stb_image 0.3.0

Bindings to the stb image encoding/decoding library.
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
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147

// Copyright 2013 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use stb_image::*;

use libc::{c_int, c_void};
use std::convert::AsRef;
use std::ffi::CString;
use std::path::Path;
use std::slice;

pub struct Image<T> {
    pub width: usize,
    pub height: usize,
    pub depth: usize,
    pub data: Vec<T>,
}

impl<T> Image<T> {
    pub fn new(width: usize, height: usize, depth: usize, data: Vec<T>) -> Image<T> {
        Image::<T> {
            width,
            height,
            depth,
            data,
        }
    }
}

pub enum LoadResult {
    Error(String),
    ImageU8(Image<u8>),
    ImageF32(Image<f32>),
}

pub fn load<T: AsRef<Path>>(path: T) -> LoadResult {
    let force_depth = 0;
    load_with_depth(path, force_depth, false)
}

fn load_internal<T: Clone>(buf: *mut T, w: c_int, h: c_int, d: c_int) -> Image<T> {
    unsafe {
        // FIXME: Shouldn't copy; instead we should use a sendable resource. They
        // aren't particularly safe yet though.
        let data = slice::from_raw_parts(buf, (w * h * d) as usize).to_vec();
        stbi_image_free(buf as *mut c_void);
        Image::<T> {
            width: w as usize,
            height: h as usize,
            depth: d as usize,
            data,
        }
    }
}

pub fn load_with_depth<T: AsRef<Path>>(
    path: T,
    force_depth: usize,
    convert_hdr: bool,
) -> LoadResult {
    let mut width = 0 as c_int;
    let mut height = 0 as c_int;
    let mut depth = 0 as c_int;
    let force_depth = force_depth as c_int;
    let path_as_cstr = match path.as_ref().as_os_str().to_str() {
        Some(s) => match CString::new(s.as_bytes()) {
            Ok(s) => s,
            Err(_) => return LoadResult::Error("path contains null character".to_string()),
        },
        None => return LoadResult::Error("path is not valid utf8".to_string()),
    };
    unsafe {
        let bytes = path_as_cstr.as_ptr();
        if !convert_hdr && stbi_is_hdr(bytes) != 0 {
            let buffer = stbi_loadf(bytes, &mut width, &mut height, &mut depth, force_depth);
            if buffer.is_null() {
                LoadResult::Error("stbi_loadf failed".to_string())
            } else {
                let actual_depth = if force_depth != 0 { force_depth } else { depth };
                LoadResult::ImageF32(load_internal(buffer, width, height, actual_depth))
            }
        } else {
            let buffer = stbi_load(bytes, &mut width, &mut height, &mut depth, force_depth);
            if buffer.is_null() {
                LoadResult::Error("stbi_load failed".to_string())
            } else {
                let actual_depth = if force_depth != 0 { force_depth } else { depth };
                LoadResult::ImageU8(load_internal(buffer, width, height, actual_depth))
            }
        }
    }
}

pub fn load_from_memory(buffer: &[u8]) -> LoadResult {
    let force_depth = 0;
    load_from_memory_with_depth(buffer, force_depth, false)
}

pub fn load_from_memory_with_depth(
    buffer: &[u8],
    force_depth: usize,
    convert_hdr: bool,
) -> LoadResult {
    unsafe {
        let mut width = 0 as c_int;
        let mut height = 0 as c_int;
        let mut depth = 0 as c_int;
        let force_depth = force_depth as c_int;
        if !convert_hdr && stbi_is_hdr_from_memory(buffer.as_ptr(), buffer.len() as c_int) != 0 {
            let buffer = stbi_loadf_from_memory(
                buffer.as_ptr(),
                buffer.len() as c_int,
                &mut width,
                &mut height,
                &mut depth,
                force_depth,
            );
            if buffer.is_null() {
                LoadResult::Error("stbi_loadf_from_memory failed".to_string())
            } else {
                let actual_depth = if force_depth != 0 { force_depth } else { depth };
                LoadResult::ImageF32(load_internal(buffer, width, height, actual_depth))
            }
        } else {
            let buffer = stbi_load_from_memory(
                buffer.as_ptr(),
                buffer.len() as c_int,
                &mut width,
                &mut height,
                &mut depth,
                force_depth,
            );
            if buffer.is_null() {
                LoadResult::Error("stbi_load_from_memory failed".to_string())
            } else {
                let actual_depth = if force_depth != 0 { force_depth } else { depth };
                LoadResult::ImageU8(load_internal(buffer, width, height, actual_depth))
            }
        }
    }
}