penpot/render-wasm/src/shapes.rs

use skia_safe::{self as skia};

use indexmap::IndexSet;

use crate::uuid::Uuid;
use std::borrow::Cow;
use std::cell::{OnceCell, RefCell};
use std::collections::HashSet;
use std::iter::once;

mod blend;
mod blurs;
mod bools;
mod corners;
mod fills;
mod fonts;
mod frames;
mod groups;
mod layouts;
pub mod modifiers;
mod paths;
mod rects;
mod shadows;
mod shape_to_path;
mod stroke_paths;
mod strokes;
mod svg_attrs;
mod svgraw;
mod text;
pub mod text_paths;
mod transform;

pub use blend::*;
pub use blurs::{radius_to_sigma, Blur, BlurType};
pub use bools::*;
pub use corners::*;
pub use fills::*;
pub use fonts::*;
pub use frames::*;
pub use groups::*;
pub use layouts::*;
pub use modifiers::*;
pub use paths::*;
pub use rects::*;
pub use shadows::*;
pub use shape_to_path::*;
pub use stroke_paths::*;
pub use strokes::*;
pub use svg_attrs::*;
pub use svgraw::*;
pub use text::*;
pub use transform::*;

use crate::math::{self, Bounds, Matrix, Point};

use crate::state::ShapesPoolRef;

const MIN_VISIBLE_SIZE: f32 = 2.0;
const MIN_STROKE_WIDTH: f32 = 0.001;

#[derive(Debug, Clone, PartialEq)]
pub enum Type {
    Frame(Frame),
    Group(Group),
    Bool(Bool),
    Rect(Rect),
    Path(Path),
    Text(TextContent),
    Circle, // FIXME: shouldn't this have a rect inside, like the Rect variant?
    SVGRaw(SVGRaw),
}

impl Type {
    pub fn corners(&self) -> Option<Corners> {
        match self {
            Type::Rect(Rect { corners, .. }) => *corners,
            Type::Frame(Frame { corners, .. }) => *corners,
            _ => None,
        }
    }

    pub fn set_corners(&mut self, corners: Corners) {
        match self {
            Type::Rect(data) => {
                data.corners = Some(corners);
            }
            Type::Frame(data) => {
                data.corners = Some(corners);
            }
            _ => {}
        }
    }

    pub fn clear_corners(&mut self) {
        match self {
            Type::Rect(data) => {
                data.corners = None;
            }
            Type::Frame(data) => {
                data.corners = None;
            }
            _ => {}
        }
    }

    pub fn path(&self) -> Option<&Path> {
        match self {
            Type::Path(path) => Some(path),
            Type::Bool(Bool { path, .. }) => Some(path),
            _ => None,
        }
    }

    pub fn path_mut(&mut self) -> Option<&mut Path> {
        match self {
            Type::Path(path) => Some(path),
            Type::Bool(Bool { path, .. }) => Some(path),
            _ => None,
        }
    }

    pub fn scale_content(&mut self, value: f32) {
        match self {
            Type::Rect(Rect {
                corners: Some(corners),
                ..
            }) => {
                corners::scale_corners(corners, value);
            }
            Type::Frame(Frame { corners, layout }) => {
                if let Some(corners) = corners {
                    corners::scale_corners(corners, value);
                }
                if let Some(layout) = layout {
                    layout.scale_content(value);
                }
            }
            Type::Text(TextContent { paragraphs, .. }) => {
                paragraphs.iter_mut().for_each(|p| p.scale_content(value));
            }
            _ => {}
        }
    }
}

#[derive(Debug, Clone, PartialEq, Copy)]
pub enum ConstraintH {
    Left,
    Right,
    LeftRight,
    Center,
    Scale,
}

#[derive(Debug, Clone, PartialEq, Copy)]
#[repr(u8)]
pub enum VerticalAlign {
    Top = 0,
    Center = 1,
    Bottom = 2,
}

#[derive(Debug, Clone, PartialEq, Copy)]
pub enum ConstraintV {
    Top,
    Bottom,
    TopBottom,
    Center,
    Scale,
}

pub type Color = skia::Color;

#[derive(Debug, Clone)]
pub struct Shape {
    pub id: Uuid,
    pub parent_id: Option<Uuid>,
    pub shape_type: Type,
    pub children: Vec<Uuid>,
    pub selrect: math::Rect,
    pub transform: Matrix,
    pub rotation: f32,
    pub constraint_h: Option<ConstraintH>,
    pub constraint_v: Option<ConstraintV>,
    pub clip_content: bool,
    pub fills: Vec<Fill>,
    pub strokes: Vec<Stroke>,
    pub blend_mode: BlendMode,
    pub vertical_align: VerticalAlign,
    pub blur: Option<Blur>,
    pub background_blur: Option<Blur>,
    pub opacity: f32,
    pub hidden: bool,
    pub svg: Option<skia::svg::Dom>,
    pub svg_attrs: Option<SvgAttrs>,
    pub shadows: Vec<Shadow>,
    pub layout_item: Option<LayoutItem>,
    pub bounds: OnceCell<math::Bounds>,
    pub extrect_cache: RefCell<Option<math::Rect>>,
    pub svg_transform: Option<Matrix>,
    pub ignore_constraints: bool,
    deleted: bool,
    /// Fills from a cold-load batch, held until text content is uploaded and laid out.
    deferred_batch_fills: Option<Vec<Fill>>,
    /// Strokes from a cold-load batch, applied together with deferred fills.
    deferred_batch_strokes: Option<Vec<Stroke>>,
}

// Returns all ancestor shapes of this shape, traversing up the parent hierarchy
//
// This function walks up the parent chain starting from this shape's parent,
// collecting all ancestor IDs. It stops when it reaches a nil UUID or when
// an ancestor is hidden (unless include_hidden is true).
//
// # Arguments
// * `shapes` - The shapes pool containing all shapes
// * `include_hidden` - Whether to include hidden ancestors in the result
//
// # Returns
// A set of ancestor UUIDs in traversal order (closest ancestor first)
pub fn all_with_ancestors(
    shapes: &[Uuid],
    shapes_pool: ShapesPoolRef,
    include_hidden: bool,
) -> Vec<Uuid> {
    let mut pending = Vec::from_iter(shapes.iter());
    let mut result = Vec::new();
    let mut seen = HashSet::new();

    while !pending.is_empty() {
        let Some(current_id) = pending.pop() else {
            break;
        };

        if !seen.insert(*current_id) {
            continue;
        }

        result.push(*current_id);

        let Some(parent_id) = shapes_pool.get(current_id).and_then(|s| s.parent_id) else {
            continue;
        };

        if parent_id == Uuid::nil() {
            continue;
        }

        if seen.contains(&parent_id) {
            continue;
        }

        // Check if the ancestor is hidden
        let Some(parent) = shapes_pool.get(&parent_id) else {
            continue;
        };

        if !include_hidden && parent.hidden() {
            continue;
        }

        pending.push(&parent.id);
    }
    result
}

impl Shape {
    pub fn get_relative_point(
        point: &Point,
        view_matrix: &Matrix,
        shape_matrix: &Matrix,
    ) -> Option<Point> {
        let inv_view_matrix = view_matrix.invert()?;
        let inv_shape_matrix = shape_matrix.invert()?;
        let transform_matrix: Matrix = Matrix::concat(&inv_shape_matrix, &inv_view_matrix);
        let shape_relative_point = transform_matrix.map_point(*point);
        Some(shape_relative_point)
    }

    pub fn new(id: Uuid) -> Self {
        Self {
            id,
            parent_id: None,
            shape_type: Type::Rect(Rect::default()),
            children: Vec::new(),
            selrect: math::Rect::new_empty(),
            transform: Matrix::default(),
            rotation: 0.,
            constraint_h: None,
            constraint_v: None,
            clip_content: true,
            fills: Vec::with_capacity(1),
            strokes: Vec::with_capacity(1),
            blend_mode: BlendMode::default(),
            vertical_align: VerticalAlign::Top,
            opacity: 1.,
            hidden: false,
            blur: None,
            background_blur: None,
            svg: None,
            svg_attrs: None,
            shadows: Vec::with_capacity(1),
            layout_item: None,
            bounds: OnceCell::new(),
            extrect_cache: RefCell::new(None),
            svg_transform: None,
            ignore_constraints: false,
            deleted: false,
            deferred_batch_fills: None,
            deferred_batch_strokes: None,
        }
    }

    pub fn scale_content(&mut self, value: f32) {
        self.ignore_constraints = true;
        self.shape_type.scale_content(value);
        self.strokes.iter_mut().for_each(|s| s.scale_content(value));

        self.shadows.iter_mut().for_each(|s| s.scale_content(value));

        if let Some(blur) = self.blur.as_mut() {
            blur.scale_content(value);
        }

        if let Some(background_blur) = self.background_blur.as_mut() {
            background_blur.scale_content(value);
        }

        self.layout_item
            .iter_mut()
            .for_each(|i| i.scale_content(value));
    }

    pub fn invalidate_bounds(&mut self) {
        self.bounds = OnceCell::new();
    }

    pub fn invalidate_extrect(&mut self) {
        *self.extrect_cache.borrow_mut() = None;
    }

    pub fn set_parent(&mut self, id: Uuid) {
        self.parent_id = Some(id);
    }

    pub fn set_shape_type(&mut self, shape_type: Type) {
        self.shape_type = shape_type;
    }

    #[allow(dead_code)]
    pub fn is_frame(&self) -> bool {
        matches!(self.shape_type, Type::Frame(_))
    }

    pub fn is_bool(&self) -> bool {
        matches!(self.shape_type, Type::Bool(_))
    }

    pub fn is_group_like(&self) -> bool {
        matches!(self.shape_type, Type::Group(_)) || matches!(self.shape_type, Type::Bool(_))
    }

    pub fn has_layout(&self) -> bool {
        matches!(
            self.shape_type,
            Type::Frame(Frame {
                layout: Some(_),
                ..
            })
        )
    }

