+            assert_eq!(layer.objects.len(), 2);
+        }
+    }
+}

lightningbeam-ui/lightningbeam-core/src/actions/mod.rs

@@ -3,6 +3,10 @@
 //! This module contains all the concrete action types that can be executed
 //! through the action system.
 
+pub mod add_shape;
 pub mod move_objects;
+pub mod transform_objects;
 
+pub use add_shape::AddShapeAction;
 pub use move_objects::MoveObjectsAction;
+pub use transform_objects::TransformObjectsAction;

lightningbeam-ui/lightningbeam-core/src/actions/transform_objects.rs

@@ -0,0 +1,60 @@
+//! Transform objects action
+//!
+//! Applies scale, rotation, and other transformations to objects with undo/redo support.
+
+use crate::action::Action;
+use crate::document::Document;
+use crate::layer::AnyLayer;
+use crate::object::Transform;
+use std::collections::HashMap;
+use uuid::Uuid;
+
+/// Action to transform multiple objects
+pub struct TransformObjectsAction {
+    layer_id: Uuid,
+    /// Map of object ID to (old transform, new transform)
+    object_transforms: HashMap<Uuid, (Transform, Transform)>,
+}
+
+impl TransformObjectsAction {
+    /// Create a new transform action
+    pub fn new(
+        layer_id: Uuid,
+        object_transforms: HashMap<Uuid, (Transform, Transform)>,
+    ) -> Self {
+        Self {
+            layer_id,
+            object_transforms,
+        }
+    }
+}
+
+impl Action for TransformObjectsAction {
+    fn execute(&mut self, document: &mut Document) {
+        if let Some(layer) = document.get_layer_mut(&self.layer_id) {
+            if let AnyLayer::Vector(vector_layer) = layer {
+                for (object_id, (_old, new)) in &self.object_transforms {
+                    vector_layer.modify_object_internal(object_id, |obj| {
+                        obj.transform = new.clone();
+                    });
+                }
+            }
+        }
+    }
+
+    fn rollback(&mut self, document: &mut Document) {
+        if let Some(layer) = document.get_layer_mut(&self.layer_id) {
+            if let AnyLayer::Vector(vector_layer) = layer {
+                for (object_id, (old, _new)) in &self.object_transforms {
+                    vector_layer.modify_object_internal(object_id, |obj| {
+                        obj.transform = old.clone();
+                    });
+                }
+            }
+        }
+    }
+
+    fn description(&self) -> String {
+        format!("Transform {} object(s)", self.object_transforms.len())
+    }
+}

lightningbeam-ui/lightningbeam-core/src/document.rs

@@ -189,7 +189,7 @@ impl Document {
     ///
     /// This method is intentionally `pub(crate)` to ensure mutations
     /// only happen through the action system.
-    pub(crate) fn get_layer_mut(&mut self, id: &Uuid) -> Option<&mut AnyLayer> {
+    pub fn get_layer_mut(&mut self, id: &Uuid) -> Option<&mut AnyLayer> {
         self.root.get_child_mut(id)
     }
 }

lightningbeam-ui/lightningbeam-core/src/layer.rs

@@ -212,7 +212,7 @@ impl VectorLayer {
     /// Applies the given function to the object if found.
     /// This method is intentionally `pub(crate)` to ensure mutations
     /// only happen through the action system.
-    pub(crate) fn modify_object_internal<F>(&mut self, id: &Uuid, f: F)
+    pub fn modify_object_internal<F>(&mut self, id: &Uuid, f: F)
     where
         F: FnOnce(&mut Object),
     {

lightningbeam-ui/lightningbeam-core/src/lib.rs

@@ -6,6 +6,7 @@ pub mod pane;
 pub mod tool;
 pub mod animation;
 pub mod path_interpolation;
+pub mod path_fitting;
 pub mod shape;
 pub mod object;
 pub mod layer;

