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//! Path building utilities.
//!
//! ## `PathBuilder` or `SvgPathBuilder`
//!
//! Path can be built via either of two abstractions:
//!
//! - [PathBuilder](trait.PathBuilder.html) is a simple and efficient interface which
//! does not deal with any ambiguous cases.
//! - [SvgPathBuilder](trait.SvgPathBuilder.html) is a higher-level interface that
//! follows SVG's specification, removing the the burden of dealing with special cases
//! from the user at a run-time cost.
//!
//! `SvgPathBuilder` may be a better choice when interactive with SVG, or dealing with arbitrary
//! input. `PathBuilder`. `PathBuilder` is probably a more useful trait to implement when creating
//! a new path data structure since all `PathBuilder` implementations automatically get an
//! `SvgPathBuilder` adapter (see the `with_svg` method). It may also make sense to use the
//! `PathBuilder` API when following a specification that behaves like SVG paths or when no
//! performance can be traded for convenience.
//!
//! ## Examples
//!
//! The following example shows how to create a simple path using the
//! [PathBuilder](trait.PathBuilder.html) interface.
//!
//! ```
//! use lyon_path::{Path, geom::point};
//!
//! let mut builder = Path::builder();
//!
//! // All sub-paths *must* have be contained in a being/end pair.
//! builder.begin(point(0.0, 0.0));
//! builder.line_to(point(1.0, 0.0));
//! builder.quadratic_bezier_to(point(2.0, 0.0), point(2.0, 1.0));
//! builder.end(false);
//!
//! builder.begin(point(10.0, 0.0));
//! builder.cubic_bezier_to(point(12.0, 2.0), point(11.0, 2.0), point(5.0, 0.0));
//! builder.close(); // close() is equivalent to end(true).
//!
//! let path = builder.build();
//! ```
//!
//! The same path can be built using the `SvgPathBuilder` API:
//!
//! ```
//! use lyon_path::{Path, geom::{point, vector}, builder::SvgPathBuilder};
//!
//! // Use the SVG adapter.
//! let mut builder = Path::builder().with_svg();
//!
//! // All sub-paths *must* have be contained in a being/end pair.
//! builder.move_to(point(0.0, 0.0));
//! builder.line_to(point(1.0, 0.0));
//! builder.quadratic_bezier_to(point(2.0, 0.0), point(2.0, 1.0));
//! // No need to explicitly end a sub-path.
//!
//! builder.move_to(point(10.0, 0.0));
//! builder.relative_cubic_bezier_to(vector(2.0, 2.0), vector(1.0, 2.0), vector(-5.0, 0.0));
//! builder.close();
//!
//! let path = builder.build();
//! ```
//!
//! Implementors of the `PathBuilder` trait automatically gain access to a few other adapters.
//! For example a builder that approximates curves with a sequence of line segments:
//!
//! ```
//! use lyon_path::{Path, traits::PathBuilder, geom::point};
//!
//! let tolerance = 0.05;// maximum distance between a curve and its approximation.
//! let mut builder = Path::builder().flattened(tolerance);
//!
//! builder.begin(point(0.0, 0.0));
//! builder.quadratic_bezier_to(point(1.0, 0.0), point(1.0, 1.0));
//! builder.end(true);
//!
//! // The resulting path contains only Begin, Line and End events.
//! let path = builder.build();
//! ```
//!
use crate::events::PathEvent;
use crate::geom::{traits::Transformation, Arc, ArcFlags, LineSegment, SvgArc};
use crate::math::*;
use crate::path::Verb;
use crate::polygon::Polygon;
use crate::{EndpointId, Winding};
use std::iter::IntoIterator;
use std::marker::Sized;
/// The radius of each corner of a rounded rectangle.
#[derive(Copy, Clone, PartialEq, PartialOrd, Debug, Default)]
pub struct BorderRadii {
pub top_left: f32,
pub top_right: f32,
pub bottom_left: f32,
pub bottom_right: f32,
}
impl BorderRadii {
pub fn new(radius: f32) -> Self {
let r = radius.abs();
BorderRadii {
top_left: r,
top_right: r,
bottom_left: r,
bottom_right: r,
}
}
}
impl std::fmt::Display for BorderRadii {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
// In the order of a well known convention (CSS) clockwise from top left
write!(
f,
"BorderRadii({}, {}, {}, {})",
self.top_left, self.top_right, self.bottom_left, self.bottom_right
)
}
}
/// The base path building interface.
///
/// Unlike `SvgPathBuilder`, this interface strictly requires sub-paths to be manually
/// started and ended (See the `begin` and `end` methods).
/// All positions are provided in absolute coordinates.
///
/// The goal of this interface is to abstract over simple and fast implementations that
/// do not deal with corner cases such as adding segments without starting a sub-path.
///
/// More elaborate interfaces are built on top of the provided primitives. In particular,
/// the `SvgPathBuilder` trait providing more permissive and richer interface is
/// automatically implemented via the `WithSvg` adapter (See the `with_svg` method).
pub trait PathBuilder {
/// Starts a new sub-path at a given position.