    #[allow(dead_code)]
    pub fn is_flex(&self) -> bool {
        matches!(
            self.shape_type,
            Type::Frame(Frame {
                layout: Some(layouts::Layout::FlexLayout(_, _)),
                ..
            })
        )
    }

    pub fn is_flex_reverse(&self) -> bool {
        matches!(
            self.shape_type,
            Type::Frame(Frame {
                layout: Some(layouts::Layout::FlexLayout(
                    _,
                    FlexData {
                        direction: layouts::FlexDirection::RowReverse
                            | layouts::FlexDirection::ColumnReverse,
                        ..
                    }
                )),
                ..
            })
        )
    }

    pub fn set_selrect(&mut self, left: f32, top: f32, right: f32, bottom: f32) {
        self.invalidate_bounds();
        self.invalidate_extrect();
        self.selrect.set_ltrb(left, top, right, bottom);
        if let Type::Text(ref mut text) = self.shape_type {
            // `update_layout` syncs bounds via set_xywh before baking fill paints.
            text.update_layout(self.selrect);
        }
    }

    pub fn set_masked(&mut self, masked: bool) {
        if let Type::Group(data) = &mut self.shape_type {
            data.masked = masked;
        }
    }

    pub fn set_clip(&mut self, value: bool) {
        self.clip_content = value;
    }

    pub fn set_rotation(&mut self, angle: f32) {
        self.rotation = angle;
        self.invalidate_extrect();
    }

    pub fn set_transform(&mut self, a: f32, b: f32, c: f32, d: f32, e: f32, f: f32) {
        self.transform = Matrix::new_all(a, c, e, b, d, f, 0.0, 0.0, 1.0);
        self.invalidate_extrect();
    }

    pub fn set_opacity(&mut self, opacity: f32) {
        self.opacity = opacity;
    }

    pub fn set_vertical_align(&mut self, align: VerticalAlign) {
        self.vertical_align = align;
    }

    pub fn vertical_align(&self) -> VerticalAlign {
        self.vertical_align
    }

    pub fn clear_constraints(&mut self) {
        self.constraint_h = None;
        self.constraint_v = None;
    }

    pub fn set_constraint_h(&mut self, constraint: Option<ConstraintH>) {
        self.constraint_h = constraint;
    }

    pub fn constraint_h(&self, default: ConstraintH) -> ConstraintH {
        self.constraint_h.unwrap_or(default)
    }

    pub fn set_constraint_v(&mut self, constraint: Option<ConstraintV>) {
        self.constraint_v = constraint;
    }

    pub fn constraint_v(&self, default: ConstraintV) -> ConstraintV {
        self.constraint_v.unwrap_or(default)
    }

    pub fn set_hidden(&mut self, value: bool) {
        self.hidden = value;
    }

    pub fn svg_transform(&self) -> Option<Matrix> {
        self.svg_transform
    }

    pub fn set_deleted(&mut self, value: bool) {
        self.deleted = value;
    }

    pub fn deleted(&self) -> bool {
        self.deleted
    }

    // FIXME: These arguments could be grouped or simplified
    #[allow(clippy::too_many_arguments)]
    pub fn set_flex_layout_child_data(
        &mut self,
        margin_top: f32,
        margin_right: f32,
        margin_bottom: f32,
        margin_left: f32,
        h_sizing: Sizing,
        v_sizing: Sizing,
        max_h: Option<f32>,
        min_h: Option<f32>,
        max_w: Option<f32>,
        min_w: Option<f32>,
        align_self: Option<AlignSelf>,
        is_absolute: bool,
        z_index: Option<i32>,
    ) {
        self.layout_item = Some(LayoutItem {
            margin_top,
            margin_right,
            margin_bottom,
            margin_left,
            h_sizing,
            v_sizing,
            max_h,
            min_h,
            max_w,
            min_w,
            is_absolute,
            z_index,
            align_self,
        });
    }

    pub fn clear_layout(&mut self) {
        self.layout_item = None;
        if let Type::Frame(data) = &mut self.shape_type {
            data.layout = None;
        }
    }

    // FIXME: These arguments could be grouped or simplified
    #[allow(clippy::too_many_arguments)]
    pub fn set_flex_layout_data(
        &mut self,
        direction: FlexDirection,
        row_gap: f32,
        column_gap: f32,
        align_items: AlignItems,
        align_content: AlignContent,
        justify_items: JustifyItems,
        justify_content: JustifyContent,
        wrap_type: WrapType,
        padding_top: f32,
        padding_right: f32,
        padding_bottom: f32,
        padding_left: f32,
    ) {
        if let Type::Frame(data) = &mut self.shape_type {
            let layout_data = LayoutData {
                align_items,
                align_content,
                justify_items,
                justify_content,
                padding_top,
                padding_right,
                padding_bottom,
                padding_left,
                row_gap,
                column_gap,
            };

            let flex_data = FlexData {
                direction,
                wrap_type,
            };

            data.layout = Some(Layout::FlexLayout(layout_data, flex_data));
        }
    }

    // FIXME: These argumoents could be grouped or simplified
    #[allow(clippy::too_many_arguments)]
    pub fn set_grid_layout_data(
        &mut self,
        direction: GridDirection,
        row_gap: f32,
        column_gap: f32,
        align_items: AlignItems,
        align_content: AlignContent,
        justify_items: JustifyItems,
        justify_content: JustifyContent,
        padding_top: f32,
        padding_right: f32,
        padding_bottom: f32,
        padding_left: f32,
    ) {
        if let Type::Frame(data) = &mut self.shape_type {
            if let Some(Layout::GridLayout(layout_data, grid_data)) = &mut data.layout {
                layout_data.align_items = align_items;
                layout_data.align_content = align_content;
                layout_data.justify_items = justify_items;
                layout_data.justify_content = justify_content;
                layout_data.padding_top = padding_top;
                layout_data.padding_right = padding_right;
                layout_data.padding_bottom = padding_bottom;
                layout_data.padding_left = padding_left;
                layout_data.row_gap = row_gap;
                layout_data.column_gap = column_gap;
                grid_data.direction = direction;
            } else {
                let layout_data = LayoutData {
                    align_items,
                    align_content,
                    justify_items,
                    justify_content,
                    padding_top,
                    padding_right,
                    padding_bottom,
                    padding_left,
                    row_gap,
                    column_gap,
                };
                let mut grid_data = GridData::default();
                grid_data.direction = direction;
                data.layout = Some(Layout::GridLayout(layout_data, grid_data));
            }
        }
    }

    pub fn set_grid_columns(&mut self, tracks: Vec<GridTrack>) {
        let Type::Frame(frame_data) = &mut self.shape_type else {
            return;
        };
        let Some(Layout::GridLayout(_, grid_data)) = &mut frame_data.layout else {
            return;
        };
        grid_data.columns = tracks;
    }

    pub fn set_grid_rows(&mut self, tracks: Vec<GridTrack>) {
        let Type::Frame(frame_data) = &mut self.shape_type else {
            return;
        };
        let Some(Layout::GridLayout(_, grid_data)) = &mut frame_data.layout else {
            return;
        };
        grid_data.rows = tracks;
    }

    pub fn set_grid_cells(&mut self, cells: Vec<GridCell>) {
        let Type::Frame(frame_data) = &mut self.shape_type else {
            return;
        };
        let Some(Layout::GridLayout(_, grid_data)) = &mut frame_data.layout else {
            return;
        };
        grid_data.cells = cells;
    }

    pub fn set_blur(&mut self, blur: Option<Blur>) {
        self.invalidate_extrect();
        self.blur = blur;
    }

    pub fn set_background_blur(&mut self, blur: Option<Blur>) {
        self.invalidate_extrect();
        self.background_blur = blur;
    }

    pub fn visible_background_blur(&self) -> Option<Blur> {
        self.background_blur.filter(|blur| !blur.hidden)
    }

    /// Visible layer blur (`!hidden`, `LayerBlur`, `value > 0`).
    pub fn visible_layer_blur(&self) -> Option<Blur> {
        self.blur.filter(|blur| {
            !blur.hidden && blur.blur_type == BlurType::LayerBlur && blur.value > 0.0
        })
    }

    #[cfg(test)]
    pub fn add_child(&mut self, id: Uuid) {
        self.children.push(id);
    }

    pub fn compute_children_differences(&mut self, children: &[Uuid]) -> (Vec<Uuid>, Vec<Uuid>) {
        let current_set: HashSet<Uuid> = self.children.iter().copied().collect();
        let new_set: HashSet<Uuid> = children.iter().copied().collect();

        let added: Vec<Uuid> = new_set.difference(&current_set).copied().collect();
        let removed: Vec<Uuid> = current_set.difference(&new_set).copied().collect();
        (added, removed)
    }

    #[allow(dead_code)]
    pub fn fills(&self) -> std::slice::Iter<'_, Fill> {
        self.fills.iter()
    }

    pub fn set_fills(&mut self, fills: Vec<Fill>) {
        self.deferred_batch_fills = None;
        self.fills = fills;
    }

    pub fn add_fill(&mut self, f: Fill) {
        self.fills.push(f);
    }

    pub fn clear_fills(&mut self) {
        self.fills.clear();
    }

    pub fn visible_strokes(&self) -> impl DoubleEndedIterator<Item = &Stroke> {
        self.strokes
            .iter()
            .filter(|stroke| stroke.max_width() > MIN_STROKE_WIDTH)
    }

    pub fn has_visible_strokes(&self) -> bool {
        self.strokes
            .iter()
            .any(|stroke| stroke.max_width() > MIN_STROKE_WIDTH)
    }

    pub fn add_stroke(&mut self, s: Stroke) {
        self.invalidate_extrect();
        self.strokes.push(s)
    }

    pub fn set_last_stroke_widths(&mut self, widths: [f32; 4]) -> Result<(), String> {
        let stroke = self.strokes.last_mut().ok_or("Shape has no strokes")?;
        stroke.widths = Some(widths);
        self.invalidate_extrect();
        Ok(())
    }

    pub fn set_stroke_fill(&mut self, f: Fill) -> Result<(), String> {
        let stroke = self.strokes.last_mut().ok_or("Shape has no strokes")?;
        stroke.fill = f;
        Ok(())
    }

    pub fn clear_strokes(&mut self) {
        self.deferred_batch_strokes = None;
        self.invalidate_extrect();
        self.strokes.clear();
    }

    pub fn set_deferred_batch_fills(&mut self, fills: Vec<Fill>) {
        self.deferred_batch_fills = Some(fills);
    }

    pub fn set_deferred_batch_strokes(&mut self, strokes: Vec<Stroke>) {
        self.deferred_batch_strokes = Some(strokes);
    }