lightningbeam-ui/lightningbeam-core/src/path_fitting.rs

@@ -0,0 +1,613 @@
+//! Path fitting algorithms for converting raw points to smooth curves
+//!
+//! Provides two main algorithms:
+//! - Ramer-Douglas-Peucker (RDP) simplification for corner detection
+//! - Schneider curve fitting for smooth Bezier curves
+//!
+//! Based on:
+//! - simplify.js by Vladimir Agafonkin
+//! - fit-curve by Philip J. Schneider (Graphics Gems, 1990)
+
+use kurbo::{BezPath, Point, Vec2};
+
+/// Configuration for RDP simplification
+#[derive(Debug, Clone, Copy)]
+pub struct RdpConfig {
+    /// Tolerance for simplification (default: 10.0)
+    /// Higher values = more simplification (fewer points)
+    pub tolerance: f64,
+    /// Whether to use highest quality (skip radial distance filter)
+    pub highest_quality: bool,
+}
+
+impl Default for RdpConfig {
+    fn default() -> Self {
+        Self {
+            tolerance: 10.0,
+            highest_quality: false,
+        }
+    }
+}
+
+/// Configuration for Schneider curve fitting
+#[derive(Debug, Clone, Copy)]
+pub struct SchneiderConfig {
+    /// Maximum error tolerance (default: 30.0)
+    /// Lower values = more accurate curves (more segments)
+    pub max_error: f64,
+}
+
+impl Default for SchneiderConfig {
+    fn default() -> Self {
+        Self { max_error: 30.0 }
+    }
+}
+
+/// Simplify a polyline using Ramer-Douglas-Peucker algorithm
+///
+/// This is a two-stage process:
+/// 1. Radial distance filter (unless highest_quality is true)
+/// 2. Douglas-Peucker recursive simplification
+pub fn simplify_rdp(points: &[Point], config: RdpConfig) -> Vec<Point> {
+    if points.len() <= 2 {
+        return points.to_vec();
+    }
+
+    let sq_tolerance = config.tolerance * config.tolerance;
+
+    let mut simplified = if config.highest_quality {
+        points.to_vec()
+    } else {
+        simplify_radial_dist(points, sq_tolerance)
+    };
+
+    simplified = simplify_douglas_peucker(&simplified, sq_tolerance);
+
+    simplified
+}
+
+/// First stage: Remove points that are too close to the previous point
+fn simplify_radial_dist(points: &[Point], sq_tolerance: f64) -> Vec<Point> {
+    if points.is_empty() {
+        return Vec::new();
+    }
+
+    let mut result = vec![points[0]];
+    let mut prev_point = points[0];
+
+    for &point in &points[1..] {
+        if sq_dist(point, prev_point) > sq_tolerance {
+            result.push(point);
+            prev_point = point;
+        }
+    }
+
+    // Always include the last point if it's different from the previous one
+    if let Some(&last) = points.last() {
+        if last != prev_point {
+            result.push(last);
+        }
+    }
+
+    result
+}
+
+/// Second stage: Douglas-Peucker recursive simplification
+fn simplify_douglas_peucker(points: &[Point], sq_tolerance: f64) -> Vec<Point> {
+    if points.len() < 2 {
+        return points.to_vec();
+    }
+
+    let last = points.len() - 1;
+    let mut simplified = vec![points[0]];
+    simplify_dp_step(points, 0, last, sq_tolerance, &mut simplified);
+    simplified.push(points[last]);
+
+    simplified
+}
+
+/// Recursive Douglas-Peucker step
+fn simplify_dp_step(
+    points: &[Point],
+    first: usize,
+    last: usize,
+    sq_tolerance: f64,
+    simplified: &mut Vec<Point>,
+) {
+    let mut max_sq_dist = sq_tolerance;
+    let mut index = 0;
+
+    for i in first + 1..last {
+        let sq_dist = sq_seg_dist(points[i], points[first], points[last]);
+
+        if sq_dist > max_sq_dist {
+            index = i;
+            max_sq_dist = sq_dist;
+        }
+    }
+
+    if max_sq_dist > sq_tolerance {
+        if index - first > 1 {
+            simplify_dp_step(points, first, index, sq_tolerance, simplified);
+        }
+        simplified.push(points[index]);
+        if last - index > 1 {
+            simplify_dp_step(points, index, last, sq_tolerance, simplified);
+        }
+    }
+}
+
+/// Square distance between two points
+#[inline]
+fn sq_dist(p1: Point, p2: Point) -> f64 {
+    let dx = p1.x - p2.x;
+    let dy = p1.y - p2.y;
+    dx * dx + dy * dy
+}
+
+/// Square distance from a point to a line segment
+fn sq_seg_dist(p: Point, p1: Point, p2: Point) -> f64 {
+    let mut x = p1.x;
+    let mut y = p1.y;
+    let dx = p2.x - x;
+    let dy = p2.y - y;
+
+    if dx != 0.0 || dy != 0.0 {
+        let t = ((p.x - x) * dx + (p.y - y) * dy) / (dx * dx + dy * dy);