///
/// There must be no sub-path in progress when this method is called.
/// `at` becomes the current position of the sub-path.
fn begin(&mut self, at: Point) -> EndpointId;
/// Ends the current sub path.
///
/// A sub-path must be in progress when this method is called.
/// After this method is called, there is no sub-path in progress until
/// `begin` is called again.
fn end(&mut self, close: bool);
/// Closes the current sub path.
///
/// Shorthand for `builder.end(true)`.
fn close(&mut self) {
self.end(true)
}
/// Adds a line segment to the current sub-path.
///
/// A sub-path must be in progress when this method is called.
fn line_to(&mut self, to: Point) -> EndpointId;
/// Adds a quadratic bézier curve to the current sub-path.
///
/// A sub-path must be in progress when this method is called.
fn quadratic_bezier_to(&mut self, ctrl: Point, to: Point) -> EndpointId;
/// Adds a cubic bézier curve to the current sub-path.
///
/// A sub-path must be in progress when this method is called.
fn cubic_bezier_to(&mut self, ctrl1: Point, ctrl2: Point, to: Point) -> EndpointId;
/// Hints at the builder that a certain number of endpoints and control
/// points will be added.
///
/// The Builder implementation may use this information to pre-allocate
/// memory as an optimization.
fn reserve(&mut self, _endpoints: usize, _ctrl_points: usize) {}
/// Applies the provided path event.
///
/// By default this calls one of `begin`, `end`, `line`, `quadratic_bezier_segment`,
/// or `cubic_bezier_segment` according to the path event.
///
/// The requirements for each method apply to the corresponding event.
fn path_event(&mut self, event: PathEvent) {
match event {
PathEvent::Begin { at } => {
self.begin(at);
}
PathEvent::Line { to, .. } => {
self.line_to(to);
}
PathEvent::Quadratic { ctrl, to, .. } => {
self.quadratic_bezier_to(ctrl, to);
}
PathEvent::Cubic {
ctrl1, ctrl2, to, ..
} => {
self.cubic_bezier_to(ctrl1, ctrl2, to);
}
PathEvent::End { close, .. } => {
self.end(close);
}
}
}
/// Adds events from an iterator.
fn extend<Evts>(&mut self, events: Evts)
where
Evts: IntoIterator<Item = PathEvent>,
{
for evt in events.into_iter() {
self.path_event(evt)
}
}
/// Adds a sub-path from a polygon.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_polygon(&mut self, polygon: Polygon<Point>) {
if polygon.points.is_empty() {
return;
}
self.reserve(polygon.points.len(), 0);
self.begin(polygon.points[0]);
for p in &polygon.points[1..] {
self.line_to(*p);
}
self.end(polygon.closed);
}
/// Adds a sub-path containing a single point.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_point(&mut self, at: Point) -> EndpointId {
let id = self.begin(at);
self.end(false);
id
}
/// Adds a sub-path containing a single line segment.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_line_segment(&mut self, line: &LineSegment<f32>) -> (EndpointId, EndpointId) {
let a = self.begin(line.from);
let b = self.line_to(line.to);
self.end(false);
(a, b)
}
/// Adds a sub-path containing an ellipse.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_ellipse(&mut self, center: Point, radii: Vector, x_rotation: Angle, winding: Winding) {
let dir = match winding {
Winding::Positive => 1.0,
Winding::Negative => -1.0,
};
use std::f32::consts::PI;
let arc = Arc {
center,
radii,
x_rotation,
start_angle: Angle::radians(0.0),
sweep_angle: Angle::radians(2.0 * PI) * dir,
};
self.begin(arc.sample(0.0));
arc.for_each_quadratic_bezier(&mut |curve| {
self.quadratic_bezier_to(curve.ctrl, curve.to);
});
self.end(true);
}
/// Adds a sub-path containing a circle.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_circle(&mut self, center: Point, radius: f32, winding: Winding)
where
Self: Sized,
{
add_circle(self, center, radius, winding);
}
/// Adds a sub-path containing a rectangle.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_rectangle(&mut self, rect: &Rect, winding: Winding) {
match winding {
Winding::Positive => self.add_polygon(Polygon {
points: &[
rect.min(),
point(rect.max_x(), rect.min_y()),
rect.max(),
point(rect.min_x(), rect.max_y()),
],
closed: true,
}),
Winding::Negative => self.add_polygon(Polygon {
points: &[
rect.min(),
point(rect.min_x(), rect.max_y()),
rect.max(),
point(rect.max_x(), rect.min_y()),
],
closed: true,
}),
};
}
/// Adds a sub-path containing a rectangle.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_rounded_rectangle(&mut self, rect: &Rect, radii: &BorderRadii, winding: Winding)
where
Self: Sized,
{
add_rounded_rectangle(self, rect, radii, winding);
}
/// Returns a builder that approximates all curves with sequences of line segments.
fn flattened(self, tolerance: f32) -> Flattened<Self>
where
Self: Sized,
{
Flattened::new(self, tolerance)
}
/// Returns a builder that applies the given transformation to all positions.
fn transformed<Transform>(self, transform: Transform) -> Transformed<Self, Transform>
where
Self: Sized,
Transform: Transformation<f32>,
{
Transformed::new(self, transform)
}
/// Returns a builder that support SVG commands.