    /// Apply fill/stroke records that were parsed from a batch upload but held
    /// back until text content exists and has been laid out.
    pub fn apply_deferred_batch_paint(&mut self) {
        if let Some(fills) = self.deferred_batch_fills.take() {
            self.fills = fills;
        }
        if let Some(strokes) = self.deferred_batch_strokes.take() {
            self.strokes = strokes;
            self.invalidate_extrect();
        }
    }

    pub fn set_path_segments(&mut self, segments: Vec<Segment>) {
        match &mut self.shape_type {
            Type::Bool(Bool { bool_type, .. }) => {
                let path = match bool_type {
                    // Exclusion booleans are computed with even-odd semantics but
                    // PathData uploads do not carry the fill rule.
                    BoolType::Exclusion => Path::new(segments).with_even_odd(true),
                    _ => Path::new(segments),
                };
                self.shape_type = Type::Bool(Bool {
                    bool_type: *bool_type,
                    path,
                });
            }
            Type::Path(_) => {
                self.shape_type = Type::Path(Path::new(segments));
            }
            _ => {}
        };
        self.invalidate_bounds();
        self.invalidate_extrect();
    }

    pub fn update_svg_raw_content(&mut self, font_manager: skia::FontMgr) {
        match &self.shape_type {
            Type::SVGRaw(sr) => {
                let dom_result = skia::svg::Dom::from_str(&sr.content, font_manager);
                match dom_result {
                    Ok(dom) => {
                        self.set_svg(dom);
                    }
                    Err(e) => {
                        eprintln!("Error parsing SVG. Error: {}", e);
                    }
                }
            }
            _ => panic!("Updating SVG raw content on non SVG Raw shape"),
        }
    }

    pub fn set_svg_raw_content(&mut self, content: String) {
        self.shape_type = Type::SVGRaw(SVGRaw::from_content(content));
    }

    pub fn set_blend_mode(&mut self, mode: BlendMode) {
        self.blend_mode = mode;
    }

    pub fn set_bool_type(&mut self, bool_type: BoolType) {
        self.shape_type = match &self.shape_type {
            Type::Bool(Bool { path, .. }) => Type::Bool(Bool {
                bool_type,
                path: path.clone(),
            }),
            _ => Type::Bool(Bool {
                bool_type,
                path: Path::default(),
            }),
        };
    }

    pub fn set_corners(&mut self, raw_corners: (f32, f32, f32, f32)) {
        if let Some(corners) = make_corners(raw_corners) {
            self.shape_type.set_corners(corners);
        } else {
            self.shape_type.clear_corners();
        }
        self.invalidate_bounds();
        self.invalidate_extrect();
    }

    pub fn set_svg(&mut self, svg: skia::svg::Dom) {
        self.svg = Some(svg);
    }

    pub fn blend_mode(&self) -> BlendMode {
        self.blend_mode
    }

    pub fn opacity(&self) -> f32 {
        self.opacity
    }

    pub fn hidden(&self) -> bool {
        self.hidden
    }

    #[allow(dead_code)]
    pub fn width(&self) -> f32 {
        self.selrect.width()
    }

    pub fn extrect(&self, shapes_pool: ShapesPoolRef, scale: f32) -> math::Rect {
        self.calculate_extrect(shapes_pool, scale)
    }

    pub fn visually_insignificant(&self, scale: f32, shapes_pool: ShapesPoolRef) -> bool {
        let extrect = self.extrect(shapes_pool, scale);
        extrect.width() * scale < MIN_VISIBLE_SIZE && extrect.height() * scale < MIN_VISIBLE_SIZE
    }

    pub fn should_use_antialias(&self, scale: f32, threshold: f32) -> bool {
        self.selrect.width() * scale > threshold || self.selrect.height() * scale > threshold
    }

    pub fn calculate_bounds(&self, apply_transform: bool) -> Bounds {
        let mut bounds = Bounds::new(
            Point::new(self.selrect.x(), self.selrect.y()),
            Point::new(self.selrect.x() + self.selrect.width(), self.selrect.y()),
            Point::new(
                self.selrect.x() + self.selrect.width(),
                self.selrect.y() + self.selrect.height(),
            ),
            Point::new(self.selrect.x(), self.selrect.y() + self.selrect.height()),
        );

        // Apply this transformation only when self.transform
        // is not the identity matrix because if it is,
        // the result of applying this transformations would be
        // the same identity matrix.
        if apply_transform && !self.transform.is_identity() {
            let mut matrix = self.transform;
            let center = self.center();
            matrix.post_translate(center);
            matrix.pre_translate(-center);
            bounds.transform_mut(&matrix);
        }

        bounds
    }

    pub fn bounds(&self) -> Bounds {
        *self.bounds.get_or_init(|| self.calculate_bounds(true))
    }

    pub fn selrect(&self) -> math::Rect {
        self.selrect
    }

    pub fn get_text_content(&self) -> &TextContent {
        match &self.shape_type {
            crate::shapes::Type::Text(text_content) => text_content,
            _ => panic!("Shape is not of type Text"),
        }
    }

    /// Calculates the bounding rectangle for a selrect shape's shadow, taking into account
    /// stroke widths and shadow properties.
    ///
    /// This method computes the expanded bounds that would be needed to fully render
    /// the shadow effect for a shape. It considers:
    /// - The base bounds (selection rectangle)
    /// - Maximum stroke width across all strokes, accounting for stroke rendering kind
    /// - Shadow offset (x, y displacement)
    /// - Shadow blur radius (expands bounds outward)
    /// - Whether the shadow is hidden
    ///
    /// # Arguments
    /// * `shadow` - The shadow configuration containing offset, blur, and visibility
    ///
    /// # Returns
    /// A `math::Rect` representing the bounding rectangle that encompasses the shadow.
    /// Returns an empty rectangle if the shadow is hidden.
    pub fn get_selrect_shadow_bounds(&self, shadow: &Shadow) -> math::Rect {
        let base_bounds = self.selrect();
        let mut rect = skia::Rect::new_empty();

        let mut max_stroke: Option<f32> = None;
        for stroke in self.strokes.iter() {
            let width = match stroke.render_kind(false) {
                StrokeKind::Inner => -stroke.width / 2.,
                StrokeKind::Center => 0.,
                StrokeKind::Outer => stroke.width,
            };
            max_stroke = Some(max_stroke.unwrap_or(f32::MIN).max(width));
        }
        if !shadow.hidden() {
            let (x, y) = shadow.offset;
            let mut shadow_rect = base_bounds;
            shadow_rect.left += x;
            shadow_rect.right += x;
            shadow_rect.top += y;
            shadow_rect.bottom += y;

            shadow_rect.left -= shadow.blur;
            shadow_rect.top -= shadow.blur;
            shadow_rect.right += shadow.blur;
            shadow_rect.bottom += shadow.blur;

            if let Some(max_stroke) = max_stroke {
                shadow_rect.left -= max_stroke;
                shadow_rect.right += max_stroke;
                shadow_rect.top -= max_stroke;
                shadow_rect.bottom += max_stroke;
            }
            rect.join(shadow_rect);
        }
        rect
    }

    fn apply_stroke_bounds(&self, bounds: Bounds, stroke_width: f32) -> Bounds {
        let mut result = bounds.to_rect();
        if stroke_width > 0.0 {
            let mut expanded_rect = bounds.to_rect();
            expanded_rect.inset((-stroke_width, -stroke_width));
            result.join(expanded_rect);
        }

        let cap_margin = self.cap_bounds_margin();
        if cap_margin > 0.0 {
            let mut cap_rect = bounds.to_rect();
            cap_rect.inset((-cap_margin, -cap_margin));
            result.join(cap_rect);
        }

        Bounds::from_rect(&result)
    }

    fn apply_cap_bounds(&self, bounds: Bounds, cap_margin: f32) -> Bounds {
        let mut result = bounds.to_rect();
        if cap_margin > 0.0 {
            result.inset((-cap_margin, -cap_margin));
        }
        Bounds::from_rect(&result)
    }

    fn apply_shadow_bounds(&self, bounds: Bounds) -> Bounds {
        let mut rect = bounds.to_rect();
        for shadow in self.shadows_visible() {
            if !shadow.hidden() {
                if let Some(filter) = shadow.get_drop_shadow_filter() {
                    let shadow_bounds = filter.compute_fast_bounds(rect);
                    rect.join(shadow_bounds);
                }
            }
        }
        Bounds::from_rect(&rect)
    }

    fn apply_blur_bounds(&self, bounds: Bounds) -> Bounds {
        let mut rect = bounds.to_rect();
        let image_filter = self.image_filter(1.);
        if let Some(image_filter) = image_filter {
            let blur_bounds = image_filter.compute_fast_bounds(rect);
            rect.join(blur_bounds);
        }
        Bounds::from_rect(&rect)
    }

    pub fn extrect_depends_on_children(&self) -> bool {
        match self.shape_type {
            Type::Group(Group { masked: true }) => true,
            Type::Group(_) | Type::Frame(_) => !self.clip_content,
            _ => false,
        }
    }

    fn apply_children_bounds(
        &self,
        bounds: Bounds,
        shapes_pool: ShapesPoolRef,
        scale: f32,
    ) -> Bounds {
        let mut rect = bounds.to_rect();

        match self.shape_type {
            Type::Group(Group { masked: true }) => {
                let mut mask_rect: Option<math::Rect> = None;
                let mut content_rect: Option<math::Rect> = None;

                for (index, child_id) in self.children.iter().enumerate() {
                    if let Some(child_shape) = shapes_pool.get(child_id) {
                        let child_extrect = child_shape.calculate_extrect(shapes_pool, scale);

                        if index == 0 {
                            mask_rect = Some(child_extrect);
                        } else {
                            match content_rect.as_mut() {
                                Some(r) => r.join(child_extrect),
                                None => content_rect = Some(child_extrect),
                            }
                        }
                    }
                }

                match (mask_rect, content_rect) {
                    (Some(mut mask), Some(content)) => {
                        if mask.intersect(content) {
                            rect.join(mask);
                        }
                    }
                    (Some(mask), None) | (None, Some(mask)) => {
                        rect.join(mask);
                    }
                    (None, None) => {}
                }
            }

            Type::Group(_) | Type::Frame(_) if !self.clip_content => {
                // For frames and groups, we must always calculate extrect for all children
                // to ensure accurate bounds that include nested content across all tiles.
                // Using selrect for children can cause frames to be incorrectly omitted from
                // tiles where they have nested content.
                for child_id in self.children_ids_iter(false) {
                    if let Some(child_shape) = shapes_pool.get(child_id) {
                        // Always calculate full extrect for children to ensure accurate bounds
                        let child_extrect = child_shape.calculate_extrect(shapes_pool, scale);
                        rect.join(child_extrect);
                    }
                }
            }