+
+        if t > 1.0 {
+            x = p2.x;
+            y = p2.y;
+        } else if t > 0.0 {
+            x += dx * t;
+            y += dy * t;
+        }
+    }
+
+    let dx = p.x - x;
+    let dy = p.y - y;
+    dx * dx + dy * dy
+}
+
+/// Fit Bezier curves to a set of points using Schneider's algorithm
+///
+/// Returns a BezPath containing the fitted cubic Bezier curves
+pub fn fit_bezier_curves(points: &[Point], config: SchneiderConfig) -> BezPath {
+    if points.len() < 2 {
+        return BezPath::new();
+    }
+
+    // Remove duplicate points
+    let mut unique_points = Vec::new();
+    unique_points.push(points[0]);
+    for i in 1..points.len() {
+        if points[i] != points[i - 1] {
+            unique_points.push(points[i]);
+        }
+    }
+
+    if unique_points.len() < 2 {
+        return BezPath::new();
+    }
+
+    let len = unique_points.len();
+    let left_tangent = create_tangent(unique_points[1], unique_points[0]);
+    let right_tangent = create_tangent(unique_points[len - 2], unique_points[len - 1]);
+
+    let curves = fit_cubic(&unique_points, left_tangent, right_tangent, config.max_error);
+
+    // Convert curves to BezPath
+    let mut path = BezPath::new();
+    if curves.is_empty() {
+        return path;
+    }
+
+    // Start at the first point
+    path.move_to(curves[0][0]);
+
+    // Add all the curves
+    for curve in curves {
+        path.curve_to(curve[1], curve[2], curve[3]);
+    }
+
+    path
+}
+
+/// Fit a cubic Bezier curve to a set of points
+///
+/// Returns an array of Bezier curves, where each curve is [p0, p1, p2, p3]
+fn fit_cubic(
+    points: &[Point],
+    left_tangent: Vec2,
+    right_tangent: Vec2,
+    error: f64,
+) -> Vec<[Point; 4]> {
+    const MAX_ITERATIONS: usize = 20;
+
+    // Use heuristic if region only has two points
+    if points.len() == 2 {
+        let dist = (points[1] - points[0]).hypot() / 3.0;
+        let bez_curve = [
+            points[0],
+            points[0] + left_tangent * dist,
+            points[1] + right_tangent * dist,
+            points[1],
+        ];
+        return vec![bez_curve];
+    }
+
+    // Parameterize points and attempt to fit curve
+    let u = chord_length_parameterize(points);
+    let (mut bez_curve, mut max_error, mut split_point) =
+        generate_and_report(points, &u, &u, left_tangent, right_tangent);
+
+    if max_error < error {
+        return vec![bez_curve];
+    }
+
+    // If error not too large, try reparameterization and iteration
+    if max_error < error * error {
+        let mut u_prime = u.clone();
+        let mut prev_err = max_error;
+        let mut prev_split = split_point;
+
+        for _ in 0..MAX_ITERATIONS {
+            u_prime = reparameterize(&bez_curve, points, &u_prime);
+
+            let result = generate_and_report(points, &u, &u_prime, left_tangent, right_tangent);
+            bez_curve = result.0;
+            max_error = result.1;
+            split_point = result.2;
+
+            if max_error < error {
+                return vec![bez_curve];
+            }
+
+            // If development grinds to a halt, abort
+            if split_point == prev_split {
+                let err_change = max_error / prev_err;
+                if err_change > 0.9999 && err_change < 1.0001 {
+                    break;
+                }
+            }
+
+            prev_err = max_error;
+            prev_split = split_point;
+        }
+    }
+
+    // Fitting failed -- split at max error point and fit recursively
+    let mut beziers = Vec::new();
+
+    // Calculate tangent at split point
+    let mut center_vector = points[split_point - 1] - points[split_point + 1];
+
+    // Handle case where points are the same
+    if center_vector.hypot() == 0.0 {
+        center_vector = points[split_point - 1] - points[split_point];
+        center_vector = Vec2::new(-center_vector.y, center_vector.x);
+    }
+
+    let to_center_tangent = normalize(center_vector);
+    let from_center_tangent = -to_center_tangent;
+
+    // Recursively fit curves
+    beziers.extend(fit_cubic(
+        &points[0..=split_point],
+        left_tangent,
+        to_center_tangent,
+        error,
+    ));
+    beziers.extend(fit_cubic(
+        &points[split_point..],
+        from_center_tangent,
+        right_tangent,
+        error,
+    ));
+
+    beziers
+}
+
+/// Generate a Bezier curve and compute its error