///
/// This must be called before starting to add any sub-path.
fn with_svg(self) -> WithSvg<Self>
where
Self: Sized,
{
WithSvg::new(self)
}
}
/// A path building interface that tries to stay close to SVG's path specification.
/// <https://svgwg.org/specs/paths/>
///
/// Some of the wording in the documentation of this trait is borrowed from the SVG
/// specification.
///
/// Unlike `PathBuilder`, implementations of this trait are expected to deal with
/// various corners cases such as adding segments without starting a sub-path.
pub trait SvgPathBuilder {
/// Start a new sub-path at the given position.
///
/// Corresponding SVG command: `M`.
///
/// This command establishes a new initial point and a new current point. The effect
/// is as if the "pen" were lifted and moved to a new location.
/// If a sub-path is in progress, it is ended without being closed.
fn move_to(&mut self, to: Point);
/// Ends the current sub-path by connecting it back to its initial point.
///
/// Corresponding SVG command: `Z`.
///
/// A straight line is drawn from the current point to the initial point of the
/// current sub-path.
/// The current position is set to the initial position of the sub-path that was
/// closed.
fn close(&mut self);
/// Adds a line segment to the current sub-path.
///
/// Corresponding SVG command: `L`.
///
/// The segment starts at the builder's current position.
/// If this is the very first command of the path (the builder therefore does not
/// have a current position), the `line_to` command is replaced with a `move_to(to)`.
fn line_to(&mut self, to: Point);
/// Adds a quadratic bézier segment to the current sub-path.
///
/// Corresponding SVG command: `Q`.
///
/// The segment starts at the builder's current position.
/// If this is the very first command of the path (the builder therefore does not
/// have a current position), the `quadratic_bezier_to` command is replaced with
/// a `move_to(to)`.
fn quadratic_bezier_to(&mut self, ctrl: Point, to: Point);
/// Adds a cubic bézier segment to the current sub-path.
///
/// Corresponding SVG command: `C`.
///
/// The segment starts at the builder's current position.
/// If this is the very first command of the path (the builder therefore does not
/// have a current position), the `cubic_bezier_to` command is replaced with
/// a `move_to(to)`.
fn cubic_bezier_to(&mut self, ctrl1: Point, ctrl2: Point, to: Point);
/// Equivalent to `move_to` in relative coordinates.
///
/// Corresponding SVG command: `m`.
///
/// The provided coordinates are offsets relative to the current position of
/// the builder.
fn relative_move_to(&mut self, to: Vector);
/// Equivalent to `line_to` in relative coordinates.
///
/// Corresponding SVG command: `l`.
///
/// The provided coordinates are offsets relative to the current position of
/// the builder.
fn relative_line_to(&mut self, to: Vector);
/// Equivalent to `quadratic_bezier_to` in relative coordinates.
///
/// Corresponding SVG command: `q`.
///
/// the provided coordinates are offsets relative to the current position of
/// the builder.
fn relative_quadratic_bezier_to(&mut self, ctrl: Vector, to: Vector);
/// Equivalent to `cubic_bezier_to` in relative coordinates.
///
/// The provided coordinates are offsets relative to the current position of
/// the builder.
fn relative_cubic_bezier_to(&mut self, ctrl1: Vector, ctrl2: Vector, to: Vector);
/// Equivalent to `cubic_bezier_to` with implicit first control point.
///
/// Corresponding SVG command: `S`.
///
/// The first control point is assumed to be the reflection of the second
/// control point on the previous command relative to the current point.
/// If there is no previous command or if the previous command was not a
/// cubic bézier segment, the first control point is coincident with
/// the current position.
fn smooth_cubic_bezier_to(&mut self, ctrl2: Point, to: Point);
/// Equivalent to `smooth_cubic_bezier_to` in relative coordinates.
///
/// Corresponding SVG command: `s`.
///
/// The provided coordinates are offsets relative to the current position of
/// the builder.
fn smooth_relative_cubic_bezier_to(&mut self, ctrl2: Vector, to: Vector);
/// Equivalent to `quadratic_bezier_to` with implicit control point.
///
/// Corresponding SVG command: `T`.
///
/// The control point is assumed to be the reflection of the control
/// point on the previous command relative to the current point.
/// If there is no previous command or if the previous command was not a
/// quadratic bézier segment, a line segment is added instead.
fn smooth_quadratic_bezier_to(&mut self, to: Point);
/// Equivalent to `smooth_quadratic_bezier_to` in relative coordinates.
///
/// Corresponding SVG command: `t`.
///
/// The provided coordinates are offsets relative to the current position of
/// the builder.
fn smooth_relative_quadratic_bezier_to(&mut self, to: Vector);
/// Adds an horizontal line segment.
///
/// Corresponding SVG command: `L`.