            _ => {}
        }

        Bounds::from_rect(&rect)
    }

    pub fn apply_children_blur(&self, bounds: Bounds, tree: ShapesPoolRef) -> Bounds {
        let mut rect = bounds.to_rect();
        let mut children_blur = 0.0;
        let mut current_parent_id = self.parent_id;

        while let Some(parent_id) = current_parent_id {
            if parent_id.is_nil() {
                break;
            }

            if let Some(parent) = tree.get(&parent_id) {
                match parent.shape_type {
                    Type::Frame(_) | Type::Group(_) => {
                        if let Some(blur) = parent.blur {
                            if !blur.hidden && blur.blur_type == BlurType::LayerBlur {
                                children_blur += blur.value;
                            }
                        }
                    }
                    _ => {}
                }

                current_parent_id = parent.parent_id;
            } else {
                break;
            }
        }

        let sigma = radius_to_sigma(children_blur);
        let blur = skia::image_filters::blur((sigma, sigma), None, None, None);
        if let Some(image_filter) = blur {
            let blur_bounds = image_filter.compute_fast_bounds(rect);
            rect.join(blur_bounds);
        }
        Bounds::from_rect(&rect)
    }

    pub fn calculate_extrect(&self, shapes_pool: ShapesPoolRef, scale: f32) -> math::Rect {
        // `scale` is forwarded to children but intentionally NOT part of the cache key.
        if let Some(cached_extrect) = *self.extrect_cache.borrow() {
            return cached_extrect;
        }

        let extrect = self.calculate_extrect_uncached(shapes_pool, scale);

        *self.extrect_cache.borrow_mut() = Some(extrect);
        extrect
    }

    fn own_extrect_bounds(&self) -> Bounds {
        self.expand_own_bounds(self.own_base_bounds(), true)
    }

    /// The shape's own geometry bounds, before stroke/shadow/blur margins.
    fn own_base_bounds(&self) -> Bounds {
        let shape = self;
        let max_stroke = Stroke::max_bounds_width(shape.strokes.iter(), shape.is_open());

        match &shape.shape_type {
            Type::Path(_) | Type::Bool(_) => {
                if let Some(path) = shape.get_skia_path() {
                    let cap_margin = shape.cap_bounds_margin();
                    let rect = path
                        .compute_tight_bounds()
                        .with_outset((max_stroke, max_stroke));
                    self.apply_cap_bounds(Bounds::from_rect(&rect), cap_margin)
                } else {
                    shape.calculate_bounds(false)
                }
            }
            Type::Text(text_content) => {
                // FIXME: we need to recalculate the text bounds here because the shape's selrect
                text_content.calculate_bounds(shape, false)
            }
            _ => shape.calculate_bounds(false),
        }
    }

    fn expand_own_bounds(&self, bounds: Bounds, include_shadows: bool) -> Bounds {
        let max_stroke = Stroke::max_bounds_width(self.strokes.iter(), self.is_open());
        let mut bounds = self.apply_stroke_bounds(bounds, max_stroke);
        if include_shadows {
            bounds = self.apply_shadow_bounds(bounds);
        }
        self.apply_blur_bounds(bounds)
    }

    /// `own_base_bounds` for layer purposes: a text is never tighter than its selrect.
    fn own_layer_base_bounds(&self) -> Bounds {
        let mut bounds = self.own_base_bounds();
        if matches!(self.shape_type, Type::Text(_)) {
            let mut rect = bounds.to_rect();
            rect.join(self.selrect);
            bounds = Bounds::from_rect(&rect);
        }
        bounds
    }

    /// Bound for a `SaveLayerRec` wrapping this shape's own drawing, in
    /// untransformed space (callers concatenate [`Self::centered_transform`]
    /// first). Includes shadow/blur margins, so it is also a valid input bound
    /// for a layer whose paint carries an image filter.
    pub fn layer_bounds(&self) -> math::Rect {
        self.expand_own_bounds(self.own_layer_base_bounds(), true)
            .to_rect()
    }

    /// Geometry, strokes and layer blur in world space, without this shape's own
    /// drop shadows: those belong to the shape, not to an ancestor's shadow mask.
    pub fn silhouette_rect(&self) -> math::Rect {
        let mut bounds = self.expand_own_bounds(self.own_layer_base_bounds(), false);
        if !self.transform.is_identity() {
            bounds.transform_mut(&self.centered_transform());
        }
        bounds.to_rect()
    }

    fn calculate_extrect_uncached(&self, shapes_pool: ShapesPoolRef, scale: f32) -> math::Rect {
        // Own outsets (strokes, shadows, blur) are local-space, so they expand before the
        // shape transform. Children extrects are already world-space: join them after it.
        let mut bounds = self.own_extrect_bounds();

        if !self.transform.is_identity() {
            let mut matrix = self.transform;
            let center = self.center();
            matrix.post_translate(center);
            matrix.pre_translate(-center);
            bounds.transform_mut(&matrix);
        }

        bounds = self.apply_children_bounds(bounds, shapes_pool, scale);
        bounds = self.apply_children_blur(bounds, shapes_pool);

        bounds.to_rect()
    }

    pub fn left_top(&self) -> Point {
        Point::new(self.selrect.left, self.selrect.top)
    }

    pub fn center(&self) -> Point {
        self.selrect.center()
    }

    // TODO: This can be used in more places
    pub fn centered_transform(&self) -> Matrix {
        let center = self.center();
        let mut matrix = self.transform;
        matrix.post_translate(center);
        matrix.pre_translate(-center);
        matrix
    }

    pub fn clip(&self) -> bool {
        self.clip_content
    }

    pub fn cap_bounds_margin(&self) -> f32 {
        if !self.is_open() {
            return 0.0;
        }
        self.strokes
            .iter()
            .map(|stroke| stroke.cap_bounds_margin())
            .fold(0.0, f32::max)
    }

    pub fn has_cap_bounds(&self) -> bool {
        self.cap_bounds_margin() > 0.0
    }

    pub fn mask_id(&self) -> Option<&Uuid> {
        self.children.first()
    }

    pub fn children_count(&self) -> usize {
        self.children_ids_iter(false).count()
    }

    pub fn children_ids(&self, include_hidden: bool) -> Vec<Uuid> {
        if include_hidden {
            return self.children.iter().rev().copied().collect();
        }

        if let Type::Bool(_) = self.shape_type {
            Vec::new()
        } else if let Type::Group(group) = self.shape_type {
            if group.masked {
                self.children
                    .iter()
                    .rev()
                    .take(self.children.len() - 1)
                    .copied()
                    .collect()
            } else {
                self.children.iter().rev().copied().collect()
            }
        } else {
            self.children.iter().rev().copied().collect()
        }
    }

    pub fn children_ids_iter(&self, include_hidden: bool) -> Box<dyn Iterator<Item = &Uuid> + '_> {
        if include_hidden {
            return Box::new(self.children.iter().rev());
        }

        if let Type::Bool(_) = self.shape_type {
            Box::new([].iter())
        } else if let Type::Group(group) = self.shape_type {
            if group.masked {
                Box::new(self.children.iter().rev().take(self.children.len() - 1))
            } else {
                Box::new(self.children.iter().rev())
            }
        } else {
            Box::new(self.children.iter().rev())
        }
    }

    /// Returns children in forward (non-reversed) order - useful for layout calculations
    pub fn children_ids_iter_forward(
        &self,
        include_hidden: bool,
    ) -> Box<dyn Iterator<Item = &Uuid> + '_> {
        if include_hidden {
            return Box::new(self.children.iter());
        }

        if let Type::Bool(_) = self.shape_type {
            Box::new([].iter())
        } else if let Type::Group(group) = self.shape_type {
            if group.masked {
                Box::new(self.children.iter().skip(1))
            } else {
                Box::new(self.children.iter())
            }
        } else {
            Box::new(self.children.iter())
        }
    }

    pub fn all_children(
        &self,
        shapes: ShapesPoolRef,
        include_hidden: bool,
        include_self: bool,
    ) -> Vec<Uuid> {
        let all_children = self.children_ids_iter(include_hidden).flat_map(|id| {
            shapes
                .get(id)
                .map(|s| s.all_children(shapes, include_hidden, true))
                .unwrap_or_default()
        });

        if include_self {
            once(self.id).chain(all_children).collect()
        } else {
            all_children.collect()
        }
    }

    pub fn all_children_iter<'a>(
        &'a self,
        shapes: ShapesPoolRef<'a>,
        include_hidden: bool,
        include_self: bool,
    ) -> Box<dyn Iterator<Item = Uuid> + 'a> {
        let all_children = self.children_ids_iter(include_hidden).flat_map(move |id| {
            if let Some(shape) = shapes.get(id) {
                shape.all_children_iter(shapes, include_hidden, true)
            } else {
                Box::new(std::iter::empty())
            }
        });

        if include_self {
            Box::new(once(self.id).chain(all_children))
        } else {
            Box::new(all_children)
        }
    }

    pub fn get_matrix(&self) -> Matrix {
        let mut matrix = Matrix::new_identity();
        matrix.post_translate(self.left_top());
        matrix.post_rotate(self.rotation, self.center());
        matrix
    }

    #[allow(dead_code)]
    pub fn get_concatenated_matrix(&self, shapes: ShapesPoolRef) -> Matrix {
        let mut matrix = Matrix::new_identity();
        let mut current_id = self.id;
        while let Some(parent_id) = shapes.get(&current_id).and_then(|s| s.parent_id) {
            if parent_id == Uuid::nil() {
                break;
            }

            if let Some(parent) = shapes.get(&parent_id) {
                matrix.pre_concat(&parent.get_matrix());
                current_id = parent_id;
            } else {
                // FIXME: This should panic! I've removed it temporarily until
                // we fix the problems with shapes without parents.
                // panic!("Parent can't be found");
                break;
            }
        }
        matrix
    }

    pub fn image_filter(&self, scale: f32) -> Option<skia::ImageFilter> {
        self.blur
            .filter(|blur| !blur.hidden)
            .and_then(|blur| match blur.blur_type {
                BlurType::LayerBlur => {
                    let sigma = radius_to_sigma(blur.value * scale);
                    skia::image_filters::blur((sigma, sigma), None, None, None)
                }
                BlurType::BackgroundBlur => None,
            })
    }

    /// Font families used by this shape (the text spans' families), or an
    /// empty vec for non-text shapes.
    pub fn font_families(&self) -> Vec<FontFamily> {
        match &self.shape_type {
            Type::Text(content) => content.font_families(),
            _ => Vec::new(),
        }
    }

    #[allow(dead_code)]
    pub fn mask_filter(&self, scale: f32) -> Option<skia::MaskFilter> {
        self.blur
            .filter(|blur| !blur.hidden)
            .and_then(|blur| match blur.blur_type {
                BlurType::LayerBlur => {
                    let sigma = radius_to_sigma(blur.value * scale);
                    skia::MaskFilter::blur(skia::BlurStyle::Normal, sigma, Some(true))
                }
                BlurType::BackgroundBlur => None,
            })
    }

    pub fn is_recursive(&self) -> bool {
        matches!(
            self.shape_type,
            Type::Frame(_) | Type::Group(_) | Type::Bool(_)
        )
    }

    pub fn is_open(&self) -> bool {
        matches!(&self.shape_type, Type::Path(p) if p.is_open())
    }

    pub fn add_shadow(&mut self, shadow: Shadow) {
        self.invalidate_extrect();
        self.shadows.push(shadow);
    }

    pub fn clear_shadows(&mut self) {
        self.invalidate_extrect();
        self.shadows.clear();
    }

