moxcms/matan/
slope_limit.rs

1/*
2 * // Copyright (c) Radzivon Bartoshyk 6/2025. All rights reserved.
3 * //
4 * // Redistribution and use in source and binary forms, with or without modification,
5 * // are permitted provided that the following conditions are met:
6 * //
7 * // 1.  Redistributions of source code must retain the above copyright notice, this
8 * // list of conditions and the following disclaimer.
9 * //
10 * // 2.  Redistributions in binary form must reproduce the above copyright notice,
11 * // this list of conditions and the following disclaimer in the documentation
12 * // and/or other materials provided with the distribution.
13 * //
14 * // 3.  Neither the name of the copyright holder nor the names of its
15 * // contributors may be used to endorse or promote products derived from
16 * // this software without specific prior written permission.
17 * //
18 * // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
22 * // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
25 * // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26 * // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29#![allow(dead_code)]
30use crate::PointeeSizeExpressible;
31use crate::matan::is_curve_descending;
32use num_traits::AsPrimitive;
33
34pub(crate) fn limit_slope<T: Copy + AsPrimitive<f32> + PartialOrd + PointeeSizeExpressible>(
35    curve: &mut [T],
36    value_cap: f32,
37) where
38    f32: AsPrimitive<T>,
39{
40    let at_begin = (curve.len() as f32 * 0.02 + 0.5).floor() as usize; // Cutoff at 2%
41    if at_begin == 0 {
42        return;
43    }
44    let at_end = curve.len() - at_begin - 1; // And 98%
45    let (begin_val, end_val) = if is_curve_descending(curve) {
46        (value_cap, 0.)
47    } else {
48        (0., value_cap)
49    };
50    let val = curve[at_begin].as_();
51    let slope = (val - begin_val) / at_begin as f32;
52    let beta = val - slope * at_begin as f32;
53    if T::FINITE {
54        for v in curve.iter_mut().take(at_begin) {
55            *v = (v.as_() * slope + beta)
56                .round()
57                .min(value_cap)
58                .max(0.0)
59                .as_();
60        }
61    } else {
62        for v in curve.iter_mut().take(at_begin) {
63            *v = (v.as_() * slope + beta).min(value_cap).max(0.0).as_();
64        }
65    }
66
67    let val = curve[at_end].as_();
68    let slope = (end_val - val) / at_begin as f32;
69    let beta = val - slope * at_end as f32;
70
71    if T::FINITE {
72        for v in curve.iter_mut().skip(at_end) {
73            *v = (v.as_() * slope + beta)
74                .round()
75                .min(value_cap)
76                .max(0.0)
77                .as_();
78        }
79    } else {
80        for v in curve.iter_mut().skip(at_end) {
81            *v = (v.as_() * slope + beta).min(value_cap).max(0.0).as_();
82        }
83    }
84}
moxcms/matan/slope_limit.rs

moxcms/matan/
slope_limit.rs