+fn generate_and_report(
+    points: &[Point],
+    params_orig: &[f64],
+    params_prime: &[f64],
+    left_tangent: Vec2,
+    right_tangent: Vec2,
+) -> ([Point; 4], f64, usize) {
+    let bez_curve = generate_bezier(points, params_prime, left_tangent, right_tangent);
+    let (max_error, split_point) = compute_max_error(points, &bez_curve, params_orig);
+
+    (bez_curve, max_error, split_point)
+}
+
+/// Use least-squares method to find Bezier control points
+fn generate_bezier(
+    points: &[Point],
+    parameters: &[f64],
+    left_tangent: Vec2,
+    right_tangent: Vec2,
+) -> [Point; 4] {
+    let first_point = points[0];
+    let last_point = points[points.len() - 1];
+
+    // Compute the A matrix
+    let mut a = Vec::new();
+    for &u in parameters {
+        let ux = 1.0 - u;
+        let a0 = left_tangent * (3.0 * u * ux * ux);
+        let a1 = right_tangent * (3.0 * ux * u * u);
+        a.push([a0, a1]);
+    }
+
+    // Create C and X matrices
+    let mut c = [[0.0, 0.0], [0.0, 0.0]];
+    let mut x = [0.0, 0.0];
+
+    for i in 0..points.len() {
+        let u = parameters[i];
+        let ai = a[i];
+
+        c[0][0] += dot(ai[0], ai[0]);
+        c[0][1] += dot(ai[0], ai[1]);
+        c[1][0] += dot(ai[0], ai[1]);
+        c[1][1] += dot(ai[1], ai[1]);
+
+        let tmp = points[i] - bezier_q(&[first_point, first_point, last_point, last_point], u);
+
+        x[0] += dot(ai[0], tmp);
+        x[1] += dot(ai[1], tmp);
+    }
+
+    // Compute determinants
+    let det_c0_c1 = c[0][0] * c[1][1] - c[1][0] * c[0][1];
+    let det_c0_x = c[0][0] * x[1] - c[1][0] * x[0];
+    let det_x_c1 = x[0] * c[1][1] - x[1] * c[0][1];
+
+    // Derive alpha values
+    let alpha_l = if det_c0_c1 == 0.0 {
+        0.0
+    } else {
+        det_x_c1 / det_c0_c1
+    };
+    let alpha_r = if det_c0_c1 == 0.0 {
+        0.0
+    } else {
+        det_c0_x / det_c0_c1
+    };
+
+    // If alpha is negative or too small, use heuristic
+    let seg_length = (last_point - first_point).hypot();
+    let epsilon = 1.0e-6 * seg_length;
+
+    let (p1, p2) = if alpha_l < epsilon || alpha_r < epsilon {
+        // Fall back on standard formula
+        (
+            first_point + left_tangent * (seg_length / 3.0),
+            last_point + right_tangent * (seg_length / 3.0),
+        )
+    } else {
+        (
+            first_point + left_tangent * alpha_l,
+            last_point + right_tangent * alpha_r,
+        )
+    };
+
+    [first_point, p1, p2, last_point]
+}
+
+/// Reparameterize points using Newton-Raphson
+fn reparameterize(bezier: &[Point; 4], points: &[Point], parameters: &[f64]) -> Vec<f64> {
+    parameters
+        .iter()
+        .zip(points.iter())
+        .map(|(&p, &point)| newton_raphson_root_find(bezier, point, p))
+        .collect()
+}
+
+/// Use Newton-Raphson iteration to find better root
+fn newton_raphson_root_find(bez: &[Point; 4], point: Point, u: f64) -> f64 {
+    let d = bezier_q(bez, u) - point;
+    let qprime = bezier_qprime(bez, u);
+    let numerator = dot(d, qprime);
+    let qprimeprime = bezier_qprimeprime(bez, u);
+    let denominator = dot(qprime, qprime) + 2.0 * dot(d, qprimeprime);
+
+    if denominator == 0.0 {
+        u
+    } else {
+        u - numerator / denominator
+    }
+}
+
+/// Assign parameter values using chord length
+fn chord_length_parameterize(points: &[Point]) -> Vec<f64> {
+    let mut u = Vec::new();
+    let mut curr_u = 0.0;
+
+    u.push(0.0);
+
+    for i in 1..points.len() {
+        curr_u += (points[i] - points[i - 1]).hypot();
+        u.push(curr_u);
+    }
+
+    let total_length = u[u.len() - 1];
+    u.iter().map(|&x| x / total_length).collect()
+}
+
+/// Find maximum squared distance of points to fitted curve
+fn compute_max_error(points: &[Point], bez: &[Point; 4], parameters: &[f64]) -> (f64, usize) {
+    let mut max_dist = 0.0;
+    let mut split_point = points.len() / 2;
+
+    let t_dist_map = map_t_to_relative_distances(bez, 10);
+
+    for i in 0..points.len() {
+        let point = points[i];
+        let t = find_t(bez, parameters[i], &t_dist_map, 10);
+
+        let v = bezier_q(bez, t) - point;
+        let dist = v.x * v.x + v.y * v.y;
+
+        if dist > max_dist {
+            max_dist = dist;
+            split_point = i;
+        }
+    }
+
+    (max_dist, split_point)
+}
+
+/// Sample t values and map to relative distances along curve