    #[allow(dead_code)]
    pub fn drop_shadows(&self) -> impl DoubleEndedIterator<Item = &Shadow> {
        self.shadows
            .iter()
            .rev()
            .filter(|shadow| shadow.style() == ShadowStyle::Drop)
    }

    pub fn drop_shadows_visible(&self) -> impl DoubleEndedIterator<Item = &Shadow> {
        self.shadows
            .iter()
            .rev()
            .filter(|shadow| shadow.style() == ShadowStyle::Drop && !shadow.hidden())
    }

    #[allow(dead_code)]
    pub fn inner_shadows(&self) -> impl DoubleEndedIterator<Item = &Shadow> {
        self.shadows
            .iter()
            .rev()
            .filter(|shadow| shadow.style() == ShadowStyle::Inner)
    }

    pub fn inner_shadows_visible(&self) -> impl DoubleEndedIterator<Item = &Shadow> {
        self.shadows
            .iter()
            .rev()
            .filter(|shadow| shadow.style() == ShadowStyle::Inner && !shadow.hidden())
    }

    pub fn shadows_visible(&self) -> impl DoubleEndedIterator<Item = &Shadow> {
        self.shadows.iter().rev().filter(|shadow| !shadow.hidden())
    }

    pub fn to_path_transform(&self) -> Option<Matrix> {
        match self.shape_type {
            Type::Path(_) | Type::Bool(_) => {
                let center = self.center();
                let mut matrix = Matrix::new_identity();
                matrix.pre_translate(center);
                matrix.pre_concat(&self.transform.invert()?);
                matrix.pre_translate(-center);
                Some(matrix)
            }
            _ => None,
        }
    }

    pub fn add_paragraph(&mut self, paragraph: Paragraph) -> Result<(), String> {
        match self.shape_type {
            Type::Text(ref mut text) => {
                text.add_paragraph(paragraph);
                Ok(())
            }
            _ => Err("Shape is not a text".to_string()),
        }
    }

    pub fn clear_text(&mut self) {
        self.invalidate_extrect();
        if let Type::Text(old_text_content) = &self.shape_type {
            let new_text_content = TextContent::new(self.selrect, old_text_content.grow_type());
            self.shape_type = Type::Text(new_text_content);
        }
    }

    pub fn get_skia_path(&self) -> Option<skia::Path> {
        if let Some(path) = self.shape_type.path() {
            let mut skia_path = path.to_skia_path(self.svg_attrs.as_ref());
            if !math::identitish(&self.transform) {
                if let Some(path_transform) = self.to_path_transform() {
                    skia_path = skia_path.make_transform(&path_transform);
                }
            }
            Some(skia_path)
        } else {
            None
        }
    }

    /// Same `concat` applied around [`center`](Self::center) as in `render_shape` (non-text branch).
    fn shape_document_transform(&self) -> Matrix {
        let c = self.center();
        let mut m = self.transform;
        m.post_translate(c);
        m.pre_translate(-c);
        m
    }

    /// Fill silhouette only, document space (matches fill rendering).
    fn drag_crop_fill_clip_path_skia(&self) -> Option<skia::Path> {
        match &self.shape_type {
            Type::Rect(r) => {
                let p = Path::new(shape_to_path::rect_segments(self, r.corners));
                Some(p.to_skia_path(self.svg_attrs.as_ref()))
            }
            Type::Circle => {
                let p = Path::new(shape_to_path::circle_segments(self));
                Some(p.to_skia_path(self.svg_attrs.as_ref()))
            }
            Type::Path(_) | Type::Bool(_) => {
                let sk = self.get_skia_path()?;
                Some(sk.make_transform(&self.shape_document_transform()))
            }
            _ => None,
        }
    }

    /// Whether this shape may use the backbuffer crop fast path during interactive drag.
    ///
    /// Conservative: only effects and fills that match what we snapshot and clip in
    /// [`drag_crop_clip_path`](Self::drag_crop_clip_path). Text is never safe (glyph layout,
    /// no `drag_crop_clip_path`).
    pub fn is_safe_for_drag_crop_cache(&self, shapes_pool: ShapesPoolRef) -> bool {
        if matches!(self.shape_type, Type::Text(_)) {
            return false;
        }

        if matches!(self.shape_type, Type::Group(_)) {
            return false;
        }

        // If a frame shows overflow (clip_content=false) and its visible content exceeds the
        // frame bounds, a cached crop anchored to the frame can easily become incorrect while
        // moving (children can extend beyond selrect). Be conservative and render live.
        if matches!(self.shape_type, Type::Frame(_)) && !self.clip_content {
            let extrect = self.extrect(shapes_pool, 1.0);
            let sr = self.selrect;
            let exceeds = extrect.left < sr.left
                || extrect.top < sr.top
                || extrect.right > sr.right
                || extrect.bottom > sr.bottom;
            if exceeds {
                return false;
            }
        }

        !self.has_cap_bounds()
            && self.blur.is_none()
            && self.background_blur.is_none()
            && self.shadows.is_empty()
            && (self.opacity - 1.0).abs() <= 1e-4
            && self.blend_mode().0 == skia::BlendMode::SrcOver
    }

    /// Fill + visible strokes in **document space** for clipping interactive drag textures.
    ///
    /// The backbuffer crop uses an axis-aligned `extrect`; we clip the blit so backdrop pixels
    /// outside the real silhouette (fill and stroke regions) are not smeared. Strokes use
    /// [`stroke_to_path`](stroke_to_path) like the main renderer, then union with the fill path.
    pub fn drag_crop_clip_path(&self) -> Option<skia::Path> {
        let mut acc = self.drag_crop_fill_clip_path_skia()?;
        if !self.has_visible_strokes() {
            return Some(acc);
        }

        let shape_path = match &self.shape_type {
            Type::Rect(r) => Path::new(shape_to_path::rect_segments(self, r.corners)),
            Type::Circle => Path::new(shape_to_path::circle_segments(self)),
            Type::Path(_) | Type::Bool(_) => self.shape_type.path()?.clone(),
            _ => return Some(acc),
        };

        let path_transform = self.to_path_transform();

        for stroke in self.visible_strokes() {
            let Some(stroke_region) = stroke_to_path(
                stroke,
                &shape_path,
                path_transform.as_ref(),
                &self.selrect,
                self.svg_attrs.as_ref(),
                true,
            ) else {
                continue;
            };
            let sk = stroke_region.to_skia_path(self.svg_attrs.as_ref());
            acc = acc.op(&sk, skia::PathOp::Union).unwrap_or(acc);
        }

        Some(acc)
    }

    fn transform_selrect(&mut self, transform: &Matrix) {
        if math::is_move_only_matrix(transform) {
            let tx = transform.translate_x();
            let ty = transform.translate_y();
            // `self.transform` (rotation/scale around center) is unchanged by translation.
            self.selrect = math::Rect::from_xywh(
                self.selrect.left + tx,
                self.selrect.top + ty,
                self.selrect.width(),
                self.selrect.height(),
            );
            return;
        }

        let mut center = self.selrect.center();
        center = transform.map_point(center);

        let bounds = self.bounds().transform(transform);
        self.transform = bounds.transform_matrix().unwrap_or_default();

        let width = bounds.width();
        let height = bounds.height();

        let new_selrect = math::Rect::from_xywh(
            center.x - width / 2.0,
            center.y - height / 2.0,
            width,
            height,
        );
        self.selrect = new_selrect;
    }

    pub fn apply_transform(&mut self, transform: &Matrix) {
        self.transform_selrect(transform);

        // Outsets (strokes, shadows, blur, children) are translation-invariant,
        // so the cached extrect can be shifted instead of invalidated.
        // The bounds cache must always be invalidated so that callers such as
        // grid_cell_data get the updated position after a drag.
        if math::is_move_only_matrix(transform) {
            let tx = transform.translate_x();
            let ty = transform.translate_y();
            if let Some(rect) = self.extrect_cache.borrow_mut().as_mut() {
                *rect = math::Rect::from_xywh(
                    rect.left + tx,
                    rect.top + ty,
                    rect.width(),
                    rect.height(),
                );
            }
            self.invalidate_bounds();
        } else {
            self.invalidate_extrect();
            self.invalidate_bounds();
        }

        if let shape_type @ (Type::Path(_) | Type::Bool(_)) = &mut self.shape_type {
            if let Some(path) = shape_type.path_mut() {
                path.transform(transform);
            }
        } else if let Type::Text(text) = &mut self.shape_type {
            text.transform(transform);
        } else if let Type::SVGRaw(_) = &mut self.shape_type {
            self.svg_transform = Some(*transform);
        }
    }

    pub fn apply_structure(&mut self, structure: &Vec<StructureEntry>) {
        let mut result = IndexSet::<Uuid>::from_iter(self.children.iter().copied());
        let mut to_remove = HashSet::<&Uuid>::new();

        for st in structure {
            match st.entry_type {
                StructureEntryType::AddChild => {
                    if result.is_empty() {
                        result.insert(st.id);
                    } else {
                        let index = usize::min(result.len() - 1, st.index as usize);
                        result.shift_insert(index, st.id);
                    }
                }
                StructureEntryType::RemoveChild => {
                    to_remove.insert(&st.id);
                }
                _ => {}
            }
        }

        self.children = result
            .iter()
            .filter(|id| !to_remove.contains(id))
            .copied()
            .collect();
    }

    pub fn transformed(
        &self,
        transform: Option<&Matrix>,
        structure: Option<&Vec<StructureEntry>>,
    ) -> Self {
        let mut shape: Cow<Shape> = Cow::Borrowed(self);
        if let Some(transform) = transform {
            shape.to_mut().apply_transform(transform);
        }
        if let Some(structure) = structure {
            shape.to_mut().apply_structure(structure);
        }

        shape.into_owned()
    }

    pub fn is_absolute(&self) -> bool {
        match &self.layout_item {
            Some(LayoutItem { is_absolute, .. }) => *is_absolute,
            _ => false,
        }
    }

    pub fn z_index(&self) -> i32 {
        match &self.layout_item {
            Some(LayoutItem {
                z_index: Some(z), ..
            }) => *z,
            _ => 0,
        }
    }

