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//! draw polygons
use crate::Image;
use crate::math::{FExt, madd};
use array_chunks::*;
use std::cmp::{max, min};
use std::f32::consts::TAU;
use vecto::Vec2;
impl<T: AsMut<[u8]> + AsRef<[u8]>, const CHANNELS: usize> Image<T, CHANNELS> {
/// Draws a filled polygon from a slice of points. Please close your poly. (first == last)
///
/// Borrowed from [imageproc](https://docs.rs/imageproc/latest/src/imageproc/drawing/polygon.rs.html#31), modified for less allocations.
/// ```
/// # use fimg::Image;
/// let mut i = Image::alloc(10, 10);
/// i.points(&[(1, 8), (3, 1), (8, 1), (6, 6), (8, 8), (1, 8)], [255]);
/// # assert_eq!(i.buffer(), b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\x00\x00\x00\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\xff\xff\xff\xff\xff\x00\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00");
/// ```
pub fn points(&mut self, poly: &[(i32, i32)], c: [u8; CHANNELS]) {
if poly.len() <= 1 {
return;
}
let (mut y_max, mut y_min) = poly[..poly.len() - 1]
.iter()
.fold((i32::MIN, i32::MAX), |(max, min), &(_, y)| {
(y.max(max), y.min(min))
});
y_min = max(0, min(y_min, self.height() as i32 - 1));
y_max = max(0, min(y_max, self.height() as i32 - 1));
let mut intersections = vec![];
for y in y_min..=y_max {
for [p0, p1] in poly.array_windows::<2>() {
if p0.1 <= y && p1.1 >= y || p1.1 <= y && p0.1 >= y {
if p0.1 == p1.1 {
intersections.push(p0.0);
intersections.push(p1.0);
} else if p0.1 == y || p1.1 == y {
if p1.1 > y {
intersections.push(p0.0);
}
if p0.1 > y {
intersections.push(p1.0);
}
} else {
let fraction = (y - p0.1) as f32 / (p1.1 - p0.1) as f32;
let inter = madd(fraction, (p1.0 - p0.0) as f32, p0.0 as f32);
intersections.push(inter.round() as i32);
}
}
}
intersections.sort_unstable();
for &[x, y_] in intersections.array_chunks::<2>() {
let mut from = min(x, self.width() as i32);
let mut to = min(y_, self.width() as i32 - 1);
if from < self.width() as i32 && to >= 0 {
// check bounds
from = max(0, from);
to = max(0, to);
for x in from..=to {
// SAFETY: bounds are checked
unsafe { self.set_pixel(x as u32, y as u32, &c) };
}
}
}
intersections.clear();
}
for &[(x1, y1), (x2, y2)] in poly.array_windows::<2>() {
self.line((x1, y1), (x2, y2), c);
}
}
/// Draws a filled quadrilateral.
/// This currently just uses [`Image::points`], but in the future this may change.
pub fn quad(
&mut self,
a: (i32, i32),
b: (i32, i32),
c: (i32, i32),
d: (i32, i32),
col: [u8; CHANNELS],
) {
self.points(&[a, b, c, d, a], col);
}
/// Draws a regular convex polygon with a specified number of sides, a radius, and a rotation (radians).
/// Prefer [`Image::circle`] over `poly(.., 600, ..)`.
/// Calls into [`Image::tri`] and [`Image::quad`].
/// ```
/// # use fimg::Image;
/// let mut i = Image::alloc(300, 300);
/// // draw a enneagon
/// // at x150, y150 │ unrotated white
/// // with a radius of ─┼──╮ │ │
/// i.poly((150., 150.), 9, 100.0, 0.0, [255]);
/// # assert_eq!(i.buffer(), include_bytes!("../../tdata/enneagon.imgbuf"));
/// ```
pub fn poly(
&mut self,
pos: impl Into<Vec2>,
sides: usize,
radius: f32,
rotation: f32,
c: [u8; CHANNELS],
) {
let pos = pos.into();
let trans = |a: f32| Vec2::from_angle(a) * radius;
let r = |v: Vec2| (v.x.round() as i32, v.y.round() as i32);
match sides {
3 => {
let space = TAU / 3.0;
self.tri::<f32>(
trans(space + rotation) + pos,
trans(rotation) + pos,
trans(madd(space, 2.0, rotation)) + pos,
c,
);
}
_ => {
let space = TAU / sides as f32;
for i in (0..sides - 1).step_by(2).map(|i| i as f32) {
self.quad(
r(pos),
r(trans(madd(space, i, rotation)) + pos),
r(trans(madd(space, i + 1., rotation)) + pos),
r(trans(madd(space, i + 2., rotation)) + pos),
c,
);
}
if sides % 2 != 0 && sides > 4 {
let i = (sides - 1) as f32;
// the missing piece
self.tri::<f32>(
pos,
trans(madd(space, i, rotation)) + pos,
trans(madd(space, i + 1., rotation)) + pos,
c,
);
}
}
}
}
/// Draw a bordered polygon.
/// Prefer [`Image::border_circle`] to draw circles.
/// See also [`Image::poly`].
/// ```
/// let mut i = fimg::Image::alloc(100, 100);
/// i.border_poly((50., 50.), 5, 25., 0., 7., [255]);
/// # assert_eq!(i.buffer(), include_bytes!("../../tdata/border_pentagon.imgbuf"));
/// ```
pub fn border_poly(
&mut self,
pos: impl Into<Vec2>,
sides: usize,
radius: f32,
rotation: f32,
stroke: f32,
c: [u8; CHANNELS],
) {
let pos = pos.into();
let space = TAU / sides as f32;
let step = stroke / 2.0 / (space / 2.0).cos();
let r1 = radius - step;
let r2 = radius + step;
let r = |a: f32, b: f32| (a.round() as i32, b.round() as i32);
for i in 0..sides {
let a = space.madd(i as f32, rotation);
self.quad(
r(r1.madd(a.cos(), pos.x), r1.madd(a.sin(), pos.y)),
r(
r1.madd((a + space).cos(), pos.x),
r1.madd((a + space).sin(), pos.y),
),
r(
r2.madd((a + space).cos(), pos.x),
r2.madd((a + space).sin(), pos.y),
),
r(r2.madd(a.cos(), pos.x), r2.madd(a.sin(), pos.y)),
c,
);
}
}
}