moxcms/matan/
curve_shape.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
30pub(crate) fn is_curve_linear16(curve: &[u16]) -> bool {
31    let scale = 1. / (curve.len() - 1) as f32 * 65535.;
32    for (index, &value) in curve.iter().enumerate() {
33        let quantized = (index as f32 * scale).round() as u16;
34        let diff = (quantized as i32 - value as i32).abs();
35        if diff > 0x0f {
36            return false;
37        }
38    }
39    true
40}
41
42pub(crate) fn is_curve_descending<T: PartialOrd>(v: &[T]) -> bool {
43    if v.is_empty() {
44        return false;
45    }
46    if v.len() == 1 {
47        return false;
48    }
49    v[0] > v[v.len() - 1]
50}
51
52pub(crate) fn is_curve_ascending<T: PartialOrd>(v: &[T]) -> bool {
53    if v.is_empty() {
54        return false;
55    }
56    if v.len() == 1 {
57        return false;
58    }
59    v[0] < v[v.len() - 1]
60}
61
62pub(crate) fn is_curve_linear8(curve: &[u8]) -> bool {
63    let scale = 1. / (curve.len() - 1) as f32 * 255.;
64    for (index, &value) in curve.iter().enumerate() {
65        let quantized = (index as f32 * scale).round() as u16;
66        let diff = (quantized as i32 - value as i32).abs();
67        if diff > 0x03 {
68            return false;
69        }
70    }
71    true
72}
moxcms/matan/curve_shape.rs

moxcms/matan/
curve_shape.rs