///
/// Equivalent to `line_to`, using the y coordinate of the current position.
fn horizontal_line_to(&mut self, x: f32);
/// Adds an horizontal line segment in relative coordinates.
///
/// Corresponding SVG command: `l`.
///
/// Equivalent to `line_to`, using the y coordinate of the current position.
/// `dx` is the horizontal offset relative to the current position.
fn relative_horizontal_line_to(&mut self, dx: f32);
/// Adds a vertical line segment.
///
/// Corresponding SVG command: `V`.
///
/// Equivalent to `line_to`, using the x coordinate of the current position.
fn vertical_line_to(&mut self, y: f32);
/// Adds a vertical line segment in relative coordinates.
///
/// Corresponding SVG command: `v`.
///
/// Equivalent to `line_to`, using the y coordinate of the current position.
/// `dy` is the horizontal offset relative to the current position.
fn relative_vertical_line_to(&mut self, dy: f32);
/// Adds an elliptical arc.
///
/// Corresponding SVG command: `A`.
///
/// The arc starts at the current point and ends at `to`.
/// The size and orientation of the ellipse are defined by `radii` and an `x_rotation`,
/// which indicates how the ellipse as a whole is rotated relative to the current coordinate
/// system. The center of the ellipse is calculated automatically to satisfy the constraints
/// imposed by the other parameters. the arc `flags` contribute to the automatic calculations
/// and help determine how the arc is built.
fn arc_to(&mut self, radii: Vector, x_rotation: Angle, flags: ArcFlags, to: Point);
/// Equivalent to `arc_to` in relative coordinates.
///
/// Corresponding SVG command: `a`.
///
/// The provided `to` coordinates are offsets relative to the current position of
/// the builder.
fn relative_arc_to(&mut self, radii: Vector, x_rotation: Angle, flags: ArcFlags, to: Vector);
/// Hints at the builder that a certain number of endpoints and control
/// points will be added.
///
/// The Builder implementation may use this information to pre-allocate
/// memory as an optimization.
fn reserve(&mut self, _endpoints: usize, _ctrl_points: usize) {}
/// Adds a sub-path from a polygon.
///
/// There must be no sub-path in progress when this method is called.
/// No sub-path is in progress after the method is called.
fn add_polygon(&mut self, polygon: Polygon<Point>) {
if polygon.points.is_empty() {
return;
}
self.reserve(polygon.points.len(), 0);
self.move_to(polygon.points[0]);
for p in &polygon.points[1..] {
self.line_to(*p);
}
if polygon.closed {
self.close();
}
}
}
/// Builds a path.
///
/// This trait is separate from `PathBuilder` and `SvgPathBuilder` to allow them to
/// be used as trait object (which isn't possible when a method returns an associated
/// type).
pub trait Build {
/// The type of object that is created by this builder.
type PathType;
/// Builds a path object and resets the builder so that it can be used again.
fn build(self) -> Self::PathType;
}
/// A Builder that approximates curves with successions of line segments.
pub struct Flattened<Builder> {
builder: Builder,
current_position: Point,
tolerance: f32,
}
impl<Builder: Build> Build for Flattened<Builder> {
type PathType = Builder::PathType;
fn build(self) -> Builder::PathType {
self.builder.build()
}
}
impl<Builder: PathBuilder> PathBuilder for Flattened<Builder> {
fn begin(&mut self, at: Point) -> EndpointId {
self.current_position = at;
self.builder.begin(at)
}
fn end(&mut self, close: bool) {
self.builder.end(close)
}
fn line_to(&mut self, to: Point) -> EndpointId {
let id = self.builder.line_to(to);
self.current_position = to;
id
}
fn quadratic_bezier_to(&mut self, ctrl: Point, to: Point) -> EndpointId {
let id = crate::private::flatten_quadratic_bezier(
self.tolerance,
self.current_position,
ctrl,
to,
self,
);
self.current_position = to;
id
}
fn cubic_bezier_to(&mut self, ctrl1: Point, ctrl2: Point, to: Point) -> EndpointId {
let id = crate::private::flatten_cubic_bezier(
self.tolerance,
self.current_position,
ctrl1,
ctrl2,
to,
self,
);
self.current_position = to;
id
}
fn reserve(&mut self, endpoints: usize, ctrl_points: usize) {
self.builder.reserve(endpoints + ctrl_points * 4, 0);
}
}
impl<Builder: PathBuilder> Flattened<Builder> {
pub fn new(builder: Builder, tolerance: f32) -> Flattened<Builder> {
Flattened {
builder,
current_position: point(0.0, 0.0),
tolerance,
}
}
pub fn build(self) -> Builder::PathType
where
Builder: Build,
{
self.builder.build()
}
pub fn set_tolerance(&mut self, tolerance: f32) {
self.tolerance = tolerance
}
}
/// Builds a path with a transformation applied.