    #[allow(dead_code)]
    pub fn has_z_index(&self) -> bool {
        matches!(
            &self.layout_item,
            Some(LayoutItem {
                z_index: Some(_),
                ..
            })
        )
    }

    pub fn is_layout_vertical_auto(&self) -> bool {
        match &self.layout_item {
            Some(LayoutItem { v_sizing, .. }) => v_sizing == &Sizing::Auto,
            _ => false,
        }
    }

    pub fn is_layout_vertical_fill(&self) -> bool {
        match &self.layout_item {
            Some(LayoutItem { v_sizing, .. }) => v_sizing == &Sizing::Fill,
            _ => false,
        }
    }

    pub fn is_layout_horizontal_auto(&self) -> bool {
        match &self.layout_item {
            Some(LayoutItem { h_sizing, .. }) => h_sizing == &Sizing::Auto,
            _ => false,
        }
    }

    pub fn is_layout_horizontal_fill(&self) -> bool {
        match &self.layout_item {
            Some(LayoutItem { h_sizing, .. }) => h_sizing == &Sizing::Fill,
            _ => false,
        }
    }

    pub fn has_fills(&self) -> bool {
        !self.fills.is_empty()
    }

    /// Determines if this frame or group can be flattened (doesn't affect children visually)
    /// A container can be flattened if it has no visual effects that affect its children
    /// and doesn't render its own content (no fills/strokes)
    pub fn can_flatten(&self) -> bool {
        // Only frames and groups can be flattened
        if !matches!(self.shape_type, Type::Frame(_) | Type::Group(_)) {
            return false;
        }

        // Cannot flatten if it has visual effects that affect children:

        if self.clip_content {
            return false;
        }

        if !self.transform.is_identity() {
            return false;
        }

        if self.opacity != 1.0 {
            return false;
        }

        if self.blend_mode() != BlendMode::default() {
            return false;
        }

        if self.blur.is_some() || self.background_blur.is_some() {
            return false;
        }

        if !self.shadows.is_empty() {
            return false;
        }

        if let Type::Group(group) = &self.shape_type {
            if group.masked {
                return false;
            }
        }

        if self.hidden {
            return false;
        }

        // If the container itself has fills/strokes, it renders something visible
        // We cannot flatten containers that render their own background/border
        // because they need to be rendered even if they don't affect children
        if self.has_fills() || self.has_visible_strokes() {
            return false;
        }

        true
    }

    /// Checks if this shape needs a layer for rendering due to visual effects
    /// (opacity < 1.0, non-default blend mode, or frame clip layer blur)
    pub fn needs_layer(&self) -> bool {
        self.opacity() < 1.0
            || self.blend_mode().0 != skia::BlendMode::SrcOver
            || self.has_frame_clip_layer_blur()
            || (matches!(self.shape_type, Type::Group(g) if g.masked))
    }

    /// Checks if this frame has clip layer blur (affects children)
    /// A frame has clip layer blur if it clips content and has layer blur
    pub fn has_frame_clip_layer_blur(&self) -> bool {
        self.frame_clip_layer_blur().is_some()
    }

    /// Returns the frame clip layer blur if this frame has one
    /// A frame has clip layer blur if it clips content and has layer blur
    pub fn frame_clip_layer_blur(&self) -> Option<Blur> {
        use crate::shapes::BlurType;
        match self.shape_type {
            Type::Frame(_) if self.clip_content => self.blur.filter(|blur| {
                !blur.hidden && blur.blur_type == BlurType::LayerBlur && blur.value > 0.0
            }),
            _ => None,
        }
    }

    /// A group whose first child clips the rest of its content.
    pub fn is_masked_group(&self) -> bool {
        matches!(self.shape_type, Type::Group(Group { masked: true }))
    }

    pub fn masked_group_layer_blur(&self) -> Option<Blur> {
        use crate::shapes::BlurType;
        match self.shape_type {
            Type::Group(Group { masked: true }) => self.blur.filter(|blur| {
                !blur.hidden && blur.blur_type == BlurType::LayerBlur && blur.value > 0.0
            }),
            _ => None,
        }
    }

    /// Shadows of the given style that the masked-group layer filter must
    /// carry, bottom-most first, already converted to device space.
    ///
    /// Containers use the stricter `is_perceptible_at_scale_for` floor: a
    /// shadow too small to see is not worth a filter pass.
    fn masked_group_layer_shadows(
        &self,
        scale: f32,
        style: ShadowStyle,
    ) -> impl Iterator<Item = Shadow> + '_ {
        self.shadows
            .iter()
            .rev()
            .filter(move |shadow| {
                shadow.style() == style
                    && !shadow.hidden()
                    && shadow.is_perceptible_at_scale_for(scale, true)
            })
            .map(move |shadow| {
                let mut scaled = *shadow;
                scaled.scale_to_device(scale);
                scaled
            })
    }

    /// Image filter for the `save_layer` that wraps a masked group, i.e. for
    /// the result *after* the mask has been composited into it.
    ///
    /// Mirrors the filter chain the SVG renderer builds for a group
    /// (`app.common.geom.shapes.bounds/shape->filters`): drop shadows, then the
    /// source graphic, then inner shadows, with the layer blur over all of it.
    /// A drop shadow on a masked group is therefore derived from the real
    /// masked pixels instead of from the group's own (empty) geometry.
    ///
    /// The layer is opened on a canvas that still has an identity matrix, so
    /// every blur radius, spread and offset is pre-multiplied by `scale`.
    /// `skip_shadows` mirrors `should_skip_drop_shadows` and `skip_blur`
    /// mirrors fast mode.
    pub fn masked_group_layer_filter(
        &self,
        scale: f32,
        skip_shadows: bool,
        skip_blur: bool,
    ) -> Option<skia::ImageFilter> {
        if !self.is_masked_group() {
            return None;
        }

        // `merge` composites its inputs bottom-to-top and reads `None` as the
        // source graphic, which is exactly the SVG primitive order.
        let mut layers: Vec<Option<skia::ImageFilter>> = Vec::new();

        if !skip_shadows {
            for shadow in self.masked_group_layer_shadows(scale, ShadowStyle::Drop) {
                layers.push(shadow.get_drop_shadow_filter());
            }
        }

        layers.push(None);

        if !skip_shadows {
            for shadow in self.masked_group_layer_shadows(scale, ShadowStyle::Inner) {
                layers.push(shadow.get_inner_shadow_filter());
            }
        }

        let mut filter = if layers.len() > 1 {
            skia::image_filters::merge(layers, None)
        } else {
            None
        };

        if !skip_blur {
            if let Some(blur) = self.masked_group_layer_blur() {
                // Scale the sigma, not the radius — see `Shadow::scale_to_device`.
                let sigma = radius_to_sigma(blur.value) * scale;
                // Keep the shadows if the blur filter cannot be built.
                if let Some(blurred) =
                    skia::image_filters::blur((sigma, sigma), None, filter.clone(), None)
                {
                    filter = Some(blurred);
                }
            }
        }

        filter
    }

    /// Checks if this shape has visual effects that might extend its bounds beyond selrect
    /// Shapes with these effects require expensive extrect calculation for accurate visibility checks
    pub fn has_effects_that_extend_bounds(&self) -> bool {
        !self.shadows.is_empty()
            || self.blur.is_some()
            || !self.strokes.is_empty()
            || !self.transform.is_identity()
            || !math::is_close_to(self.rotation, 0.0)
            || matches!(self.shape_type, Type::Group(_) | Type::Frame(_))
            || matches!(self.shape_type, Type::Text(_))
    }

    pub fn count_visible_inner_strokes(&self) -> usize {
        self.visible_strokes()
            .filter(|s| s.kind == StrokeKind::Inner)
            .count()
    }

    /// True when the shape has at least one visible inner stroke (open paths render strokes as center).
    pub fn has_inner_stroke(&self) -> bool {
        let is_open = self.is_open();
        self.visible_strokes()
            .any(|s| s.render_kind(is_open) == StrokeKind::Inner)
    }

    /// When true, the frame drop shadow can use the direct geometry path
    /// (`render_direct_frame_drop_shadow`) instead of filter surfaces and
    /// descendant silhouettes.
    ///
    /// Requires at least one fill; fill opacity/type does not matter because the fast
    /// path shadows the frame geometry as a solid mask.
    ///
    /// The fast path draws fill geometry only. On the slow path, visible strokes also
    /// contribute to the shadow silhouette, so frames with outer/center strokes can
    /// look slightly narrower here. We keep them eligible anyway for performance.
    pub fn uses_direct_container_drop_shadow(&self, tree: ShapesPoolRef) -> bool {
        if !matches!(self.shape_type, Type::Frame(_)) {
            return false;
        }
        if !self.has_fills() {
            return false;
        }
        if self.blend_mode() != BlendMode::default() {
            return false;
        }
        if self.blur.is_some() || self.background_blur.is_some() {
            return false;
        }
        if self.has_frame_clip_layer_blur() {
            return false;
        }

        if self.clip_content {
            return !self.descendants_have_drop_shadows(tree);
        }

        self.descendants_contained_for_frame_shadow(tree, self.selrect())
    }

    /// When true, the container's own fill shadow mask is enough and descendant
    /// silhouettes can be skipped (same geometry assumption as the direct path).
    pub fn container_fill_covers_shadow_descendants(&self, tree: ShapesPoolRef) -> bool {
        self.has_fills() && self.descendants_contained_for_frame_shadow(tree, self.selrect())
    }

    fn descendants_have_drop_shadows(&self, tree: ShapesPoolRef) -> bool {
        for child_id in self.children_ids_iter(false) {
            let Some(child) = tree.get(child_id) else {
                continue;
            };
            if child.hidden {
                continue;
            }
            if child.drop_shadows_visible().next().is_some() {
                return true;
            }
            if child.is_recursive() && child.descendants_have_drop_shadows(tree) {
                return true;
            }
        }
        false
    }

    fn descendants_contained_for_frame_shadow(
        &self,
        tree: ShapesPoolRef,
        bounds: math::Rect,
    ) -> bool {
        const MARGIN: f32 = 0.5;
        for child_id in self.children_ids_iter(false) {
            let Some(child) = tree.get(child_id) else {
                continue;
            };
            if child.hidden {
                continue;
            }
            if !rect_contains_with_margin(bounds, child.silhouette_rect(), MARGIN) {
                return false;
            }
            if child.is_recursive() && !child.descendants_contained_for_frame_shadow(tree, bounds) {
                return false;
            }
        }
        true
    }

    pub fn drop_shadow_paints(&self) -> Vec<skia_safe::Paint> {
        let drop_shadows: Vec<&Shadow> = self.drop_shadows_visible().collect();

        drop_shadows
            .into_iter()
            .map(|shadow| {
                let mut paint = skia_safe::Paint::default();
                let filter = shadow.get_drop_shadow_filter();
                paint.set_image_filter(filter);
                paint
            })
            .collect()
    }

    pub fn inner_shadow_paints(&self) -> Vec<skia_safe::Paint> {
        let inner_shadows: Vec<&Shadow> = self.inner_shadows_visible().collect();

        inner_shadows
            .into_iter()
            .map(|shadow| {
                let mut paint = skia_safe::Paint::default();
                let filter = shadow.get_inner_shadow_filter();
                paint.set_image_filter(filter);
                paint
            })
            .collect()
    }
}

