skia_safe/core/
scalar_.rs

1use std::ops::Mul;
2
3#[allow(non_camel_case_types)]
4pub type scalar = skia_bindings::SkScalar;
5
6// TODO: wrap more core/SkScalar.h functions / macros.
7
8pub trait Scalar: Copy {
9    const ZERO: Self;
10    const NEARLY_ZERO: Self;
11    const ONE: Self;
12    const HALF: Self;
13
14    fn nearly_equal(x: scalar, y: scalar, tolerance: impl Into<Option<scalar>>) -> bool;
15    fn nearly_zero(&self, tolerance: impl Into<Option<scalar>>) -> bool;
16}
17
18pub trait Scalars {
19    fn are_finite(&self) -> bool;
20}
21
22impl Scalar for scalar {
23    const ZERO: Self = 0.0;
24    const NEARLY_ZERO: Self = 1.0 / ((1 << 12) as Self);
25    const ONE: Self = 1.0;
26    const HALF: Self = 0.5;
27
28    fn nearly_equal(x: scalar, y: scalar, tolerance: impl Into<Option<scalar>>) -> bool {
29        let tolerance = tolerance.into().unwrap_or(Self::NEARLY_ZERO);
30        debug_assert!(tolerance >= 0.0);
31        (x - y).abs() <= tolerance
32    }
33
34    fn nearly_zero(&self, tolerance: impl Into<Option<scalar>>) -> bool {
35        let tolerance = tolerance.into().unwrap_or(Self::NEARLY_ZERO);
36        debug_assert!(tolerance >= 0.0);
37        self.abs() <= tolerance
38    }
39}
40
41impl<T> Scalars for [T]
42where
43    T: Scalar,
44    T: Mul<Output = T>,
45    T: PartialEq,
46{
47    fn are_finite(&self) -> bool {
48        self.iter().fold(T::ZERO, |prod, value| prod * *value) == T::ZERO
49    }
50}
51
52pub fn radians_to_degrees(radians: scalar) -> scalar {
53    radians * (180.0 / std::f32::consts::PI)
54}
skia_safe/core/scalar_.rs

skia_safe/core/
scalar_.rs