+fn map_t_to_relative_distances(bez: &[Point; 4], b_parts: usize) -> Vec<f64> {
+    let mut b_t_dist = vec![0.0];
+    let mut b_t_prev = bez[0];
+    let mut sum_len = 0.0;
+
+    for i in 1..=b_parts {
+        let b_t_curr = bezier_q(bez, i as f64 / b_parts as f64);
+        sum_len += (b_t_curr - b_t_prev).hypot();
+        b_t_dist.push(sum_len);
+        b_t_prev = b_t_curr;
+    }
+
+    // Normalize to 0..1
+    b_t_dist.iter().map(|&x| x / sum_len).collect()
+}
+
+/// Find t value for a given parameter distance
+fn find_t(bez: &[Point; 4], param: f64, t_dist_map: &[f64], b_parts: usize) -> f64 {
+    if param < 0.0 {
+        return 0.0;
+    }
+    if param > 1.0 {
+        return 1.0;
+    }
+
+    for i in 1..=b_parts {
+        if param <= t_dist_map[i] {
+            let t_min = (i - 1) as f64 / b_parts as f64;
+            let t_max = i as f64 / b_parts as f64;
+            let len_min = t_dist_map[i - 1];
+            let len_max = t_dist_map[i];
+
+            let t = (param - len_min) / (len_max - len_min) * (t_max - t_min) + t_min;
+            return t;
+        }
+    }
+
+    1.0
+}
+
+/// Evaluate cubic Bezier at parameter t
+fn bezier_q(ctrl_poly: &[Point; 4], t: f64) -> Point {
+    let tx = 1.0 - t;
+    let p_a = ctrl_poly[0].to_vec2() * (tx * tx * tx);
+    let p_b = ctrl_poly[1].to_vec2() * (3.0 * tx * tx * t);
+    let p_c = ctrl_poly[2].to_vec2() * (3.0 * tx * t * t);
+    let p_d = ctrl_poly[3].to_vec2() * (t * t * t);
+
+    (p_a + p_b + p_c + p_d).to_point()
+}
+
+/// Evaluate first derivative of cubic Bezier at parameter t
+fn bezier_qprime(ctrl_poly: &[Point; 4], t: f64) -> Vec2 {
+    let tx = 1.0 - t;
+    let p_a = (ctrl_poly[1] - ctrl_poly[0]) * (3.0 * tx * tx);
+    let p_b = (ctrl_poly[2] - ctrl_poly[1]) * (6.0 * tx * t);
+    let p_c = (ctrl_poly[3] - ctrl_poly[2]) * (3.0 * t * t);
+
+    p_a + p_b + p_c
+}
+
+/// Evaluate second derivative of cubic Bezier at parameter t
+fn bezier_qprimeprime(ctrl_poly: &[Point; 4], t: f64) -> Vec2 {
+    let v0 = ctrl_poly[2].to_vec2() - ctrl_poly[1].to_vec2() * 2.0 + ctrl_poly[0].to_vec2();
+    let v1 = ctrl_poly[3].to_vec2() - ctrl_poly[2].to_vec2() * 2.0 + ctrl_poly[1].to_vec2();
+    v0 * (6.0 * (1.0 - t)) + v1 * (6.0 * t)
+}
+
+/// Create a unit tangent vector from A to B
+fn create_tangent(point_a: Point, point_b: Point) -> Vec2 {
+    normalize(point_a - point_b)
+}
+
+/// Normalize a vector to unit length
+fn normalize(v: Vec2) -> Vec2 {
+    let len = v.hypot();
+    if len == 0.0 {
+        Vec2::ZERO
+    } else {
+        v / len
+    }
+}
+
+/// Dot product of two vectors
+fn dot(v1: Vec2, v2: Vec2) -> f64 {
+    v1.x * v2.x + v1.y * v2.y
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_rdp_simplification() {
+        let points = vec![
+            Point::new(0.0, 0.0),
+            Point::new(1.0, 0.1),
+            Point::new(2.0, 0.0),
+            Point::new(3.0, 0.0),
+            Point::new(4.0, 0.0),
+            Point::new(5.0, 0.0),
+        ];
+
+        let config = RdpConfig {
+            tolerance: 0.5,
+            highest_quality: false,
+        };
+
+        let simplified = simplify_rdp(&points, config);
+
+        // Should simplify the nearly-straight line
+        assert!(simplified.len() < points.len());
+        assert_eq!(simplified[0], points[0]);
+        assert_eq!(simplified[simplified.len() - 1], points[points.len() - 1]);
+    }
+
+    #[test]
+    fn test_schneider_curve_fitting() {
+        let points = vec![
+            Point::new(0.0, 0.0),
+            Point::new(50.0, 100.0),
+            Point::new(100.0, 50.0),
+            Point::new(150.0, 100.0),
+        ];
+
+        let config = SchneiderConfig { max_error: 30.0 };
+
+        let path = fit_bezier_curves(&points, config);
+
+        // Should create a valid BezPath
+        assert!(!path.is_empty());
+    }
+
+    #[test]
+    fn test_chord_length_parameterization() {
+        let points = vec![
+            Point::new(0.0, 0.0),
+            Point::new(1.0, 0.0),
+            Point::new(2.0, 0.0),
+        ];
+
+        let params = chord_length_parameterize(&points);
+
+        // Should start at 0 and end at 1
+        assert_eq!(params[0], 0.0);
+        assert_eq!(params[params.len() - 1], 1.0);
+        // Should be evenly spaced for uniform spacing
+        assert!((params[1] - 0.5).abs() < 0.01);
+    }
+}