#[inline]
fn rect_contains_with_margin(outer: math::Rect, inner: math::Rect, margin: f32) -> bool {
    inner.left >= outer.left - margin
        && inner.top >= outer.top - margin
        && inner.right <= outer.right + margin
        && inner.bottom <= outer.bottom + margin
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::state::ShapesPool;

    fn any_shape() -> Shape {
        Shape::new(Uuid::nil())
    }

    #[test]
    fn add_fill_pushes_a_new_fill() {
        let mut shape = any_shape();
        assert_eq!(shape.fills.len(), 0);

        shape.add_fill(Fill::Solid(SolidColor(Color::TRANSPARENT)));
        assert_eq!(
            shape.fills.first(),
            Some(&Fill::Solid(SolidColor(Color::TRANSPARENT)))
        )
    }

    #[test]
    fn layer_blur_and_background_blur_can_coexist() {
        let mut shape = any_shape();

        let layer_blur = Blur::new(BlurType::LayerBlur, false, 4.0);
        let background_blur = Blur::new(BlurType::BackgroundBlur, false, 8.0);

        shape.set_blur(Some(layer_blur));
        shape.set_background_blur(Some(background_blur));

        assert_eq!(shape.blur, Some(layer_blur));
        assert_eq!(shape.background_blur, Some(background_blur));
        assert_eq!(shape.visible_background_blur(), Some(background_blur));

        // Clearing one type must not affect the other.
        shape.set_blur(None);
        assert_eq!(shape.blur, None);
        assert_eq!(shape.background_blur, Some(background_blur));

        shape.set_blur(Some(layer_blur));
        shape.set_background_blur(None);
        assert_eq!(shape.blur, Some(layer_blur));
        assert_eq!(shape.background_blur, None);
    }

    #[test]
    fn hidden_background_blur_is_not_visible() {
        let mut shape = any_shape();
        shape.set_background_blur(Some(Blur::new(BlurType::BackgroundBlur, true, 8.0)));
        assert_eq!(shape.visible_background_blur(), None);
    }

    /// Cases mirrored from Penpot MCP board `layer-blur-cases` (file "blur"):
    /// leaf-visible-blur, leaf-hidden-blur, leaf-zero-blur, leaf-background-blur,
    /// group-with-blur.
    #[test]
    fn visible_layer_blur_requires_non_hidden_positive_layer_blur() {
        let mut shape = any_shape();

        // leaf-visible-blur / group-with-blur
        let visible = Blur::new(BlurType::LayerBlur, false, 10.0);
        shape.set_blur(Some(visible));
        assert_eq!(shape.visible_layer_blur(), Some(visible));

        let group_blur = Blur::new(BlurType::LayerBlur, false, 6.0);
        shape.set_blur(Some(group_blur));
        assert_eq!(shape.visible_layer_blur(), Some(group_blur));

        // leaf-hidden-blur
        shape.set_blur(Some(Blur::new(BlurType::LayerBlur, true, 10.0)));
        assert_eq!(shape.visible_layer_blur(), None);

        // leaf-zero-blur
        shape.set_blur(Some(Blur::new(BlurType::LayerBlur, false, 0.0)));
        assert_eq!(shape.visible_layer_blur(), None);

        // no blur
        shape.set_blur(None);
        assert_eq!(shape.visible_layer_blur(), None);
    }

    #[test]
    fn visible_layer_blur_ignores_background_blur() {
        let mut shape = any_shape();
        // leaf-background-blur: Plugin API uses `backgroundBlur`, not `blur`.
        shape.set_background_blur(Some(Blur::new(BlurType::BackgroundBlur, false, 8.0)));
        assert_eq!(shape.visible_layer_blur(), None);
        assert_eq!(
            shape.visible_background_blur(),
            Some(Blur::new(BlurType::BackgroundBlur, false, 8.0))
        );

        let layer = Blur::new(BlurType::LayerBlur, false, 4.0);
        shape.set_blur(Some(layer));
        assert_eq!(shape.visible_layer_blur(), Some(layer));
    }

    #[test]
    fn test_set_corners() {
        let mut shape = any_shape();
        shape.set_corners((10.0, 20.0, 30.0, 40.0));
        if let Type::Rect(Rect { corners, .. }) = shape.shape_type {
            assert_eq!(
                corners,
                Some([
                    Point { x: 10.0, y: 10.0 },
                    Point { x: 20.0, y: 20.0 },
                    Point { x: 30.0, y: 30.0 },
                    Point { x: 40.0, y: 40.0 }
                ])
            );
        } else {
            unreachable!();
        }

        shape.set_corners((0.0, 0.0, 0.0, 0.0));
        if let Type::Rect(Rect { corners, .. }) = shape.shape_type {
            assert_eq!(corners, None);
        } else {
            unreachable!();
        }
    }

    #[test]
    fn test_set_masked() {
        let mut shape = any_shape();
        shape.set_shape_type(Type::Group(Group { masked: false }));
        shape.set_masked(true);

        if let Type::Group(Group { masked, .. }) = shape.shape_type {
            assert!(masked);
        } else {
            unreachable!()
        }
    }

    fn masked_group_with(shadows: Vec<Shadow>, blur: Option<Blur>) -> Shape {
        let mut shape = any_shape();
        shape.set_shape_type(Type::Group(Group { masked: true }));
        shape.set_selrect(0.0, 0.0, 100.0, 100.0);
        for shadow in shadows {
            shape.add_shadow(shadow);
        }
        shape.set_blur(blur);
        shape
    }

    fn drop_shadow(blur: f32, spread: f32, offset: (f32, f32)) -> Shadow {
        Shadow::new(
            skia::Color::BLACK,
            blur,
            spread,
            offset,
            ShadowStyle::Drop,
            false,
        )
    }

    fn inner_shadow(blur: f32, offset: (f32, f32)) -> Shadow {
        Shadow::new(
            skia::Color::BLACK,
            blur,
            0.0,
            offset,
            ShadowStyle::Inner,
            false,
        )
    }

    fn hidden_drop_shadow(blur: f32, offset: (f32, f32)) -> Shadow {
        Shadow::new(
            skia::Color::BLACK,
            blur,
            0.0,
            offset,
            ShadowStyle::Drop,
            true,
        )
    }

    fn unit_rect() -> math::Rect {
        math::Rect::from_ltrb(0.0, 0.0, 100.0, 100.0)
    }

    #[test]
    fn masked_group_layer_filter_is_none_without_effects() {
        let shape = masked_group_with(vec![], None);
        assert!(shape.masked_group_layer_filter(1.0, false, false).is_none());
    }

    #[test]
    fn masked_group_layer_filter_ignores_unmasked_groups() {
        let mut shape = masked_group_with(vec![drop_shadow(4.0, 0.0, (10.0, 0.0))], None);
        shape.set_shape_type(Type::Group(Group { masked: false }));

        assert!(shape.masked_group_layer_filter(1.0, false, false).is_none());
    }

    #[test]
    fn masked_group_layer_filter_ignores_hidden_shadows() {
        let shape = masked_group_with(vec![hidden_drop_shadow(4.0, (10.0, 0.0))], None);
        assert!(shape.masked_group_layer_filter(1.0, false, false).is_none());
    }

    #[test]
    fn masked_group_layer_filter_extends_bounds_towards_the_drop_shadow() {
        let shape = masked_group_with(vec![drop_shadow(4.0, 0.0, (20.0, 10.0))], None);

        let filter = shape
            .masked_group_layer_filter(1.0, false, false)
            .expect("drop shadow should produce a filter");
        let bounds = filter.compute_fast_bounds(unit_rect());

        assert!(bounds.right > unit_rect().right + 20.0);
        assert!(bounds.bottom > unit_rect().bottom + 10.0);
        // The source graphic is kept, so the rect never shrinks.
        assert!(bounds.left <= unit_rect().left);
        assert!(bounds.top <= unit_rect().top);
    }

    #[test]
    fn masked_group_layer_filter_includes_inner_shadows() {
        let shape = masked_group_with(vec![inner_shadow(4.0, (20.0, 10.0))], None);

        assert!(shape.masked_group_layer_filter(1.0, false, false).is_some());

        // Inner shadows are shadows too: `skip_shadows` drops them.
        assert!(shape.masked_group_layer_filter(1.0, true, false).is_none());
    }

    #[test]
    fn masked_group_layer_filter_scales_shadows_to_device_space() {
        // No blur, so the reach is the offset alone and doubling the scale
        // must double it exactly.
        let shape = masked_group_with(vec![drop_shadow(0.0, 0.0, (20.0, 0.0))], None);

        let at_1x = shape
            .masked_group_layer_filter(1.0, false, false)
            .expect("filter at 1x")
            .compute_fast_bounds(unit_rect());
        let at_2x = shape
            .masked_group_layer_filter(2.0, false, false)
            .expect("filter at 2x")
            .compute_fast_bounds(unit_rect());

        let reach_1x = at_1x.right - unit_rect().right;
        let reach_2x = at_2x.right - unit_rect().right;

        assert!((reach_1x - 20.0).abs() < 0.001);
        assert!((reach_2x - 40.0).abs() < 0.001);
    }

    #[test]
    fn masked_group_layer_filter_honours_skip_flags() {
        let shape = masked_group_with(
            vec![drop_shadow(4.0, 0.0, (20.0, 0.0))],
            Some(Blur::new(BlurType::LayerBlur, false, 8.0)),
        );

        let without_shadows = shape
            .masked_group_layer_filter(1.0, true, false)
            .expect("blur still produces a filter");
        let bounds = without_shadows.compute_fast_bounds(unit_rect());
        // Blur grows the rect symmetrically; the shadow offset would not.
        assert!(
            (bounds.right - unit_rect().right - (bounds.left - unit_rect().left).abs()).abs()
                < 0.001
        );

        assert!(shape.masked_group_layer_filter(1.0, false, true).is_some());
        assert!(shape.masked_group_layer_filter(1.0, true, true).is_none());
    }

