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//! Path constructors for rectangles, polylines and SVG path-data import.
use super::{MAX_PATH_VERBS, MAX_SVG_PATH_BYTES, Path2D, PathVerb, invalid};
use crate::{Point, Rect, ValidationError, Vector2};
impl Path2D {
/// Builds a closed rectangle, rejecting invalid bounds before any mutation.
pub fn from_rect(bounds: Rect) -> Result<Self, ValidationError> {
crate::drawing::validate_rect(bounds, "path2d", "bounds")?;
let mut path = Self::new();
path.try_move_to(Point::new(bounds.left, bounds.top))?;
path.try_line_to(Point::new(bounds.right, bounds.top))?;
path.try_line_to(Point::new(bounds.right, bounds.bottom))?;
path.try_line_to(Point::new(bounds.left, bounds.bottom))?;
path.try_close()?;
Ok(path)
}
/// Builds a bounded polyline, rejecting nonfinite points and verb overflow.
pub fn polyline(points: impl IntoIterator<Item = Point>) -> Result<Self, ValidationError> {
let mut path = Self::new();
for (index, point) in points.into_iter().take(MAX_PATH_VERBS + 1).enumerate() {
if index == 0 {
path.try_move_to(point)?;
} else {
path.try_line_to(point)?;
}
}
Ok(path)
}
/// Imports SVG path data, not an XML document, without rasterizing geometry.
///
/// Supports absolute/relative M/L/H/V/C/S/Q/T/A/Z, including repeated argument
/// groups and reflected smooth controls. Empty data produces an empty path.
/// A/a arcs become bounded cubic segments; zero radii become lines and
/// coincident endpoints emit nothing. Syntax, nonfinite
/// arithmetic and overflowing control extents return InvalidValue; input
/// beyond MAX_SVG_PATH_BYTES or MAX_PATH_VERBS returns StructuralLimit.
/// Parsed commands and expanded verbs have independent MAX_PATH_VERBS caps. Errors
/// discard the entire result; there is no partial-path recovery, I/O or cache.
///
/// ```
/// use motion_core::prelude::*;
/// use motion_core::{
/// DisplayList, RasterLimits, ResourceStore, ValidatedDisplayList, MAX_PATH_VERBS,
/// MAX_STROKE_VERBS, MAX_SVG_PATH_BYTES, sample_offsets,
/// };
/// let path = Path2D::parse_svg("M1 1h6v6H1z")?;
/// assert_eq!(path, Path2D::from_rect(Rect::new(1.0, 1.0, 7.0, 7.0))?);
/// let frame = Node::from(path.fill(Color::WHITE)).compile(
/// Size::new(8.0, 8.0),
/// PixelSize::new(8, 8),
/// ValidationLimits::default(),
/// )?;
/// # Ok::<(), motion_core::ValidationError>(())
/// ```
pub fn parse_svg(path_data: &str) -> Result<Self, ValidationError> {
if path_data.len() > MAX_SVG_PATH_BYTES {
return Err(ValidationError::limit(
"path2d.svg",
"svg_bytes",
"SVG path data exceeds 1048576 bytes",
));
}
let mut result = Self::new();
let mut previous_cubic = false;
let mut previous_quadratic = false;
for (index, segment) in svgtypes::PathParser::from(path_data).enumerate() {
let path = format!("path2d.svg.commands[{index}]");
if index >= MAX_PATH_VERBS {
return Err(ValidationError::limit(
path,
"commands",
"SVG path data exceeds 16384 commands",
));
}
let segment = segment
.map_err(|error| ValidationError::invalid(&path, "data", error.to_string()))?;
let current = result.data.current.unwrap_or(Point::ORIGIN);
let absolute = segment.is_abs();
let point = |x, y| {
if absolute {
Point::new(x, y)
} else {
Point::new(current.x + x, current.y + y)
}
};
let reflect = |control: Point| {
Point::new(
current.x + (current.x - control.x),
current.y + (current.y - control.y),
)
};
let verb =
match segment {
svgtypes::PathSegment::MoveTo { x, y, .. } => PathVerb::MoveTo(point(x, y)),
svgtypes::PathSegment::LineTo { x, y, .. } => PathVerb::LineTo(point(x, y)),
svgtypes::PathSegment::HorizontalLineTo { x, .. } => PathVerb::LineTo(
Point::new(if absolute { x } else { current.x + x }, current.y),
),
svgtypes::PathSegment::VerticalLineTo { y, .. } => PathVerb::LineTo(
Point::new(current.x, if absolute { y } else { current.y + y }),
),
svgtypes::PathSegment::CurveTo {
x1,
y1,
x2,
y2,
x,
y,
..
} => PathVerb::CubicTo(point(x1, y1), point(x2, y2), point(x, y)),
svgtypes::PathSegment::SmoothCurveTo { x2, y2, x, y, .. } => {
let control = match result.verbs().last() {
Some(PathVerb::CubicTo(_, previous, _)) if previous_cubic => {
reflect(*previous)
}
_ => current,
};
PathVerb::CubicTo(control, point(x2, y2), point(x, y))
}
svgtypes::PathSegment::Quadratic { x1, y1, x, y, .. } => {
PathVerb::QuadraticTo(point(x1, y1), point(x, y))
}
svgtypes::PathSegment::SmoothQuadratic { x, y, .. } => {
let control = match result.verbs().last() {
Some(PathVerb::QuadraticTo(previous, _)) if previous_quadratic => {
reflect(*previous)
}
_ => current,
};
PathVerb::QuadraticTo(control, point(x, y))
}
svgtypes::PathSegment::ClosePath { .. } => PathVerb::Close,
svgtypes::PathSegment::EllipticalArc {
rx,
ry,
x_axis_rotation,
large_arc,
sweep,
x,
y,
..
} => {
let converted = (|| -> Result<(), ValidationError> {
if result.data.current.is_none() {
return Err(invalid("data", "SVG arcs require a current point"));
}
if ![rx, ry, x_axis_rotation, x, y]
.iter()
.all(|value| value.is_finite())
{
return Err(invalid("data", "SVG arc parameters must be finite"));
}
let end = point(x, y);
let arc = kurbo::SvgArc {
from: kurbo::Point::new(current.x, current.y),
to: kurbo::Point::new(end.x, end.y),
radii: kurbo::Vec2::new(rx.abs(), ry.abs()),
x_rotation: x_axis_rotation.to_radians(),
large_arc,
sweep,
};
if current != end {
if let Some(arc) = kurbo::Arc::from_svg_arc(&arc) {
let mut converted = Self::new();
converted.elliptical_arc(
Point::new(arc.center.x, arc.center.y),
Vector2::new(arc.radii.x, arc.radii.y),
arc.start_angle,
arc.sweep_angle,
arc.x_rotation,
)?;
for (index, verb) in
converted.verbs().iter().copied().enumerate().skip(1)
{
let verb = if index + 1 == converted.verbs().len() {
match verb {
PathVerb::CubicTo(first, second, _) => {
PathVerb::CubicTo(first, second, end)
}
_ => verb,
}
} else {
verb
};
result.push(verb)?;
}
} else {
result.try_line_to(end)?;
}
}
Ok(())
})();
converted.map_err(|mut error| {
error.path = path;
error
})?;
previous_cubic = false;
previous_quadratic = false;
continue;
}
};
previous_cubic = matches!(verb, PathVerb::CubicTo(..));
previous_quadratic = matches!(verb, PathVerb::QuadraticTo(..));
result.push(verb).map_err(|mut error| {
error.path = path;
error
})?;
}
Ok(result)
}
}