lightningbeam-ui/lightningbeam-core/src/shape.rs

@@ -177,6 +177,16 @@ impl ShapeColor {
     pub fn to_brush(&self) -> Brush {
         Brush::Solid(self.to_peniko())
     }
+
+    /// Create from egui Color32
+    pub fn from_egui(color: egui::Color32) -> Self {
+        Self {
+            r: color.r(),
+            g: color.g(),
+            b: color.b(),
+            a: color.a(),
+        }
+    }
 }
 
 impl Default for ShapeColor {

lightningbeam-ui/lightningbeam-core/src/tool.rs

@@ -54,14 +54,18 @@ pub enum ToolState {
 
     /// Creating a rectangle shape
     CreatingRectangle {
-        start_corner: Point,
-        current_corner: Point,
+        start_point: Point,      // Starting point (corner or center depending on modifiers)
+        current_point: Point,    // Current mouse position
+        centered: bool,          // If true, start_point is center; if false, it's a corner
+        constrain_square: bool,  // If true, constrain to square (equal width/height)
     },
 
     /// Creating an ellipse shape
     CreatingEllipse {
-        center: Point,
-        current_point: Point,
+        start_point: Point,      // Starting point (center or corner depending on modifiers)
+        current_point: Point,    // Current mouse position
+        corner_mode: bool,       // If true, start is corner; if false, start is center
+        constrain_circle: bool,  // If true, constrain to circle (equal radii)
     },
 
     /// Transforming selected objects (scale, rotate)
@@ -69,6 +73,9 @@ pub enum ToolState {
         mode: TransformMode,
         original_transforms: HashMap<Uuid, crate::object::Transform>,
         pivot: Point,
+        start_mouse: Point,    // Mouse position when transform started
+        current_mouse: Point,  // Current mouse position during drag
+        original_bbox: vello::kurbo::Rect,  // Bounding box at start of transform (fixed)
     },
 }
 

lightningbeam-ui/lightningbeam-editor/assets/com.lightningbeam.editor.desktop

@@ -0,0 +1,10 @@
+[Desktop Entry]
+Version=1.0
+Type=Application
+Name=Lightningbeam Editor
+Comment=Animation and video editing software
+Exec=lightningbeam-editor
+Icon=lightningbeam-editor
+Terminal=false
+Categories=Graphics;AudioVideo;Video;
+StartupWMClass=lightningbeam-editor