    #[test]
    fn masked_group_layer_filter_preserves_blur_only_behaviour() {
        let shape = masked_group_with(vec![], Some(Blur::new(BlurType::LayerBlur, false, 8.0)));

        let filter = shape
            .masked_group_layer_filter(1.0, false, false)
            .expect("layer blur should produce a filter");
        let bounds = filter.compute_fast_bounds(unit_rect());

        let sigma = radius_to_sigma(8.0);
        let expected = skia::image_filters::blur((sigma, sigma), None, None, None)
            .expect("reference blur")
            .compute_fast_bounds(unit_rect());

        assert!((bounds.left - expected.left).abs() < 0.001);
        assert!((bounds.right - expected.right).abs() < 0.001);
    }

    #[test]
    fn masked_group_layer_filter_drops_imperceptible_shadows() {
        // A container shadow needs a 4 device px footprint to be worth drawing.
        let shape = masked_group_with(vec![drop_shadow(8.0, 0.0, (0.0, 0.0))], None);

        assert!(shape.masked_group_layer_filter(1.0, false, false).is_some());
        assert!(shape.masked_group_layer_filter(0.1, false, false).is_none());
    }

    #[test]
    fn masked_group_splits_its_mask_from_its_content() {
        // The masked-group shadow silhouette relies on this split: the mask is
        // the first child, and iterating the children yields only the content.
        let mut group = any_shape();
        group.set_shape_type(Type::Group(Group { masked: true }));

        let mask_id = Uuid::new_v4();
        let content_a = Uuid::new_v4();
        let content_b = Uuid::new_v4();
        group.children = vec![mask_id, content_a, content_b];

        assert_eq!(group.mask_id(), Some(&mask_id));

        let content: Vec<Uuid> = group.children_ids_iter(false).copied().collect();
        assert_eq!(content.len(), 2);
        assert!(content.contains(&content_a));
        assert!(content.contains(&content_b));
        assert!(!content.contains(&mask_id));
    }

    #[test]
    fn masked_group_extrect_grows_with_a_drop_shadow() {
        let mut pool = ShapesPool::new();
        pool.initialize(3);

        let group_id = Uuid::new_v4();
        let mask_id = Uuid::new_v4();
        let content_id = Uuid::new_v4();

        {
            let group = pool.add_shape(group_id);
            group.set_shape_type(Type::Group(Group { masked: true }));
            group.set_selrect(0.0, 0.0, 50.0, 50.0);
            group.children = vec![mask_id, content_id];
            group.add_shadow(drop_shadow(4.0, 0.0, (20.0, 20.0)));
        }

        {
            let mask = pool.add_shape(mask_id);
            mask.set_shape_type(Type::Rect(Rect::default()));
            mask.set_selrect(0.0, 0.0, 50.0, 50.0);
            mask.set_parent(group_id);
        }

        {
            let content = pool.add_shape(content_id);
            content.set_shape_type(Type::Rect(Rect::default()));
            content.set_selrect(0.0, 0.0, 50.0, 50.0);
            content.set_parent(group_id);
        }

        let group = pool.get(&group_id).expect("group should exist");
        let extrect = group.calculate_extrect(&pool, 1.0);

        assert!(extrect.right > 50.0 + 20.0);
        assert!(extrect.bottom > 50.0 + 20.0);
    }

    #[test]
    fn test_apply_transform() {
        let mut shape = Shape::new(Uuid::new_v4());
        shape.set_shape_type(Type::Rect(Rect::default()));
        shape.set_selrect(0.0, 10.0, 10.0, 0.0);
        shape.apply_transform(&Matrix::scale((2.0, 2.0)));

        assert_eq!(shape.selrect().width(), 20.0);
        assert_eq!(shape.selrect().height(), 20.0);
    }

    #[test]
    fn masked_group_extrect_matches_mask_intersection() {
        let mut pool = ShapesPool::new();
        pool.initialize(3);

        let group_id = Uuid::new_v4();
        let mask_id = Uuid::new_v4();
        let content_id = Uuid::new_v4();

        {
            let group = pool.add_shape(group_id);
            group.set_shape_type(Type::Group(Group { masked: true }));
            group.children = vec![mask_id, content_id];
        }

        {
            let mask = pool.add_shape(mask_id);
            mask.set_shape_type(Type::Rect(Rect::default()));
            mask.set_selrect(0.0, 0.0, 50.0, 50.0);
            mask.set_parent(group_id);
        }

        {
            let content = pool.add_shape(content_id);
            content.set_shape_type(Type::Rect(Rect::default()));
            content.set_selrect(-10.0, -10.0, 110.0, 110.0);
            content.set_parent(group_id);
        }

        let group = pool.get(&group_id).expect("group should exist");
        let extrect = group.calculate_extrect(&pool, 1.0);

        assert_eq!(extrect.left, 0.0);
        assert_eq!(extrect.top, 0.0);
        assert_eq!(extrect.right, 50.0);
        assert_eq!(extrect.bottom, 50.0);
    }

    fn frame_with_fill_and_child(fill: Fill, opacity: f32) -> (ShapesPool, Uuid) {
        let mut pool = ShapesPool::new();
        pool.initialize(2);

        let frame_id = Uuid::new_v4();
        let child_id = Uuid::new_v4();

        {
            let frame = pool.add_shape(frame_id);
            frame.set_shape_type(Type::Frame(Frame::default()));
            frame.set_selrect(0.0, 0.0, 200.0, 100.0);
            frame.add_fill(fill);
            frame.opacity = opacity;
            frame.children = vec![child_id];
        }

        {
            let child = pool.add_shape(child_id);
            child.set_shape_type(Type::Rect(Rect::default()));
            child.set_selrect(10.0, 10.0, 180.0, 80.0);
            child.set_parent(frame_id);
        }

        (pool, frame_id)
    }

    #[test]
    fn frame_with_any_fill_uses_direct_container_drop_shadow() {
        for (fill, opacity) in [
            (Fill::Solid(SolidColor(skia::Color::WHITE)), 1.0),
            (
                Fill::Solid(SolidColor(skia::Color::from_argb(128, 255, 255, 255))),
                0.5,
            ),
        ] {
            let (pool, frame_id) = frame_with_fill_and_child(fill, opacity);
            let frame = pool.get(&frame_id).expect("frame");
            assert!(frame.uses_direct_container_drop_shadow(&pool));
        }
    }

    #[test]
    fn clipped_frame_with_child_drop_shadow_rejects_direct_path() {
        let (mut pool, frame_id) =
            frame_with_fill_and_child(Fill::Solid(SolidColor(skia::Color::WHITE)), 1.0);
        let child_id = pool.get(&frame_id).expect("frame").children[0];

        {
            let child = pool.get_mut(&child_id).expect("child");
            child.add_shadow(Shadow::new(
                skia::Color::BLACK,
                4.0,
                0.0,
                (0.0, 4.0),
                ShadowStyle::Drop,
                false,
            ));
        }

        let frame = pool.get(&frame_id).expect("frame");
        assert!(!frame.uses_direct_container_drop_shadow(&pool));
    }

    #[test]
    fn clipped_frame_ignores_outside_child_extrect_for_direct_path() {
        let mut pool = ShapesPool::new();
        pool.initialize(2);

        let frame_id = Uuid::new_v4();
        let child_id = Uuid::new_v4();

        {
            let frame = pool.add_shape(frame_id);
            frame.set_shape_type(Type::Frame(Frame::default()));
            frame.set_selrect(0.0, 0.0, 200.0, 100.0);
            frame.add_fill(Fill::Solid(SolidColor(skia::Color::WHITE)));
            frame.set_clip(true);
            frame.children = vec![child_id];
        }

        {
            let child = pool.add_shape(child_id);
            child.set_shape_type(Type::Rect(Rect::default()));
            child.set_selrect(-50.0, -50.0, 250.0, 150.0);
            child.set_parent(frame_id);
        }

        let frame = pool.get(&frame_id).expect("frame");
        assert!(frame.uses_direct_container_drop_shadow(&pool));
    }

    #[test]
    fn overflow_frame_with_outside_child_rejects_direct_path() {
        let mut pool = ShapesPool::new();
        pool.initialize(2);

        let frame_id = Uuid::new_v4();
        let child_id = Uuid::new_v4();

        {
            let frame = pool.add_shape(frame_id);
            frame.set_shape_type(Type::Frame(Frame::default()));
            frame.set_selrect(0.0, 0.0, 200.0, 100.0);
            frame.add_fill(Fill::Solid(SolidColor(skia::Color::WHITE)));
            frame.set_clip(false);
            frame.children = vec![child_id];
        }

        {
            let child = pool.add_shape(child_id);
            child.set_shape_type(Type::Rect(Rect::default()));
            child.set_selrect(-50.0, -50.0, 250.0, 150.0);
            child.set_parent(frame_id);
        }

        let frame = pool.get(&frame_id).expect("frame");
        assert!(!frame.uses_direct_container_drop_shadow(&pool));
        assert!(!frame.container_fill_covers_shadow_descendants(&pool));
    }

    #[test]
    fn frame_with_contained_child_covers_shadow_descendants() {
        let (pool, frame_id) =
            frame_with_fill_and_child(Fill::Solid(SolidColor(skia::Color::WHITE)), 1.0);
        let frame = pool.get(&frame_id).expect("frame");
        assert!(frame.container_fill_covers_shadow_descendants(&pool));
    }

    #[test]
    fn unclipped_frame_with_contained_shadowed_child_covers_descendants() {
        let (mut pool, frame_id) =
            frame_with_fill_and_child(Fill::Solid(SolidColor(skia::Color::WHITE)), 1.0);
        let child_id = pool.get(&frame_id).expect("frame").children[0];
        pool.get_mut(&frame_id).expect("frame").set_clip(false);

        {
            let child = pool.get_mut(&child_id).expect("child");
            // Shadow reaches past the frame; the geometry stays inside.
            child.add_shadow(Shadow::new(
                skia::Color::BLACK,
                20.0,
                0.0,
                (0.0, 20.0),
                ShadowStyle::Drop,
                false,
            ));
        }

        let frame = pool.get(&frame_id).expect("frame");
        assert!(frame.container_fill_covers_shadow_descendants(&pool));
        assert!(frame.uses_direct_container_drop_shadow(&pool));
    }

    #[test]
    fn rotated_frame_with_contained_child_uses_direct_container_drop_shadow() {
        let (mut pool, frame_id) =
            frame_with_fill_and_child(Fill::Solid(SolidColor(skia::Color::WHITE)), 1.0);

        {
            let frame = pool.get_mut(&frame_id).expect("frame");
            // 45° rotation around the shape center (100, 50).
            let angle = std::f32::consts::FRAC_PI_4;
            frame.set_transform(
                angle.cos(),
                angle.sin(),
                -angle.sin(),
                angle.cos(),
                0.0,
                0.0,
            );
        }

        let frame = pool.get(&frame_id).expect("frame");
        assert!(frame.uses_direct_container_drop_shadow(&pool));
    }
}