pub struct Transformed<Builder, Transform> {
builder: Builder,
transform: Transform,
}
impl<Builder, Transform> Transformed<Builder, Transform> {
#[inline]
pub fn new(builder: Builder, transform: Transform) -> Self {
Transformed { builder, transform }
}
#[inline]
pub fn set_transform(&mut self, transform: Transform) {
self.transform = transform;
}
}
impl<Builder: Build, Transform> Build for Transformed<Builder, Transform> {
type PathType = Builder::PathType;
#[inline]
fn build(self) -> Builder::PathType {
self.builder.build()
}
}
impl<Builder, Transform> PathBuilder for Transformed<Builder, Transform>
where
Builder: PathBuilder,
Transform: Transformation<f32>,
{
#[inline]
fn begin(&mut self, at: Point) -> EndpointId {
self.builder.begin(self.transform.transform_point(at))
}
#[inline]
fn end(&mut self, close: bool) {
self.builder.end(close)
}
#[inline]
fn line_to(&mut self, to: Point) -> EndpointId {
self.builder.line_to(self.transform.transform_point(to))
}
#[inline]
fn quadratic_bezier_to(&mut self, ctrl: Point, to: Point) -> EndpointId {
self.builder.quadratic_bezier_to(
self.transform.transform_point(ctrl),
self.transform.transform_point(to),
)
}
#[inline]
fn cubic_bezier_to(&mut self, ctrl1: Point, ctrl2: Point, to: Point) -> EndpointId {
self.builder.cubic_bezier_to(
self.transform.transform_point(ctrl1),
self.transform.transform_point(ctrl2),
self.transform.transform_point(to),
)
}
#[inline]
fn reserve(&mut self, endpoints: usize, ctrl_points: usize) {
self.builder.reserve(endpoints, ctrl_points);
}
}
/// Implements an SVG-like building interface on top of a PathBuilder.
pub struct WithSvg<Builder: PathBuilder> {
builder: Builder,
first_position: Point,
current_position: Point,
last_ctrl: Point,
last_cmd: Verb,
need_moveto: bool,
is_empty: bool,
}
impl<Builder: PathBuilder> WithSvg<Builder> {
pub fn new(builder: Builder) -> Self {
WithSvg {
builder,
first_position: point(0.0, 0.0),
current_position: point(0.0, 0.0),
last_ctrl: point(0.0, 0.0),
need_moveto: true,
is_empty: true,
last_cmd: Verb::End,
}
}
pub fn build(mut self) -> Builder::PathType
where
Builder: Build,
{
self.end_if_needed();
self.builder.build()
}
pub fn flattened(self, tolerance: f32) -> WithSvg<Flattened<Builder>> {
WithSvg::new(Flattened::new(self.builder, tolerance))
}
pub fn transformed<Transform>(
self,
transform: Transform,
) -> WithSvg<Transformed<Builder, Transform>>
where
Transform: Transformation<f32>,
{
WithSvg::new(Transformed::new(self.builder, transform))
}
pub fn move_to(&mut self, to: Point) -> EndpointId {
self.end_if_needed();
let id = self.builder.begin(to);
self.is_empty = false;
self.need_moveto = false;
self.first_position = to;
self.current_position = to;
self.last_cmd = Verb::Begin;
id
}
pub fn line_to(&mut self, to: Point) -> EndpointId {
if let Some(id) = self.begin_if_needed(&to) {
return id;
}
self.current_position = to;
self.last_cmd = Verb::LineTo;
self.builder.line_to(to)
}
pub fn close(&mut self) {
if self.need_moveto {
return;
}
// Relative path ops tend to accumulate small floating point imprecisions
// which results in the last segment ending almost but not quite at the
// start of the sub-path, causing a new edge to be inserted which often
// intersects with the first or last edge. This can affect algorithms that
// Don't handle self-intersecting paths.
// Deal with this by snapping the last point if it is very close to the
// start of the sub path.
//
// TODO
// if let Some(p) = self.builder.points.last_mut() {
// let d = (*p - self.first_position).abs();
// if d.x + d.y < 0.0001 {
// *p = self.first_position;
// }
// }
self.current_position = self.first_position;
self.need_moveto = true;
self.last_cmd = Verb::Close;
self.builder.close();
}
pub fn quadratic_bezier_to(&mut self, ctrl: Point, to: Point) -> EndpointId {
if let Some(id) = self.begin_if_needed(&to) {
return id;
}
self.current_position = to;
self.last_cmd = Verb::QuadraticTo;
self.last_ctrl = ctrl;
self.builder.quadratic_bezier_to(ctrl, to)
}
pub fn cubic_bezier_to(&mut self, ctrl1: Point, ctrl2: Point, to: Point) -> EndpointId {
if let Some(id) = self.begin_if_needed(&to) {
return id;
}
self.current_position = to;
self.last_cmd = Verb::CubicTo;
self.last_ctrl = ctrl2;
self.builder.cubic_bezier_to(ctrl1, ctrl2, to)
}
pub fn arc(&mut self, center: Point, radii: Vector, sweep_angle: Angle, x_rotation: Angle) {
nan_check(center);
nan_check(radii.to_point());
debug_assert!(!sweep_angle.get().is_nan());
debug_assert!(!x_rotation.get().is_nan());
self.last_ctrl = self.current_position;
// If the center is equal to the current position, the start and end angles aren't
// defined, so we just skip the arc to avoid generating NaNs that will cause issues
// later.