lightningbeam-ui/lightningbeam-editor/src/main.rs

@@ -68,10 +68,36 @@ fn main() -> eframe::Result {
         }
     }
 
-    let options = eframe::NativeOptions {
-        viewport: egui::ViewportBuilder::default()
+    // Load window icon
+    let icon_data = include_bytes!("../../../src-tauri/icons/icon.png");
+    let icon_image = match image::load_from_memory(icon_data) {
+        Ok(img) => {
+            let rgba = img.to_rgba8();
+            let (width, height) = (rgba.width(), rgba.height());
+            println!("✅ Loaded window icon: {}x{}", width, height);
+            Some(egui::IconData {
+                rgba: rgba.into_raw(),
+                width,
+                height,
+            })
+        }
+        Err(e) => {
+            eprintln!("❌ Failed to load window icon: {}", e);
+            None
+        }
+    };
+
+    let mut viewport_builder = egui::ViewportBuilder::default()
         .with_inner_size([1920.0, 1080.0])
-            .with_title("Lightningbeam Editor"),
+        .with_title("Lightningbeam Editor")
+        .with_app_id("lightningbeam-editor"); // Set app_id for Wayland
+
+    if let Some(icon) = icon_image {
+        viewport_builder = viewport_builder.with_icon(icon);
+    }
+
+    let options = eframe::NativeOptions {
+        viewport: viewport_builder,
         ..Default::default()
     };
 
@@ -235,6 +261,10 @@ struct EditorApp {
     active_layer_id: Option<Uuid>, // Currently active layer for editing
     selection: lightningbeam_core::selection::Selection, // Current selection state
     tool_state: lightningbeam_core::tool::ToolState, // Current tool interaction state
+    // Draw tool configuration
+    draw_simplify_mode: lightningbeam_core::tool::SimplifyMode, // Current simplification mode for draw tool
+    rdp_tolerance: f64, // RDP simplification tolerance (default: 10.0)
+    schneider_max_error: f64, // Schneider curve fitting max error (default: 30.0)
 }
 
 impl EditorApp {
@@ -289,6 +319,9 @@ impl EditorApp {
             active_layer_id: Some(layer_id),
             selection: lightningbeam_core::selection::Selection::new(),
             tool_state: lightningbeam_core::tool::ToolState::default(),
+            draw_simplify_mode: lightningbeam_core::tool::SimplifyMode::Smooth, // Default to smooth curves
+            rdp_tolerance: 10.0, // Default RDP tolerance
+            schneider_max_error: 30.0, // Default Schneider max error
         }
     }
 
@@ -610,11 +643,14 @@ impl eframe::App for EditorApp {
                 &mut fallback_pane_priority,
                 &mut pending_handlers,
                 &self.theme,
-                self.action_executor.document(),
+                &mut self.action_executor,
                 &mut self.selection,
                 &self.active_layer_id,
                 &mut self.tool_state,
                 &mut pending_actions,
+                &mut self.draw_simplify_mode,
+                &mut self.rdp_tolerance,
+                &mut self.schneider_max_error,
             );
 
             // Execute action on the best handler (two-phase dispatch)
@@ -697,15 +733,18 @@ fn render_layout_node(
     fallback_pane_priority: &mut Option<u32>,
     pending_handlers: &mut Vec<panes::ViewActionHandler>,
     theme: &Theme,
-    document: &lightningbeam_core::document::Document,
+    action_executor: &mut lightningbeam_core::action::ActionExecutor,
     selection: &mut lightningbeam_core::selection::Selection,
     active_layer_id: &Option<Uuid>,
     tool_state: &mut lightningbeam_core::tool::ToolState,
     pending_actions: &mut Vec<Box<dyn lightningbeam_core::action::Action>>,
+    draw_simplify_mode: &mut lightningbeam_core::tool::SimplifyMode,
+    rdp_tolerance: &mut f64,
+    schneider_max_error: &mut f64,
 ) {
     match node {
         LayoutNode::Pane { name } => {
-            render_pane(ui, name, rect, selected_pane, layout_action, split_preview_mode, icon_cache, tool_icon_cache, selected_tool, fill_color, stroke_color, pane_instances, path, pending_view_action, fallback_pane_priority, pending_handlers, theme, document, selection, active_layer_id, tool_state, pending_actions);
+            render_pane(ui, name, rect, selected_pane, layout_action, split_preview_mode, icon_cache, tool_icon_cache, selected_tool, fill_color, stroke_color, pane_instances, path, pending_view_action, fallback_pane_priority, pending_handlers, theme, action_executor, selection, active_layer_id, tool_state, pending_actions, draw_simplify_mode, rdp_tolerance, schneider_max_error);
         }
         LayoutNode::HorizontalGrid { percent, children } => {
             // Handle dragging
@@ -749,11 +788,14 @@ fn render_layout_node(
                 fallback_pane_priority,
                 pending_handlers,
                 theme,
-                document,
+                action_executor,
                 selection,
                 active_layer_id,
                 tool_state,
                 pending_actions,
+                draw_simplify_mode,
+                rdp_tolerance,
+                schneider_max_error,
             );
 
             let mut right_path = path.clone();
@@ -778,11 +820,14 @@ fn render_layout_node(
                 fallback_pane_priority,
                 pending_handlers,
                 theme,
-                document,
+                action_executor,
                 selection,
                 active_layer_id,
                 tool_state,
                 pending_actions,
+                draw_simplify_mode,
+                rdp_tolerance,
+                schneider_max_error,
             );
 
