Add an example to read various fields.
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//
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// Copyright (c) 2017 KAMADA Ken'ichi.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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// 1. Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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// SUCH DAMAGE.
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//
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extern crate exif;
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use std::fs::File;
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use std::io::BufReader;
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use exif::{DateTime, Reader, Value, tag};
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fn main() {
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let file = File::open("tests/exif.jpg").unwrap();
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let reader = Reader::new(&mut BufReader::new(&file)).unwrap();
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// To obtain a string representation, `Value::display_as` can be used
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// for any tag.
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let tag_list = [tag::ExifVersion,
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tag::ImageWidth,
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tag::XResolution,
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tag::ImageDescription,
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tag::DateTime];
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for &tag in tag_list.iter() {
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if let Some(field) = reader.get_field(tag, false) {
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println!("{}: {}", field.tag, field.value.display_as(field.tag));
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}
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}
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// To get unsigned integer value(s) from either of BYTE, SHORT,
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// or LONG, `Value::get_uint` or `Value::iter_uint` can be used.
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if let Some(field) = reader.get_field(tag::ImageWidth, false) {
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if let Some(width) = field.value.get_uint(0) {
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println!("Image width is {}.", width);
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}
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}
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// To convert a Rational or SRational to an f64, `Rational::to_f64`
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// or `SRational::to_f64` can be used.
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if let Some(field) = reader.get_field(tag::XResolution, false) {
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match field.value {
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Value::Rational(ref vec) if !vec.is_empty() =>
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println!("X resolution is {}.", vec[0].to_f64()),
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_ => {},
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}
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}
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// To parse a DateTime-like field, `DateTime::from_ascii` can be used.
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if let Some(field) = reader.get_field(tag::DateTime, false) {
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match field.value {
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Value::Ascii(ref vec) if !vec.is_empty() => {
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if let Ok(datetime) = DateTime::from_ascii(vec[0]) {
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println!("Year of DateTime is {}.", datetime.year);
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}
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},
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_ => {},
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}
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}
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}
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tests/exif.jpg
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tests/exif.jpg
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Before Width: | Height: | Size: 1.2 KiB After Width: | Height: | Size: 1.2 KiB |
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