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|
use super::*;
use std::mem;
/// A rectangle with rounded corners.
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct RoundedRect {
/// The size of the rectangle.
pub size: Size,
/// The radius at each corner.
pub radius: Corners<Length>,
}
impl RoundedRect {
/// Create a new rounded rectangle.
pub fn new(size: Size, radius: Corners<Length>) -> Self {
Self { size, radius }
}
/// Output all constituent shapes of the rectangle in order. The last one is
/// in the foreground. The function will output multiple items if the stroke
/// properties differ by side.
pub fn shapes(
self,
fill: Option<Paint>,
stroke: Sides<Option<Stroke>>,
) -> Vec<Shape> {
let mut res = vec![];
if fill.is_some() || (stroke.iter().any(Option::is_some) && stroke.is_uniform()) {
res.push(Shape {
geometry: self.fill_geometry(),
fill,
stroke: if stroke.is_uniform() { stroke.top } else { None },
});
}
if !stroke.is_uniform() {
for (path, stroke) in self.stroke_segments(stroke) {
if stroke.is_some() {
res.push(Shape {
geometry: Geometry::Path(path),
fill: None,
stroke,
});
}
}
}
res
}
/// Output the shape of the rectangle as a path or primitive rectangle,
/// depending on whether it is rounded.
fn fill_geometry(self) -> Geometry {
if self.radius.iter().copied().all(Length::is_zero) {
Geometry::Rect(self.size)
} else {
let mut paths = self.stroke_segments(Sides::splat(None));
assert_eq!(paths.len(), 1);
Geometry::Path(paths.pop().unwrap().0)
}
}
/// Output the minimum number of paths along the rectangles border.
fn stroke_segments(
self,
strokes: Sides<Option<Stroke>>,
) -> Vec<(Path, Option<Stroke>)> {
let mut res = vec![];
let mut connection = Connection::default();
let mut path = Path::new();
let mut always_continuous = true;
for side in [Side::Top, Side::Right, Side::Bottom, Side::Left] {
let continuous = strokes.get(side) == strokes.get(side.next_cw());
connection = connection.advance(continuous && side != Side::Left);
always_continuous &= continuous;
draw_side(
&mut path,
side,
self.size,
self.radius.get(side.start_corner()),
self.radius.get(side.end_corner()),
connection,
);
if !continuous {
res.push((mem::take(&mut path), strokes.get(side)));
}
}
if always_continuous {
path.close_path();
}
if !path.0.is_empty() {
res.push((path, strokes.left));
}
res
}
}
/// Draws one side of the rounded rectangle. Will always draw the left arc. The
/// right arc will be drawn halfway if and only if there is no connection.
fn draw_side(
path: &mut Path,
side: Side,
size: Size,
start_radius: Length,
end_radius: Length,
connection: Connection,
) {
let angle_left = Angle::deg(if connection.prev { 90.0 } else { 45.0 });
let angle_right = Angle::deg(if connection.next { 90.0 } else { 45.0 });
let length = size.get(side.axis());
// The arcs for a border of the rectangle along the x-axis, starting at (0,0).
let p1 = Point::with_x(start_radius);
let mut arc1 = bezier_arc(
p1 + Point::new(
-angle_left.sin() * start_radius,
(1.0 - angle_left.cos()) * start_radius,
),
Point::new(start_radius, start_radius),
p1,
);
let p2 = Point::with_x(length - end_radius);
let mut arc2 = bezier_arc(
p2,
Point::new(length - end_radius, end_radius),
p2 + Point::new(
angle_right.sin() * end_radius,
(1.0 - angle_right.cos()) * end_radius,
),
);
let transform = match side {
Side::Left => Transform::rotate(Angle::deg(-90.0))
.post_concat(Transform::translate(Length::zero(), size.y)),
Side::Bottom => Transform::rotate(Angle::deg(180.0))
.post_concat(Transform::translate(size.x, size.y)),
Side::Right => Transform::rotate(Angle::deg(90.0))
.post_concat(Transform::translate(size.x, Length::zero())),
_ => Transform::identity(),
};
arc1 = arc1.map(|x| x.transform(transform));
arc2 = arc2.map(|x| x.transform(transform));
if !connection.prev {
path.move_to(if start_radius.is_zero() { arc1[3] } else { arc1[0] });
}
if !start_radius.is_zero() {
path.cubic_to(arc1[1], arc1[2], arc1[3]);
}
path.line_to(arc2[0]);
if !connection.next && !end_radius.is_zero() {
path.cubic_to(arc2[1], arc2[2], arc2[3]);
}
}
/// Indicates which sides of the border strokes in a 2D polygon are connected to
/// their neighboring sides.
#[derive(Debug, Default, Copy, Clone, Eq, PartialEq)]
struct Connection {
prev: bool,
next: bool,
}
impl Connection {
/// Advance to the next clockwise side of the polygon. The argument
/// indicates whether the border is connected on the right side of the next
/// edge.
pub fn advance(self, next: bool) -> Self {
Self { prev: self.next, next }
}
}
|
