reading/
reading.rs

1//
2// Copyright (c) 2017 KAMADA Ken'ichi.
3// All rights reserved.
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions
7// are met:
8// 1. Redistributions of source code must retain the above copyright
9//    notice, this list of conditions and the following disclaimer.
10// 2. Redistributions in binary form must reproduce the above copyright
11//    notice, this list of conditions and the following disclaimer in the
12//    documentation and/or other materials provided with the distribution.
13//
14// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24// SUCH DAMAGE.
25//
26
27extern crate exif;
28
29use std::fs::File;
30use std::io::BufReader;
31
32use exif::{DateTime, In, Reader, Value, Tag};
33
34fn main() {
35    let file = File::open("tests/exif.jpg").unwrap();
36    let exif = Reader::new().read_from_container(
37        &mut BufReader::new(&file)).unwrap();
38
39    // To obtain a string representation, `Value::display_as`
40    // or `Field::display_value` can be used.  To display a value with its
41    // unit, call `with_unit` on the return value of `Field::display_value`.
42    let tag_list = [Tag::ExifVersion,
43                    Tag::PixelXDimension,
44                    Tag::XResolution,
45                    Tag::ImageDescription,
46                    Tag::DateTime];
47    for tag in tag_list {
48        if let Some(field) = exif.get_field(tag, In::PRIMARY) {
49            println!("{}: {}",
50                     field.tag, field.display_value().with_unit(&exif));
51        }
52    }
53
54    // To get unsigned integer value(s) from either of BYTE, SHORT,
55    // or LONG, `Value::get_uint` or `Value::iter_uint` can be used.
56    if let Some(field) = exif.get_field(Tag::PixelXDimension, In::PRIMARY) {
57        if let Some(width) = field.value.get_uint(0) {
58            println!("Valid width of the image is {}.", width);
59        }
60    }
61
62    // To convert a Rational or SRational to an f64, `Rational::to_f64`
63    // or `SRational::to_f64` can be used.
64    if let Some(field) = exif.get_field(Tag::XResolution, In::PRIMARY) {
65        match field.value {
66            Value::Rational(ref vec) if !vec.is_empty() =>
67                println!("X resolution is {}.", vec[0].to_f64()),
68            _ => {},
69        }
70    }
71
72    // To parse a DateTime-like field, `DateTime::from_ascii` can be used.
73    if let Some(field) = exif.get_field(Tag::DateTime, In::PRIMARY) {
74        match field.value {
75            Value::Ascii(ref vec) if !vec.is_empty() => {
76                if let Ok(datetime) = DateTime::from_ascii(&vec[0]) {
77                    println!("Year of DateTime is {}.", datetime.year);
78                }
79            },
80            _ => {},
81        }
82    }
83}
reading/reading.rs

reading/
reading.rs
