pic-scale 0.7.8

High performance image scaling
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125

/*
 * Copyright (c) Radzivon Bartoshyk. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1.  Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2.  Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3.  Neither the name of the copyright holder nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#![forbid(unsafe_code)]

#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub(crate) enum Rgb30 {
    Ar30 = 0,
    Ra30 = 1,
}

impl From<usize> for Rgb30 {
    fn from(value: usize) -> Self {
        match value {
            0 => Rgb30::Ar30,
            1 => Rgb30::Ra30,
            _ => {
                unimplemented!("Rgb30 is not implemented for value {}", value)
            }
        }
    }
}

/// Converts a value from host byte order to network byte order.
#[inline]
const fn htonl(hostlong: u32) -> u32 {
    hostlong.to_be()
}

/// Converts a value from network byte order to host byte order.
#[inline]
const fn ntohl(netlong: u32) -> u32 {
    u32::from_be(netlong)
}

impl Rgb30 {
    // #[inline]
    // pub(crate) const fn pack_w_a<const STORE: usize>(self, r: i32, g: i32, b: i32, a: i32) -> u32 {
    //     let value: u32 = match self {
    //         Rgb30::Ar30 => (((a << 30) | (b << 20)) | ((g << 10) | r)) as u32,
    //         Rgb30::Ra30 => (((r << 22) | (g << 12)) | ((b << 2) | a)) as u32,
    //     };
    //     if STORE == 0 {
    //         value
    //     } else {
    //         htonl(value)
    //     }
    // }

    #[inline]
    pub(crate) const fn pack_w_a<const STORE: usize>(self, r: i32, g: i32, b: i32, _: i32) -> u32 {
        let value: u32 = match self {
            Rgb30::Ar30 => ((3u32 << 30u32) | ((b as u32) << 20)) | (((g as u32) << 10) | r as u32),
            Rgb30::Ra30 => (((r as u32) << 22) | ((g as u32) << 12)) | (((b as u32) << 2) | 3),
        };
        if STORE == 0 { value } else { htonl(value) }
    }

    #[inline(always)]
    pub(crate) const fn unpack<const STORE: usize>(self, value: u32) -> (u32, u32, u32, u32) {
        let pixel = if STORE == 0 { value } else { ntohl(value) };
        match self {
            Rgb30::Ar30 => {
                let r10 = pixel & 0x3ff;
                let g10 = (pixel >> 10) & 0x3ff;
                let b10 = (pixel >> 20) & 0x3ff;
                // let a10 = pixel >> 30;
                (r10, g10, b10, 3)
            }
            Rgb30::Ra30 => {
                // let a2 = pixel & 0x3;
                let r10 = (pixel >> 22) & 0x3ff;
                let g10 = (pixel >> 12) & 0x3ff;
                let b10 = (pixel >> 2) & 0x3ff;
                (r10, g10, b10, 3)
            }
        }
    }
}

#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
/// Defines storage byte order for RGBA1010102 or RGBA2101010
///
/// Some systems require to be bytes in network byte order instead of host.
pub enum Ar30ByteOrder {
    Host = 0,
    Network = 1,
}

impl From<usize> for Ar30ByteOrder {
    fn from(value: usize) -> Self {
        match value {
            0 => Ar30ByteOrder::Host,
            1 => Ar30ByteOrder::Network,
            _ => {
                unimplemented!("Rgb30ByteOrder is not implemented for value {}", value)
            }
        }
    }
}