use lyon_geom::euclid::approxeq::ApproxEq;
if self.current_position.approx_eq(¢er) {
return;
}
let start_angle = (self.current_position - center).angle_from_x_axis() - x_rotation;
let arc = Arc {
center,
radii,
start_angle,
sweep_angle,
x_rotation,
};
// If the current position is not on the arc, move or line to the beginning of the
// arc.
let arc_start = arc.from();
if self.need_moveto {
self.move_to(arc_start);
} else if (arc_start - self.current_position).square_length() < 0.01 {
self.builder.line_to(arc_start);
}
arc.for_each_quadratic_bezier(&mut |curve| {
self.builder.quadratic_bezier_to(curve.ctrl, curve.to);
self.current_position = curve.to;
});
}
/// Ensures the current sub-path has a moveto command.
///
/// Returns an ID if the command should be skipped and the ID returned instead.
#[inline(always)]
fn begin_if_needed(&mut self, default: &Point) -> Option<EndpointId> {
if self.need_moveto {
return self.insert_move_to(default);
}
None
}
#[inline(never)]
fn insert_move_to(&mut self, default: &Point) -> Option<EndpointId> {
if self.is_empty {
return Some(self.move_to(*default));
}
self.move_to(self.first_position);
None
}
fn end_if_needed(&mut self) {
if (self.last_cmd as u8) <= (Verb::Begin as u8) {
self.builder.end(false);
}
}
pub fn current_position(&self) -> Point {
self.current_position
}
pub fn reserve(&mut self, endpoints: usize, ctrl_points: usize) {
self.builder.reserve(endpoints, ctrl_points);
}
fn get_smooth_cubic_ctrl(&self) -> Point {
match self.last_cmd {
Verb::CubicTo => self.current_position + (self.current_position - self.last_ctrl),
_ => self.current_position,
}
}
fn get_smooth_quadratic_ctrl(&self) -> Point {
match self.last_cmd {
Verb::QuadraticTo => self.current_position + (self.current_position - self.last_ctrl),
_ => self.current_position,
}
}
fn relative_to_absolute(&self, v: Vector) -> Point {
self.current_position + v
}
}
impl<Builder, Transform> WithSvg<Transformed<Builder, Transform>>
where
Builder: PathBuilder,
Transform: Transformation<f32>,
{
#[inline]
pub fn set_transform(&mut self, transform: Transform) {
self.builder.set_transform(transform);
}
}
impl<Builder: PathBuilder + Build> Build for WithSvg<Builder> {
type PathType = Builder::PathType;
fn build(mut self) -> Builder::PathType {
self.end_if_needed();
self.builder.build()
}
}
impl<Builder: PathBuilder> SvgPathBuilder for WithSvg<Builder> {
fn move_to(&mut self, to: Point) {
self.move_to(to);
}
fn line_to(&mut self, to: Point) {
self.line_to(to);
}
fn quadratic_bezier_to(&mut self, ctrl: Point, to: Point) {
self.quadratic_bezier_to(ctrl, to);
}
fn cubic_bezier_to(&mut self, ctrl1: Point, ctrl2: Point, to: Point) {
self.cubic_bezier_to(ctrl1, ctrl2, to);
}
fn close(&mut self) {
self.close();
}
fn relative_move_to(&mut self, to: Vector) {
let to = self.relative_to_absolute(to);
self.move_to(to);
}
fn relative_line_to(&mut self, to: Vector) {
let to = self.relative_to_absolute(to);
self.line_to(to);
}
fn relative_quadratic_bezier_to(&mut self, ctrl: Vector, to: Vector) {
let ctrl = self.relative_to_absolute(ctrl);
let to = self.relative_to_absolute(to);
self.quadratic_bezier_to(ctrl, to);
}
fn relative_cubic_bezier_to(&mut self, ctrl1: Vector, ctrl2: Vector, to: Vector) {
let to = self.relative_to_absolute(to);
let ctrl1 = self.relative_to_absolute(ctrl1);
let ctrl2 = self.relative_to_absolute(ctrl2);
self.cubic_bezier_to(ctrl1, ctrl2, to);
}
fn smooth_cubic_bezier_to(&mut self, ctrl2: Point, to: Point) {
let ctrl1 = self.get_smooth_cubic_ctrl();
self.cubic_bezier_to(ctrl1, ctrl2, to);
}
