bendns' repos / fimg
fast image operations
Diffstat (limited to 'src/drawing/poly.rs')
-rw-r--r--src/drawing/poly.rs74
1 files changed, 74 insertions, 0 deletions
diff --git a/src/drawing/poly.rs b/src/drawing/poly.rs
new file mode 100644
index 0000000..408aa47
--- /dev/null
+++ b/src/drawing/poly.rs
@@ -0,0 +1,74 @@
+//! draw polygons
+use std::{
+ cmp::{max, min},
+ ops::{Deref, DerefMut},
+};
+
+use crate::Image;
+
+impl<T: Deref<Target = [u8]> + DerefMut<Target = [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\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\xff\xff\xff\xff\xff\xff\xff\x00\x00\x00\xff\xff\xff\xff\xff\xff\x00\x00\x00\xff\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\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 = fraction.mul_add((p1.0 - p0.0) as f32, p0.0 as f32);
+ intersections.push(inter.round() as i32);
+ }
+ }
+ }
+ intersections.sort_unstable();
+ // SAFETY: must.
+ unsafe { crate::assert_unchecked!(intersections.len() % 2 == 0) };
+ 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);
+ }
+ }
+}