             // Draw divider with interaction
@@ -899,11 +944,14 @@ fn render_layout_node(
                 fallback_pane_priority,
                 pending_handlers,
                 theme,
-                document,
+                action_executor,
                 selection,
                 active_layer_id,
                 tool_state,
                 pending_actions,
+                draw_simplify_mode,
+                rdp_tolerance,
+                schneider_max_error,
             );
 
             let mut bottom_path = path.clone();
@@ -928,11 +976,14 @@ fn render_layout_node(
                 fallback_pane_priority,
                 pending_handlers,
                 theme,
-                document,
+                action_executor,
                 selection,
                 active_layer_id,
                 tool_state,
                 pending_actions,
+                draw_simplify_mode,
+                rdp_tolerance,
+                schneider_max_error,
             );
 
             // Draw divider with interaction
@@ -1029,11 +1080,14 @@ fn render_pane(
     fallback_pane_priority: &mut Option<u32>,
     pending_handlers: &mut Vec<panes::ViewActionHandler>,
     theme: &Theme,
-    document: &lightningbeam_core::document::Document,
+    action_executor: &mut lightningbeam_core::action::ActionExecutor,
     selection: &mut lightningbeam_core::selection::Selection,
     active_layer_id: &Option<Uuid>,
     tool_state: &mut lightningbeam_core::tool::ToolState,
     pending_actions: &mut Vec<Box<dyn lightningbeam_core::action::Action>>,
+    draw_simplify_mode: &mut lightningbeam_core::tool::SimplifyMode,
+    rdp_tolerance: &mut f64,
+    schneider_max_error: &mut f64,
 ) {
     let pane_type = PaneType::from_name(pane_name);
 
@@ -1208,11 +1262,14 @@ fn render_pane(
                 fallback_pane_priority,
                 theme,
                 pending_handlers,
-                document,
+                action_executor,
                 selection,
                 active_layer_id,
                 tool_state,
                 pending_actions,
+                draw_simplify_mode,
+                rdp_tolerance,
+                schneider_max_error,
             };
             pane_instance.render_header(&mut header_ui, &mut shared);
         }
@@ -1248,11 +1305,14 @@ fn render_pane(
                 fallback_pane_priority,
                 theme,
                 pending_handlers,
-                document,
+                action_executor,
                 selection,
                 active_layer_id,
                 tool_state,
                 pending_actions,
+                draw_simplify_mode,
+                rdp_tolerance,
+                schneider_max_error,
             };
 
             // Render pane content (header was already rendered above)

lightningbeam-ui/lightningbeam-editor/src/panes/mod.rs

@@ -43,8 +43,9 @@ pub struct SharedPaneState<'a> {
     /// Registry of handlers for the current pending action
     /// Panes register themselves here during render, execution happens after
     pub pending_handlers: &'a mut Vec<ViewActionHandler>,
-    /// Active document being edited (read-only, mutations go through actions)
-    pub document: &'a lightningbeam_core::document::Document,
+    /// Action executor for immediate action execution (for shape tools to avoid flicker)
+    /// Also provides read-only access to the document via action_executor.document()
+    pub action_executor: &'a mut lightningbeam_core::action::ActionExecutor,
     /// Current selection state (mutable for tools to modify)
     pub selection: &'a mut lightningbeam_core::selection::Selection,
     /// Currently active layer ID
@@ -53,6 +54,10 @@ pub struct SharedPaneState<'a> {
     pub tool_state: &'a mut lightningbeam_core::tool::ToolState,
     /// Actions to execute after rendering completes (two-phase dispatch)
     pub pending_actions: &'a mut Vec<Box<dyn lightningbeam_core::action::Action>>,
+    /// Draw tool configuration
+    pub draw_simplify_mode: &'a mut lightningbeam_core::tool::SimplifyMode,
+    pub rdp_tolerance: &'a mut f64,
+    pub schneider_max_error: &'a mut f64,
 }
 
 /// Trait for pane rendering