fn smooth_relative_cubic_bezier_to(&mut self, ctrl2: Vector, to: Vector) {
let ctrl1 = self.get_smooth_cubic_ctrl();
let ctrl2 = self.relative_to_absolute(ctrl2);
let to = self.relative_to_absolute(to);
self.cubic_bezier_to(ctrl1, ctrl2, to);
}
fn smooth_quadratic_bezier_to(&mut self, to: Point) {
let ctrl = self.get_smooth_quadratic_ctrl();
self.quadratic_bezier_to(ctrl, to);
}
fn smooth_relative_quadratic_bezier_to(&mut self, to: Vector) {
let ctrl = self.get_smooth_quadratic_ctrl();
let to = self.relative_to_absolute(to);
self.quadratic_bezier_to(ctrl, to);
}
fn horizontal_line_to(&mut self, x: f32) {
let y = self.current_position.y;
self.line_to(point(x, y));
}
fn relative_horizontal_line_to(&mut self, dx: f32) {
let p = self.current_position;
self.line_to(point(p.x + dx, p.y));
}
fn vertical_line_to(&mut self, y: f32) {
let x = self.current_position.x;
self.line_to(point(x, y));
}
fn relative_vertical_line_to(&mut self, dy: f32) {
let p = self.current_position;
self.line_to(point(p.x, p.y + dy));
}
fn arc_to(&mut self, radii: Vector, x_rotation: Angle, flags: ArcFlags, to: Point) {
let svg_arc = SvgArc {
from: self.current_position,
to,
radii,
x_rotation,
flags: ArcFlags {
large_arc: flags.large_arc,
sweep: flags.sweep,
},
};
if svg_arc.is_straight_line() {
self.line_to(to);
} else {
let arc = svg_arc.to_arc();
self.arc(arc.center, arc.radii, arc.sweep_angle, arc.x_rotation);
}
}
fn relative_arc_to(&mut self, radii: Vector, x_rotation: Angle, flags: ArcFlags, to: Vector) {
let to = self.relative_to_absolute(to);
self.arc_to(radii, x_rotation, flags, to);
}
fn reserve(&mut self, endpoints: usize, ctrl_points: usize) {
self.builder.reserve(endpoints, ctrl_points);
}
}
/// Tessellate the stroke for an axis-aligned rounded rectangle.
fn add_circle<Builder: PathBuilder>(
builder: &mut Builder,
center: Point,
radius: f32,
winding: Winding,
) {
let radius = radius.abs();
let dir = match winding {
Winding::Positive => 1.0,
Winding::Negative => -1.0,
};
// https://spencermortensen.com/articles/bezier-circle/
const CONSTANT_FACTOR: f32 = 0.55191505;
let d = radius * CONSTANT_FACTOR;
builder.begin(center + vector(-radius, 0.0));
let ctrl_0 = center + vector(-radius, -d * dir);
let ctrl_1 = center + vector(-d, -radius * dir);
let mid = center + vector(0.0, -radius * dir);
builder.cubic_bezier_to(ctrl_0, ctrl_1, mid);
let ctrl_0 = center + vector(d, -radius * dir);
let ctrl_1 = center + vector(radius, -d * dir);
let mid = center + vector(radius, 0.0);
builder.cubic_bezier_to(ctrl_0, ctrl_1, mid);
let ctrl_0 = center + vector(radius, d * dir);
let ctrl_1 = center + vector(d, radius * dir);
let mid = center + vector(0.0, radius * dir);
builder.cubic_bezier_to(ctrl_0, ctrl_1, mid);
let ctrl_0 = center + vector(-d, radius * dir);
let ctrl_1 = center + vector(-radius, d * dir);
let mid = center + vector(-radius, 0.0);
builder.cubic_bezier_to(ctrl_0, ctrl_1, mid);
builder.close();
}
/// Tessellate the stroke for an axis-aligned rounded rectangle.
fn add_rounded_rectangle<Builder: PathBuilder>(
builder: &mut Builder,
rect: &Rect,
radii: &BorderRadii,
winding: Winding,
) {
let w = rect.size.width;
let h = rect.size.height;
let x_min = rect.min_x();
let y_min = rect.min_y();
let x_max = rect.max_x();
let y_max = rect.max_y();
let min_wh = w.min(h);
let mut tl = radii.top_left.abs().min(min_wh);
let mut tr = radii.top_right.abs().min(min_wh);
let mut bl = radii.bottom_left.abs().min(min_wh);
let mut br = radii.bottom_right.abs().min(min_wh);
// clamp border radii if they don't fit in the rectangle.
if tl + tr > w {
let x = (tl + tr - w) * 0.5;
tl -= x;
tr -= x;
}
if bl + br > w {
let x = (bl + br - w) * 0.5;
bl -= x;
br -= x;
}
if tr + br > h {
let x = (tr + br - h) * 0.5;
tr -= x;
br -= x;
}
if tl + bl > h {
let x = (tl + bl - h) * 0.5;
tl -= x;
bl -= x;
}
// https://spencermortensen.com/articles/bezier-circle/
const CONSTANT_FACTOR: f32 = 0.55191505;
let tl_d = tl * CONSTANT_FACTOR;
let tl_corner = point(x_min, y_min);
let tr_d = tr * CONSTANT_FACTOR;
let tr_corner = point(x_max, y_min);
let br_d = br * CONSTANT_FACTOR;
let br_corner = point(x_max, y_max);
let bl_d = bl * CONSTANT_FACTOR;
let bl_corner = point(x_min, y_max);
let points = [
point(x_min, y_min + tl), // begin
tl_corner + vector(0.0, tl - tl_d), // control
tl_corner + vector(tl - tl_d, 0.0), // control
tl_corner + vector(tl, 0.0), // end
point(x_max - tr, y_min),
tr_corner + vector(-tr + tr_d, 0.0),
tr_corner + vector(0.0, tr - tr_d),
tr_corner + vector(0.0, tr),
point(x_max, y_max - br),
br_corner + vector(0.0, -br + br_d),
br_corner + vector(-br + br_d, 0.0),
br_corner + vector(-br, 0.0),
point(x_min + bl, y_max),
bl_corner + vector(bl - bl_d, 0.0),
bl_corner + vector(0.0, -bl + bl_d),
bl_corner + vector(0.0, -bl),
];
if winding == Winding::Positive {
builder.begin(points[0]);
if tl > 0.0 {
builder.cubic_bezier_to(points[1], points[2], points[3]);
}
builder.line_to(points[4]);
if tl > 0.0 {
builder.cubic_bezier_to(points[5], points[6], points[7]);
}
builder.line_to(points[8]);
if br > 0.0 {
builder.cubic_bezier_to(points[9], points[10], points[11]);
}
builder.line_to(points[12]);
if bl > 0.0 {
builder.cubic_bezier_to(points[13], points[14], points[15]);
}
} else {
builder.begin(points[15]);
if bl > 0.0 {
builder.cubic_bezier_to(points[14], points[13], points[12]);
}
builder.line_to(points[11]);
if br > 0.0 {
builder.cubic_bezier_to(points[10], points[9], points[8]);
}
builder.line_to(points[7]);
if tl > 0.0 {
builder.cubic_bezier_to(points[6], points[5], points[4]);
}
builder.line_to(points[3]);
if tl > 0.0 {
builder.cubic_bezier_to(points[2], points[1], points[0]);
}
}
builder.end(true);
}
#[inline]
fn nan_check(p: Point) {
debug_assert!(p.x.is_finite());
debug_assert!(p.y.is_finite());
}
#[test]
fn svg_builder_line_to_after_close() {
use crate::Path;
use crate::PathEvent;
let mut p = Path::svg_builder();
p.line_to(point(1.0, 0.0));
p.close();
p.line_to(point(2.0, 0.0));
let path = p.build();
let mut it = path.iter();
assert_eq!(
it.next(),
Some(PathEvent::Begin {
at: point(1.0, 0.0)
})
);
assert_eq!(
it.next(),
Some(PathEvent::End {
last: point(1.0, 0.0),
first: point(1.0, 0.0),
close: true
})
);
assert_eq!(
it.next(),
Some(PathEvent::Begin {
at: point(1.0, 0.0)
})
);
assert_eq!(
it.next(),
Some(PathEvent::Line {
from: point(1.0, 0.0),
to: point(2.0, 0.0)
})
);
assert_eq!(
it.next(),
Some(PathEvent::End {
last: point(2.0, 0.0),
first: point(1.0, 0.0),
close: false
})
);
assert_eq!(it.next(), None);
}
#[test]
fn svg_builder_relative_curves() {
use crate::Path;
use crate::PathEvent;
let mut p = Path::svg_builder();
p.move_to(point(0.0, 0.0));
p.relative_quadratic_bezier_to(vector(0., 100.), vector(-100., 100.));
p.relative_line_to(vector(-50., 0.));
let path = p.build();
let mut it = path.iter();
assert_eq!(
it.next(),
Some(PathEvent::Begin {
at: point(0.0, 0.0)
})
);
assert_eq!(
it.next(),
Some(PathEvent::Quadratic {
from: point(0.0, 0.0),
ctrl: point(0.0, 100.0),
to: point(-100., 100.),
})
);
assert_eq!(
it.next(),
Some(PathEvent::Line {
from: point(-100.0, 100.0),
to: point(-150., 100.)
})
);
assert_eq!(
it.next(),
Some(PathEvent::End {
first: point(0.0, 0.0),
last: point(-150., 100.),
close: false,
})
);
assert_eq!(it.next(), None);
}
#[test]
fn svg_builder_arc_to_update_position() {
use crate::Path;
let mut p = Path::svg_builder();
p.move_to(point(0.0, 0.0));
assert_eq!(p.current_position(), point(0.0, 0.0));
p.arc_to(
vector(100., 100.),
Angle::degrees(0.),
ArcFlags::default(),
point(0.0, 100.0),
);
assert_ne!(p.current_position(), point(0.0, 0.0));
}
#[test]
fn issue_650() {
use std::f32::consts::PI;
let mut builder = crate::path::Builder::new().with_svg();
builder.arc(
point(0.0, 0.0),
vector(50.0, 50.0),
Angle::radians(PI),
Angle::radians(0.0),
);
builder.build();
}
#[test]
fn straight_line_arc() {
use crate::Path;
let mut p = Path::svg_builder();
p.move_to(point(100.0, 0.0));
// Don't assert on a "false" arc that's a straight line
p.arc_to(
vector(100., 100.),
Angle::degrees(0.),
ArcFlags::default(),
point(100.0, 0.0),
);
}